Interplay of yeast global transcriptional regulators Ssn6p-Tup1p and Swi-Snf and their effect on chromatin structure

• Published in: The EMBO journal Vol. 16; no. 20; pp. 6263 - 6271
• Main Authors: Gavin, I.M, Simpson, R.T
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 15.10.1997
• Subjects: beta-Fructofuranosidase; binding; chromatin; Chromatin - metabolism; Chromatin - ultrastructure; chromatin remodeling; Chromosomal Proteins, Non-Histone; chromosome mapping; DNA Footprinting; DNA-Binding Proteins - metabolism; Fungal Proteins - metabolism; gene expression; Gene Expression Regulation, Fungal; Glycoside Hydrolases - genetics; interactions; loci; mutants; Nuclear Proteins; nucleosomes; promoter regions; Promoter Regions, Genetic; Repressor Proteins; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae Proteins; Ssn6p(Cyc8p)-Tup1p; structure; suc2 locus; suc2 promoter; Swi-Snf; transcription; transcription (genetics); transcription factors; Transcription Factors - metabolism; Transcription, Genetic
• ISSN: 0261-4189; 1460-2075; 1460-2075
• DOI: 10.1093/emboj/16.20.6263

Transcriptional regulation in yeast involves a number of general trans‐acting factors affecting chromatin structure. The Swi–Snf complex is required for expression of a large number of genes and has the ability to remodel chromatin in vitro. The Ssn6p–Tup1p repressor complex may be involved in chromatin organization through the interaction with pathway‐specific DNA‐binding proteins. To study the interplay of these factors and their effect on chromatin we have analyzed SUC2 chromatin structure in wild‐type cells and in strains bearing combinations of ssn6/tup1 and swi1 mutations. We have mapped nucleosome positioning of the repressed gene in wild‐type cells using primer extension methodology, allowing base pair resolution, and have analyzed details of chromatin remodeling in the derepressed state. In ssn6 or tup1 mutants under repressing conditions the observed changes in SUC2 chromatin structure may be suppressed by the swi1 mutation, suggesting that Ssn6p–Tup1p is not required for the establishment of nucleosome positioning at the SUC2 promoter. Our data indicate the involvement of chromatin remodeling factors distinct from the Swi–Snf complex in SUC2 transcriptional regulation and suggest that Swi–Snf may antagonize Ssn6p–Tup1p by controlling remodeling activity. We also show that a relatively high level of SUC2 transcription can coexist with positioned nucleosomes.