Gonadotrope lineage differentiation is a stepwise process taking place during pituitary development. The early step of gonadotrope lineage specification is characterized by the expression of the Nr5a1 transcription factor, a crucial factor for gonadotrope cell fate determination. Abnormalities affecting Nr5a1 expression lead to hypogonadotropic hypogonadism and infertility. Although significant knowledge has been gained on the signaling and transcriptional events controlling gonadotrope differentiation, epigenetic mechanisms regulating Nr5a1 expression during early gonadotrope lineage specification are still poorly understood. Using ATAC chromatin accessibility analyses on three cell lines recapitulating gradual stages of gonadotrope differentiation and in vivo on developing pituitaries, we demonstrate that a yet undescribed enhancer is transiently recruited during gonadotrope specification. Using CRISPR/Cas9, we show that this enhancer is mandatory for the emergence of Nr5a1 during gonadotrope specification. Furthermore, we identify a highly conserved estrogen-binding element and demonstrate that the enhancer activation is dependent upon estrogen acting through ERα. Lastly, we provide evidence that binding of ERα is crucial for chromatin remodeling of Nr5a1 enhancer and promoter, leading to RNA polymerase recruitment and transcription. This study identifies the earliest regulatory sequence involved in gonadotrope lineage specification and highlights the key epigenetic role played by ERα in this differentiation process.

中文翻译：

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垂体ERα激活的增强子的鉴定触发了最早的促性腺家族谱系特异性转录因子Nr5a1的表达。

性腺家族谱系分化是垂体发育过程中发生的逐步过程。促性腺激素谱系规范的早期特征是Nr5a1转录因子的表达，这是决定促性腺激素细胞命运的关键因素。影响Nr5a1表达的异常导致性腺功能减退性腺功能减退症和不育症。尽管已经获得了有关控制性腺型生殖分化的信号传导和转录事件的大量知识，但在早期性腺型生殖谱系规范中调控Nr5a1表达的表观遗传机制仍知之甚少。使用ATAC染色质可及性分析在三个细胞系上概括性腺促性腺激素分化的逐步阶段以及体内垂体发育的垂体，我们证明了在性腺规范期间会暂时募集一个尚未描述的增强子。使用CRISPR / Cas9，我们证明了该增强子对于性腺规范期间Nr5a1的出现是必不可少的。此外，我们确定了高度保守的雌激素结合元件，并证明增强子的激活取决于通过ERα作用的雌激素。最后，我们提供的证据表明，ERα的结合对于Nr5a1增强子和启动子的染色质重塑至关重要，从而导致RNA聚合酶募集和转录。这项研究确定了涉及性腺形态谱系的最早调控序列，并强调了ERα在此分化过程中所起的关键表观遗传作用。我们表明，在促性腺激素规范中，这种增强剂对于Nr5a1的出现是必不可少的。此外，我们确定了高度保守的雌激素结合元件，并证明增强子的激活取决于通过ERα作用的雌激素。最后，我们提供的证据表明，ERα的结合对于Nr5a1增强子和启动子的染色质重塑至关重要，从而导致RNA聚合酶募集和转录。这项研究确定了涉及性腺形态谱系的最早调控序列，并强调了ERα在此分化过程中所起的关键表观遗传作用。我们表明，在促性腺激素规范期间，这种增强剂对于Nr5a1的出现是必不可少的。此外，我们确定了高度保守的雌激素结合元件，并证明增强子的激活取决于通过ERα作用的雌激素。最后，我们提供的证据表明，ERα的结合对于Nr5a1增强子和启动子的染色质重塑至关重要，从而导致RNA聚合酶募集和转录。这项研究确定了涉及性腺形态谱系的最早调控序列，并强调了ERα在此分化过程中所起的关键表观遗传作用。我们提供的证据表明，ERα的结合对于Nr5a1增强子和启动子的染色质重塑至关重要，从而导致RNA聚合酶募集和转录。这项研究确定了涉及性腺形态谱系的最早调控序列，并强调了ERα在此分化过程中所起的关键表观遗传作用。我们提供的证据表明，ERα的结合对于Nr5a1增强子和启动子的染色质重塑至关重要，从而导致RNA聚合酶募集和转录。这项研究确定了促性腺激素谱系规范中涉及的最早的调控序列，并强调了ERα在此分化过程中所起的关键表观遗传作用。