The RSC complex remodels nucleosomes in transcribed coding sequences and promotes transcription in Saccharomyces cerevisiae

RSC (Remodels the Structure of Chromatin) is a conserved ATP-dependent chromatin remodeling complex that regulates many biological processes, including transcription by RNA polymerase II (Pol II). We report that not only RSC binds to nucleosomes in coding sequences (CDSs) but also remodels them to promote transcription. RSC MNase ChIP-seq data revealed that RSC-protected fragments were very heterogenous (~80 bp to 180 bp) compared to the sharper profile displayed by the MNase inputs (140 bp to 160 bp), supporting the idea that RSC activity promotes accessibility of nucleosomal DNA. Importantly, RSC binding to +1 nucleosomes and CDSs, but not with -1 nucleosomes, strongly correlated with Pol II occupancies suggesting that the RSC enrichment in CDSs is important for efficient transcription. This is further supported by a similar heterogenous distribution of Pol II-protected fragments. As such, the genes harboring high-levels of RSC in their CDSs were the most strongly affected by ablating RSC function. Altogether, this study provides a mechanism by which RSC-mediated remodeling aids in RNA Pol II traversal though coding sequence nucleosomes in vivo. Formaldehyde crosslinked yeast cells were subjected either to MNase digestion or sonication to obtain chromatin. The input MNase, and ChIPed sonicated and MNase chroamtin was subjected to paired-end Illumina 4K sequencing.