GSE65902
The SAGA/TREX-2 subunit Sus1 binds widely to transcribed genes and affects mRNA turnover globally
Eukaryotic transcription is regulated through two complexes, the general transcription factor IID (TFIID) and the coactivator Spt-Ada-Gcn5 acetyltransferase (SAGA). Recent findings confirm that both TFIID and SAGA contribute to the synthesis of nearly all transcripts and are recruited genome-wide in yeast. However, how this broad recruitment confers selectivity under specific conditions remains an open question. Here we find that the SAGA DUBm subunit Sus1 associates upstream regulatory regions of many yeast genes and that heat shock drastically changes Sus1 binding pattern. While Sus1 binding to TFIID-dominated genes is not affected by temperature, its recruitment to SAGA-dominated genes and RP genes is significantly disturbed under heat shock, being Sus1 relocated to environmental stress responsive genes in these conditions. Moreover, in contrast to recent results showing that SAGA deubiquitinating enzyme Ubp8 is dispensable for RNA synthesis, genomic run-on experiments demonstrate that Sus1 contributes to synthesis and stability for a wide range of transcripts. Our study provides support for a model in which SAGA acts as a global transcriptional regulator in yeast but acquires differential binding affinities under thermal stress conditions. Overall design: Genome wide analysis of Sus1 in wild type and Spt7 and Spt8 deletion mutants using ChIP-exo and genomic run-on experiments