1. |
- Krivosheeva, A, et al.
(author)
-
Cold acclimation and photoinhibition of photosynthesis in Scots pine
- 1996
-
In: Planta. - 0032-0935 .- 1432-2048. ; 200:3, s. 296-305
-
Journal article (peer-reviewed)abstract
- Cold acclimation of Scots pine did not affect the susceptibility of photosynthesis to photoinhibition. Cold acclimation did however cause a suppression of the rate of CO2 uptake, and at given light and temperature conditions a larger fraction of the photosystem Il reaction centres were closed in cold-acclimated than in nonacclimated pine. Therefore, when assayed at the level of photosystem II reaction centres, i.e. in relation to the degree of photosystem closure, cold acclimation caused a significant increase in resistance to photoinhibition; at given levels of photosystem II closure the resistance to photoinhibition was higher after cold acclimation. This was particularly evident in measurements at 20 degrees C. The amounts and activities of the majority of analysed active oxygen scavengers were higher after cold acclimation. We suggest that this increase in protective enzymes and compounds, particularly superoxide dismutase, ascorbate peroxidase, glutathione reductase and ascorbate of the chloroplasts, enables Scots pine to avoid excessive photoinhibition of photosynthesis despite partial suppression of photosynthesis upon cold acclimation. An increased capacity for light-induced de-epoxidation of violaxanthin to zeaxanthin upon cold acclimation may also be of significance.
|
|
2. |
- Tao, D L, et al.
(author)
-
Active oxygen scavengers during cold acclimation of Scots pine seedlings in relation to freezing tolerance
- 1998
-
In: Cryobiology. - 0011-2240 .- 1090-2392. ; 37:1, s. 38-45
-
Journal article (peer-reviewed)abstract
- Freezing injury of plants may be caused by the deleterious reactions of active oxygen species, and free-radical scavenging systems may be important in the alleviation of freezing stress. To test the feasibility of this hypothesis, enzymes and metabolites that cooperatively scavenge O-2(-) and H2O2 were analyzed in Scots pine (Pinus sylvestris L.) seedlings during a stepwise cold acclimation procedure. Elevated levels of enzymatic scavengers such as ascorbate peroxidase, glutathione reductase, monodehydroascorbate reductase, and dehy droascorbate reductase were found, along with increased freezing tolerance during cold acclimation, supporting the hypothesis. Induction of the scavenging systems during acclimation is discussed in relation to freezing tolerance. (C) 1998 Academic Press.
|
|
3. |
|
|
4. |
- Arias, Carolina, et al.
(author)
-
Nuclear proteome analysis of Chlamydomonas with response to CO2 limitation
- 2020
-
In: Algal Research. - : Elsevier. - 2211-9264. ; 46
-
Journal article (peer-reviewed)abstract
- Chlamydomonas reinhardtii is a unicellular green alga that can survive at a wide range of inorganic carbon (Ci) concentrations by regulating the activity of a CO2-concentrating mechanism (CCM) as well as other cellular functions. Under CO2 limited conditions, C. reinhardtii cells display a wide range of adaptive responses including changes in photosynthetic electron transport, mitochondria localization in the cells, the structure of the pyrenoid starch sheath, and primary metabolism. In addition to these functional and structural changes, gene and protein expression are also affected. Several physiological aspects of the CO2 response mechanism have been studied in detail. However, the regulatory components (transcription factors and transcriptional regulators) involved in this process are not fully characterized. Here we report a comprehensive analysis of the C. reinhardtii nuclear proteome using liquid chromatography electrospray ionization spectrometry (LC-ESI-MS). The study aims to identify the proteins that govern adaptation to varying CO2 concentrations in Chlamydomonas. The nuclear proteome of C. reinhardtii cells grown in the air at high (5%) and low (0.04%) CO2 concentrations were analyzed. Using this approach, we identified 1378 proteins in total, including 90 putative transcription factors and 27 transcriptional regulators. Characterization of these new regulatory components could shed light on the molecular mechanisms underlying acclimation to CO2 stress.
|
|
5. |
- Bergemalm, Daniel, et al.
(author)
-
Superoxide dismutase-1 and other proteins in inclusions from transgenic amyotrophic lateral sclerosis model mice
- 2010
-
In: Journal of Neurochemistry. - : Wiley. - 0022-3042 .- 1471-4159. ; 114:2, s. 408-418
-
Journal article (peer-reviewed)abstract
- Mutant superoxide dismutase-1 (SOD1) causes amyotrophic lateral sclerosis (ALS) through a cytotoxic mechanism of unknown nature. A hallmark in ALS patients and transgenic mouse models carrying human SOD1 (hSOD1) mutations are hSOD1-immunoreactive inclusions in spinal cord ventral horns. The hSOD1 inclusions may block essential cellular functions or cause toxicity through sequestering of other proteins. Inclusions from four different transgenic mouse models were examined after density gradient ultracentrifugation. The inclusions are complex structures with heterogeneous densities and are disrupted by detergents. The aggregated hSOD1 was mainly composed of subunits that lacked the native stabilizing intra-subunit disulfide bond. A proportion of subunits formed hSOD1 oligomers or was bound to other proteins through disulfide bonds. Dense inclusions could be isolated and the protein composition was analyzed using proteomic techniques. Mutant hSOD1 accounted for half of the protein. Ten other proteins were identified. Two were cytoplasmic chaperones, four were cytoskeletal proteins, and 4 were proteins that normally reside in the endoplasmic reticulum (ER). The presence of ER proteins in inclusions containing the primarily cytosolic hSOD1 further supports the notion that ER stress is involved in ALS.
|
|
6. |
- Bergemalm, Daniel, 1977-, et al.
(author)
-
Superoxide dismutase-1 and other proteins in inclusions from transgenic amyotrophic lateral sclerosis model mice
-
Other publication (other academic/artistic)abstract
- Mutant superoxide dismutase-1 (SOD1) causes amyotrophic lateral sclerosis (ALS) through a cytotoxic mechanism of unknown nature. A hallmark in ALS patients and transgenic mouse models carrying human SOD1 (hSOD1) mutations are hSOD1-immunoreactive inclusions in spinal cord ventral horns. The hSOD1 inclusions may block essential cellular functions or cause toxicity through sequestering of other proteins. Inclusions from 4 different transgenic mouse models were examined after density gradient ultracentrifugation. The inclusions are complex structures with heterogeneous densities and are disrupted by detergents. The aggregated hSOD1 was mainly composed of subunits that lacked the native stabilizing intrasubunit disulfide bond. A proportion of subunits formed hSOD1 oligomers or was bound to other proteins through disulfide bonds. Dense inclusions could be isolated and the protein composition was analyzed using proteomic techniques. Mutant hSOD1 accounted for half of the protein. Ten other proteins were identified. Two were cytoplasmic chaperones, 4 were cytoskeletal proteins, and 4 were proteins that normally reside in the endoplasmic reticulum (ER). The presence of ER proteins in inclusions containing the primarily cytosolic hSOD1 further supports the notion that ER stress is involved in ALS.
|
|
7. |
- Bollhöner, Benjamin, et al.
(author)
-
The function of two type II metacaspases in woody tissues of Populus trees
- 2018
-
In: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 217:4, s. 1551-1565
-
Journal article (peer-reviewed)abstract
- Metacaspases (MCs) are cysteine proteases that are implicated in programmed cell death of plants. AtMC9 (Arabidopsis thaliana Metacaspase9) is a member of the Arabidopsis MC family that controls the rapid autolysis of the xylem vessel elements, but its downstream targets in xylem remain uncharacterized. PttMC13 and PttMC14 were identified as AtMC9 homologs in hybrid aspen (Populustremulaxtremuloides). A proteomic analysis was conducted in xylem tissues of transgenic hybrid aspen trees which carried either an overexpression or an RNA interference construct for PttMC13 and PttMC14. The proteomic analysis revealed modulation of levels of both previously known targets of metacaspases, such as Tudor staphylococcal nuclease, heat shock proteins and 14-3-3 proteins, as well as novel proteins, such as homologs of the PUTATIVE ASPARTIC PROTEASE3 (PASPA3) and the cysteine protease RD21 by PttMC13 and PttMC14. We identified here the pathways and processes that are modulated by PttMC13 and PttMC14 in xylem tissues. In particular, the results indicate involvement of PttMC13 and/or PttMC14 in downstream proteolytic processes and cell death of xylem elements. This work provides a valuable reference dataset on xylem-specific metacaspase functions for future functional and biochemical analyses.
|
|
8. |
- Businge, Edward, et al.
(author)
-
The effect of carbohydrates and osmoticum on storage reserve accumulation and germination of Norway spruce somatic embryos
- 2013
-
In: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 149, s. 273-285
-
Journal article (peer-reviewed)abstract
- Somatic embryogenesis (SE) represents a useful experimental system for studying the regulatory mechanisms of embryo development. In this study, the effect of carbohydrates and osmoticum on storage reserve accumulation and germination of Norway spruce [Picea abies (L.) Karst] somatic embryos were investigated. Using time lapse photography, we monitored development from proliferation of proembryogenic masses (PEMs) to maturation of somatic embryos in two P. abies cell lines cultured on two maturation treatments. A combination of sugar assays, metabolic and proteomic analyses were used to quantify storage reserves in the mature somatic embryos. The maturation treatment containing a nonpermeating osmoticum, polyethylene glycol (PEG, 7.5%) and maltose (3%) as the carbohydrate gave significantly high maturation and low germination frequencies of somatic embryos compared to the treatment with only 3% sucrose. Somatic embryos treated with 3% sucrose contained high levels of sucrose, raffinose and late embryogenesis abundant (LEA) proteins. These compounds are known to be involved in the acquisition of desiccation tolerance during seed development and maturation. In addition the sucrose treatment significantly increased the content of starch in the somatic embryos while the maltose and PEG treatment resulted in somatic embryos with a high content of storage proteins. The high levels of sucrose, raffinose and LEA proteins in the embryos treated with 3% sucrose suggest that sucrose may improve the germination of somatic embryos by promoting the acquisition of desiccation tolerance.
|
|
9. |
- Bygdell, Joakim, et al.
(author)
-
Protein expression in tension wood formation monitored at high tissue resolution in Populus
- 2017
-
In: Journal of Experimental Botany. - : Oxford University Press. - 0022-0957 .- 1460-2431. ; 68:13, s. 3405-3417
-
Journal article (peer-reviewed)abstract
- Tension wood (TW) is a specialized tissue with contractile properties that is formed by the vascular cambium in response to gravitational stimuli. We quantitatively analysed the proteomes of Populus tremula cambium and its xylem cell derivatives in stems forming normal wood (NW) and TW to reveal the mechanisms underlying TW formation. Phloem-, cambium-, and wood-forming tissues were sampled by tangential cryosectioning and pooled into nine independent samples. The proteomes of TW and NW samples were similar in the phloem and cambium samples, but diverged early during xylogenesis, demonstrating that reprogramming is an integral part of TW formation. For example, 14-3-3, reactive oxygen species, ribosomal and ATPase complex proteins were found to be up-regulated at early stages of xylem differentiation during TW formation. At later stages of xylem differentiation, proteins involved in the biosynthesis of cellulose and enzymes involved in the biosynthesis of rhamnogalacturonan-I, rhamnogalacturonan-II, arabinogalactan-II and fasciclin-like arabinogalactan proteins were up-regulated in TW. Surprisingly, two isoforms of exostosin family proteins with putative xylan xylosyl transferase function and several lignin biosynthesis proteins were also up-regulated, even though xylan and lignin are known to be less abundant in TW than in NW. These data provided new insight into the processes behind TW formation.
|
|
10. |
- Bylesjö, Max, et al.
(author)
-
Integrated analysis of transcript, protein and metabolite data to study lignin biosynthesis in hybrid aspen
- 2009
-
In: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 8:1, s. 199-210
-
Journal article (peer-reviewed)abstract
- Tree biotechnology will soon reach a mature state where it will influence the overall supply of fiber, energy and wood products. We are now ready to make the transition from identifying candidate genes, controlling important biological processes, to discovering the detailed molecular function of these genes on a broader, more holistic, systems biology level. In this paper, a strategy is outlined for informative data generation and integrated modeling of systematic changes in transcript, protein and metabolite profiles measured from hybrid aspen samples. The aim is to study characteristics of common changes in relation to genotype-specific perturbations affecting the lignin biosynthesis and growth. We show that a considerable part of the systematic effects in the system can be tracked across all platforms and that the approach has a high potential value in functional characterization of candidate genes.
|
|
11. |
|
|
12. |
- Ekström, Jens-Ola, et al.
(author)
-
Drosophila Nora virus capsid proteins differ from those of other picorna-like viruses
- 2011
-
In: Virus Research. - Amsterdam : Elsevier. - 0168-1702 .- 1872-7492. ; 160:1-2, s. 51-58
-
Journal article (peer-reviewed)abstract
- The recently discovered Nora virus from Drosophila melanogaster is a single-stranded RNA virus. Its published genomic sequence encodes a typical picorna-like cassette of replicative enzymes, but no capsid proteins similar to those in other picorna-like viruses. We have now done additional sequencing at the termini of the viral genome, extending it by 455 nucleotides at the 5' end, but no more coding sequence was found. The completeness of the final 12,333-nucleotide sequence was verified by the production of infectious virus from the cloned genome. To identify the capsid proteins, we purified Nora virus particles and analyzed their proteins by mass spectrometry. Our results show that the capsid is built from three major proteins, VP4A, B and C, encoded in the fourth open reading frame of the viral genome. The viral particles also contain traces of a protein from the third open reading frame, VP3. VP4A and B are not closely related to other picorna-like virus capsid proteins in sequence, but may form similar jelly roll folds. VP4C differs from the others and is predicted to have an essentially α-helical conformation. In a related virus, identified from EST database sequences from Nasonia parasitoid wasps, VP4C is encoded in a separate open reading frame, separated from VP4A and B by a frame-shift. This opens a possibility that VP4C is produced in non-equimolar quantities. Altogether, our results suggest that the Nora virus capsid has a different protein organization compared to the order Picornavirales.
|
|
13. |
- Elfving, Nils, et al.
(author)
-
The Arabidopsis thaliana Med25 mediator subunit integrates environmental cues to control plant development
- 2011
-
In: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 108:20, s. 8245-8250
-
Journal article (peer-reviewed)abstract
- Development in plants is controlled by abiotic environmental cues such as day length, light quality, temperature, drought, and salinity. These signals are sensed by a variety of systems and transmitted by different signal transduction pathways. Ultimately, these pathways are integrated to control expression of specific target genes, which encode proteins that regulate development and differentiation. The molecular mechanisms for such integration have remained elusive. We here show that a linear 130-amino-acids-long sequence in the Med25 subunit of the Arabidopsis thaliana Mediator is a common target for the drought response element binding protein 2A, zinc finger homeodomain 1, and Myb-like transcription factors which are involved in different stress response pathways. In addition, our results show that Med25 together with drought response element binding protein 2A also function in repression of PhyB-mediated light signaling and thus integrate signals from different regulatory pathways.
|
|
14. |
- Ferreira, Sílvia, et al.
(author)
-
Proteome profiling of Populus euphratica Oliv. upon heat stress.
- 2006
-
In: Annals of Botany. - : Oxford University Press (OUP). - 0305-7364 .- 1095-8290. ; 98:2, s. 361-77
-
Journal article (peer-reviewed)abstract
- BACKGROUND AND AIMS: Populus euphratica is a light-demanding species ecologically characterized as a pioneer. It grows in shelter belts along riversides, being part of the natural desert forest ecosystems in China and Middle Eastern countries. It is able to survive extreme temperatures, drought and salt stress, marking itself out as an important plant species to study the mechanisms responsible for survival of woody plants under heat stress. METHODS: Heat effects were evaluated through electrolyte leakage on leaf discs, and LT(50) was determined to occur above 50 degrees C. Protein accumulation profiles of leaves from young plants submitted to 42/37 degrees C for 3 d in a phytotron were determined through 2D-PAGE, and a total of 45 % of up- and downregulated proteins were detected. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF)/TOF analysis, combined with searches in different databases, enabled the identification of 82 % of the selected spots. KEY RESULTS: Short-term upregulated proteins are related to membrane destabilization and cytoskeleton restructuring, sulfur assimilation, thiamine and hydrophobic amino acid biosynthesis, and protein stability. Long-term upregulated proteins are involved in redox homeostasis and photosynthesis. Late downregulated proteins are involved mainly in carbon metabolism. CONCLUSIONS: Moderate heat response involves proteins related to lipid biogenesis, cytoskeleton structure, sulfate assimilation, thiamine and hydrophobic amino acid biosynthesis, and nuclear transport. Photostasis is achieved through carbon metabolism adjustment, a decrease of photosystem II (PSII) abundance and an increase of PSI contribution to photosynthetic linear electron flow. Thioredoxin h may have a special role in this process in P. euphratica upon moderate heat exposure.
|
|
15. |
- Gandla, Madhavi Latha, et al.
(author)
-
Overexpression of vesicle-associated membrane protein PttVAP27-17 as a tool to improve biomass production and the overall saccharification yields in Populus trees
- 2021
-
In: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834. ; 14:1
-
Journal article (peer-reviewed)abstract
- Background Bioconversion of wood into bioproducts and biofuels is hindered by the recalcitrance of woody raw material to bioprocesses such as enzymatic saccharification. Targeted modification of the chemical composition of the feedstock can improve saccharification but this gain is often abrogated by concomitant reduction in tree growth. Results In this study, we report on transgenic hybrid aspen (Populus tremula x tremuloides) lines that showed potential to increase biomass production both in the greenhouse and after 5 years of growth in the field. The transgenic lines carried an overexpression construct for Populus tremula x tremuloides vesicle-associated membrane protein (VAMP)-associated protein PttVAP27-17 that was selected from a gene-mining program for novel regulators of wood formation. Analytical-scale enzymatic saccharification without any pretreatment revealed for all greenhouse-grown transgenic lines, compared to the wild type, a 20-44% increase in the glucose yield per dry weight after enzymatic saccharification, even though it was statistically significant only for one line. The glucose yield after enzymatic saccharification with a prior hydrothermal pretreatment step with sulfuric acid was not increased in the greenhouse-grown transgenic trees on a dry-weight basis, but increased by 26-50% when calculated on a whole biomass basis in comparison to the wild-type control. Tendencies to increased glucose yields by up to 24% were present on a whole tree biomass basis after acidic pretreatment and enzymatic saccharification also in the transgenic trees grown for 5 years on the field when compared to the wild-type control. Conclusions The results demonstrate the usefulness of gene-mining programs to identify novel genes with the potential to improve biofuel production in tree biotechnology programs. Furthermore, multi-omic analyses, including transcriptomic, proteomic and metabolomic analyses, performed here provide a toolbox for future studies on the function of VAP27 proteins in plants.
|
|
16. |
- LEVERENZ, JW, et al.
(author)
-
PHOTOSYNTHESIS AND PHOTOINHIBITION IN LEAVES OF CHLOROPHYLL-B-LESS BARLEY IN RELATION TO ABSORBED LIGHT
- 1992
-
In: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 85:3, s. 495-502
-
Journal article (peer-reviewed)abstract
- The response of photosynthesis to absorbed light by intact leaves of wild-type (Hordeum vulgare L. cv. Gunilla) and chlorophyll b-less barley (H. vulgare L. cv. Dornaria, chlorina-f2(2800)) was measured in a light integrating sphere. Up to the section where the light response curve bends most sharply the responses of the b-less and wild-type barley were similar but not identical. Average quantum yield and convexity for the mutant light response curves were 0.89 and 0.90, respectively times those of the wild-type barley. The maximum quantum yield for PSII photochemistry was also 10% lower as indicated by fluorescence induction kinetics (F(v)/F(m)). Just above the region where the light curve bends most sharply, photosynthesis decreased with time in thc mutant but not in the wild-type barley. This decrease was associated with a decrease in F(v)/F(m) indicating photoinhibition of PSII. This photoinhibition occurred in the same region of the light response curve where zeaxanthin formation occurs. Zeaxanthin formation occurred in both the chlorophyll b-less and wild-type leaves. However, the epoxidation state was lower in the mutant than in the wild-type barley. The results indicate that chlorophyll b-less mutants will have reduced photosynthetic production as a result of an increased sensitivity to photoinhibition and possibly a lowered quantum yield and convexity in the absence of photoinhibition.
|
|
17. |
- Lövgren, Mattias, et al.
(author)
-
The PRC-barrel domain of the ribosome maturation protein RimM mediates binding to ribosomal protein S19 in the 30S ribosomal subunits
- 2004
-
In: RNA. - : Cold Spring Harbor Laboratory Press (CSHL). - 1355-8382 .- 1469-9001. ; 10:11, s. 1798-1812
-
Journal article (peer-reviewed)abstract
- The RimM protein in Escherichia coli is associated with free 30S ribosomal subunits but not with 70S ribosomes. A DeltarimM mutant is defective in 30S maturation and accumulates 17S rRNA. To study the interaction of RimM with the 30S and its involvement in 30S maturation, RimM amino acid substitution mutants were constructed. A mutant RimM (RimM-YY-->AA), containing alanine substitutions for two adjacent tyrosines within the PRC beta-barrel domain, showed a reduced binding to 30S and an accumulation of 17S rRNA compared to wild-type RimM. The (RimM-YY-->AA) and DeltarimM mutants had significantly lower amounts of polysomes and also reduced levels of 30S relative to 50S compared to a wild-type strain. A mutation in rpsS, which encodes r-protein S19, suppressed the polysome- and 16S rRNA processing deficiencies of the RimM-YY-->AA but not that of the DeltarimM mutant. A mutation in rpsM, which encodes r-protein S13, suppressed the polysome deficiency of both rimM mutants. Suppressor mutations, found in either helices 31 or 33b of 16S rRNA, improved growth of both the RimM-YY-->AA and DeltarimM mutants. However, they suppressed the 16S rRNA processing deficiency of the RimM-YY-->AA mutant more efficiently than that of the DeltarimM mutant. Helices 31 and 33b are known to interact with S13 and S19, respectively, and S13 is known to interact with S19. A GST-RimM but not a GST-RimM(YY-->AA) protein bound strongly to S19 in 30S. Thus, RimM likely facilitates maturation of the region of the head of 30S that contains S13 and S19 as well as helices 31 and 33b.
|
|
18. |
- Miguel, Sissi, et al.
(author)
-
A GDSL lipase-like from Ipomoea batatas catalyzes efficient production of 3,5-diCQA when expressed in Pichia pastoris
- 2020
-
In: Communications Biology. - : Springer Nature. - 2399-3642. ; 3:1
-
Journal article (peer-reviewed)abstract
- The synthesis of 3,5-dicaffeoylquinic acid (3,5-DiCQA) has attracted the interest of many researchers for more than 30 years. Recently, enzymes belonging to the BAHD acyltransferase family were shown to mediate its synthesis, albeit with notably low efficiency. In this study, a new enzyme belonging to the GDSL lipase-like family was identified and proven to be able to transform chlorogenic acid (5-O-caffeoylquinic acid, 5-CQA, CGA) in 3,5-DiCQA with a conversion rate of more than 60%. The enzyme has been produced in different expression systems but has only been shown to be active when transiently synthesized in Nicotiana benthamiana or stably expressed in Pichia pastoris. The synthesis of the molecule could be performed in vitro but also by a bioconversion approach beginning from pure 5-CQA or from green coffee bean extract, thereby paving the road for producing it on an industrial scale. Miguel et al. identify a new enzyme belonging to the GDSL lipase-like family that is involved in the final stage of transformation of 5-CQA into 3,5-diCQA. This enzyme is able to realize an efficient transformation by over 60%, making the transformation process a valuable technological tool that can be easily transferred on an industrial scale.
|
|
19. |
- Nibbering, Petrus, et al.
(author)
-
CAGEs are Golgi-localized GT31 enzymes involved in cellulose biosynthesis in Arabidopsis
- 2022
-
In: Plant Journal. - : Wiley. - 0960-7412 .- 1365-313X. ; 110, s. 1271-1285
-
Journal article (peer-reviewed)abstract
- Cellulose is the main structural component in the plant cell walls. We show that two glycosyltransferase family 31 (GT31) enzymes of Arabidopsis thaliana, here named cellulose synthesis associated glycosyltransferases 1 and 2 (CAGE1 and 2), influence both primary and secondary cell wall cellulose biosynthesis. cage1cage2 mutants show primary cell wall defects manifesting as impaired growth and cell expansion in seedlings and etiolated hypocotyls, along with secondary cell wall defects, apparent as collapsed xylem vessels and reduced xylem wall thickness in the inflorescence stem. Single and double cage mutants also show increased sensitivity to the cellulose biosynthesis inhibitor isoxaben. The cage1cage2 phenotypes were associated with an approximately 30% reduction in cellulose content, an approximately 50% reduction in secondary cell wall CELLULOSE SYNTHASE (CESA) protein levels in stems and reduced cellulose biosynthesis rate in seedlings. CESA transcript levels were not significantly altered in cage1cage2 mutants, suggesting that the reduction in CESA levels was caused by a post-transcriptional mechanism. Both CAGE1 and 2 localize to the Golgi apparatus and are predicted to synthesize beta-1,3-galactans on arabinogalactan proteins. In line with this, the cage1cage2 mutants exhibit reduced levels of beta-Yariv binding to arabinogalactan protein linked beta-1,3-galactan. This leads us to hypothesize that defects in arabinogalactan biosynthesis underlie the cellulose deficiency of the mutants.
|
|
20. |
- Nickolov, Kaloian, et al.
(author)
-
Regulation of PaRBOH1-mediated ROS production in Norway spruce by Ca2+ binding and phosphorylation
- 2022
-
In: Frontiers in Plant Science. - : Frontiers Media S.A.. - 1664-462X. ; 13
-
Journal article (peer-reviewed)abstract
- Plant respiratory burst oxidase homologs (RBOHs) are plasma membrane-localized NADPH oxidases that generate superoxide anion radicals, which then dismutate to H2O2, into the apoplast using cytoplasmic NADPH as an electron donor. PaRBOH1 is the most highly expressed RBOH gene in developing xylem as well as in a lignin-forming cell culture of Norway spruce (Picea abies L. Karst.). Since no previous information about regulation of gymnosperm RBOHs exist, our aim was to resolve how PaRBOH1 is regulated with a focus on phosphorylation. The N-terminal part of PaRBOH1 was found to contain several putative phosphorylation sites and a four-times repeated motif with similarities to the Botrytis-induced kinase 1 target site in Arabidopsis AtRBOHD. Phosphorylation was indicated for six of the sites in in vitro kinase assays using 15 amino-acid-long peptides for each of the predicted phosphotarget site in the presence of protein extracts of developing xylem. Serine and threonine residues showing positive response in the peptide assays were individually mutated to alanine (kinase-inactive) or to aspartate (phosphomimic), and the wild type PaRBOH1 and the mutated constructs transfected to human kidney embryogenic (HEK293T) cells with a low endogenous level of extracellular ROS production. ROS-producing assays with HEK cells showed that Ca2+ and phosphorylation synergistically activate the enzyme and identified several serine and threonine residues that are likely to be phosphorylated including a novel phosphorylation site not characterized in other plant species. These were further investigated with a phosphoproteomic study. Results of Norway spruce, the first gymnosperm species studied in relation to RBOH regulation, show that regulation of RBOH activity is conserved among seed plants.
|
|
21. |
- Nilsson, Robert, et al.
(author)
-
Metacaspase Substrate Screening using Filter Aided Sample Preparation
- 2011
-
In: HUPO-2011: 10th World Congress of the Human Proteome Organization (HUPO): Geneva, Switzerland, September 3rd-7th, 2011: Proceedings-Posters.
-
Conference paper (peer-reviewed)abstract
- Background Metacaspases are proteases essential for programmed cell death (apoptosis) in plants, though most of their substrates remain unknown (1). The activity of metacaspases is a key issue in understanding wood (dead xylem cells) formation in trees. Here, we performed a substrate screening using a recombinant metacaspase that have an expression profile associated with the programmed cell death during wood formation in poplar. Methods Substrate preparation was initiated by total protein extraction from xylem tissue of plants down-regulated (RNA interference) in the expression of the metacaspase gene. Proper conditions intended for screening of the enzyme substrates were achieved by combinations of enzyme and substrate ultrafiltration. Utilizing the low pH activation of the enzyme allowed prompt activation and minute monitoring of newly formed peptides. Peptides were analysed by LC-MSMS using a nano-LC system coupled to a Synapt G2 mass spectrometer. Additional extractions including wild-type plants were performed to support detected substrate processing. Results The results revealed an enzyme active at low temperature (< 7 °C) with properties fitting criteria for cold-adapted enzymes. High specific activity was detected at low temperature and degradation products from the enzyme were formed after 30 min incubation at room temperature. Conclusions Our preliminary data suggest a substrate that has global responses that would clarify the metacaspase involvement in programmed cell death and wood formation. 1.Sundstrom, J. F., Vaculova, A., Smertenko, A. P., Savenkov, E. I., Golovko, A., Minina, E., Tiwari, B. S., Rodriguez-Nieto, S., Zamyatnin, A. A., Valineva, T., Saarikettu, J., Frilander, M. J., Suarez, M. F., Zavialov, A., Stahl, U., Hussey, P. J., Silvennoinen, O., Sundberg, E., Zhivotovsky, B., and Bozhkov, P. V. (2009) Tudor staphylococcal nuclease is an evolutionarily conserved component of the programmed cell death degradome. Nat. Cell Biol. 11, 1347-U198.
|
|
22. |
- Nilsson, Robert, et al.
(author)
-
Proteomics of Plasma Membranes from Poplar Trees Reveals Tissue Distribution of Transporters, Receptors, and Proteins in Cell Wall Formation
- 2010
-
In: Molecular & Cellular Proteomics. - 1535-9484 .- 1535-9476. ; 9:2, s. 368-387
-
Journal article (peer-reviewed)abstract
- By exploiting the abundant tissues available from Populus trees, 3-4 m high, we have been able to isolate plasma membranes of high purity from leaves, xylem, and cambium/phloem at a time (4 weeks after bud break) when photosynthesis in the leaves and wood formation in the xylem should have reached a steady state. More than 40% of the 956 proteins identified were found in the plasma membranes of all three tissues and may be classified as "housekeeping" proteins, a typical example being P-type H+-ATPases. Among the 213 proteins predicted to be integral membrane proteins, transporters constitute the largest class (41%) followed by receptors (14%) and proteins involved in cell wall and carbohydrate metabolism (8%) and membrane trafficking (8%). ATP-binding cassette transporters (all members of subfamilies B, C, and G) and receptor-like kinases (four subfamilies) were two of the largest protein families found, and the members of these two families showed pronounced tissue distribution. Leaf plasma membranes were characterized by a very high proportion of transporters, constituting almost half of the integral proteins. Proteins involved in cell wall synthesis (such as cellulose and sucrose synthases) and membrane trafficking were most abundant in xylem plasma membranes in agreement with the role of the xylem in wood formation. Twenty-five integral proteins and 83 soluble proteins were exclusively found in xylem plasma membranes, which identifies new candidates associated with cell wall synthesis and wood formation. Among the proteins uniquely found in xylem plasma membranes were most of the enzymes involved in lignin biosynthesis, which suggests that they may exist as a complex linked to the plasma membrane. Molecular & Cellular Proteomics 9:368-387, 2010.
|
|
23. |
- Obudulu, Ogonna, et al.
(author)
-
A multi-omics approach reveals function of Secretory Carrier-Associated Membrane Proteins in wood formation of Populus trees
- 2018
-
In: BMC Genomics. - : Springer Publishing Company. - 1471-2164. ; 19
-
Journal article (peer-reviewed)abstract
- Background: Secretory Carrier-Associated Membrane Proteins (SCAMPs) are highly conserved 32–38 kDa proteins that are involved in membrane trafficking. A systems approach was taken to elucidate function of SCAMPs in wood formation of Populus trees. Phenotypic and multi-omics analyses were performed in woody tissues of transgenic Populus trees carrying an RNAi construct for Populus tremula x tremuloides SCAMP3 (PttSCAMP3;Potri.019G104000).Results: The woody tissues of the transgenic trees displayed increased amounts of both polysaccharides and lignin oligomers, indicating increased deposition of both the carbohydrate and lignin components of the secondary cell walls. This coincided with a tendency towards increased wood density as well as significantly increased thickness of the suberized cork in the transgenic lines. Multivariate OnPLS (orthogonal projections to latent structures) modeling of five different omics datasets (the transcriptome, proteome, GC-MS metabolome, LC-MS metabolome and pyrolysis-GC/MS metabolome) collected from the secondary xylem tissues of the stem revealed systemic variation in the different variables in the transgenic lines, including changes that correlated with the changes in the secondary cell wall composition. The OnPLS model also identified a rather large number of proteins that were more abundant in the transgenic lines than in the wild type. Several of these were related to secretion and/or endocytosis as well as both primary and secondary cell wall biosynthesis.Conclusions: Populus SCAMP proteins were shown to influence accumulation of secondary cell wall components, including polysaccharides and phenolic compounds, in the woody tissues of Populus tree stems. Our multi-omics analyses combined with the OnPLS modelling suggest that this function is mediated by changes in membrane trafficking to fine-tune the abundance of cell wall precursors and/or proteins involved in cell wall biosynthesis and transport. The data provides a multi-level source of information for future studies on the function of the SCAMP proteins in plant stem tissues.
|
|
24. |
- Obudulu, Ogonna, et al.
(author)
-
Quantitative proteomics reveals protein profiles underlying major transitions in aspen wood development
- 2016
-
In: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 17
-
Journal article (peer-reviewed)abstract
- Background: Wood development is of outstanding interest both to basic research and industry due to the associated cellulose and lignin biomass production. Efforts to elucidate wood formation (which is essential for numerous aspects of both pure and applied plant science) have been made using transcriptomic analyses and/or low-resolution sampling. However, transcriptomic data do not correlate perfectly with levels of expressed proteins due to effects of post-translational modifications and variations in turnover rates. In addition, high-resolution analysis is needed to characterize key transitions. In order to identify protein profiles across the developmental region of wood formation, an in-depth and tissue specific sampling was performed. Results: We examined protein profiles, using an ultra-performance liquid chromatography/quadrupole time of flight mass spectrometry system, in high-resolution tangential sections spanning all wood development zones in Populus tremula from undifferentiated cambium to mature phloem and xylem, including cell expansion and cell death zones. In total, we analyzed 482 sections, 20-160 mu m thick, from four 47-year-old trees growing wild in Sweden. We obtained high quality expression profiles for 3,082 proteins exhibiting consistency across the replicates, considering that the trees were growing in an uncontrolled environment. A combination of Principal Component Analysis (PCA), Orthogonal Projections to Latent Structures (OPLS) modeling and an enhanced stepwise linear modeling approach identified several major transitions in global protein expression profiles, pinpointing (for example) locations of the cambial division leading to phloem and xylem cells, and secondary cell wall formation zones. We also identified key proteins and associated pathways underlying these developmental landmarks. For example, many of the lignocellulosic related proteins were upregulated in the expansion to the early developmental xylem zone, and for laccases with a rapid decrease in early xylem zones. We observed upregulation of two forms of xylem cysteine protease (Potri.002G005700.1 and Potri.005G256000.2; Pt-XCP2.1) in early xylem and their downregulation in late maturing xylem. Our data also show that Pt-KOR1.3 (Potri.003G151700.2) exhibits an expression pattern that supports the hypothesis put forward in previous studies that this is a key xyloglucanase involved in cellulose biosynthesis in primary cell walls and reduction of cellulose crystallinity in secondary walls. Conclusion: Our novel multivariate approach highlights important processes and provides confirmatory insights into the molecular foundations of wood development.
|
|
25. |
- Overmyer, Kirk, et al.
(author)
-
Complex phenotypic profiles leading to ozone sensitivity in Arabidopsis thaliana mutants
- 2008
-
In: Plant, Cell and Environment. - : John Wiley & Sons. - 0140-7791 .- 1365-3040. ; 31:9, s. 1237-1249
-
Journal article (peer-reviewed)abstract
- Genetically tractable model plants offer the possibility of defining the plant O3 response at the molecular level. To this end, we have isolated a collection of ozone (O3)‐sensitive mutants of Arabidopsis thaliana. Mutant phenotypes and genetics were characterized. Additionally, parameters associated with O3 sensitivity were analysed, including stomatal conductance, sensitivity to and accumulation of reactive oxygen species, antioxidants, stress gene‐expression and the accumulation of stress hormones. Each mutant has a unique phenotypic profile, with O3 sensitivity caused by a unique set of alterations in these systems. O3 sensitivity in these mutants is not caused by gross deficiencies in the antioxidant pathways tested here. The rcd3 mutant exhibits misregulated stomata. All mutants exhibited changes in stress hormones consistent with the known hormonal roles in defence and cell death regulation. One mutant, dubbed re‐8, is an allele of the classic leaf development mutant reticulata and exhibits phenotypes dependent on light conditions. This study shows that O3 sensitivity can be determined by deficiencies in multiple interacting plant systems and provides genetic evidence linking these systems.
|
|
26. |
- Palm, Maria E, et al.
(author)
-
Cisplatin binds human copper chaperone Atox1 and promotes unfolding in vitro.
- 2011
-
In: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 108:17, s. 6951-6
-
Journal article (peer-reviewed)abstract
- Cisplatin (cisPt), Pt(NH(3))(2)Cl(2), is a cancer drug believed to kill cells via DNA binding and damage. Recent work has implied that the cellular copper (Cu) transport machinery may be involved in cisPt cell export and drug resistance. Normally, the Cu chaperone Atox1 binds Cu(I) via two cysteines and delivers the metal to metal-binding domains of ATP7B; the ATP7B domains then transfer the metal to the Golgi lumen for loading on cuproenzymes. Here, we use spectroscopic methods to test if cisPt interacts with purified Atox1 in solution in vitro. We find that cisPt binds to Atox1's metal-binding site regardless of the presence of Cu or not: When Cu is bound to Atox1, the near-UV circular dichroism signals indicate Cu-Pt interactions. From NMR data, it is evident that cisPt binds to the folded protein. CisPt-bound Atox1 is however not stable over time and the protein begins to unfold and aggregate. The reaction rates are limited by slow cisPt dechlorination. CisPt-induced unfolding of Atox1 is specific because this effect was not observed for two unrelated proteins that also bind cisPt. Our study demonstrates that Atox1 is a candidate for cisPt drug resistance: By binding to Atox1 in the cytoplasm, cisPt transport to DNA may be blocked. In agreement with this model, cell line studies demonstrate a correlation between Atox1 expression levels, and cisplatin resistance.
|
|
27. |
- Rouhier, Nicolas, et al.
(author)
-
Identification of plant glutaredoxin targets
- 2005
-
In: Antioxidants and Redox Signaling. - Larchmont, NY : Mary Ann Liebert. - 1523-0864 .- 1557-7716. ; 7:7-8, s. 919-929
-
Journal article (peer-reviewed)abstract
- Glutaredoxins (Grxs) are small ubiquitous proteins of the thioredoxin (Trx) family, which catalyze dithiol–disulfide exchange reactions or reduce protein-mixed glutathione disulfides. In plants, several Trx-interacting proteins have been isolated from different compartments, whereas very few Grx-interacting proteins are known. We describe here the determination of Grx target proteins using a mutated poplar Grx, various tissular and subcellular plant extracts, and liquid chromatography coupled to tandem mass spectrometry detection. We have identified 94 putative targets, involved in many processes, including oxidative stress response [peroxiredoxins (Prxs), ascorbate peroxidase, catalase], nitrogen, sulfur, and carbon metabolisms (methionine synthase, alanine aminotransferase, phosphoglycerate kinase), translation (elongation factors E and Tu), or protein folding (heat shock protein 70). Some of these proteins were previously found to interact with Trx or to be glutathiolated in other organisms, but others could be more specific partners of Grx. To substantiate further these data, Grx was shown to support catalysis of the stroma β-type carbonic anhydrase and Prx IIF of Arabidopsis thaliana, but not of poplar 2-Cys Prx. Overall, these data suggest that the interaction could occur randomly either with exposed cysteinyl disulfide bonds formed within or between target proteins or with mixed disulfides between a protein thiol and glutathione.
|
|
28. |
- Selles, Benjamin, et al.
(author)
-
Hydroperoxide and peroxynitrite reductase activity of poplar thioredoxin-dependent glutathione peroxidase 5 : kinetics, catalytic mechanism and oxidative inactivation.
- 2012
-
In: Biochemical Journal. - 0264-6021 .- 1470-8728. ; 442, s. 369-380
-
Journal article (peer-reviewed)abstract
- Glutathione peroxidases constitute a family of peroxidases, including selenocysteine- or cysteine-containing isoforms ((SeCys- or Cys-Gpxs) which are regenerated by glutathione or thioredoxins, (Trxs) respectively. We present here new data concerning the substrates of poplar Gpx5 and the residues involved in its catalytic mechanism. This study establishes the capacity of this Cys-Gpx to reduce peroxynitrite with a catalytic efficiency of 106 M-1 s-1. In PtGpx5, Glu79, which replaces the Gln usually found in Gpx catalytic tetrad, is likely involved in substrate selectivity. Although the redox midpoint potential of the Cys44-Cys92 disulfide and the pKa of Cys44 are not modified in the E79Q variant, it exhibited significantly improved kinetic parameters (Kperoxide and kcat) with tert-butyl hydroperoxide. The characterization of the monomeric Y151R variant demonstrated that PtGpx5 is not an obligate homodimer. Also, we show that the conserved Phe90 is important for Trx recognition and that Trx-mediated recycling of PtGpx5 occurs via the formation of a transient disulfide between the Trx catalytic cysteine and the Gpx5 resolving cysteine. Finally, we demonstrate that the conformational changes observed during the transition from the reduced to the oxidized form of PtGpx5 are primarily determined by the oxidation of the peroxidatic cysteine into sulfenic acid. Besides, mass spectrometry analysis of in vitro oxidized PtGpx5 demonstrated that the peroxidatic cysteine can be over-oxidized into sulfinic or sulfonic acids. This suggests that some isoforms could have dual functions potentially acting as hydrogen peroxide- and peroxynitrite-scavenging systems and/or as mediators of peroxide signalling as proposed for 2-Cys peroxiredoxins.
|
|
29. |
- Shaikhali, Jehad, et al.
(author)
-
Biochemical and redox characterization of the mediator complex and its associated transcription factor GeBPL, a GLABROUS1 enhancer binding protein
- 2015
-
In: Biochemical Journal. - 0264-6021 .- 1470-8728. ; 468:3, s. 385-400
-
Journal article (peer-reviewed)abstract
- The eukaryotic mediator integrates regulatory signals from promoter-bound transcription factors (TFs) and transmits them to RNA polymerase II (Pol II) machinery. Although redox signalling is important in adjusting plant metabolism and development, nothing is known about a possible redox regulation of mediator. In the present study, using pull-down and yeast two-hybrid assays, we demonstrate the association of mediator (MED) subunits MED10a, MED28 and MED32 with the GLABROUS1 (GL1) enhancer-binding protein-like (GeBPL), a plant-specific TF that binds a promoter containing cryptochrome 1 response element 2 (CryR2) element. All the corresponding recombinant proteins form various types of covalent oligomers linked by intermolecular disulfide bonds that are reduced in vitro by the thioredoxin (TRX) and/or glutathione/glutaredoxin (GRX) systems. The presence of recombinant MED10a, MED28 and MED32 subunits or changes of its redox state affect the DNA-binding capacity of GeBPL suggesting that redox-driven conformational changes might modulate its activity. Overall, these results advance our understanding of how redox signalling affects transcription and identify mediator as a novel actor in redox signalling pathways, relaying or integrating redox changes in combinationwith specific TFs as GeBPL.
|
|
30. |
- Shaikhali, Jehad, et al.
(author)
-
Redox-mediated Mechanisms Regulate DNA Binding Activity of the G-group of Basic Region Leucine Zipper (bZIP) Transcription Factors in Arabidopsis
- 2012
-
In: Journal of Biological Chemistry. - Rockville : The American Society for Biochemistry and Molecular Biology. - 0021-9258 .- 1083-351X. ; 287:33, s. 27510-27525
-
Journal article (peer-reviewed)abstract
- Plant genes that contain the G-box in their promoters are responsive to a variety of environmental stimuli. Bioinformatics analysis of transcriptome data revealed that the G-box element is significantly enriched in promoters of high light-responsive genes. From nuclear extracts of high light-treated Arabidopsis plants, we identified the AtbZIP16 transcription factor as a component binding to the G-box-containing promoter fragment of light-harvesting chlorophyll a/b-binding protein2.4 (LHCB2.4). AtbZIP16 belongs to the G-group of Arabidopsis basic region leucine zipper (bZIP) type transcription factors. Although AtbZIP16 and its close homologues AtbZIP68 and AtGBF1 bind the G-box, they do not bind the mutated half-sites of the G-box palindrome. In addition, AtbZIP16 interacts with AtbZIP68 and AtGBF1 in the yeast two-hybrid system. A conserved Cys residue was shown to be necessary for redox regulation and enhancement of DNA binding activity in all three proteins. Furthermore, transgenic Arabidopsis lines overexpressing the wild type version of bZIP16 and T-DNA insertion mutants for bZIP68 and GBF1 demonstrated impaired regulation of LHCB2.4 expression. Finally, overexpression lines for the mutated Cys variant of bZIP16 provided support for the biological significance of Cys330 in redox regulation of gene expression. Thus, our results suggest that environmentally induced changes in the redox state regulate the activity of members of the G-group of bZIP transcription factors.
|
|
31. |
- Shaikhali, Jehad, et al.
(author)
-
Redox-regulated transcription in plants: Emerging concepts
- 2017
-
In: AIMS molecular science. - : American Institute of Mathematical Sciences (AIMS). - 2372-0301. ; 4, s. 301-338
-
Research review (peer-reviewed)abstract
- In plants, different stimuli, both internal and external, activate production of reactive oxygen species (ROS). Photosynthesis is considered as high rate redox-metabolic process with rapid transients including light/photon capture, electron fluxes, and redox potentials that can generate ROS; thus, regulatory systems are required to minimize ROS production. Despite their potential for causing harmful oxidations, it is now accepted that redox homeostasis mechanisms that maintain the intracellular reducing environment make it possible to use ROS as powerful signaling molecules within and between cells. Redox and ROS information from the chloroplasts is a fine-tuning mechanism both inside the chloroplast and as retrograde signal to the cytosol and nucleus to control processes such as gene expression/transcription and translation. Wide repertoires of downstream target genes expression (activation/repression) is regulated by transcription factors. In many cases, transcription factors function through various mechanisms that affect their subcellular localization and or activity. Some post-translational modifications (PTMs) known to regulate the functional state of transcription factors are phosphorylation, acetylation, and SUMOylation, ubiquitylation and disulfide formation. Recently, oxPTMs, targeted in redox proteomics, can provide the bases to study redox regulation of low abundant nuclear proteins. This review summarizes the recent advances on how cellular redox status can regulate transcription factor activity, the implications of this regulation for plant growth and development, and by which plants respond to environmental/abiotic stresses.
|
|
32. |
|
|
33. |
- Shaikhali, Jehad, et al.
(author)
-
Redox regulation of the MED28 and MED32 mediator subunits is important for development and senescence
- 2016
-
In: Protoplasma. - : Springer Science and Business Media LLC. - 0033-183X .- 1615-6102. ; 253:3, s. 957-963
-
Journal article (peer-reviewed)abstract
- Mediator is a conserved multi-protein complex that acts as a bridge between promoter-bound transcriptional regulators and RNA polymerase II. While redox signaling is important in adjusting plant metabolism and development, the involvement of Mediator in redox homeostasis and regulation only recently started to emerge. Our previous results show that the MED10a, MED28, and MED32 Mediator subunits form various types of covalent oligomers linked by intermolecular disulfide bonds in vitro. To link that with biological significance we have characterized Arabidopsis med32 and med28 mutants and found that they are affected in root development and senescence, phenotypes possibly associated to redox changes.
|
|
34. |
- Shaikhali, Jehad, et al.
(author)
-
The CRYPTOCHROME1-Dependent Response to Excess Light Is Mediated through the Transcriptional Activators ZINC FINGER PROTEIN EXPRESSED IN INFLORESCENCE MERISTEM LIKE1 and ZML2 in Arabidopsis
- 2012
-
In: The Plant Cell. - : Oxford University Press (OUP). - 1040-4651 .- 1532-298X. ; 24:7, s. 3009-3025
-
Journal article (peer-reviewed)abstract
- Exposure of plants to light intensities that exceed the electron utilization capacity of the chloroplast has a dramatic impact on nuclear gene expression. The photoreceptor Cryptochrome 1 (cry1) is essential to the induction of genes encoding photoprotective components in Arabidopsis thaliana. Bioinformatic analysis of the cry1 regulon revealed the putative ciselement CryR1 (GnTCKAG), and here we demonstrate an interaction between CryR1 and the zinc finger GATA-type transcription factors ZINC FINGER PROTEIN EXPRESSED IN INFLORESCENCE MERISTEM LIKE1 (ZML1) and ZML2. The ZML proteins specifically bind to the CryR1 cis-element as demonstrated in vitro and in vivo, and TCTAG was shown to constitute the core sequence required for ZML2 binding. In addition, ZML2 activated transcription of the yellow fluorescent protein reporter gene driven by the CryR1 cis-element in Arabidopsis leaf protoplasts. T-DNA insertion lines for ZML2 and its homolog ZML1 demonstrated misregulation of several cry1-dependent genes in response to excess light. Furthermore, the zml1 and zml2 T-DNA insertion lines displayed a high irradiance-sensitive phenotype with significant photoinactivation of photosystem II (PSII), indicated by reduced maximum quantum efficiency of PSII, and severe photobleaching. Thus, we identified the ZML2 and ZML1 GATA transcription factors as two essential components of the cry1-mediated photoprotective response.
|
|
35. |
- Srivastava, Vaibhav, et al.
(author)
-
Alternative splicing studies of the reactive oxygen species gene network in Populus reveal two isoforms of high-isoelectric-point superoxide dismutase
- 2009
-
In: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 149:4, s. 1848-1859
-
Journal article (peer-reviewed)abstract
- Recent evidence has shown that alternative splicing (AS) is widely involved in the regulation of gene expression, substantially extending the diversity of numerous proteins. In this study, a subset of expressed sequence tags representing members of the reactive oxygen species gene network was selected from the PopulusDB database to investigate AS mechanisms in Populus. Examples of all known types of AS were detected, but intron retention was the most common. Interestingly, the closest Arabidopsis (Arabidopsis thaliana) homologs of half of the AS genes identified in Populus are not reportedly alternatively spliced. Two genes encoding the protein of most interest in our study (high-isoelectric-point superoxide dismutase [hipI-SOD]) have been found in black cottonwood (Populus trichocarpa), designated PthipI-SODC1 and PthipI-SODC2. Analysis of the expressed sequence tag libraries has indicated the presence of two transcripts of PthipI-SODC1 (hipI-SODC1b and hipI-SODC1s). Alignment of these sequences with the PthipI-SODC1 gene showed that hipI-SODC1b was 69 bp longer than hipI-SODC1s due to an AS event involving the use of an alternative donor splice site in the sixth intron. Transcript analysis showed that the splice variant hipI-SODC1b was differentially expressed, being clearly expressed in cambial and xylem, but not phloem, regions. In addition, immunolocalization and mass spectrometric data confirmed the presence of hipI-SOD proteins in vascular tissue. The functionalities of the spliced gene products were assessed by expressing recombinant hipI-SOD proteins and in vitro SOD activity assays.
|
|
36. |
- Srivastava, Vaibhav, et al.
(author)
-
Downregulation of high-isoelectric-point extracellular superoxide dismutase mediates alterations in the metabolism of reactive oxygen species and developmental disturbances in hybrid aspen
- 2007
-
In: The Plant Journal. - : Blackwell Publishing. - 0960-7412 .- 1365-313X. ; 49:1, s. 135-148
-
Journal article (peer-reviewed)abstract
- Transgenic hybrid aspen (Populus tremula L. x P. tremuloides Michx.) plants expressing a high-isoelectric-point superoxide dismutase (hipI-SOD) gene in antisense orientation were generated to investigate its function. Immunolocalization studies showed the enzyme to be localized extracellularly, in the secondary cell wall of xylem vessels and phloem fibers. The antisense lines of hipI-SOD exhibited a distinct phenotype; growth rate was reduced, stems were thinner and leaves smaller than in wild-type (WT) plants. The abundance of hipI-SOD was reduced in the bark and xylem of plants from these antisense lines. The vascular tissue of transgenic lines became lignified earlier than in WT plants and also showed an increased accumulation of reactive oxygen species (ROS). Xylem fibers and vessels were shorter and thinner in the transgenic lines than in WT plants. The total phenolic content was enhanced in the antisense lines. Furthermore, microarray analysis indicated that several enzymes involved in cell signaling, lignin biosynthesis and stress responses were upregulated in apical vascular tissues of transgenic plants. The upregulation of selected genes involved in lignin biosynthesis was also verified by real-time PCR. The results suggest that, in the transgenic plants, a premature transition into maturation occurs and the process is discussed in terms of the effects of increased accumulation of ROS due to reduced expression of hipI-SOD during development and differentiation.
|
|
37. |
- Srivastava, Vaibhav, et al.
(author)
-
OnPLS integration of transcriptomic, proteomic and metabolomic data shows multi-level oxidative stress responses in the cambium of transgenic hipI- superoxide dismutase Populus plants
- 2013
-
In: BMC Genomics. - : BioMed Central. - 1471-2164. ; 14
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Reactive oxygen species (ROS) are involved in the regulation of diverse physiological processes in plants, including various biotic and abiotic stress responses. Thus, oxidative stress tolerance mechanisms in plants are complex, and diverse responses at multiple levels need to be characterized in order to understand them. Here we present system responses to oxidative stress in Populus by integrating data from analyses of the cambial region of wild-type controls and plants expressing high-isoelectric-point superoxide dismutase (hipI-SOD) transcripts in antisense orientation showing a higher production of superoxide. The cambium, a thin cell layer, generates cells that differentiate to form either phloem or xylem and is hypothesized to be a major reason for phenotypic perturbations in the transgenic plants. Data from multiple platforms including transcriptomics (microarray analysis), proteomics (UPLC/QTOF-MS), and metabolomics (GC-TOF/MS, UPLC/MS, and UHPLC-LTQ/MS) were integrated using the most recent development of orthogonal projections to latent structures called OnPLS. OnPLS is a symmetrical multi-block method that does not depend on the order of analysis when more than two blocks are analysed. Significantly affected genes, proteins and metabolites were then visualized in painted pathway diagrams.RESULTS: The main categories that appear to be significantly influenced in the transgenic plants were pathways related to redox regulation, carbon metabolism and protein degradation, e.g. the glycolysis and pentose phosphate pathways (PPP). The results provide system-level information on ROS metabolism and responses to oxidative stress, and indicate that some initial responses to oxidative stress may share common pathways.CONCLUSION: The proposed data evaluation strategy shows an efficient way of compiling complex, multi-platform datasets to obtain significant biological information.
|
|
38. |
- Vaisanen, E., et al.
(author)
-
Hunting monolignol transporters: membrane proteomics and biochemical transport assays with membrane vesicles of Norway spruce
- 2020
-
In: Journal of Experimental Botany. - : Oxford University Press (OUP). - 0022-0957 .- 1460-2431. ; 71:20, s. 6379-6395
-
Journal article (peer-reviewed)abstract
- Both the mechanisms of monolignol transport and the transported form of monolignols in developing xylem of trees are unknown. We tested the hypothesis of an active, plasma membrane-localized transport of monolignol monomers, dimers, and/or glucosidic forms with membrane vesicles prepared from developing xylem and lignin-forming tissuecultured cells of Norway spruce (Picea abies L. Karst.), as well as from control materials, comprising non-lignifying Norway spruce phloem and tobacco (Nicotiana tabacum L.) BY-2 cells. Xylem and BY-2 vesicles transported both coniferin and p-coumaryl alcohol glucoside, but inhibitor assays suggested that this transport was through the tonoplast. Membrane vesicles prepared from lignin-forming spruce cells showed coniferin transport, but the K-m value for coniferin was much higher than those of xylem and BY-2 cells. Liquid chromatography-mass spectrometry analysis of membrane proteins isolated from spruce developing xylem, phloem, and lignin-forming cultured cells revealed multiple transporters. These were compared with a transporter gene set obtained by a correlation analysis with a selected set of spruce monolignol biosynthesis genes. Biochemical membrane vesicle assays showed no support for ABC-transporter-mediated monolignol transport but point to a role for secondary active transporters (such as MFS or MATE transporters). In contrast, proteomic and co-expression analyses suggested a role for ABC transporters and MFS transporters.
|
|
39. |
- Wiklund, Susanne, et al.
(author)
-
A new metabonomic strategy for analysing the growth process of the poplar tree
- 2005
-
In: Plant Biotechnology Journal. - : Wiley. - 1467-7644 .- 1467-7652. ; 3:3, s. 353-362
-
Journal article (peer-reviewed)abstract
- High-resolution, magic angle spinning, proton nuclear magnetic resonance (H-1 HR/MAS NMR) spectroscopy and multivariate data analysis using batch processing (BP) were applied to the analysis of two different genotypes of poplar tree (Populus tremula L. x tremuloides Michx.) containing an antisense construct of PttMYB76 and control (wild-type). A gene encoding a MYB transcription factor, with unknown function, PttMYB76, was selected from a cambial expressed sequence tag (EST) library of poplar tree (Populus tremula L. x tremuloides Michx.) for metabonomic characterization. The PttMYB76 gene is believed to affect different paths in the phenyl propanoid synthetic pathway. This pathway leads to the formation of S- and G-lignin, flavonoids and sinapate esters. Milled poplar samples collected at the internodes of the tree were analysed using H-1 HR/MAS NMR spectroscopy. The application of multivariate BP of the NMR results revealed a growth-related gradient in the plant internode direction, as well as the discrimination between the trees with down-regulated PttMYB76 expression and wild-type populations. This paper focuses on the potential of a new analytical multivariate approach for analysing time-related plant metabonomic data. The techniques used could, with the aid of suitable model compounds, be of high relevance to the detection and understanding of the different lignification processes within the two types of poplar tree. Additionally, the findings highlight the importance of applying robust and organized multivariate data analysis approaches to facilitate the modelling and interpretation of complex biological data sets.
|
|
40. |
- Wingsle, Gunnar
(author)
-
Atypical Thioredoxins in Poplar: The Glutathione-Dependent Thioredoxin-Like 2.1 Supports the Activity of Target Enzymes Possessing a Single Redox Active Cysteine
- 2012
-
In: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 159, s. 592-605
-
Journal article (peer-reviewed)abstract
- Plant thioredoxins (Trxs) constitute a complex family of thiol oxidoreductases generally sharing a WCGPC active site sequence. Some recently identified plant Trxs (Clot, Trx-like1 and -2, Trx-lilium1, -2, and -3) display atypical active site sequences with altered residues between the two conserved cysteines. The transcript expression patterns, subcellular localizations, and biochemical properties of some representative poplar (Populus spp.) isoforms were investigated. Measurements of transcript levels for the 10 members in poplar organs indicate that most genes are constitutively expressed. Using transient expression of green fluorescent protein fusions, Clot and Trx-like1 were found to be mainly cytosolic, whereas Trx-like2.1 was located in plastids. All soluble recombinant proteins, except Clot, exhibited insulin reductase activity, although with variable efficiencies. Whereas Trx-like2.1 and Trx-lilium2.2 were efficiently regenerated both by NADPH-Trx reductase and glutathione, none of the proteins were reduced by the ferredoxin-Trx reductase. Only Trx-like2.1 supports the activity of plastidial thiol peroxidases and methionine sulfoxide reductases employing a single cysteine residue for catalysis and using a glutathione recycling system. The second active site cysteine of Trx-like2.1 is dispensable for this reaction, indicating that the protein possesses a glutaredoxin-like activity. Interestingly, the Trx-like2.1 active site replacement, from WCRKC to WCGPC, suppresses its capacity to use glutathione as a reductant but is sufficient to allow the regeneration of target proteins employing two cysteines for catalysis, indicating that the nature of the residues composing the active site sequence is crucial for substrate selectivity/recognition. This study provides another example of the cross talk existing between the glutathione/glutaredoxin and Trx-dependent pathways.
|
|
41. |
- Wingsle, Gunnar
(author)
-
Comparative Genomic Study of the Thioredoxin Family in Photosynthetic Organisms with Emphasis on Populus trichocarpa
- 2009
-
In: Molecular Plant. - : Elsevier BV. - 1674-2052 .- 1752-9867. ; 2, s. 308-322
-
Journal article (peer-reviewed)abstract
- The recent genome sequencing of Populus trichocarpa and Vitis vinifera, two models of woody plants, of Sorghum bicolor, a model of monocot using C4 metabolism, and of the moss Physcomitrella patens, together with the availability of photosynthetic organism genomes allows performance of a comparative genomic study with organisms having different ways of life, reproduction modes, biological traits, and physiologies. Thioredoxins (Trxs) are small ubiquitous proteins involved in the reduction of disulfide bridges in a variety of target enzymes present in all sub-cellular compartments and involved in many biochemical reactions. The genes coding for these enzymes have been identified in these newly sequenced genomes and annotated. The gene content, organization and distribution were compared to other photosynthetic organisms, leading to a refined classification. This analysis revealed that higher plants and bryophytes have a more complex family compared to algae and cyanobacteria and to non-photosynthetic organisms, since poplar exhibits 49 genes coding for typical and atypical thioredoxins and thioredoxin reductases, namely one-third more than monocots such as Oryza sativa and S. bicolor. The higher number of Trxs in poplar is partially explained by gene duplication in the Trx m, h, and nucleoredoxin classes. Particular attention was paid to poplar genes with emphasis on Trx-like classes called Clot, thioredoxin-like, thioredoxins of the lilium type and nucleoredoxins, which were not described in depth in previous genomic studies.
|
|
42. |
- Wingsle, Gunnar, et al.
(author)
-
ISOLATION, PURIFICATION, AND SUBCELLULAR-LOCALIZATION OF ISOZYMES OF SUPEROXIDE-DISMUTASE FROM SCOTS PINE (PINUS-SYLVESTRIS L) NEEDLES
- 1991
-
In: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 95:1, s. 21-28
-
Journal article (peer-reviewed)abstract
- Two of four isozymes of superoxide dismutase (SOD) (EC 1.15.1.1) were purified from Scots pine (Pinus sylvestris L.) needles. One form was cytosolic (SOD-1) and the other was associated with chloroplasts (SOD-3). The holoenzyme molecular masses was estimated at approximately 35 kilodaltons by gel filtration. The subunit molecular weight of the dimeric enzymes was estimated to 16.5 kilodaltons (SOD-1) and 20.4 kilodaltons (SOD-3) on sodium dodecyl sulfatepolyacrylamide gels. The NH2-terminal sequence of the pine enzymes showed similarities to other purified superoxide dismutases located in the corresponding compartment. The cytosolic form revealed two additional amino acids at position 1 and 2 at the NH2-terminal. Both forms were cyanide- and hydrogenperoxide-sensitive and SOD-3 was found to contain approximately one copper atom per subunit, indicating that they belong to the cupro-zinc SODs. The isoelectric point was 4.9 and 4.5 for SOD-1 and SOD-3, respectively.
|
|
43. |
|
|
44. |
- Xu, Hao, et al.
(author)
-
Yeast Elongator protein Elp1p does not undergo proteolytic processing in exponentially growing cells
- 2015
-
In: MicrobiologyOpen. - : Wiley. - 2045-8827. ; 4:6, s. 867-878
-
Journal article (peer-reviewed)abstract
- In eukaryotic organisms, Elongator is a six-subunit protein complex required for the formation of 5-carbamoylmethyl (ncm5) and 5-methylcarboxymethyl (mcm5) side chains on uridines present at the wobble position (U34) of tRNA. The open reading frame encoding the largest Elongator subunit Elp1p has two in-frame 5′ AUG methionine codons separated by 48 nucleotides. Here, we show that the second AUG acts as the start codon of translation. Furthermore, Elp1p was previously shown to exist in two major forms of which one was generated by proteolysis of full-length Elp1p and this proteolytic cleavage was suggested to regulate Elongator complex activity. In this study, we found that the vacuolar protease Prb1p was responsible for the cleavage of Elp1p. The cleavage occurs between residues 203 (Lys) and 204 (Ala) as shown by amine reactive Tandem Mass Tag followed by LC-MS/MS (liquid chromatography mass spectrometry) analysis. However, using a modified protein extraction procedure, including trichloroacetic acid, only full-length Elp1p was observed, showing that truncation of Elp1p is an artifact occurring during protein extraction. Consequently, our results indicate that N-terminal truncation of Elp1p is not likely to regulate Elongator complex activity.
|
|
45. |
- Yanamandra, Kiran, 1977-, et al.
(author)
-
Amyloid formation by the pro-inflammatory S100A8/A9 proteins in the ageing prostate.
- 2009
-
In: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 4:5, s. e5562-
-
Journal article (peer-reviewed)abstract
- BACKGROUND: The conversion of soluble peptides and proteins into polymeric amyloid structures is a hallmark of many age-related degenerative disorders, including Alzheimer's disease, type II diabetes and a variety of systemic amyloidoses. We report here that amyloid formation is linked to another major age-related phenomenon--prostate tissue remodelling in middle-aged and elderly men. METHODOLOGY/PRINCIPAL FINDINGS: By using multidisciplinary analysis of corpora amylacea inclusions in prostate glands of patients diagnosed with prostate cancer we have revealed that their major components are the amyloid forms of S100A8 and S100A9 proteins associated with numerous inflammatory conditions and types of cancer. In prostate protease rich environment the amyloids are stabilized by dystrophic calcification and lateral thickening. We have demonstrated that material closely resembling CA can be produced from S100A8/A9 in vitro under native and acidic conditions and shows the characters of amyloids. This process is facilitated by calcium or zinc, both of which are abundant in ex vivo inclusions. These observations were supported by computational analysis of the S100A8/A9 calcium-dependent aggregation propensity profiles. We found DNA and proteins from Escherichia coli in CA bodies, suggesting that their formation is likely to be associated with bacterial infection. CA inclusions were also accompanied by the activation of macrophages and by an increase in the concentration of S100A8/A9 in the surrounding tissues, indicating inflammatory reactions. CONCLUSIONS/SIGNIFICANCE: These findings, taken together, suggest a link between bacterial infection, inflammation and amyloid deposition of pro-inflammatory proteins S100A8/A9 in the prostate gland, such that a self-perpetuating cycle can be triggered and may increase the risk of malignancy in the ageing prostate. The results provide strong support for the prediction that the generic ability of polypeptide chains to convert into amyloids could lead to their involvement in an increasing number of otherwise apparently unrelated diseases, particularly those associated with ageing.
|
|
46. |
- Zhang, Xueyang, et al.
(author)
-
Cellulose Synthase Stoichiometry in Aspen Differs from Arabidopsis and Norway Spruce
- 2018
-
In: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 177, s. 1096-1107
-
Journal article (peer-reviewed)abstract
- Cellulose is synthesized at the plasma membrane by cellulose synthase complexes (CSCs) containing cellulose synthases (CESAs). Genetic analysis and CESA isoform quantification indicate that cellulose in the secondary cell walls of Arabidopsis (Arabidopsis thaliana) is synthesized by isoforms CESA4, CESA7, and CESA8 in equimolar amounts. Here, we used quantitative proteomics to investigate whether the CSC model based on Arabidopsis secondary cell wall CESA stoichiometry can be applied to the angiosperm tree aspen (Populus tremula) and the gymnosperm tree Norway spruce (Picea abies). In the developing xylem of aspen, the secondary cell wall CESA stoichiometry was 3:2:1 for PtCESA8a/b:PtCESA4:PtCESA7a/b, while in Norway spruce, the stoichiometry was 1:1:1, as observed previously in Arabidopsis. Furthermore, in aspen tension wood, the secondary cell wall CESA stoichiometry changed to 8:3:1 for PtCESA8a/b:PtCESA4:PtCESA7a/b. PtCESA8b represented 73% of the total secondary cell wall CESA pool, and quantitative polymerase chain reaction analysis of CESA transcripts in cryosectioned tension wood revealed increased PtCESA8b expression during the formation of the cellulose-enriched gelatinous layer, while the transcripts of PtCESA4, PtCESA7a/b, and PtCESA8a decreased. A wide-angle x-ray scattering analysis showed that the shift in CESA stoichiometry in tension wood coincided with an increase in crystalline cellulose microfibril diameter, suggesting that the CSC CESA composition influences microfibril properties. The aspen CESA stoichiometry results raise the possibility of alternative CSC models and suggest that homomeric PtCESA8b complexes are responsible for cellulose biosynthesis in the gelatinous layer in tension wood.
|
|
47. |
- Zhu, Shaochun, et al.
(author)
-
Targeted Multiple Reaction Monitoring Analysis of CSF Identifies UCHL1 and GPNMB as Candidate Biomarkers for ALS
- 2019
-
In: Journal of Molecular Neuroscience. - : Springer. - 0895-8696 .- 1559-1166. ; 69:4, s. 643-657
-
Journal article (peer-reviewed)abstract
- The neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and Parkinson's disease (PD) share some common molecular deficits including disruption of protein homeostasis leading to disease-specific protein aggregation. While insoluble protein aggregates are the defining pathological confirmation of diagnosis, patient stratification based on early molecular etiologies may identify distinct subgroups within a clinical diagnosis that would respond differently in therapeutic development programs. We are developing targeted multiple reaction monitoring (MRM) mass spectrometry methods to rigorously quantify CSF proteins from known disease genes involved in lysosomal, ubiquitin-proteasomal, and autophagy pathways. Analysis of CSF from 21 PD, 21 ALS, and 25 control patients, rigorously matched for gender, age, and age of sample, revealed significant changes in peptide levels between PD, ALS, and control. In patients with PD, levels of two peptides for chromogranin B (CHGB, secretogranin 1) were significantly reduced. In CSF of patients with ALS, levels of two peptides from ubiquitin carboxy-terminal hydrolase like protein 1 (UCHL1) and one peptide each for glycoprotein non-metastatic melanoma protein B (GPNMB) and cathepsin D (CTSD) were all increased. Analysis of patients with ALS separated into two groups based on length of survival after CSF sampling revealed that the increases in GPNMB and UCHL1 were specific for short-lived ALS patients. While analysis of additional cohorts is required to validate these candidate biomarkers, this study suggests methods for stratification of ALS patients for clinical trials and identifies targets for drug efficacy measurements during therapeutic development.
|
|