European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany.
Collaboration for joint PhD degree between the European Molecular Biology Laboratory and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany.
Nat Genet. 2020 Mar;52(3):273-282. doi: 10.1038/s41588-020-0586-5. Epub 2020 Mar 5.
Mutations in enzymes that modify histone H3 at lysine 4 (H3K4) or lysine 36 (H3K36) have been linked to human disease, yet the role of these residues in mammals is unclear. We mutated K4 or K36 to alanine in the histone variant H3.3 and showed that the K4A mutation in mouse embryonic stem cells (ESCs) impaired differentiation and induced widespread gene expression changes. K4A resulted in substantial H3.3 depletion, especially at ESC promoters; it was accompanied by reduced remodeler binding and increased RNA polymerase II (Pol II) activity. Regulatory regions depleted of H3.3K4A showed histone modification alterations and changes in enhancer activity that correlated with gene expression. In contrast, the K36A mutation did not alter H3.3 deposition and affected gene expression at the later stages of differentiation. Thus, H3K4 is required for nucleosome deposition, histone turnover and chromatin remodeler binding at regulatory regions, where tight regulation of Pol II activity is necessary for proper ESC differentiation.
在赖氨酸 4（H3K4）或赖氨酸 36（H3K36）上修饰组蛋白 H3 的酶的突变与人类疾病有关，但这些残基在哺乳动物中的作用尚不清楚。我们在组蛋白变体 H3.3 中突变了 K4 或 K36 为丙氨酸，并表明在小鼠胚胎干细胞（ESCs）中的 K4A 突变会损害分化并诱导广泛的基因表达变化。K4A 导致 H3.3 的大量耗竭，特别是在 ESC 启动子处；它伴随着重塑酶结合减少和 RNA 聚合酶 II（Pol II）活性增加。耗尽 H3.3K4A 的调控区域表现出组蛋白修饰的改变和增强子活性的变化，与基因表达相关。相比之下，K36A 突变不会改变 H3.3 的沉积，并且在分化的后期阶段影响基因表达。因此，H3K4 对于核小体沉积、组蛋白周转和染色质重塑酶在调控区域的结合是必需的，而 Pol II 活性的严格调控对于正确的 ESC 分化是必要的。
