Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China.
Frontier Science Center for Stem Cell Research, Tongji University, Shanghai, 200092, China.
Sci China Life Sci. 2024 Oct;67(10):2132-2148. doi: 10.1007/s11427-024-2631-x. Epub 2024 Jul 5.
The TET family is well known for active DNA demethylation and plays important roles in regulating transcription, the epigenome and development. Nevertheless, previous studies using knockdown (KD) or knockout (KO) models to investigate the function of TET have faced challenges in distinguishing its enzymatic and nonenzymatic roles, as well as compensatory effects among TET family members, which has made the understanding of the enzymatic role of TET not accurate enough. To solve this problem, we successfully generated mice catalytically inactive for specific Tet members (Tet). We observed that, compared with the reported KO mice, mutant mice exhibited distinct developmental defects, including growth retardation, sex imbalance, infertility, and perinatal lethality. Notably, Tet mouse embryonic stem cells (mESCs) were successfully established but entered an impaired developmental program, demonstrating extended pluripotency and defects in ectodermal differentiation caused by abnormal DNA methylation. Intriguingly, Tet3, traditionally considered less critical for mESCs due to its lower expression level, had a significant impact on the global hydroxymethylation, gene expression, and differentiation potential of mESCs. Notably, there were common regulatory regions between Tet1 and Tet3 in pluripotency regulation. In summary, our study provides a more accurate reference for the functional mechanism of Tet hydroxymethylase activity in mouse development and ESC pluripotency regulation.
TET 家族以其活跃的 DNA 去甲基化作用而闻名，在调节转录、表观基因组和发育方面发挥着重要作用。然而，以前使用敲低（KD）或敲除（KO）模型来研究 TET 功能的研究面临着区分其酶和非酶作用以及 TET 家族成员之间补偿效应的挑战，这使得对 TET 酶作用的理解不够准确。为了解决这个问题，我们成功地生成了特定 Tet 成员（Tet）催化失活的小鼠。与报道的 KO 小鼠相比，我们观察到突变小鼠表现出明显的发育缺陷，包括生长迟缓、性别失衡、不育和围产期致死。值得注意的是，Tet 小鼠胚胎干细胞（mESC）成功建立，但进入受损的发育程序，表现出延长的多能性和异常 DNA 甲基化引起的外胚层分化缺陷。有趣的是，由于表达水平较低，传统上认为 Tet3 对 mESC 不太重要，但它对 mESC 的全局羟甲基化、基因表达和分化潜能有显著影响。值得注意的是，在多能性调控中，Tet1 和 Tet3 之间存在共同的调控区域。总之，我们的研究为 Tet 羟甲基化酶活性在小鼠发育和 ESC 多能性调控中的功能机制提供了更准确的参考。
