RNF8 和 SCML2 合作调节泛素化和 H3K27 乙酰化,以逃避性染色体上基因的激活。

RNF8 and SCML2 cooperate to regulate ubiquitination and H3K27 acetylation for escape gene activation on the sex chromosomes.

机构信息

Division of Reproductive Sciences, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States of America.

Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America.

出版信息

PLoS Genet. 2018 Feb 20;14(2):e1007233. doi: 10.1371/journal.pgen.1007233. eCollection 2018 Feb.

Abstract

The sex chromosomes are enriched with germline genes that are activated during the late stages of spermatogenesis. Due to meiotic sex chromosome inactivation (MSCI), these sex chromosome-linked genes must escape silencing for activation in spermatids, thereby ensuring their functions for male reproduction. RNF8, a DNA damage response protein, and SCML2, a germline-specific Polycomb protein, are two major, known regulators of this process. Here, we show that RNF8 and SCML2 cooperate to regulate ubiquitination during meiosis, an early step to establish active histone modifications for subsequent gene activation. Double mutants of Rnf8 and Scml2 revealed that RNF8-dependent monoubiquitination of histone H2A at Lysine 119 (H2AK119ub) is deubiquitinated by SCML2, demonstrating interplay between RNF8 and SCML2 in ubiquitin regulation. Additionally, we identify distinct functions of RNF8 and SCML2 in the regulation of ubiquitination: SCML2 deubiquitinates RNF8-independent H2AK119ub but does not deubiquitinate RNF8-dependent polyubiquitination. RNF8-dependent polyubiquitination is required for the establishment of H3K27 acetylation, a marker of active enhancers, while persistent H2AK119ub inhibits establishment of H3K27 acetylation. Following the deposition of H3K27 acetylation, H3K4 dimethylation is established as an active mark on poised promoters. Together, we propose a model whereby regulation of ubiquitin leads to the organization of poised enhancers and promoters during meiosis, which induce subsequent gene activation from the otherwise silent sex chromosomes in postmeiotic spermatids.

摘要

性染色体富含在减数分裂后期被激活的生殖细胞基因。由于减数分裂性染色体失活(MSCI),这些与性染色体连锁的基因必须逃避沉默以在精母细胞中被激活,从而确保它们在雄性生殖中的功能。RNF8 是一种 DNA 损伤反应蛋白,SCML2 是一种生殖细胞特异性多梳蛋白,是这一过程的两个主要已知调节因子。在这里,我们表明 RNF8 和 SCML2 合作调节减数分裂中的泛素化,这是建立随后基因激活的活性组蛋白修饰的早期步骤。Rnf8 和 Scml2 的双突变体表明,RNF8 依赖的组蛋白 H2A 赖氨酸 119 单泛素化(H2AK119ub)被 SCML2 去泛素化,表明 RNF8 和 SCML2 在泛素调节中相互作用。此外,我们确定了 RNF8 和 SCML2 在泛素化调节中的不同功能:SCML2 去泛素化 RNF8 独立的 H2AK119ub,但不泛素化 RNF8 依赖的多泛素化。RNF8 依赖性多泛素化对于 H3K27 乙酰化的建立是必需的,H3K27 乙酰化是活性增强子的标志,而持续的 H2AK119ub 抑制 H3K27 乙酰化的建立。在 H3K27 乙酰化的沉积之后,H3K4 二甲基化作为一个活跃的标记建立在有潜力的启动子上。总的来说,我们提出了一个模型,即泛素化的调节导致减数分裂中潜在增强子和启动子的组织,这导致随后在减数分裂后精母细胞中从沉默的性染色体中激活基因。

https://cdn.ncbi.nlm.nih.gov/pmc/blobs/e33f/5834201/b16cbe010e57/pgen.1007233.g001.jpg

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