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The control mechanisms of initiation of meiosis in fish spermatogenesis

鱼类精子发生减数分裂起始的控制机制

基本信息

批准号：
16380133
负责人：
MIURA Takeshi
金额：
$ 9.16万
依托单位：
Ehime University
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 2007
项目状态：
已结题

项目摘要

Meiosis is indispensable process for ensuring the sexual reproduction. However, detailed information on the regulational mechanisms of its initiation is not clear. Progestin is an important steroid for regulation of final maturation in male and female. In male teleosts, it is known that progestin induces spermiation and maturation. However, the function of progestin in early spermatogenesis including meiosis is not completely known. In this study, we examined the functions of progestin on initiation of meiosis in spermatogenesis of the Japanese eel. 17?, 20? -dihydroxy-4-pregnen-3-one (DHP), a natural progestin in teleost, and its receptor was presented in the testis of early stage of spermatogenesis. Using eel testicular culture systems, DHP induced the DNA synthesis of spermatogonia. 11-Ketotestosterone, which is initiator of spermatogenesis, also stimulated the DNA synthesis of spermatogonia, but this DNA synthesis prevented by anti-DHP antibody treatment at the phase of initiation of meiosis. DHP treatment also induced the expression of meiosis specific marker; DmcI and Spo11. Furthermore, the expression of Spo11 and synaptonemal complexes (specific construct of meiotic prophase) were also detected in some germ cells, which cell type is spermatogonial stem cell in testicular fragments cultured with DHP. In oogenesis, DHP induced meiotic prophase using ovarian culture of common carp which is newly developed for this analysis. We therefore concluded from these results that DHP, a progestin is essential factor for initiation of meiosis in both spermatogenesis and oogenesis.

减数分裂是保证有性生殖不可缺少的过程。然而，关于其启动的调控机制的详细信息尚不清楚。孕激素是调节男性和女性最终成熟的重要类固醇。在雄性硬骨鱼中，已知孕激素诱导精子和成熟。然而，孕激素在包括减数分裂在内的早期精子发生中的作用尚不完全清楚。在本研究中，我们研究了孕激素在鳗鱼精子发生过程中启动减数分裂的作用。17，20-二羟基-4-孕烯-3-酮(DHP)是硬骨中的一种天然孕激素，其受体存在于精子发生的早期。在鳗鱼睾丸培养体系中，DHP诱导精原细胞DNA合成。精子发生的起始物11-酮睾酮也能刺激精原细胞的DNA合成，但这种DNA合成在减数分裂启动阶段被抗DHP抗体阻断。DHP处理还诱导了减数分裂特异标记DMCI和Spo11的表达。此外，在用DHP培养的睾丸碎片中，还检测到Spo11和联会复合体(减数分裂前期的特异性结构)在一些生殖细胞中的表达，这些细胞类型是精原干细胞。在卵子发生方面，DHP利用新开发的鲤鱼卵巢培养诱导减数分裂前期。因此，我们得出结论，DHP是一种孕激素，在精子发生和卵子发生中都是启动减数分裂的关键因素。