He Meina, Zhang Tuo, Yang Yi, Wang Chao
Department of Biology, School of Basic Medical Science, Guizhou Medical University, Guiyang, China.
State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China.
Front Cell Dev Biol. 2021 Mar 19;9:654028. doi: 10.3389/fcell.2021.654028. eCollection 2021.
Meiosis is the basis of sexual reproduction. In female mammals, meiosis of oocytes starts before birth and sustains at the dictyate stage of meiotic prophase I before gonadotropins-induced ovulation happens. Once meiosis gets started, the oocytes undergo the leptotene, zygotene, and pachytene stages, and then arrest at the dictyate stage. During each estrus cycle in mammals, or menstrual cycle in humans, a small portion of oocytes within preovulatory follicles may resume meiosis. It is crucial for females to supply high quality mature oocytes for sustaining fertility, which is generally achieved by fine-tuning oocyte meiotic arrest and resumption progression. Anything that disturbs the process may result in failure of oogenesis and seriously affect both the fertility and the health of females. Therefore, uncovering the regulatory network of oocyte meiosis progression illuminates not only how the foundations of mammalian reproduction are laid, but how mis-regulation of these steps result in infertility. In order to provide an overview of the recently uncovered cellular and molecular mechanism during oocyte maturation, especially epigenetic modification, the progress of the regulatory network of oocyte meiosis progression including meiosis arrest and meiosis resumption induced by gonadotropins is summarized. Then, advances in the epigenetic aspects, such as histone acetylation, phosphorylation, methylation, glycosylation, ubiquitination, and SUMOylation related to the quality of oocyte maturation are reviewed.
减数分裂是有性生殖的基础。在雌性哺乳动物中，卵母细胞的减数分裂在出生前就开始了，并在促性腺激素诱导排卵发生之前，维持在减数分裂前期I的双线期阶段。减数分裂一旦开始，卵母细胞就会经历细线期、偶线期和粗线期阶段，然后停滞在双线期阶段。在哺乳动物的每个发情周期或人类的月经周期中，排卵前卵泡内的一小部分卵母细胞可能会恢复减数分裂。对雌性来说，提供高质量的成熟卵母细胞以维持生育能力至关重要，这通常是通过精细调节卵母细胞减数分裂停滞和恢复进程来实现的。任何干扰这一过程的因素都可能导致卵子发生失败，并严重影响雌性的生育能力和健康。因此，揭示卵母细胞减数分裂进程的调控网络，不仅能阐明哺乳动物生殖基础是如何奠定的，还能揭示这些步骤的调控失常如何导致不孕。为了概述最近在卵母细胞成熟过程中发现的细胞和分子机制，特别是表观遗传修饰，本文总结了卵母细胞减数分裂进程调控网络的进展，包括减数分裂停滞和促性腺激素诱导的减数分裂恢复。然后，综述了与卵母细胞成熟质量相关的表观遗传方面的进展，如组蛋白乙酰化、磷酸化、甲基化、糖基化、泛素化和类泛素化修饰。
