Qu Ling, Xiang Kunlun
School of Engineering, Guangzhou College of Technology and Business, Guangzhou, 510850, China.
Guangdong Ecological Meteorological Centre, Guangzhou, 510640, China.
Biochem Biophys Rep. 2025 Aug 27;44:102188. doi: 10.1016/j.bbrep.2025.102188. eCollection 2025 Dec.
The protogynous orange-spotted grouper (), a sequentially hermaphroditic teleost, relies on dynamic regulation of germ cell development and sex reversal mechanisms to achieve reproductive plasticity. The gene family, pivotal for germ cell development and transposon silencing across metazoans, remains poorly characterized in hermaphroditic species. Here, we investigate , a homologue in the orange-spotted grouper (. ), to elucidate its role in germ cell fate determination and sex reversal. We cloned a 3084-bp Ecpiwi1 cDNA encoding an 855-amino-acid protein containing conserved PAZ and PIWI domains, phylogenetically clustering with vertebrate Piwi proteins. Real-time PCR showed that the expression level of mRNA increases during sex reversal, transitioning from ovary to testis. Spatial expression analysis by in situ hybridization and immunohistochemistry demonstrated localization to oogonia, previtellogenic oocytes, and spermatogonia-spermatocyte transition zones. During natural and 17α-methyltestosterone (MT)-induced sex reversal, mRNA exhibited progressive upregulation during sex reversal. Notably, MT-treated gonads showed identical expression dynamics and subcellular localization patterns compared to natural sex change, validating the MT induction model. These findings establish Ecpiwi1 as a germline-specific regulator coordinating oogenesis, spermatogenesis, and sex reversal in protogynous hermaphrodites. The conserved expression patterns under exogenous androgen induction position as a robust molecular marker for teleost germline stem cell studies and advance our understanding of reproductive plasticity in hermaphroditic teleosts.
雌性先熟的点带石斑鱼（）是一种序列性雌雄同体的硬骨鱼，它依靠生殖细胞发育的动态调控和性逆转机制来实现生殖可塑性。在整个后生动物中，对于生殖细胞发育和转座子沉默起关键作用的基因家族，在雌雄同体物种中的特征仍知之甚少。在这里，我们研究了点带石斑鱼（. ）中的 同源物 ，以阐明其在生殖细胞命运决定和性逆转中的作用。我们克隆了一个 3084 碱基对的 Ecpiwi1 cDNA，其编码一个含有保守 PAZ 和 PIWI 结构域的 855 个氨基酸的蛋白质，在系统发育上与脊椎动物的 Piwi 蛋白聚类。实时 PCR 表明，在性逆转过程中，即从卵巢向精巢转变时，mRNA 的表达水平增加。通过原位杂交和免疫组织化学进行的空间表达分析表明， 定位于卵原细胞、卵黄生成前的卵母细胞以及精原细胞 - 精母细胞过渡区。在自然和 17α - 甲基睾酮（MT）诱导的性逆转过程中，mRNA 在性逆转过程中表现出逐渐上调。值得注意的是，与自然性转变相比，MT 处理的性腺显示出相同的 表达动态和亚细胞定位模式，验证了 MT 诱导模型。这些发现确立了 Ecpiwi1 作为一种生殖系特异性调节因子，可协调雌性先熟雌雄同体中的卵子发生、精子发生和性逆转。在外源雄激素诱导下保守的表达模式将 定位为硬骨鱼生殖系干细胞研究的一个强大分子标记，并推进了我们对雌雄同体硬骨鱼生殖可塑性的理解。
