Cell Cycle Regulation of Vertebrate Female Meiotic Divisions
摘要
Cell division is the basis of development and gametogenesis, its misregulation can lead to growth defects and, if affecting germ cells, infertility. During female meiosis, germ cells undergo two successive divisions, meiosis I and meiosis II, without intervening S-phase. Moreover, they segregate the homologous chromosomes in meiosis I and then sister chromatids in meiosis II to reduce by half the genome content. Besides controlling ploidy, female meiosis must halt at the proper cell-cycle stage to avoid parthenogenesis. Moreover, oocytes stockpile maternal transcripts and proteins required for early embryogenesis after fertilization. These processes are orchestrated by oocyte-specific mechanisms operating between the two divisions, under the control of protein turnover and protein phosphorylation. Here, we will discuss how key molecular meiotic events of female meiosis are intertwined with the regulation of maternal proteins to form a functional oocyte in vertebrates. Although some clear differences exist between vertebrates, the core machinery controlling meiosis is conserved, and therefore provides an encompassing view of the orchestration of female meiosis.