INO1 induction requires chromatin remodelers Ino80p and Snf2p but not the histone acetylases.

Transcriptional co-activators contribute to gene expression through different mechanisms. We used various biochemical tools available for Saccharomyces cerevisiae to examine the mechanism of INO1 expression. INO1 encodes inositol-3-phosphate synthase, which catalyzes the rate-limiting step in the synthesis of inositol, a key player in phospholipid biosynthesis. Herein, we had demonstrated that the recruitment of histone acetylases Gcn5p and Esa1p mainly relied on the presence of transcriptional activator Ino2p during INO1 activation. However, the presence of the chromatin remodelers, Ino80p and Snf2p, may contribute to the additive effect of Gcn5p recruitment. We also showed that the recruitment of chromatin remodelers, Ino80p and Snf2p, is independent of the presence of histone acetylases. Furthermore, INO1 expression can be activated exclusively by the activator and chromatin remodelers, suggesting a dispensable role of histone acetylases in INO1 induction. Therefore, our data provide a mechanism for cross talk within transcriptional co-activators during INO1 activation.