Histone H3K36 Methylation is Required for Efficient Pre‐mRNA Splicing in Saccharomyces cerevisiae

Abstract

Proper gene expression involves multiple steps, including RNA splicing where non‐protein coding regions of RNA are removed from the RNA transcript. RNA splicing is carried out by the large and dynamic spliceosome, which is comprised of small nucleoprotein complexes (snRNPs) that assemble on an RNA molecule in a precise order. Assembly of the spliceosome occurs co‐transcriptionally and RNA splicing is tightly coordinated with transcription to ensure precise and efficient gene expression. However, the mechanisms that underlie this coordination are poorly understood. In order to identify proteins that function to coordinate RNA splicing with transcription we carried out a genetic interaction study using Saccharomyces cerevisiae. We identified negative genetic interactions between genes encoding RNA splicing factors and the SET2 gene, a histone methyltransferase that methylates lysine36 on histone H3 (H3K36) to regulate transcription. Furthermore, we show that mutations that block H3K36 methylation also have negative genetic interactions with splicing factor genes, suggesting that H3K36 methylation is important for RNA splicing. Indeed, we have shown that deletion of SET2 or point mutation of H3K36 inhibits RNA splicing and exacerbates splicing defects in yeast strains harboring deletions of splicing factor genes. Using chromatin immunoprecipitation, we demonstrate that deletion of SET2 reduces the association of snRNPs with chromatin. Furthermore, we tested for reciprocal/reverse coordination between RNA splicing and transcription. We found that mutation of Prp28, a helicase protein that normally promotes RNA splicing, alters RNA polymerase II association with DNA. We are currently testing whether perturbation of RNA splicing alters H3K36 methylation. Thus, we provide evidence that H3K36 methylation is required for appropriate RNA splicing in yeast and suggest a model in which Set2 or H3K36 methylation help to recruit splicing factors to RNA during transcription.Support or Funding InformationCottrell College Science Award from the Research Corporation for Science Advancement (#20186) to T.L.KAmerican Cancer Society (RSG‐05‐137‐01‐GMC) to S.W.S National Institutes of Health (GM084246 to S.W.S and GM110058 to B.D.S) Cancer Prevention & Research Institute of Texas (RP101501) to M.R.SGateway to Graduate School funded by The National Science Foundation (NSF‐URM) to D.M.F