SETD2/KMT3A

SETD2 (KMT3A) is a SET domain-containing histone methyltransferase that catalyzes histone H3 lysine 36 trimethylation (H3K36me3), a chromatin mark associated with active transcription and epigenetic regulation^[1]. Mechanistically, SETD2 associates with RNA polymerase II and coordinates transcription-coupled chromatin modification, thereby linking gene expression programs with chromatin state maintenance^[1][2]. H3K36 methylation represents a central epigenetic pathway controlling faithful gene regulation, and SETD2 functions as the principal enzyme responsible for H3K36me3 deposition within gene bodies^[3]. Beyond chromatin regulation, SETD2 also acts as a dual-function methyltransferase that remodels both chromatin and the cytoskeleton, supporting genomic stability and proper cellular division^[4]. In disease contexts, recurrent SETD2 loss or mutation has been reported across multiple malignancies, including leukemia and lymphoid cancers, supporting a tumor-suppressive role for this enzyme and highlighting the biological importance of H3K36me3-dependent pathways^[5][6]. Compared with related H3K36 methyltransferases such as NSD1, NSD2, NSD3, and ASH1L, SETD2 is distinguished by its predominant role in H3K36me3 deposition, whereas other family members primarily contribute to H3K36 mono- and dimethylation^[3]. Experimental studies further demonstrate that SETD2 cooperates with NSD3 and other chromatin regulators during transcriptional activation, providing useful mechanistic models for investigating epigenetic control of gene expression and chromatin-dependent disease mechanisms^[7].