Estrogen represses SOX9 during sex determination in the red-eared slider turtle Trachemys scripta
Estrogen represses SOX9 during sex determination in the red-eared slider turtle Trachemys scripta
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DOI：
10.1016/j.ydbio.2010.02.010
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发表时间：
2010-05-01
影响因子：
2.7
通讯作者：
Capel, Blanche
中科院分区：
文献类型：
--
作者：
Barske, Lindsey A.;Capel, Blanche
胎生真兽类哺乳动物产生雄性后代需要一种抵抗母体激素的性别决定机制。这种限制在产卵物种中得到了放松，它们在性别决定过程中对激素敏感，并且经常使用芳香酶（雌激素合成酶）的增加作为关键的女性化信号。在龟龟中，性别通常由温度决定，但雌激素处理超越了这一线索，只导致雌性发育。我们评估了龟中雌性激素信号传导是否调节 SOX9（哺乳动物中雄性决定性别的中心基因）或其他三个保守转录因子（WT1、GATA4 和 LHX9）的表达。与小鼠一样，未成熟龟性腺中的所有体细胞类型最初都表达 WT1 和 GATA4，而 SOX9 仅限于支持细胞前体，LHX9 仅限于体腔上皮和间质。双潜能期过后，SOX9 在雌性体温下突然下调。引人注目的是，在雄性温度下用 β-雌二醇处理的胚胎比对照早两个阶段失去 SOX9 表达，尽管 WT1、GATA4 和 LHX9 不受影响。相反，抑制雌激素合成和信号传导可阻止或延迟 SOX9 在雌性体温下的下调。这些结果表明内源性雌激素通过抑制 SOX9 表达使双能龟性腺髓质女性化。这种机制可能与暴露于环境雌激素的野生种群中的雄性向雌性性逆转有关，并且与雌激素受体抑制Sox9以阻止成年小鼠卵巢中颗粒细胞转分化为支持样细胞的结果一致。 (C) 2010 Elsevier Inc. 保留所有权利。
Production of male offspring in viviparous eutherian mammals requires a sex-determining mechanism resistant to maternal hormones. This constraint is relaxed in egg-laying species, which are sensitive to hormones during sex determination and often use an increase in aromatase, the estrogen-synthesizing enzyme, as a key feminizing signal. In the turtle Trachemys scripta, sex is normally determined by temperature, but estrogen treatment overrides this cue and leads exclusively to female development We assessed whether the expression of SOX9, a central male sex-determining gene in mammals, or three other conserved transcription factors (WT1, GATA4, and LHX9) was regulated by estrogen signaling in the turtle. As in mice, all somatic cell types in the immature turtle gonad initially expressed WT1 and GATA4, whereas SOX9 was restricted to the Sertoli precursors and LHX9 to the coelomic epithelium and interstitium. After the bipotential period, SOX9 was abruptly down-regulated at the female temperature. Strikingly, embryos treated with beta-estradiol at the male temperature lost SOX9 expression more than two stages earlier than controls, though WT1, GATA4, and LHX9 were unaffected. Conversely, inhibition of estrogen synthesis and signaling prevented or delayed SOX9 down-regulation at the female temperature. These results suggest that endogenous estrogen feminizes the medulla of the bipotential turtle gonad by inhibiting SOX9 expression. This mechanism may be involved in the male-to-female sex reversal in wild populations exposed to environmental estrogens, and is consistent with results showing that the estrogen receptor represses Sox9 to block transdifferentiation of granulosa cells into Sertoli-like cells in the adult mouse ovary. (C) 2010 Elsevier Inc. All rights reserved.