Analysis of the functional relationship between eIF5A and the transcription factor Hac1 in Saccharomyces cerevisiae

Abstract

The eukaryotic initiation fator 5A (eIF5A) is highly conserved in Archaea and mammals. This factor undergoes a unique and specific post-translational modification called hypusination. Although it was initially suggested a function for eIF5A in the translation initiation, it was in the elongation step that eIF5A was better demonstrated. Recent data from our group revealed a possible role for eIF5A in the secretory pathway and Endoplasmic Reticulum (ER) stress response, suggesting an involvement for eIF5A on the translation of specific mRNAs related to these pathways. The transcription factor Hac1 is the major element of the Unfolded Protein Response (UPR), a classic via activated after ER stress. In order to study the biological role of eIF5A and its possible mechanism in the specific translation, it is proposed to evaluate the functional relation between eIF5A and the UPR elements as Hac1 and Ire1, in Saccharomyces cerevisiae. Initially, it will be evaluated the level of mRNA Hac1, before and after activation, and Ire1 in different strains including eIF5A mutants. Genetic interactions between mutants of TIF51A and genes coding to different elements of UPR will be also screened searching for a functional role for eIF5A in the specific translation. Finally, the analysis of Hac1-GFP and Ire1-GFP localization in eIF5A mutants will help for the understanding of the role of eIF5A in the ER stress response. (AU)