Dax1 suppresses P450arom expression in medaka ovarian follicles
Dax1 suppresses P450arom expression in medaka ovarian follicles
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DOI：
10.1002/mrd.20689
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发表时间：
2007-10-01
影响因子：
2.5
通讯作者：
Shibata, Naoki
中科院分区：
文献类型：
--
作者：
Nakamoto, Masatoshi;Wang, De-Shou;Shibata, Naoki
Dax 1是一个罕见的孤儿核受体家族的成员，已知在哺乳动物中调节P450 arom，并参与一些脊椎动物的性别分化。为了研究是否Dax 1参与调节青鳉卵巢卵泡中雌激素生物合成的类固醇生成途径，我们分离了成年青鳉卵巢的Dax 1 cDNA，并分析了其在青鳉性腺中的表达模式。在成年卵巢中，Dax 1 mRNA仅在卵黄发生后卵泡中检测到，而在卵黄发生前卵泡和卵黄发生卵泡中未检测到。在成年睾丸中未检测到Dax 1 mRNA。我们比较了Dax 1与Fox 12，Ad 4 BP/Sf-1，P450 c17和P450 arom的表达模式，通过原位杂交使用相邻切片。与Dax 1表达相反，这些基因在卵黄发生卵泡中共表达，但在卵黄发生后卵泡中未检测到。因此，在青鳉卵巢卵泡中，Dax 1没有显示出任何与Fox 12，Ad 4 BP/Sf-1，P450 c17和P450 arom重叠的表达模式。此外，共转染实验表明，Dax 1抑制Ad 4 BP/Sf-1-和Fox 12-介导的P450 arom表达。另一方面，在性别分化早期，Dax 1 mRNA在雄性和雌性中均未检测到。我们的研究结果表明，Dax 1下调Ad 4 BP/Sf-l-和Fox 12介导的青鳉卵巢卵泡P450 arom的表达。
Dax1 is a member of an unusual orphan nuclear receptor family, and is known to regulate P450arom in mammals and is involved in sex differentiation in some vertebrates. To investigate whether Dax1 is involved in the regulation of the steroidogenic pathway for estrogen biosynthesis in medaka ovarian follicles, we isolated Dax1 cDNA from adult medaka ovaries and analyzed its expression pattern in medaka gonads. In adult ovaries, Dax1 mRNA was detected only in postvitellogenic follicles and was not detected in previtellogenic and vitellogenic follicles. In adult testis, Dax1 mRNA was not detected. We compared the expression pattern of Dax1 with that of Fox12, Ad4BP/Sf-1, P450c17, and P450arom by in situ hybridization using adjacent sections. In contrast to Dax1 expression, these genes were co-expressed in vitellogenic follicles but were not detected in postvitellogenic follicles. Thus, in medaka ovarian follicles, Dax1 did not show any overlapping expression patterns against Fox12, Ad4BP/Sf-1, P450c17, and P450arom. Moreover, co-transfection experiments demonstrated that Dax1 inhibits Ad4BP/Sf-l- and Fox12-mediated P450arom expression. On the other hand, during early sex differentiation, Dax1 mRNA was not detected in both males and females. Our results suggest that Dax1 down-regulates Ad4BP/Sf-l- and Fox12-mediated P450arom expression in medaka ovarian follicles.