| 1. |
- Ahlqvist, Margary
(författare)
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Peripheral venous catheters : quality of care assessment
- 2010
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- About half of the patients admitted to hospitals receive intravenous therapy through peripheral venous catheters (PVCs). Unfortunately, the use of PVCs is associated with the risk of complications that may lead to increased morbidity and prolonged hospitalisation. Because of the frequent use of PVCs and the risk of PVC-related complications, there are good reasons to assess quality of care. The overall aim of this study was to attain increased knowledge about PVC documentation in the patient s medical record and to develop methods for assessment of inserted PVCs. Patients were recruited on medical and surgical wards at two emergency hospitals (Study I) and at one university hospital (Study I, II). A convenient sample of 933 adult inpatients with PVCs inserted into a vein on their upper extremity was included in study I. A study-specific data collection form was used for bedside registration of PVC insertion site, hand side, lumen size, patient s age and gender. The post-insertion documentation of the same PVCs was checked in patient medical record and recorded. The data were descriptively analysed via frequency distribution and factors associated with PVC documentation were examined using univariate and multivariate logistic regression analysis. Results showed that 10 descriptions could be used to explain PVC insertion site. Any kind of PVC documentation was found in 72% of the patients medical records. Notes that included information on insertion site, hand side and lumen size were identified in 46%. Documentation, including the latter three variables, was significantly associated with medical wards at general hospitals and smaller lumen size. A PVC assessment tool (PVC ASSESS) was developed through confirmation of content validity, evaluation of face validity, inter-rater and test-retest reliability (Study II). The tool consists of three sections: PVC management, signs and symptoms of PVC-related thrombophlebitis and PVC documentation. To test the reliability two groups of registered nurses (RNs) (Study II) and nursing students (NSs) (Thesis) used the tool to perform PVC assessments on 67 PVCs on actual patients at bedside (inter-rater reliability). Two other groups of RNs and NSs assessed 67 PVC photographs taken concurrently with the bedside assessments (test-retest reliability). The tool s reliability was evaluated by calculation of proportion of agreement and Cohen s unweighted kappa coefficient (κ) among the RNs and NSs. The inter-rater reliability (κ) ranged from moderate to almost perfect in 93% and 81% of the tested items among RNs and NSs, respectively. Test-retest reliability (κ) ranged between moderate and almost perfect in 95-100% of the items tested among RNs and in 90-95% among NSs. In conclusion, the findings imply the need for education of RNs in PVC documentation and development of terms for documentation of PVC insertion site. The reliability of the PVC ASSESS instrument is considered satisfactory and of relevance for use in research and clinical audits.
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| 2. |
- Ali, Zeina M F
(författare)
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Side-chain oxidized oxysterols as metabolic regulators in liver and brain
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Oxysterols are oxygenated derivatives of cholesterol characterized by a very short half-life and their ability to pass lipophilic membranes easily, thus they are considered as important intermediates in cholesterol excretion pathways and its conversion to bile acids. The two major oxysterols in the circulation of human and mouse are 24S-hydroxycholesterol (24S-OH) and 27-hydroxycholesterol (27-OH), which are formed by the cytochrome P450 enzymes cholesterol 24-hydroxylase (CYP46A1) and sterol 27-hydroxylase (CYP27A1), respectively. The two oxysterols 27-OH and 24S-OH are both strong inhibitors of cholesterol synthesis and activators of LXR in vitro. However, their role as physio- logical regulators under in vivo conditions is controversial. The overall aim of this thesis was to investigate the regulatory role of side chain oxidized oxysterols as metabolic regulators in vivo. In particular we have studied the role of 24S-and 27-hydroxycholesterols (24S- and 27-OH) as regulators of cholesterol synthesis and activators of LXR. We used mouse models with increased levels of 27-OH (CYP27A1) transgenic mice and Cyp7b1 knock-out mice (Cyp7b1-/-) as well as a mouse model with no detectable levels of 27-OH in their circulation, Cyp27a1 knock-out mice (Cyp 27-/-). The latter mice were treated with cholic acid to compensate for the reduced formation of bile acids. In Paper I, we studied a possible regulatory role of 27-OH and 24S-OH in the brain using human CYP27A1 transgenic mice(CYP27A1tg) and Cyp27a1 knock-out (Cyp 27a1-/-) mice. The levels of 27-OH were increased about 12-fold in the brain of CYP27A1tg mice while the levels of 24S-OH was decreased by about 25%, most probably due to increased metabolism by the CYP27A1 enzyme. The mRNA levels of HMG-CoA reductase and HMG-CoA synthase in the brain were increased. In accordance with increased cholesterol synthesis, most of cholesterol precursors were also increased. The increased cholesterol synthesis is likely due to reduced inhibition by 24S-OH. 27-OH is an activator of LXR and in spite of this, there was no upregulation of the LXR-target genes in the brain of the transgenic mice. In contrast, some of the genes were downregulated. In Cyp27a1-/- mouse brain, cholesterol synthesis was slightly increased with increased levels of cholesterol precursors. The increased synthesis is probably the consequence of the absence of an inhibitory effect of the flux of 27-OH into the brain. The results of this study are consistent with the possibility that both 24S-OH and 27-OH have a suppressive effect on cholesterol synthesis in the brain. Since there was no activation of the LXR-target genes in the brain of the transgenic mice, we concluded that 27-OH is not a general activator of LXR in the brain. In Paper II, this study has examined the role of 27-OH in the liver using the above three mouse models. In the liver of CYP27A1tg mice we found a modest increase of the mRNA levels corresponding to the LXR target genes Cyp7b1, and Abca1. There was no effect on a number of other LXR-regulated genes. There were no significant effects on cholesterol synthesis at the transcriptional level and cholesterol precursors were not affected as well. However, there was a modest decrease in T-MAS levels in the liver of CYP27A1tg mice. In the liver of the Cyp7b1-/-mice, there were also no effects on cholesterol synthesis neither at the transcriptional level nor in the levels of cholesterol precursors, with the exception of increase in desmosterol. In connection to the LXR-target genes in these mice, there were no differences in the expression between the Cyp7b1-/- and the wild type mice. If the high levels of 27-OH are important, the same effects would be expected in the two mouse models. In the liver of the Cyp27a1-/- mice there was a slight activation of some LXR- regulated genes, Abcg5, Abcg8, Fas and Srebp1c. If 27-OH is of importance as a normal activator of the above genes a suppressing effect would be expected. The overall results do not support the contention that 27-OH is an important regulator of cholesterol homeostasis or an activator of LXR-regulated genes under basal conditions in the liver. In conclusion our results suggest that both 24S-OH and 27-OH may be of some regulatory importance for cholesterol synthesis in the brain but not in the liver. Under normal basal conditions 27-OH does not seem to be a general activator of LXR neither in the brain nor in the liver. The different effects on cholesterol synthesis in the two organs may be related to the fact that almost all oxysterols in the brain are in the free form whereas most of them are esterified in the liver.
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| 3. |
- Alvarez-Corrales, Nancy Montserrat
(författare)
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Immune responses against Mycobacterium tuberculosis targets associated to latent and active tuberculosis infection
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Tuberculosis is a worldwide problem particularly in developing countries. Different clinical outcomes, such as the asymptomatic phase during infection or the symptomatic stage during active disease leads to activation and expansion of cellular immune responses in order to control the infection. This process of latency and active TB infection is a highly dynamic interaction between the host and the immunogenicity of M.tb. The detailed antigen specific analysis of the M.tb host response will likely lead to a better understanding of the pathogenesis of TB in human subjects and may help to identify markers of immune protection. There is a need to develop an effective TB vaccine and biomarkers of protection. Currently, different TB vaccine candidates contain M.tb components that are able to induce T cell activation and subsequent IFN-γ release. For instance, TB10.4 is such a novel vaccine candidate, it is highly immunogenic and present in M.tb and in the BCG vaccine strain. We characterized immune recognition patterns from Honduran patients with TB with a particularly focus on TB10.4 in order to better understand the infection biology, heterologous immune responses and the role of memory T cell formation. Aims: i) Defining and comparing M.tb specific immune responses in individuals with active and latent tuberculosis infection using cell based immune assays and a panel of specific M.tb target antigens; ii) Characterization of the recognition pattern of the humoral and cellular responses towards TB10.4 (Rv0288); and iii) Studying the relationship between molecular mimicry and tuberculosis using TB10.4 as a paradigm. Methodology: We selected a clinically well-defined population in order to perform cell- based immune assays (i.e Interferon gamma release assay), microarray peptide technology, and a bioplex assay, to gauge immune responses against a panel of recombinant or synthetic M.tb target antigens. Results and discussion: Paper I. This work represents the first analysis of cellular immune responses directed against M.tb associated targets in individuals from Honduras and provides a robust concept for identification of TB targets; we were able to identify differential target recognition patterns in TB+ patients vs TB exposed health care workers. Comprehensive pattern recognition analysis using biologically relevant targets revealed that enzymes involved in M.tb lipid synthesis serve as targets for T cells, defined by IFN-γ and IL-17 production. Paper II. We mapped humoral and cellular immune responses against the TB10.4 protein in non-human primates (NHPs) as well as in TB patients from Honduras. Immune responses in NHP were very focused, in contrast toTB10.4 directed immune responses in humans. We postulated that cross recognition of closely related antigens could be one possible explanation. The report shows substantial differences in cellular recognition comparing NHP and human immune responses. This T cell responses may be sustained via cross reactive immune responses recognizing the TB10.4 target and non-M.tb related target antigens.
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| 4. |
- Amin, Risul
(författare)
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Renal Klotho in mineral metabolism
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Calcium and phosphorous are critical elements in a number of physiological processes, including maintenance of bone structure, cell signaling and energy metabolism. Their endocrine regulation is tightly controlled through a number of feedback mechanisms involving parathyroid hormone (PTH), vitamin D and the recently discovered fibroblast growth factor 23 (FGF23). The kidney is a key organ in maintaining normal serum levels of calcium and inorganic phosphorous, and disturbances in mineral metabolism are commonly observed in patients with chronic kidney disease (CKD). Klotho is a membrane-bound protein expressed in the renal tubules that acts as a co-receptor for FGF23. In addition, Klotho can be shedded from the cell surface to extra-cellular compartments and function as a hormone with effects on mineral metabolism independent of FGF23. During the progression of CKD the expression of Klotho rapidly declines, and accumulating evidence point to lack of Klotho as a pathogenic factor driving clinical complications in CKD. The main focus of this thesis has been to elucidate the role of renal Klotho in mineral metabolism and on systemic effects. In Study I we generated distal tubule-specific Klotho knockout mice (Ksp-KL-/-) by employing cre-lox recombination. Ksp-KL-/- mice were hyperphosphatemic with elevated serum Fgf23 levels, indicating that distal tubular Klotho affects phosphate reabsorption in the proximal tubules. The exact mechanism of this proposed distal-toproximal tubular signaling remains unknown. In Study II we generated mice with Klotho deleted throughout the nephron (Six2-KL-/- ). Six2-KL-/- mice were infertile, kyphotic, growth retarded and had a decreased life span, closely resembling the phenotype seen in systemic Klotho knockout mice. Also the serum and urine biochemistries, low serum Klotho levels as well as profound histological abnormalities were indistinguishable from systemic Klotho knockout mice, unraveling the kidney as the principle contributor to circulating Klotho and mediator of Klotho anti-ageing traits. Taken together, the studies presented in this licentiate thesis substantially contribute to the understanding of renal Klotho function.
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| 5. |
- Anania, Cristina
(författare)
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Studies of atherosclerosis in systemic lupus erythematosus
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The role of inflammation in the development of atherosclerosis is now accepted and a focus of many studies because of its complex mechanisms. The risk of cardiovascular disease (CVD) and atherosclerosis is reported to be increased in systemic lupus erythematosus (SLE), especially in the group of young women. The introduction of statins in the 1990’s lowered considerably the morbidity and mortality in CVD. In the last decade, research efforts were concentrated on the immunological mechanisms of atherosclerosis and on the possibility to influence these mechanisms. Our group recently reported a negative association between natural IgM-antibodies against phosphorylcholine (IgM anti-PC) and CVD outcome in the general population. Potential mechanisms considered include anti-inflammatory properties and inhibition of uptake of oxidized low density lipoprotein (oxLDL) in macrophages. The objective herein was to study mechanisms of atherosclerosis in SLE and the relation to traditional and non-traditional risk factors in an SLE cohort, in comparison with an age and sex matched control group. As systemic endothelial dysfunction is one of the earliest signs of atherosclerosis in the general population, we also assessed skin microvascular endothelial function in SLE patients and controls. A total of 114 patients with SLE were compared with 122 age and sex-matched population-based controls. Common carotid intima-media thickness (IMT), calculated intima-media area (cIMa) and plaque occurrence were determined by B-mode ultrasound. Plaques were graded according to echogenicity. Anti-PC was assessed by enzyme-linked immunosorbent assay (ELISA). Endothelial function in skin was tested with local application of acetylcholine (ACh) and any concomitant increase in skin perfusion was measured with Laser Doppler Fluxmetry (LDF) in 84 of the SLE-patients and 81 of the age- and sex-matched controls. Incidence of hypertension, presence of insulin resistance (determined by homeostasis model assessment of insulin resistance, HOMA-IR) and the levels of triglycerides and C-reactive protein (CRP) were increased in the SLE patients, while smoking, cholesterol and high density lipoprotein (HDL) did not differ from controls. Low levels of IgM anti-PC were more common in the SLE patients than in the controls. IMT and cIMa did not differ significantly between groups. However, plaques were more often found in the SLE patients. Age, LDL and IgM anti-PC were independently associated with plaque occurrence in the SLE patients. Furthermore, in the left carotid arteries echolucent plaques were more prevalent in SLE when compared to controls. There were no significant differences in skin microvascular endothelial function between SLE patients and controls. In the SLE group, endothelial function did not vary in relation to presence of skin manifestations, Raynaud’s phenomenon, nephritis or plaque occurrence. In SLE patients with CVD, however, endothelial function was impaired. Conclusion: Plaque occurrence in the carotid arteries was increased in SLE and was independently associated with age, LDL and low anti-PC levels. Vulnerable plaques were more common in SLE than in controls. Anti-PC could be a novel risk marker for atherosclerosis with therapeutic potential in SLE. Skin microvascular endothelial function was associated with CVD but not with early signs of atherosclerosis in SLE-patients. The endothelial function was not different in SLE-patients, as compared to controls.
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| 6. |
- Berg Doukkali, Eva
(författare)
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Life after childhood cancer
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Young people who have undergone treatment for childhood cancer have a high risk of developing chronic health problems that could have a potential strong impact on their lives. How a childhood cancer experience affects the lives of young survivors has only been studied to a limited extent. The overall aim was therefore to investigate how adolescent and young adult survivors of childhood cancer perceive that their lives are affected by having had cancer. In study I, the aim was to gain a deeper understanding of how childhood cancer affects the lives of survivors by exploring adolescents’ and young adults’ views of what it is like living with this experience. In study II, the aim was to describe quality of life in relation to self-reported health status and socio-demographic characteristics among long-term survivors of childhood cancer as compared to that among a sample from the general population. The thesis includes two studies using cross-sectional designs, drawing on data from two different samples based on interview and survey data. In study I, 59 young survivors (12-22 years) were interviewed a median of five years after diagnosis (response rate 66%), and the interviews were analysed with qualitative content analysis. In study II, 246 long-term survivors (18-35 years) were interviewed a median of 16 years after diagnosis (response rate 64%), as well as 296 randomly selected controls (response rate 51%). Quality of life was assessed using the Schedule for the Evaluation of Individual Quality of Life- Direct Weighting (SEIQoL-DW) and self-reported health status was assessed using the Short Form Health Survey (SF-36). The results from study I revealed that the young survivors of childhood cancer could be divided into three groups depending on how they perceived having had cancer affected their current lives: ‘Feeling like anyone else’ (the informants who described that the cancer experience had almost no influence on their current life) (49%), ‘Feeling almost like others’ (those who described some influence) (44%) and ‘Feeling different’ (those describing a great influence on current life) (7%). The results from study II showed that long-term survivors rated their overall quality of life and self-reported health status almost in parity with the comparison group. In both groups, family life, relations to other people, work and career, interests and leisure activities were the areas most frequently reported to influence quality of life. The long-term survivors only differed from the comparison group on one of eight SF-36 scales, which reflected problems with daily activities owing to physical health. In conclusion, survivors appear to get along well after treatment for childhood cancer, although many informants described lives that were to some extent affected by having had cancer. To meet the needs of young survivors who perceive that the cancer experience to a large extent influences daily life and may find the health impairments hindering, follow-up care should be able to identify those having trouble in daily life and offer them support to strengthen their resources and ability achieve a good quality of life.
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| 7. |
- Bonilla, Carolina
(författare)
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Studies of histone modification systems in Schizosaccharomyces pombe
- 2010
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The genetic information in every cell is carried in the DNA. In eukaryotes the DNA is wrapped twice around proteins called histones forming a repeating unit called the nucleosome, in fibers known as chromatin. Nucleosomes are folded into higher order structures forming the chromosomes. The chromatin can be more or less compacted, controlling the accessibility of the DNA to ensure correct gene expression. Histones have long N-terminal tails, which can be covalently modified by different modifying enzymes. Different types of histone modifications are linked to the different functional properties of chromatin. In this thesis we have studied three histone modification systems in the model organism Schizosaccharomyces pombe (fission yeast). In paper I, the Rpb7 subunit of the RNA Pol II polymerase function is analyzed in cells with a missense mutation in the rpb7 gene (rpb7-G150D). Chromatin Immunoprecipitation showed decreased levels of methylation of histone H3 at lysine 9 (H3K9me2), heterochromatin protein Swi6 and cohesin Rad21, which is the cause of lagging chromosomes and defects in chromosome segregation in rpb7-G150D. Analysis of centromeric forward and reverse pre-siRNA transcripts showed accumulation in the dcr1delta mutant. In rpb7-G150D the reverse transcripts decreased to 25% of wild type levels. In the double mutant dcr1delta/rpb7-G150D the reverse transcript levels remained low indicating that Rpb7 functions upstream of Dcr1 in the RNAi pathway that maintains the H3K9me2 in heterochromatin. More specifically, we show that Rpb7 is required for initiation of pre-siRNA transcription in this pathway. In paper II, we show that the amino-oxidase family demethylases Lsd1 and Lsd2 from fission yeast are able to demethylate H3K9 but not H3K4 in vitro. Microarray studies showed increased H3K9me2 in 8,2% of the genes both in promoter and coding regions in the lsd1delta knock-out and 3,8% of the genes also showed increased H3K4me2 in promoter regions. These genes also tend to become upregulated in lsd1delta. Conversely, the down-regulated genes in lsd1delta showed increased levels of H3K9me2, consistent with the notion that H3K9me2 is needed for gene repression and silencing. Our data also suggest that Lsd1 and the HDAC Clr6 cooperate to repression of genes. Thus, Lsd1 seems to have demethylase activity at both H3K4 and K9 in vivo but in vitro only K9me activity was detected, suggesting that additional factors are directing Lsd1 specificity in vivo. In paper III, we found that Pst3, one of the three Sin3 homologs in fission yeast, is localized to the entire nuclear space, including the nucleolar core. The deletion of the pst3+ gene affects genome stability, and causes sporulation defects, altered nucleolar structure and chomosome mis-segregation. Our data indicate that genome stability requires an established heterochromatic environment at rDNA repeats maintained by the Clr6 HDAC and Pst3. Pst3 co-purifies with two different Clr6 multi-protein complexes, suggesting that Clr6 HDAC complexes are dynamic. We show that Pst3 is associated with rDNA chromatin and is involved in rDNA silencing. Interestingly, Pst3 is specifically required for repression of endogenous Pol II mediated non-coding RNA transcripts within the rDNA spacer region.
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| 8. |
- Borg, Paula
(författare)
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Plasticity of salamander skeletal muscle cells
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Regeneration is unevenly spread throughout the animal kingdom. Some of the invertebrates have a very high regenerative capacity but the capacity to replace lost or damaged tissues in mammals is limited. Among the vertebrates, the aquatic salamanders are the champions of regeneration, being able to regenerate body parts such as their limbs, tail, and jaw. Understanding the cell- and molecular machinery underlying these events can in the end lead to improvements in the field of regenerative medicine. When a salamander limb is amputated, a so called blastema is formed at the tip of the stump. This is a mesenchymal growth zone, from where the cells for the new limb originate. The skeletal muscle is believed to contribute to the blastema and the newly formed limb during regeneration in salamanders. There are two possible mechanisms by which this could occur. First, the muscle reserve cells, satellite cells, become activated, and after subsequent expansion they incorporate in to the blastema. Second, the multinucleated muscle cell dedifferentiates in a cellularization process, forming several new progenitor cells that contribute to the regenerate. These two mechanisms are the subjects of study in this thesis. In the first paper, satellite cells were monitored during the regeneration of the salamander limb. The satellite cell population was found to be restored after several rounds of amputation/regeneration, demonstrating a robust mechanism to replenish this cell population. By genetically labeling satellite cell progeny with GFP, cells were traced during limb regeneration. The labeled cells were found to contribute to cartilage tissue as well as to muscle, suggesting that they have lineage switching potential. The satellite cell marker Pax7 was rapidly down regulated in the blastema, indicating that the blastema has a reprogramming activity. In the second paper, the link between injury and dedifferentiation of muscle was explored. Previously it was shown that the skeletal muscle fiber must suffer a direct cellular injury in order to dedifferentiate in vivo. This led us to hypothesize that a programmed cell death response initiated by the injury, is linked to the dedifferentiation of this cell type. In order to investigate this, cellular events were examined after treating the cells with a known cellularization inducer called myoseverin, and pro-apoptotic drugs. The responses after these treatments were found to be similar, they both evoked cellularization of the muscle cells, and this was preceded by features of an activated apoptotic machinery. By inhibiting the intrinsic pathway of the apoptotic machinery, cellularization was inhibited. Finally, dedifferentiated progeny generated by pro-apoptotic stimuli was found to be capable of reentering the cell cycle and proliferate. Together these results indicate that the injury is directly linked to dedifferentiation through the apoptotic machinery.
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| 9. |
- Bosdotter, Cecilia
(författare)
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Signaling via the bHLH-PAS proteins AhR and HIF
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis concerns some mechanistic properties of the basic helix-loop-helix/PAS (bHLH-PAS) factors aryl hydrocarbon receptor (AhR) and hypoxia-inducible factor 1 alpha (HIF-1α). The bHLH-PAS family of proteins is a family of factors that controls a variety of developmental and physiological events. A common feature for this family of proteins is that they act mainly as intracellular transcription factors. They bind to DNA as a heterodimeric complex, usually together with a bHLH-PAS protein belonging to the aryl hydrocarbon receptor nuclear translocator (ARNT) subfamily. The AhR bind ligands that are environmental pollutants, as well as possibly physiological compounds occurring in the diet. Known functions of the ligand-activated AhR include activation of genes involved in xenobiotic metabolism and an ubiquitin ligase activity targeting nuclear receptors (such as the estrogen receptor) and beta-catenin. HIF-1α mediates signal transduction and gene regulation in cells exposed to deprived oxygen conditions (hypoxia). In paper I, we have shown that the Ah-receptor can be activated by stimulus other than xenobiotics, e.g dioxin. AhR is recruited to target genes in both ligand treated and in suspension culture, suggesting a common mechanism of activation between these two routes of AhR activation. The gene expression profiles critically differ between xenobiotic and suspension activated AhR signaling. The classical xenobiotic metabolizing AhR targets such as Cyp 1a1, Cyp 1b1 and Nqo were regulated by both ligand and suspension conditions. Sequence analysis coupled with ChIP assays and reporter gene analysis identified a functional xenobiotic response element (XRE) within the mouse TIPARP gene that features a concatamer of 4 XRE cores residing in the first intron. In paper II we have shown that ectopic expression of ARNT, in mammalian cells and yeast cells, was sufficient to promote nuclear accumulation of the Ah-receptor in a ligand-independent manner. We further observed that overexpression of ARNT promotes derepression of Ah-receptor function in the absence of ligand, thereby possibly representing an alternative mechanism of activation that is distinct from activation by xenobiotic ligands and thus may be of physiological relevance. We also describe that an excess of ARNT in relation to the Ah-receptor and HIF-1α promotes derepression of the receptor and stabilization of HIF-1α in vivo and in vitro, representing a possible alternative mechanism of activation of bHLH-PAS proteins.
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| 10. |
- Crafoord, Ellinor
(författare)
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Functional interaction studies of different transmembrane proteins, activities occurring in the pore membrane and in the inner nuclear membrane
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Aim: The overall aim of my research has been to investigate protein‐protein interactions of nuclear envelope proteins. One specific aim has been to study the effect of mitotic phosphorylation on binding of the pore membrane protein gp210 to the nuclear pore complex. The second specific aim has been to identify binding partners to the INM protein Samp1. Conclusions: Paper I) Phosphomimetic substitution of Ser1880 to Glu of gp210 compromises its interaction with the NPC; Phosphomimetic substitution of Ser1880 to Glu of gp210 hinders its recruitment to the reforming NPC; and The results support a model where phosphorylation plays a direct role in the disassembly the NPC during mitosis. Paper II) We have developed a cross‐link immunoprecipitation protocol for transmembrane proteins in vivo; Using crosslink immunoprecipitation we show that Samp1 interacts with the INM protein Emerin in vivo; Using crosslink immunoprecipitation we show that Sun1 and Samp1 interact in vivo; and Using crosslink immunoprecipitation we show an in vivo interaction between Ran and Samp1 at the INM.
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