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Molecular mechanisms of sex determination in birds

鸟类性别决定的分子机制

基本信息

批准号：
10044201
负责人：
SHIMADA Kiyoshi
金额：
$ 11.26万
依托单位：
NAGOYA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

Since sex determination and differentiation mechanisms remain unsolved in birds, this project was conducted to elucidate the molecular mechanisms of sexual differentiation of the chicken gonad. The testis produces anti-Mullerian hormone (AMH) and androgen, whereas the ovary produces little AMH but produces estrogen predominantly. Our in situ hybridization study demonstrated that AMH mRNA was expressed as early as day 5 of incubation followed by a sharp increase on day 6 of incubation in males, which was subsequently maintained. In contrast, the female showed minimum levels of expression. Conversely, aromatase mRNA was expressed in the gonad as early as day 6 of incubation in female but little in the male. Possible transcription factors affecting the AMH and aromatase genes include Sox 9, Sf-1, Dax-1, and Dmrt-1. Sox 9 mRNA is predominantly expressed in male gonad, although it is expressed after the expression of AMH.The Sf-1 mRNA expression is sexually dimorphic after day 7.5 of incubation and expression is higher in the female gonad than in the male gonad. In the chicken Dax-1 mRNA is expressed in the chicken gonad in both sexes. Chicken Dmrt-1 gene on the Z chromosome was expressed in the genital ridge and Wolffian duct prior to sexual differentiation and is expressed at higher levels in male than in female embryos. Furthermore, this is expressed prior to AMH expression in male. This sex- and time-specific expression makes this gene an especially good candidate to be involved in avian sex determination.

由于鸟类的性别决定和分化机制仍未解决，因此该项目旨在阐明鸡性腺性别分化的分子机制。睾丸产生抗苗勒氏管激素 (AMH) 和雄激素，而卵巢产生少量 AMH，但主要产生雌激素。我们的原位杂交研究表明，AMH mRNA 早在孵化第 5 天就在雄性中表达，随后在孵化第 6 天急剧增加，并随后得以维持。相比之下，雌性表现出最低水平的表达。相反，芳香酶 mRNA 早在孵化第 6 天就在雌性性腺中表达，但在雄性中表达很少。影响 AMH 和芳香酶基因的可能转录因子包括 Sox 9、Sf-1、Dax-1 和 Dmrt-1。 Sox 9 mRNA 主要在雄性性腺中表达，尽管它在 AMH 表达之后表达。Sf-1 mRNA 表达在孵育 7.5 天后呈两性二态性，并且雌性性腺中的表达高于雄性性腺中的表达。在鸡中，Dax-1 mRNA 在两性鸡的性腺中都有表达。鸡 Z 染色体上的 Dmrt-1 基因在性分化之前在生殖嵴和沃尔夫管中表达，并且在雄性胚胎中的表达水平高于雌性胚胎。此外，其在男性中的表达早于AMH表达。这种性别和时间特异性表达使该基因成为参与鸟类性别决定的特别好的候选基因。