The SUV4-20 inhibitor A-196 verifies a role for epigenetics in genomic integrity
The SUV4-20 inhibitor A-196 verifies a role for epigenetics in genomic integrity
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DOI：
10.1038/nchembio.2282
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发表时间：
2017-03-01
影响因子：
14.8
通讯作者：
Pappano, William N.
中科院分区：
文献类型：
--
作者：
Bromberg, Kenneth D.;Mitchell, Taylor R. H.;Pappano, William N.
蛋白质赖氨酸甲基转移酶（PKMTs）调控多种生理过程，包括转录和基因组完整性的维持。遗传学研究表明，PKMTs SUV420H1和SUV420H2通过催化组蛋白4上赖氨酸20的二甲基化和三甲基化（分别为me2和me3）促进高效的非同源末端连接（NHEJ）导向的DNA修复。在此我们报道A - 196的鉴定，它是一种对SUV420H1和SUV420H2有效的选择性抑制剂。生化和共结晶分析表明，A - 196是两种SUV4 - 20酶的底物竞争性抑制剂。在细胞中，A - 196导致H4K20me2和H4K20me3整体减少，同时H4K20me1增加。A - 196在电离辐射时抑制53BP1焦点形成，减少NHEJ介导的DNA断裂修复，但不影响同源导向修复。这些结果证明了SUV4 - 20酶活性在H4K20甲基化和DNA修复中的作用。A - 196是SUV4 - 20的首个化学探针，用于研究组蛋白甲基转移酶在基因组完整性中的作用。
Protein lysine methyltransferases (PKMTs) regulate diverse physiological processes including transcription and the maintenance of genomic integrity. Genetic studies suggest that the PKMTs SUV420H1 and SUV420H2 facilitate proficient non-homologous end-joining (NHEJ)-directed DNA repair by catalyzing the di- and trimethylation (me2 and me3, respectively) of lysine 20 on histone 4 (H4K20). Here we report the identification of A-196, a potent and selective inhibitor of SUV420H1 and SUV420H2. Biochemical and co-crystallization analyses demonstrate that A-196 is a substrate-competitive inhibitor of both SUV4-20 enzymes. In cells, A-196 induced a global decrease in H4K20me2 and H4K20me3 and a concomitant increase in H4K20me1. A-196 inhibited 53BP1 foci formation upon ionizing radiation and reduced NHEJ-mediated DNA-break repair but did not affect homology-directed repair. These results demonstrate the role of SUV4-20 enzymatic activity in H4K20 methylation and DNA repair. A-196 represents a first-in-class chemical probe of SUV4-20 to investigate the role of histone methyltransferases in genomic integrity.