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Impact d'un stress viral sur la transcription des SINE d'Arabidopsis thaliana et influence de l'ARN SINE sur la kinase GCN2

Abstract : In mammals cells, adenovirus infection induces transcription of individual Alu loci. This mechanism is well-conserved and observed with other virus families. Adenovirus encodes a protein, E1A, capable of interacting with the retinoblastoma protein (RB). This interaction inactivates RB which probably leads to the transcriptional inactivation of Alu elements. Thus, in mammals, viral proteins can negatively regulate Rb and cause cell cycle deregulation, general pol III transcription and particularly SINE transcription. In plants, SINE transcriptional activation following viral stress is still to demonstrate. However, the FBNYV virus genome encodes a protein, CLINK, which contains a RB binding domain also found in the adenovirus protein E1A. The first step of this work was to analyze the CLINK protein and more precisely the impact of this protein on cell cycle deregulation, on general pol III transcription and particularly on endogenous plant SINE transcription. The second part of this study focuses on SINE elements functions within the cell. In mammals, SINE element Alu has been shown to modulate the cell physiology in response to stresses. Indeed, transcription of those elements is activated following some viral infections. Those transcripts are able to interact with the PKR protein, an eIF2α kinase. Thus, SINE elements are capable to modulate cellular functions such as translation regulation. Only one eIF2α kinase has been identified in plants: the GCN2 protein. Thus, we characterized the function of this protein in Arabidopsis. We shown mechanisms that regulate the protein function and also found some plant-specific inductors. This study has shown that GCN2 is important in plants and that this protein intervenes in some plant-specific stress pathway. Finally, SINE impact on GCN2 activity has been study in plants.
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Submitted on : Tuesday, September 11, 2012 - 5:07:49 PM
Last modification on : Tuesday, February 23, 2021 - 11:34:02 AM
Long-term archiving on: : Friday, December 16, 2016 - 11:59:05 AM

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  • HAL Id : tel-00731032, version 1

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Sébastien Lageix. Impact d'un stress viral sur la transcription des SINE d'Arabidopsis thaliana et influence de l'ARN SINE sur la kinase GCN2. Génétique des populations [q-bio.PE]. Université Blaise Pascal - Clermont-Ferrand II, 2008. Français. ⟨NNT : 2008CLF21872⟩. ⟨tel-00731032⟩

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