Thesis (MS)--University of Montana, 2007. / Contents viewed on March 26, 2010. Title from author supplied metadata. Includes bibliographical references.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009. / Title from title screen (site viewed January 12, 2010). PDF text: 164 p. : col. ill. ; 5 Mb. UMI publication number: AAT 3359465. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thesis (doctoral)--Karolinska Institutet, Stockholm, 1988. / Extra t.p. with thesis statement inserted. Includes bibliographical references.

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on April 6, 2010). Vita. Thesis advisor: Shivendra D. Shukla. "August 2008" Includes bibliographical references

Thesis (M.Med.Sc.)--University of Hong Kong, 2004. / Also available in print.

Thèse (M.Sc.)--Université Laval, 2002. / Bibliogr.: f. 74-89. Publié aussi en version électronique.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (sites viewed on August 10, 2006). PDF text of dissertation: 98 p. : ill. ; 1.16Mb. UMI publication number: AAT 3208087. Includes bibliographical references. Also available in microfilm, microfiche and paper format.

No description available.

Analyser les modalités de l'interaction des virus neurotropes avec leurs cellules cibles représente un défi majeur, cela pourrait favoriser notre compréhension de la physiopathologie de certains troubles neurologiques dont l'origine virale est parfois suspectée. Le Bornavirus (BDV), un virus neurotrope, représente un modèle idéal pour analyser les mécanismes moléculaires de la persistance virale dans les neurones et en étudier les conséquences sur l'homéostasie neuronale. Au cours de ma thèse, nous avons découvert une nouvelle forme d'interaction virus/cellule dans laquelle une protéine du BDV perturbe la signalisation épigénétique associée à l'acétylation des histones. Cette perturbation de l'acétylation des histones cellulaires est accompagnée d'une modulation de la réplication virale qui permettrait de favoriser la persistance du BDV dans les neurones tout en limitant les dommages cellulaires associés, démontrant ainsi la parfaite adaptation du BDV à sa cellule hôte. / In response to various environmental stimuli, neurons undertake specific cognitive functions, such as learning and memory. Many studies have shown that epigenetics, notably histone acetylation, is crucial for the regulation of gene expression involved in these processes. Moreover, dysregulation of signaling pathways that regulate epigenetics is clearly recognized as a main actor in the pathogenesis of several neurological disorders. Even if the origin of these disorders is sometimes genetic, their etiology remains elusive and environmental factors are also suspected. In particular, infectious agents are considered as serious candidates, notably for viruses that persist in the central nervous system (CNS). The Bornavirus (BDV) constitutes an interesting model to assess the impact of viral infection on neuronal epigenetics. This non-cytolytic RNA virus infects neurons of the CNS and causes various cognitive disorders in animals. It has the remarkable property to replicate in the nucleus, in close association with chromatin, thus leading to our working hypothesis that it may modify the epigenetics of infected neurons. During my Ph.D., we used primary cultures of cortical neurons to demonstrate that BDV infection decreases H2B and H4 acetylation levels on selected lysine residues, through inhibition of histone acetyltransferase (HAT) activities. We also showed that the viral phosphoprotein was responsible for this perturbation, acting on histone acetylation and HAT activities in a protein kinase C dependent manner. Finally, using pharmacological agents, we observed that histone acetylation levels were correlated with replication of BDV. Thus, BDV action on histone acetylation pathway may represent an original mechanism to control viral replication, thereby favoring long-term persistence in neurons. I am currently examining the consequences of this virus-mediated perturbation on H2B/H4 acetylation at the genome scale, using ChIP-sequencing experiments.

Histones are the basic proteins complexed with DNA in the chromosomes of eukaryotic organisms. A previously undescribed histone (histone T.) was discovered in chromatin prepared from rainbow trout (Salmo gairdnerii) testes. Histone T was purified by selective extraction and ion-exchange chromatography on CM-cellulose. The homogeneity of this protein was examined by polyacrylamide disc gel electrophoresis, SDS disc gel electrophoresis, urea starch gel electrophoresis and gel filtration chromatography. Histone T was homogeneous as judged by the above different criteria. The molecular weight was found to be 14,500 by the mobility of formylated or acetylated histone Ton SDS gel electrophoresis. The amino acid composition and the N-terminal amino acid were determined. Peptide maps of the tryptic peptides of histone T and the major histones indicated that histone T is not a degradation product of the major histones. Details of the mechanism of initiation of protein synthesis in eukaryotes have only recently been discovered. Protamines are the small, highly basic proteins complexed with DNA in the mature sperm cells of most higher animals. The synthesis of protamine in trout testes was studied. Cell suspensions prepared from trout testes at the protamine stage of differentiation were incubated in vitro and were found to incorporate intact, isotopically labelled methionine into the N-terminal sequence, Met-Pro-Arg..., methionine residue is removed from protamine after chain completion. Enzymatic activity capable of cleaving the dipeptide, Met-Pro, was found in testis cell fractions. The amino group of methionine incorporated into ribosome-bound nascent protamine was not blocked. Methionine incorporation was extremely sensitive to inhibition by cyclo-heximide. The evidence obtained indicates a role for methionine in the initiation of protamine biosynthesis in the trout, a eukaryote / Medicine, Faculty of / Medical Genetics, Department of / Graduate