R-spondin1同时参与尼罗罗非鱼卵巢和精巢发育

摘要： 在哺乳动物中，富含弗林蛋白结构域的R-spondin1(RSPO1)肽通过激活/增强WNT/β-catenin信号通路阻止精巢结构的形成。但是有关Rspo1信号通路在硬骨鱼类中的报道相对比较少。在本研究中，我们从尼罗罗非鱼中分离出Rspo1基因，原位杂交结果表明Rspo1在罗非鱼卵巢和精巢的生殖细胞表达。个体发生表明Rspo1在罗非鱼早期性腺发育过程中在卵巢和精巢各自减数分裂前期上调，并且从孵化后20天开始出现性差，卵巢高于精巢。我们使用转录激活因子样效应物核酸酶敲降Rspo1基因，发现在卵巢中敲降Rspo1导致卵巢发育延迟，表达雄性基因，同时血清中11-酮基睾酮水平上调；有趣的是，精巢中敲降Rspo1基因导致精子发生延迟，igf3和amh表达下调，血清中11-酮基睾酮水平下调。使用Rspo1/Wnt信号通路抑制剂FH535离体孵育罗非鱼性腺，导致β-catenin表达下调，卵巢中cyp11c1和dmrt1上调；精巢中cyp11c1、amh和igf3下调。综上，我们的数据表明，在罗非鱼中Rspo1信号通路同时参与卵巢和精巢发育过程。
关键词： Rspo1；卵巢和精巢发育；延迟；精子发生受阻

Wu Limin^1,， Yang Peng^2,， Wang Deshou^1,， Zhou Linyan^1,*

（  1、Key labotrary of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing 400715, China；       2、 College of Fisheries, Henan Normanl University, Xinxiang, 453007, China.；  ）

Abstract： The furin-domain-containing peptide R-spondin1 (RSPO1) has recently emerged as an important regulator of ovarian development, upregulating the WNT/β-catenin pathway to oppose testis formation in mammals. However, little information has been reported on the Rspo1 signaling pathway in teleosts. In this study, Rspo1 was isolated from the gonads of the Nile tilapia, Oreochromis niloticus. An in situ hybridization analysis demonstrated that Rspo1 is expressed in the germ cells of the ovary and the testis. An ontogenic analysis demonstrated that Rspo1 expression is upregulated just before meiotic initiation in both the ovary and testis during the early developmental stages of the tilapia. The expression pattern is sexually dimorphic from 20 days after hatching, with higher expression in the ovary. The reduction of Rspo1 expression by transcription activator-like (TAL) effector nuclease (TALEN) caused retarded ovarian development, the ectopic expression of male-dominant genes, and increased serum 11-ketotestosterone. Intriguingly, a deficiency of Rspo1 in XY fish caused a delay in spermatogenesis, the inhibition of igf3 and amh expression and a reduction in serum 11-ketotestosterone. Furthermore, FH535, an inhibitor of the Rspo1/Wnt pathway, decreased β-catenin, while increased cyp11c1 and dmrt1 expression in the in vitro culture ovaries; decreased cyp11c1, amh and igf3 expression in the in vitro cultured testes. Taken together, our data suggest that the fish Rspo1 signaling pathway is involved in both ovarian and testicular development in the tilapia.
Keywords： Rspo1; ovarian and testicular development; retardation; impaired spermatogenesis