A novel 15-subunit complex with the capacity to remodel the structure
of chromatin, termed RSC, has been isolated from S. cerevisiae on the
basis of homology to the SWI/SNF complex. At least three RSC subunits
are related to SWI/SNF polypeptides: Sth1p, Rsc6p, and Rsc8p are signi
ficantly similar to Swi2/Snf2p, Swp73p, and Swi3p, respectively, and w
ere identified by mass spectrometric and sequence analysis of peptide
fragments. Like SWI/SNF, RSC exhibits a DNA-dependent ATPase activity
stimulated by both free and nucleosomal DNA and a capacity to perturb
nucleosome structure. RSC is, however, at least 10-fold more abundant
than SWI/SNF complex and is essential for mitotic growth. Contrary to
a report for SWI/SNF complex, no association of RSC (nor of SWI/SNF co
mplex) with RNA polymerase II holoenzyme was detected.