西亚试剂：Histone H3 Lysine 4 Hypermethylation Prevents Aberrant Nucl

Histone H3 Lysine 4 Hypermethylation Prevents Aberrant Nucleosome Remodeling at the PHO5 Promoter

Shan-Shan Wang, Bo O. Zhou, and Jin-Qiu Zhou

Recent studies have highlighted the histone H3K4 methylation (H3K4me)-dependent transcriptional repression in Saccharomyces cerevisiae, however, the underlying mechanism remains inexplicit. Here, we reported that H3K4me inhibits the basal PHO5 transcription under high-phosphate conditions by suppressing nucleosome disassembly at the promoter. We found that derepression of the PHO5 promoter by SET1 deletion resulted in a labile chromatin structure, allowing more binding of RNA Pol II, but not the transactivators Pho2 and Pho4. We further showed that Pho23 and Cti6, two PHD-containing proteins, cooperatively anchored the Rpd3L complex to the H3K4-methylated PHO5 promoter. The deacetylation activity of Rpd3 on histone H3 was required for the function of Set1 at the PHO5 promoter. Taken together, our data suggest that Set1-mediated H3K4me suppresses nucleosome remodeling at the PHO5 promoter so as to reduce basal transcription of PHO5 under repressive conditions. We propose that the restriction of aberrant nucleosome remodeling contributes to strict control of gene transcription by the transactivators.