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Molecular Mechanisms of Sex Change in Fish

鱼类性别变化的分子机制

基本信息

批准号：
16370032
负责人：
NAGAHAMA Yoshitaka
金额：
$ 9.54万
依托单位：
National Institute for Basic Biology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

项目摘要

The gobiid fish, Trimma okinawae, possesses ovarian and testicular tissues simultaneously in its gonad and is able to change sex repeatedly in both directions depending on its social surroundings. As sex change in both directions can be socially manipulated, T.okinawae provides an excellent animal model to investigate molecular mechanisms of sex change. The involvement of gonadotropins in sex change was examined by determining the changes in gonadotropin (FSH and LH) receptor gene (GtHRs) expression in gonads during the onset of sex changes from female to male and male to female. The results were intriguing as the expression of the GtHRs was found to be confined to the active gonad of the corresponding sexual phase. When the sex change was occurring from female to male, initially the ovary had high levels of FSHR and LHR, which eventually went up in the testicular tissue once the fish had realized the fact that it was bigger than the other in the aquarium. Opposite of this scenario was … More observed if another fish bigger than the newly sex-changed male was introduced into this aquarium. Swapping of the gonads started with switching of the GtHR expression that was discernible within 12-24 hrs of the visual cue. Our findings show that the gonads of successive sex changing fish possess the intrinsic mechanism to respond to the social cue differentially. Additionally, this location switching of GtHR expression also could substantiate the importance of hypothalamo-pituitary-gonadotropic axis.The wrasse, Pseudolabrus sieboldi, changes sex from female to male. In this study, to investigate the role of estradio1-17β (E2) and 11-ketotestosterone (11KT) in the conversion between oogenesis and spermatogenesis in the gonad, ovarian and testicular tissues were incubated with E2 or 11-KT respectively using in vitro organ culture system. In the culture of ovarian tissues with 11KT, the cysts of spermatozoa, spermatids, and spermatocytes appeared, while oocytes disappeared. On the contrary, E2 treatment could not organize the cysts of any testicular germ cells in ovarian tissues. In the culture of testicular tissues with 11KT, the cysts of spermatozoa, spermatids, and spermatocytes were observed, while with E2, there was a complete degeneration of testicular tissues. This newly developed organ culture system will provide an excellent in vitro system to study the molecular mechanisms of sex change in fish. Less

虎鱼，Trimma okinawae，在其性腺中同时具有卵巢和睾丸组织，并且能够根据其社会环境在两个方向上反复改变性别。由于两个方向的性别变化都可以被社会操纵，因此冲绳锥虫提供了一个很好的动物模型来研究性别变化的分子机制。通过测定从雌性到雄性和从雄性到雌性的性别变化开始期间性腺中促性腺激素（FSH和LH）受体基因（GtHRs）表达的变化，检查促性腺激素在性别变化中的参与。结果是有趣的，因为发现GtHRs的表达仅限于相应性阶段的活跃性腺。当从雌性到雄性发生性别变化时，最初卵巢具有高水平的FSHR和LHR，一旦鱼意识到它比水族馆中的其他鱼大，睾丸组织中的FSHR和LHR最终会上升。与这种情况相反的是， ...更多信息观察是否有另一条比刚变性的雄鱼更大的鱼被引入这个水族馆。性腺的交换开始于GtHR表达的转换，这在视觉提示的12 - 24小时内是可辨别的。我们的研究结果表明，连续性别转换鱼类的性腺具有内在的机制，以响应社会线索的差异。此外，GtHR表达的这种位置转换也证实了下丘脑-垂体-促性腺激素轴的重要性。本研究采用体外器官培养系统，分别用雌二醇（E2）和11-酮睾酮（11-KT）孵育卵巢和睾丸组织，探讨E2和11-KT在性腺卵子发生和精子发生转换中的作用。在卵巢组织中加入11KT后，精子、精子细胞和精母细胞出现包囊，而卵母细胞消失。相反，E2处理不能组织卵巢组织中的任何睾丸生殖细胞的囊肿。在睾丸组织培养中，11KT可观察到精子、精子细胞和精母细胞的包囊，而E2则可观察到睾丸组织的完全变性。这种新开发的器官培养系统将为研究鱼类性别变化的分子机制提供一个良好的体外系统。少