Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Hubei Hongshan Laboratory, Institute of Hydrobiology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Wuhan, Hubei 430072, China.
School of Marine Biology and Fisheries, Hainan University, Haikou, Hainan 570228, China.
Zool Res. 2024 Sep 18;45(5):1116-1130. doi: 10.24272/j.issn.2095-8137.2024.046.
Zebrafish serve as a valuable model organism for studying germ cell biology and reproductive processes. The AB strain of zebrafish is proposed to exhibit a polygenic sex determination system, where most males initially develop juvenile ovaries before committing to male fate. In species with chromosomal sex determination, gonadal somatic cells are recognized as key determinants of germ cell fate. Notably, the loss of germ cells in zebrafish leads to masculinization, implying that germ cells harbor an intrinsic feminization signal. However, the specific signal triggering oogenesis in zebrafish remains unclear. In the present study, we identified as an oocyte progenitor-specific gene essential for initiating oogenesis in germ cells. Results showed that -knockout zebrafish bypassed the juvenile ovary stage and exclusively developed into fertile males. Further analysis revealed that loss of hindered the initiation of oocyte-specific meiosis and prevented entry into oogenesis, leading to premature spermatogenesis during early gonadal development. Furthermore, while mutation of the pro-male gene led to fertile female differentiation, simultaneous disruption of in mutants completely blocked oogenesis, with a large proportion of germ cells arrested as germline stem cells, highlighting the crucial role of in oogenesis. Overall, this study highlights the unique function of as a germ cell-intrinsic gatekeeper of oogenesis in zebrafish.
斑马鱼是研究生殖细胞生物学和生殖过程的重要模式生物。AB 品系的斑马鱼被认为具有多基因性别决定系统，大多数雄性个体在决定雄性命运之前，最初会发育成幼年卵巢。在染色体性别决定的物种中，性腺体细胞被认为是生殖细胞命运的关键决定因素。值得注意的是，斑马鱼生殖细胞的缺失会导致雄性化，这表明生殖细胞内存在内在的雌性化信号。然而，触发斑马鱼卵发生的具体信号仍不清楚。本研究鉴定出 是生殖细胞中启动卵发生所必需的卵原细胞特异性基因。结果表明，-敲除斑马鱼跳过幼年卵巢阶段，仅发育为可育雄性。进一步的分析表明，缺失 会阻碍卵母细胞特异性减数分裂的启动，并阻止卵发生，导致早期性腺发育过程中过早的精子发生。此外，虽然雄性基因 的突变导致可育雌性的分化，但在 突变体中同时破坏 则完全阻断卵发生，大部分生殖细胞停滞为生殖干细胞，突出了 在卵发生中的关键作用。总的来说，这项研究强调了 作为斑马鱼卵发生中生殖细胞内在门控因子的独特功能。
