The SFP1 Controls Translation Termination in Saccharomyces cerevisiae via Regulation of Sup35p (eRF3) Level

摘要

Translation termination in yeast performed by Sup45 (eRFI) and Sup35 (eRF3) proteins is a subject to complicated genetic control. Among the potential candidate genes that participate in regulation of translation termination, SFPl encodes the global transcription factor Sfplp. The data obtained earlier in our work indicate that SFPl deletion causes a weak nonsense suppression mediated by a decrease in Sup35p amount. In this work, we performed a further study of mechanism by which SFPl regulates translation termination efficiency. With this aim, effects of SFPl overexpression on manifestation of SUP45 mutations that disturb termination and cause nonsense suppression, and on Sup35p and Sup45p production were studied. It was shown that SFPl overexpression causes a specific phenotypic change in mutants and increases the termination efficiency. Notably, the Sup45p amount in strains overexpressing SFPl is not altered, while Sup35p amount increases. Thus, we may state that SFPl participates in the control of translation termination by means of regulation of Sup35p level.