TAVENET Arounie
University : Paris XI Orsay
Jury :
- Président :Pr. Gautheret D.
- Rapporteurs : Drs Devaux F. et Teichmann M.
- Examinateurs : Drs Morillon A. et Lesage P.
- Directeur de thèse : Dr Acker J.
Summary
RNA polymerase III synthetizes many small untranslated RNA, including tRNA and 5S rRNA which are essential to cell growth. In this work, we took an interest in RNA polymerase III transcription regulation in the baker's yeast, Saccharomyces cerevisiae. We have detected Sub1 on all class III genes in vivo. We also observed that Sub1 is able to stimulate RNA polymerase III transcription which has been reconstituted in vitro with TFIIIB et TFIIIC recombinants factors and purified RNA polymerase III. Sub1 stimulates two steps of RNA polymerase III transcription : initiation and facilitated reinitiation. Supplementary experiments established that Sub1 directly interacts with TFIIIB and TFIIIC transcription factors. Finally, we showed that Sub1 deletion in yeast leads to a decrease in RNA polymerase III transcription during exponential phase. Then, we tried to determine which link could exist between Sub1, the activator, and Maf1, the repressor of RNA polymerase III transcription. Furthermore, we attempted to identify other elements which could interact with Sub1 during transcription regulation.
Key words : Sub1, RNA polymerase III, Maf1, regulation of transcription