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Terminaison de la traduction et translecture chez Saccharomces cerevisiae

Abstract : Translation termination takes place when a stop codon enters the A site of the ribosome. eRF1p directly recognizes the stop codon and, in combination with eRF3p, it induces termination of translation. The nucleotide context of the stop codon can significantly modulate the efficiency of translation termination. A tRNA can therefore be efficiently incorporated by ribosomes if the stop codon is located in a " leaky " context. This event is called readthrough. I have demonstrated that a sequence of six nucleotides downstream of the stop codon is a key determinant of readthrough efficiency in Saccharomyces cerevisiae. The highest readthrough efficiency is observed with the degenerate motif -CA(A/G)N(T/C/G)A-. This work also highlights that readthrough events are not restricted to viral genes but also occur in nuclear genes. Moreover, gene expression can be regulated by means of a readthrough event under certain environmental conditions. In the case of the PDE2 gene, encoding the cAMP phosphodiesterase, the stability of the protein is controlled by a readthrough event which ultimately results in a modulation of the cAMP level in the cell. The increase of cAMP in a [PSI+] strain could be responsible for a large number of the [PSI+] phenotypes. Finally, screening of a multicopy genomic DNA library allowed us to identify new relationships between the cytoskeleton network and the translation termination mechanism. This work demonstrates that termination of translation can be used as a means to control expression of nuclear genes in S. cerevisiae.
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Contributor : Olivier Namy Connect in order to contact the contributor
Submitted on : Tuesday, September 20, 2005 - 10:31:02 PM
Last modification on : Saturday, July 3, 2021 - 3:39:25 AM
Long-term archiving on: : Friday, April 2, 2010 - 10:35:37 PM


  • HAL Id : tel-00010226, version 1


Olivier Namy. Terminaison de la traduction et translecture chez Saccharomces cerevisiae. Biologie cellulaire. Université Pierre et Marie Curie - Paris VI, 2001. Français. ⟨tel-00010226⟩



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