SMYD5 catalyzes histone H3 lysine 36 trimethylation at promoters

Histone mark, one carrier of epigenetic information, regulates the gene expression in cells. Studies have shown that H3K36me3 is mainly catalyzed by SETD2 to be deposited at gene body regions in mammalian cells. Here, we profile the distributions of H3K36me3 in native cells and uncover that H3K36me3 is also enriched at the promoters beyond the gene body regions. We identify SMYD5 as one methyltransferase responsible for the enrichment of H3K36me3 at promoters. Through RNA polymerase II, SMYD5 is recruited to chromatin to regulate H3K36me3 and gene expression. The enzymatic activity of SMYD5 is dependent on its C-terminal glutamic acid rich domain. Depletion of C-terminal domain reduces the reestablishment of H3K36me3 at promoters when Smyd5 is over-expressed in Smyd5 knockout cells. Furthermore, elevated Smyd5 expression contributes to the tumorigenesis of liver hepatocellular carcinoma. Together, our study reveals SMYD5 as the H3K36me3 methyltransferase at promoters to regulate the gene expression, providing important insights into the localization and function of H3K36me3. Overall design: Examination of histone modifications and SMYD5 in mouse embryonic stem cells.