Zhu Kun, Lei Pin-Ji, Ju Lin-Gao, Wang Xiang, Huang Kai, Yang Bo, Shao Changwei, Zhu Yuan, Wei Gang, Fu Xiang-Dong, Li Lianyun, Wu Min
Hubei Key Laboratory of Cell Homeostasis, Hubei Key Laboratory of Developmentally Originated Disease, Department of Biochemistry and Molecular Biology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China.
Department of Developmental Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9133, USA.
Nucleic Acids Res. 2017 Jan 9;45(1):92-105. doi: 10.1093/nar/gkw814. Epub 2016 Sep 9.
Trimethylation of histone H3K36 is a chromatin mark associated with active gene expression, which has been implicated in coupling transcription with mRNA splicing and DNA damage response. SETD2 is a major H3K36 trimethyltransferase, which has been implicated as a tumor suppressor in mammals. Here, we report the regulation of SETD2 protein stability by the proteasome system, and the identification of SPOP, a key subunit of the CUL3 ubiquitin E3 ligase complex, as a SETD2-interacting protein. We demonstrate that SPOP is critically involved in SETD2 stability control and that the SPOP/CUL3 complex is responsible for SETD2 polyubiquitination both in vivo and in vitro ChIP-Seq analysis and biochemical experiments demonstrate that modulation of SPOP expression confers differential H3K36me3 on SETD2 target genes, and induce H3K36me3-coupled alternative splicing events. Together, these findings establish a functional connection between oncogenic SPOP and tumor suppressive SETD2 in the dynamic regulation of gene expression on chromatin.
组蛋白H3K36的三甲基化是一种与活跃基因表达相关的染色质标记，它与转录与mRNA剪接以及DNA损伤反应的偶联有关。SETD2是一种主要的H3K36三甲基转移酶，在哺乳动物中被认为是一种肿瘤抑制因子。在此，我们报道蛋白酶体系统对SETD2蛋白稳定性的调控，以及鉴定出CUL3泛素E3连接酶复合物的关键亚基SPOP作为与SETD2相互作用的蛋白。我们证明SPOP在SETD2稳定性控制中起关键作用，并且SPOP/CUL3复合物在体内和体外负责SETD2的多聚泛素化。ChIP-Seq分析和生化实验表明，SPOP表达的调节赋予SETD2靶基因不同的H3K36me3，并诱导H3K36me3偶联的可变剪接事件。总之，这些发现建立了致癌性SPOP与肿瘤抑制性SETD2在染色质上基因表达动态调控中的功能联系。
