engleski

The RSC chromatin remodeling complex has a crucial role in the complete remodeler set for yeast PHO5 promoter opening

Although yeast PHO5 promoter chromatin opening is a founding model for chromatin remodeling, the complete set of involved remodelers remained unknown for a long time. The SWI/SNF and INO80 remodelers cooperate here, but non-essentially, and none of the many tested single or combined remodeler gene mutations could prevent PHO5 promoter opening. RSC, the most abundant and only remodeler essential for viability, was a controversial candidate for the unrecognized remodeling activity but unassessed in vivo. Now we show that RSC is crucially involved in PHO5 promoter opening. Further, the isw1 chd1 double deletion also delayed chromatin remodeling. Strikingly, combined absence of RSC and Isw1/Chd1 or Snf2 abolished for the first time promoter opening upon otherwise sufficient induction in vivo. Together with previous findings we recognize now a surprisingly complex network of five remodelers (RSC, SWI/SNF, INO80, Isw1, Chd1) from four subfamilies (SWI/SNF, INO80, ISWI, CHD) as involved in PHO5 promoter chromatin remodeling and as likely the first described complete remodeler set for a physiological chromatin transition. RSC was hardly involved at the coregulated PHO8 or PHO84 promoters despite cofactor recruitment by the same transactivator and RSC’s presence at all three promoters. Therefore, promoter-specific chromatin rather than transactivators determine remodeler requirements.

budding yeast chromatin; PHO promoters; chromatin remodeling; RSC remodeling complex

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