HORMONAL REGULATION OF GENE EXPRESSION IN SERTOLI CELLS

FSH和雄激素作用于支持细胞，调节 蛋白质的功能，在控制精子发生，但是， 这些激素调节Sertoli基因表达的机制不是 知道的 一种主要的分泌蛋白，雄激素- 结合蛋白（ABP），平行的精子发生的调节。 期间 在两年的资助下，我们开发了大鼠ABP基因作为模型， 系统来研究酶介导的基因的分子机制 支持细胞的调节。 我们的成就包括隔离和 睾丸ABP cDNA和ABP基因的表征。 此外如 通过合作，我们克隆了大鼠雄激素， 受体（AR）cDNA，并产生特异性抗体AR。 ABP cDNA 作为探针，我们已经开始阐明ABP激素的作用机制， 调控 与上述开发的工具，我们建议扩展这些 研究有三个具体目标：1。 定位ABP基因调控元件， 包括启动子、支持细胞特异性增强子元件和激素 调节元件，利用CAT载体的体外转染 在原代支持细胞和转基因动物上的构建体。 2. 划定 FSH和雄激素对ABP基因表达的影响。 体外研究 支持细胞培养将用于确定这些激素是否具有 直接或间接影响ABP基因表达。 我们还将确定 其他激素、旁分泌和自分泌因子的调节作用。 3. 帮助破译ABP在睾丸中的功能和作用方式， 附睾 这些研究包括ABP的细胞定位 睾丸和附睾的膜受体和类固醇的定位， 通过体外诱变测定ABP的结合结构域。 这些研究还包括 通过小鼠ABP基因的连锁分析寻找ABP突变体。 研究ABP基因在脑组织中的表达可能为ABP的研究提供新的思路 功能 我们的研究将有助于对支持细胞基因的认识 ABP是一种主要的支持细胞分泌蛋白， 蛋白 这种维持精子发生的作用，将有助于 生育缺陷的鉴定和可能的治疗。

FSH and androgens act on Sertoli cells to regulate the secretion of proteins that function in the control of spermatogenesis, however, the mechanisms by which these hormones regulate Sertoli gene expression is not known. The expression of one of the major secretory proteins, androgen- binding protein (ABP), parallels the regulation of spermatogenesis. During the two years of funding we have developed the rat ABP gene as a model system to study the molecular mechanisms of hormone-mediated gene regulation of the Sertoli cell. Our accomplishments include isolation and characterization of testicular ABP cDNA and the ABP gene. Furthermore, as a collaborative effort we have cloned and characterized the rat androgen receptor (AR) cDNA and generated specific antibodies to AR. With ABP cDNA as probe we have begun elucidation of the mechanisms of ABP hormonal regulation. With the developed tools described above, we propose to extend these studies with three specific aims: 1. Locate ABP gene regulatory elements, including promoters, Sertoli cell specific enhancer elements and hormone regulatory elements, utilizing in vitro transfection of CAT vector constructs on primary Sertoli cells and transgenic animals. 2. Delineate the effects of FSH and androgen on ABP gene expression. In vitro studies with Sertoli cell cultures will be used to determine if these hormones have direct or indirect effects on ABP gene expression. We will also determine modulatory effects of other hormones, paracrine and autocrine factors. 3. Help decipher the function(s) and mode of action of ABP in the testis and epididymis. These studies include cellular localization of the ABP membrane receptor in testis and epididymis and mapping of the steroid- binding domain of ABP by in vitro mutagenesis. These studies also include a search for ABP mutants by linkage analysis of the mouse ABP gene. Studies of ABP gene expression in brain may provide new insights into ABP function. Our studies will contribute greatly to the knowledge of Sertoli cell gene regulation and the function(s) of ABP, a major Sertoli cell secretory protein. This maintenance of spermatogenesis, and will aid in the identification and possible treatment of fertility defects.