Stable propagation of epigenetic information is important for maintaining cell identity in multicellular organisms. However, it remains largely unknown how mono-ubiquitinated histone H2A on lysine 119 (H2AK119ub1) is established and stably propagated during cell division. In this study, we found that the proteins RYBP and YAF2 each specifically bind H2AK119ub1 to recruit the RYBP-PRC1 or YAF2-PRC1 complex to catalyse the ubiquitination of H2A on neighbouring nucleosomes through a positive-feedback model. Additionally, we demonstrated that histone H1-compacted chromatin enhances the distal propagation of H2AK119ub1, thereby reinforcing the inheritance of H2AK119ub1 during cell division. Moreover, we showed that either disruption of RYBP/YAF2-PRC1 activity or impairment of histone H1-dependent chromatin compaction resulted in a significant defect of the maintenance of H2AK119ub1. Therefore, our results suggest that histone H1-dependent chromatin compaction plays a critical role in the stable propagation of H2AK119ub1 by RYBP/YAF2-PRC1 during cell division.

中文翻译：

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RYBP / YAF2-PRC1复合物和组蛋白H1依赖的染色质压实在细胞分裂过程中介导H2AK119ub1的繁殖。

表观遗传信息的稳定传播对于维持多细胞生物中的细胞身份非常重要。然而，在细胞分裂过程中如何在赖氨酸119（H2AK119ub1）上建立单泛素化的组蛋白H2A并稳定地传播仍是一个未知数。在这项研究中，我们发现蛋白质RYBP和YAF2各自特异性结合H2AK119ub1，以募集RYBP-PRC1或YAF2-PRC1复合物，以通过正反馈模型催化H2A在邻近核小体上的泛素化。此外，我们证明了组蛋白H1压缩的染色质增强了H2AK119ub1的远端传播，从而增强了H2AK119ub1在细胞分裂过程中的遗传。此外，我们发现，RYBP / YAF2-PRC1活性的破坏或组蛋白H1依赖的染色质紧密性的损害均会导致H2AK119ub1的维持存在重大缺陷。因此，我们的结果表明，在细胞分裂过程中，组蛋白H1依赖的染色质紧实在RYBP / YAF2-PRC1稳定传播H2AK119ub1中起着关键作用。