Yamamoto I, Tsukada A, Saito N, Shimada K
Laboratory of Animal Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, 464-8601 Japan.
Poult Sci. 2003 Sep;82(9):1462-7. doi: 10.1093/ps/82.9.1462.
Sex is determined genetically in birds. The homogametic sex is male (ZZ), whereas the heterogametic sex is female (ZW). According to the genetic sex, gonads develop into testes or ovary. In this study, we performed experiments to reveal mRNA expression patterns in the gonad between d 5.5 and 8.5 of incubation and examined a possible role of Dss-Ahc critical region on the X chromosome 1 (Dax1), Steroidogenic factor 1 (Sf1), P450aromatase (P450arom), Estrogen receptor alpha (ER alpha), doublesex and mab3 related transcription factor 1 (Dmrt1), Sry-related HMG box gene 9 (Sox9), Gata binding protein 4 (Gata4), and anti-müllerian hormone (Amh) in sex differentiation in chicken embryonic gonads using RNase protection assay. In embryonic chicken gonads, Dax1 mRNA was expressed in both sexes but was higher in females than in males at d 6.5 and 7.5 of incubation. The Sf1 mRNA was expressed in both sexes, but it was expressed more in males at d 5.5 than in females but more in females than in males at d 7.5 and 8.5 of incubation. The P450arom mRNA was expressed only in female gonads from d 5.5 of incubation. The ER alpha mRNA was expressed in both sexes, but it did not show a sex difference. On the other hand, the Dmrt1 mRNA was expressed in both sexes, but it showed a male-specific expression pattern. The male-specific expression pattern was observed in Sox9 mRNA, but it was not expressed in female gonads. The Gata4 mRNA was expressed in both sexes, and sex differences were not revealed throughout the observational period. Amh mRNA was expressed in both sexes, but it had male-specific mRNA expression pattern at d 6.5 to 8.5 of incubation. These results indicate that Dax1, Sf1, and P450arom have possible roles in ovary formation, whereas Dmrt1, Sox9, and Amh are related to testis formation in differentiating chicken gonads at d 5.5 to 8.5 of incubation.
鸟类的性别由基因决定。同配性别为雄性（ZZ），而异配性别为雌性（ZW）。根据基因性别，性腺发育为睾丸或卵巢。在本研究中，我们进行了实验，以揭示孵化第5.5天至8.5天性腺中的mRNA表达模式，并使用核糖核酸酶保护分析检测了X染色体1上的Dss-Ahc关键区域（Dax1）、类固醇生成因子1（Sf1）、细胞色素P450芳香化酶（P450arom）、雌激素受体α（ERα）、双性和mab3相关转录因子1（Dmrt1）、Sry相关HMG盒基因9（Sox9）、Gata结合蛋白4（Gata4）和抗苗勒管激素（Amh）在鸡胚性腺性别分化中的可能作用。在胚胎期鸡性腺中，Dax1 mRNA在两性中均有表达，但在孵化第6.5天和7.5天时，雌性中的表达高于雄性。Sf1 mRNA在两性中均有表达，但在孵化第5.5天时，雄性中的表达高于雌性，而在孵化第7.5天和8.5天时，雌性中的表达高于雄性。P450arom mRNA仅在孵化第5.5天起的雌性性腺中表达。ERα mRNA在两性中均有表达，但未表现出性别差异。另一方面，Dmrt1 mRNA在两性中均有表达，但呈现雄性特异性表达模式。Sox9 mRNA也呈现雄性特异性表达模式，在雌性性腺中不表达。Gata4 mRNA在两性中均有表达，在整个观察期内未发现性别差异。Amh mRNA在两性中均有表达，但在孵化第6.5天至8.5天时具有雄性特异性mRNA表达模式。这些结果表明，Dax1、Sf1和P450arom在卵巢形成中可能发挥作用，而Dmrt1、Sox9和Amh在孵化第5.5天至8.5天分化中的鸡性腺睾丸形成中有关联。
