Tracing the Emergence of a Novel Sex-Determining Gene in Medaka, Oryzias luzonensis
Tracing the Emergence of a Novel Sex-Determining Gene in Medaka, Oryzias luzonensis
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DOI：
10.1534/genetics.111.137497
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发表时间：
2012-05-01
期刊：
影响因子：
3.3
通讯作者：
Sakaizumi, Mitsuru
中科院分区：
文献类型：
--
作者：
Myosho, Taijun;Otake, Hiroyuki;Sakaizumi, Mitsuru
到目前为止，已在脊椎动物中鉴定出三个性别决定(SD)基因：SRY(哺乳动物)、DMY(青竹)和DM-W(非洲爪哇)。然而，一个新的性别决定基因是如何以及为什么出现的，以及主要性别决定基因的切换机制仍然未知。在此，我们利用定位克隆的方法对吕宋稻的性别决定基因进行了研究，发现GSDF(Y)(Y染色体上的性腺体源生长因子)已取代DMY成为该物种的性别决定基因。我们发现在性别分化过程中，GSDF(Y)在雄性中呈高表达。此外，包含GSDF(Y)的基因组片段的存在将XX个个体转化为可生育的XX个雄性个体。荧光素酶分析表明，GSDF(Y)的上游序列有助于雄性特异性的高表达。在欧洲野生稻性别决定级联中，GSDF位于DMY下游，这表明不依赖于DMY的GSDF等位基因的出现导致了这一新的性别决定基因在吕宋野生稻中的出现。
Three sex-determining (SD) genes, SRY (mammals), Dmy (medaka), and DM-W (Xenopus laevis), have been identified to date in vertebrates. However, how and why a new sex-determining gene appears remains unknown, as do the switching mechanisms of the master sex-determining gene. Here, we used positional cloning to search for the sex-determining gene in Oryzias luzonensis and found that Gsdf(Y) (gonadal soma derived growth factor on the Y chromosome) has replaced Dmy as the master sex-determining gene in this species. We found that Gsdf(Y) showed high expression specifically in males during sex differentiation. Furthermore, the presence of a genomic fragment that included Gsdf(Y) converts XX individuals into fertile XX males. Luciferase assays demonstrated that the upstream sequence of Gsdf(Y) contributes to the male-specific high expression. Gsdf is downstream of Dmy in the sex-determining cascade of O. latipes, suggesting that emergence of the Dmy-independent Gsdf allele led to the appearance of this novel sexdetermining gene in O. luzonensis.