MECHANISMS OF GNRH RECEPTOR GENE EXPRESSION

促性腺激素释放激素释放、促性腺激素释放激素受体数量与血管生成的关系 促性腺激素中黄体生成素和卵泡刺激素的合成和分泌已得到很好的证实。 虽然对促性腺激素释放激素受体基因的表达知之甚少 促性腺激素--常见α-糖蛋白亚单位基因的启动子 似乎被多个反式作用的协同结合激活 包括孤儿核受体、类固醇生成因子-1(SF-1)在内的因子。 1)。转基因小鼠中SF-1基因的破坏导致 其他方面，编码共同阿尔法的基因表达减少 以及独特的促黄体生成素和卵泡刺激素β亚基，以及促性腺激素释放激素受体。最近， 我们已经证明了GnRH近端启动子的500个碱基对 受体基因足以驱动瞬时荧光素酶的表达 促性腺激素来源的α-T3细胞系的转染。这是一样的 载体也被过表达的SF-1激活，去掉了它的配体 结合区域，在非促性腺激素细胞中。此外，暂时性的 含系列报告载体的α-T3细胞的转基因研究 从-500到-400的5‘缺失显示启动子的逐步减少 被几个反式作用因子结合的活性。在灯光下 在这些数据中，我们假设SF-1结合是必要的，但不是 足以表达促性腺激素释放激素受体基因。 因此，这项研究提案的目的是：1)确定SF-1是否 是GnRH受体启动子充分基础活性所必需的；以及2) 要确定全面基础活动所需的其他组件 促性腺激素。这些研究将有助于我们理解 促性腺激素基因表达与多个顺式作用机制的相互作用 赋予细胞特异性基因表达的元件。

The relationship between GnRH release, GnRH receptor numbers, and the synthesis and secretion of LH and FSH in gonadotropes is well established. While relatively little is known about GnRH receptor gene expression in gonadotropes, the promoter of the common alpha-glycoprotein subunit gene appears to be activated by cooperative binding of multiple trans-acting factors including the orphan-nuclear receptor, steroidogenic factor-1(SF- 1). Disruption of the SF-1 gene in transgenic mice resulted in, among other things, decreased expression of the genes encoding the common alpha and unique beta subunits of LH and FSH, and the GnRH receptor. Recently, we have shown that 500 basepairs of proximal promoter from the GnRH receptor gene are sufficient to drive luciferase expression in transient transfections of the gonadotrope-derived alphaT3 cell line. This same vector was also activated by overexpression of SF-1, minus its ligand binding domain, in non-gonadotrope cells. Furthermore, transient transfections of alphaT3 cells with reporter constructs containing serial 5' deletions from -500 to -400 revealed a stepwise decrease in promoter activity indicative of binding by several trans-acting factors. In light of these data, we hypothesize that SF-1 binding is necessary, but not sufficient for gonadotrope expression of the GnRH receptor gene. Therefore, the aims of this research proposal are: 1) to determine if SF-1 is necessary for full basal activity of the GnRH receptor promoter; and 2) to identify the other components necessary for full basal activity in gonadotropes. These studies will contribute to our understanding of gonadotrope gene expression and the interactions of multiple cis-acting elements to confer cell-specific gene expression.