GSE192592
Distinct functions of three chromatin remodelers in activator binding and preinitiation complex assembly
ATP-dependent chromatin remodelers (CRs), including SWI/SNF, RSC and Ino80C in budding yeast, are thought to stimulate transcription by repositioning or evicting promoter nucleosomes. The relative importance of these CRs in stimulating activator binding and recruitment of TATA-binding protein (TBP) to promoters is incompletely understood. Examining mutants depleted of the catalytic subunits of these CRs, we determined that RSC and Ino80C stimulate binding of transcription factor Gcn4 to nucleosome-depleted regions, or linkers between genic nucleosomes, at multiple target genes activated by Gcn4 in amino acid-starved cells, frequently by evicting nucleosomes from the Gcn4 binding motifs.  At some genes, SWI/SNF functionally complements RSC, while opposing RSC at others to limit Gcn4 binding. The CRs in turn are recruited by Gcn4 to establish positive or negative feedback loops that control Gcn4 binding.  The three CRs also cooperate to enhance TBP recruitment, again involving nucleosome depletion, at both Gcn4 target genes and highly expressed ribosomal protein genes, whereas only RSC and Ino80C act broadly throughout the genome to enhance this key step in preinitiation complex assembly. Our findings illuminate functional cooperation among multiple CRs in regulating activator binding and promoter activation. Overall design: Formaldehyde-fixed and sonicated DNA fragments were immunopurified and subjected to paired-end sequencing.