雌激素对中华鳖性腺分化及DMRT1、SOX9基因表达的影响

THE EFFECTS OF ESTROGEN ON GONADAL DIFFERENTIATION AND EXPRESSIONS OF DMRT1 AND SOX9 IN PELODISCUS SINENSIS

中华鳖(Pelodiscus sinensis)性别决定的方式一直存在较大的争议,分子机制更是不清楚。在大部分脊椎动物中,雌激素在性别决定和性腺分化中扮演重要的调控作用。实验通过对性别分化前胚胎进行雌二醇(E2)和芳香化酶抑制剂(AI)处理,研究雌激素在中华鳖性腺分化中的作用及机理。实验结果显示,与对照组(雌性比例49%)相比,E2处理组中雌性中华鳖仔鳖比例显著增加,高达92.3%;而在AI处理组中,雌性比例显著下调至13.1%。HE染色分析表明,ZZ(雄性)和ZW(雌性)胚胎分别经过E2和AI处理后,ZZ和ZW性腺结构呈现明显的雌性化和雄性化特征。同时,通过RT-PCR和免疫荧光染色发现,E2能显著降低雄性性别关键因子DMRT1和SOX9 mRNA和蛋白表达水平;AI则表现相反的调节作用。综上所述,雌激素通过抑制雄性性别关键因子DMRT1和SOX9的表达来抑制雄性分化,促进雌性分化,揭示雌激素在中华鳖雌性性别分化中起着重要的调控作用。

The molecular mechanism of sex determination in Pelodiscus sinensis has been a long-standing mystery.In many vertebrate species,estrogens play a key role in sex determination and gonadal differentiation.To investigate the effect of estrogens in the gonadal differentiation of P.sinensis and the underlying molecular mechanism,we treated the undifferentiated embryos with 17β-estradiol（E2） and aromatase inhibitor（AI）.Results showed that the female ratio increased by 92.3% after E2 treatment,whereas female ratio in AI treatment group decreased dramatically to 13.1%.Meanwhile,the obvious masculinization of genetically female embryos and feminization of genetically male embryos were observed after AI and E2 treatment,respectively.Moreover,RT-PCR and immunofluorescence analysis showed that E2 could significantly downregulated mRNA and protein expressions of DMRT1 and SOX9,which were the key factors involving in male development.However,AI exerted the opposite effect.In conclusion,estrogens inhibited the male development via the inhibition of expression of DMRT1 and SOX9,and consequently led to female development,indicating the important role of estrogens in the female sexual differentiation in Pelodiscus sinensis.