| 1. |
- Baniol, Marion, et al.
(författare)
-
Identification and characterization of distinct cell cycle stages in cardiomyocytes using the FUCCI transgenic system
- 2021
-
Ingår i: Experimental Cell Research. - : Elsevier BV. - 0014-4827 .- 1090-2422. ; 408:2
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding the regulatory mechanism by which cardiomyocyte proliferation transitions to endoreplication and cell cycle arrest during the neonatal period is crucial for identifying proproliferative factors and developing regenerative therapies. We used a transgenic mouse model based on the fluorescent ubiquitination-based cell cycle indicator (FUCCI) system to isolate and characterize cycling cardiomyocytes at different cell cycle stages at a single-cell resolution. Single-cell transcriptome analysis of cycling and noncycling cardiomyocytes was performed at postnatal days 0 (P0) and 7 (P7). The FUCCI system proved to be efficient for the identification of cycling cardiomyocytes with the highest mitotic activity at birth, followed by a gradual decline in the number of cycling and mitotic cardiomyocytes during the neonatal period. Cardiomyocytes showed premature cell cycle exit at G1/S shortly after birth and delayed G1/S progression during endoreplication at P7. Single-cell RNA-seq confirmed previously described signaling pathways involved in cardiomyocyte proliferation (Erbb2 and Hippo/YAP), and maturation-related transcriptional changes during postnatal development, including the metabolic switch from glycolysis to fatty acid oxidation in cardiomyocytes. Importantly, we generated transcriptional profiles specific to cell division and endoreplication in cardiomyocytes at different developmental stages that may facilitate the identification of genes important for adult cardiomyocyte proliferation and heart regeneration. In conclusion, the FUCCI mouse provides a valuable system to study cardiomyocyte cell cycle activity at single cell resolution that can help to decipher the switch from cardiomyocyte proliferation to endoreplication, and to revert this process to facilitate endogenous repair.
|
|
| 2. |
- Bauer, Stefanie L., 1990-, et al.
(författare)
-
Sir2 and Reb1 antagonistically regulate nucleosome occupancy in subtelomeric X-elements and repress TERRAs by distinct mechanisms
- 2022
-
Ingår i: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 18:9
-
Tidskriftsartikel (refereegranskat)abstract
- Telomere chromatin structure is pivotal for maintaining genome stability by regulating the binding of telomere-associated proteins and inhibiting the DNA damage response. In Saccharomyces cerevisiae, silent information regulator (Sir) proteins bind to terminal repeats and to subtelomeric X-elements, resulting in transcriptional silencing. Herein, we show that sir2 mutant strains display a specific loss of a nucleosome residing in the X-elements and that this deficiency is remarkably consistent between different telomeres. The X-elements contain several binding sites for the transcription factor Reb1 and we found that Sir2 and Reb1 compete for stabilizing/destabilizing this nucleosome, i.e. inactivation of Reb1 in a sir2 background reinstated the lost nucleosome. The telomeric-repeat-containing RNAs (TERRAs) originate from subtelomeric regions and extend into the terminal repeats. Both Sir2 and Reb1 repress TERRAs and in a sir2 reb1 double mutant, TERRA levels increased synergistically, showing that Sir2 and Reb1 act in different pathways for repressing TERRAs. We present evidence that Reb1 restricts TERRAs by terminating transcription. Mapping the 5′-ends of TERRAs from several telomeres revealed that the Sir2-stabilized nucleosome is the first nucleosome downstream from the transcriptional start site for TERRAs. Finally, moving an X-element to a euchromatic locus changed nucleosome occupancy and positioning, demonstrating that X-element nucleosome structure is dependent on the local telomere environment.
|
|
| 3. |
- Bruhn-Olszewska, Bozena, et al.
(författare)
-
Loss of Y in leukocytes as a risk factor for critical COVID-19 in men.
- 2022
-
Ingår i: Genome medicine. - : Springer Science and Business Media LLC. - 1756-994X. ; 14:1
-
Tidskriftsartikel (refereegranskat)abstract
- The COVID-19 pandemic, which has a prominent social and economic impact worldwide, shows a largely unexplained male bias for the severity and mortality of the disease. Loss of chromosome Y (LOY) is a risk factor candidate in COVID-19 due to its prior association with many chronic age-related diseases, and its impact on immune gene transcription.Publicly available scRNA-seq data of PBMC samples derived from male patients critically ill with COVID-19 were reanalyzed, and LOY status was added to the annotated cells. We further studied LOY in whole blood for 211 COVID-19 patients treated at intensive care units (ICU) from the first and second waves of the pandemic. Of these, 139 patients were subject to cell sorting for LOY analysis in granulocytes, low-density neutrophils (LDNs), monocytes, and PBMCs.Reanalysis of available scRNA-seq data revealed LDNs and monocytes as the cell types most affected by LOY. Subsequently, DNA analysis indicated that 46%, 32%, and 29% of critically ill patients showed LOY above 5% cut-off in LDNs, granulocytes, and monocytes, respectively. Hence, the myeloid lineage that is crucial for the development of severe COVID-19 phenotype is affected by LOY. Moreover, LOY correlated with increasing WHO score (median difference 1.59%, 95% HDI 0.46% to 2.71%, p=0.025), death during ICU treatment (median difference 1.46%, 95% HDI 0.47% to 2.43%, p=0.0036), and history of vessel disease (median difference 2.16%, 95% HDI 0.74% to 3.7%, p=0.004), among other variables. In 16 recovered patients, sampled during ICU stay and 93-143 days later, LOY decreased significantly in whole blood and PBMCs. Furthermore, the number of LDNs at the recovery stage decreased dramatically (median difference 76.4 per 10,000 cell sorting events, 95% HDI 55.5 to 104, p=6e-11).We present a link between LOY and an acute, life-threatening infectious disease. Furthermore, this study highlights LOY as the most prominent clonal mutation affecting the myeloid cell lineage during emergency myelopoiesis. The correlation between LOY level and COVID-19 severity might suggest that this mutation affects the functions of monocytes and neutrophils, which could have consequences for male innate immunity.
|
|
| 4. |
- Celorio-Mancera, Maria de la Paz, et al.
(författare)
-
Larval transcriptomes reflect the evolutionary history of plant-insect associations
- 2023
-
Ingår i: Evolution. - : Oxford University Press (OUP). - 0014-3820 .- 1558-5646. ; 77:2, s. 519-533
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, we investigated whether patterns of gene expression in larvae feeding on different plants can explain important aspects of the evolution of insect-plant associations, such as phylogenetic conservatism of host use and re-colonization of ancestral hosts that have been lost from the host repertoire. To this end, we performed a phylogenetically informed study comparing the transcriptomes of 4 nymphalid butterfly species in Polygonia and the closely related genus Nymphalis. Larvae were reared on Urtica dioica, Salix spp., and Ribes spp. Plant-specific gene expression was found to be similar across butterfly species, even in the case of host plants that are no longer used by two of the butterfly species. These results suggest that plant-specific transcriptomes can be robust over evolutionary time. We propose that adaptations to particular larval food plants can profitably be understood as an evolved set of modules of co-expressed genes, promoting conservatism in host use and facilitating re-colonization. Moreover, we speculate that the degree of overlap between plant-specific transcriptomes may correlate with the strength of trade-offs between plants as resources and hence to the probability of colonizing hosts and complete host shifts.
|
|
| 5. |
- Gossing, Michael, 1982, et al.
(författare)
-
Impact of forced fatty acid synthesis on metabolism and physiology of Saccharomyces cerevisiae
- 2018
-
Ingår i: FEMS Yeast Research. - : Oxford University Press (OUP). - 1567-1356 .- 1567-1364. ; 18:8
-
Tidskriftsartikel (refereegranskat)abstract
- Nutrient sensing and signaling controls the cellular response to extracellular nutrients and intracellular metabolites. Nutrient-dependent regulation of metabolism ensures balanced energy production and expenditure. We show that disturbing energy balance by forcing fatty acid synthesis has profound impact on metabolism and physiology of the yeast cell. In addition to an expected increase in storage lipids, we observed increased β-oxidation and reduced amino acid biosynthesis, indicating increased activity of nutrient-sensitive kinase Snf1p. We also observed increased sensitivity to rapamycin as well as decreased ribosome biogenesis and translation, indicating reduced activity of nutrient-sensitive kinase target of rapamycin complex 1. Additionally, we detected increased levels of oxidative stress and lower levels of amino acids. This study provides detailed insight into cellular resource redistribution in response to forced fatty acid synthesis and enables optimized engineering of microbial lipid production.
|
|
| 6. |
- Kärblane, Kairi, et al.
(författare)
-
ABCE1 is a highly conserved RNA silencing suppressor
- 2015
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203 .- 1932-6203. ; 10:2
-
Tidskriftsartikel (refereegranskat)abstract
- ATP-binding cassette sub-family E member 1 (ABCE1) is a highly conserved protein among eukaryotes and archaea. Recent studies have identified ABCE1 as a ribosomerecycling factor important for translation termination in mammalian cells, yeast and also archaea. Here we report another conserved function of ABCE1. We have previously described AtRLI2, the homolog of ABCE1 in the plant Arabidopsis thaliana, as an endogenous suppressor of RNA silencing. In this study we show that this function is conserved: human ABCE1 is able to suppress RNA silencing in Nicotiana benthamiana plants, in mammalian HEK293 cells and in the worm Caenorhabditis elegans. Using co-immunoprecipitation and mass spectrometry, we found a number of potential ABCE1-interacting proteins that might support its function as an endogenous suppressor of RNA interference. The interactor candidates are associated with epigenetic regulation, transcription, RNA processing and mRNA surveillance. In addition, one of the identified proteins is translin, which together with its binding partner TRAX supports RNA interference.
|
|
| 7. |
- Lahtvee, Petri-Jaan, 1985, et al.
(författare)
-
Absolute Quantification of Protein and mRNA Abundances Demonstrate Variability in Gene-Specific Translation Efficiency in Yeast
- 2017
-
Ingår i: Cell Systems. - : Elsevier BV. - 2405-4712 .- 2405-4720. ; 4:5, s. 495-504.e5
-
Tidskriftsartikel (refereegranskat)abstract
- Protein synthesis is the most energy-consuming process in a proliferating cell, and understanding what controls protein abundances represents a key question in biology and biotechnology. We quantified absolute abundances of 5,354 mRNAs and 2,198 proteins in Saccharomyces cerevisiae under ten environmental conditions and protein turnover for 1,384 proteins under a reference condition. The overall correlation between mRNA and protein abundances across all conditions was low (0.46), but for differentially expressed proteins (n = 202), the median mRNA-protein correlation was 0.88. We used these data to model translation efficiencies and found that they vary more than 400-fold between genes. Non-linear regression analysis detected that mRNA abundance and translation elongation were the dominant factors controlling protein synthesis, explaining 61% and 15% of its variance. Metabolic flux balance analysis further showed that only mitochondrial fluxes were positively associated with changes at the transcript level. The present dataset represents a crucial expansion to the current resources for future studies on yeast physiology.
|
|
| 8. |
|
|
| 9. |
- Rhind, Nicholas, et al.
(författare)
-
Comparative Functional Genomics of the Fission Yeasts
- 2011
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 332:6032, s. 930-936
-
Tidskriftsartikel (refereegranskat)abstract
- The fission yeast clade-comprising Schizosaccharomyces pombe, S. octosporus, S. cryophilus, and S. japonicus-occupies the basal branch of Ascomycete fungi and is an important model of eukaryote biology. A comparative annotation of these genomes identified a near extinction of transposons and the associated innovation of transposon-free centromeres. Expression analysis established that meiotic genes are subject to antisense transcription during vegetative growth, which suggests a mechanism for their tight regulation. In addition, trans-acting regulators control new genes within the context of expanded functional modules for meiosis and stress response. Differences in gene content and regulation also explain why, unlike the budding yeast of Saccharomycotina, fission yeasts cannot use ethanol as a primary carbon source. These analyses elucidate the genome structure and gene regulation of fission yeast and provide tools for investigation across the Schizosaccharomyces clade.
|
|
| 10. |
- Smialowska, Agata, et al.
(författare)
-
RNAi mediates post-transcriptional repression of gene expression in fission yeast Schizosaccharomyces pombe
- 2014
-
Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 444:2, s. 254-259
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- RNA interference (RNAi) is a gene silencing mechanism conserved from fungi to mammals. Small interfering RNAs are products and mediators of the RNAi pathway and act as specificity factors in recruiting effector complexes. The Schizosaccharomyces pombe genome encodes one of each of the core RNAi proteins, Dicer, Argonaute and RNA-dependent RNA polymerase (dcr1, ago1, rdp1). Even though the function of RNAi in heterochromatin assembly in S. pombe is established, its role in controlling gene expression is elusive. Here, we report the identification of small RNAs mapped anti-sense to protein coding genes in fission yeast. We demonstrate that these genes are up-regulated at the protein level in RNAi mutants, while their mRNA levels are not significantly changed. We show that the repression by RNAi is not a result of heterochromatin formation. Thus, we conclude that RNAi is involved in post-transcriptional gene silencing in S. pombe.
|
|
