INTRATESTICULAR REGULATION OF INHIBIN AND POMC GENES

在本供资期间，我们和其他人证明了 睾丸POMC基因不仅在间质细胞中表达，而且在 生殖细胞。该基因的表达依赖于相互作用 在这两种细胞类型之间。最近关于抑制素的研究已经开始 生殖生理调控研究的新领域。 由Sertoli细胞合成的抑制素肽被证明可以调节 间质细胞类固醇合成及其众所周知的功能 调节脑下FSH的分泌。因此，抑制素也被认为是 是精子发生的重要调节因子。此外，POMC派生的 多肽是Sertoli细胞功能的重要旁分泌调节剂 抑制素的产生。这些新的观察结果表明， 抑制素基因在Sertoli细胞中的表达及POMC基因在间质中的表达 生殖细胞之间可能相互调节。因此，我们建议 以抑制素和POMC为模型系统研究睾丸内 支持细胞、间质细胞和生殖细胞中基因表达的调控。这个 植物POMC基因结构及其调控的研究进展 在过去的几年里，睾丸已经积累起来了。然而， 抑制素基因在支持细胞中的表达及其调控 还没有得到很好的研究。我们的第一个具体目标是 大鼠睾丸抑制素亚单位编码基因的结构。 其次，我们将研究体外差异性调控。 抑制素亚单位基因在大鼠支持细胞原代培养中的表达 旁分泌调节剂已知影响支持细胞功能的因素 (POMC衍生的多肽和间质细胞蛋白)，或通过细胞 互动。我们将进一步调查上述调节器是否 影响基因转录或mRNA的稳定性。使用这个 信息，然后我们将调查该区域内的 Leydig对动物体内抑制素基因表达的影响 和/或生殖细胞功能或POMC基因调节，受 垂体激素、雄激素或生殖细胞的不同阶段 (具体目标A.3)。最后，我们将确定调控DNA元件， 启动子/调节区和激素反应元件， 负责抑制素α亚单位基因转录，以及 确定参与组织特异性的分子机制 大鼠睾丸POMC基因转录改变(特异靶A.4)。 我们将从这些研究中获得的信息将有助于我们 对男性生殖的性腺内控制的理解。

During the present funding period, we and others demonstrated that testicular POMC gene is expressed not only in Leydig cells but also in germ cells. the expression of this gene depends upon the interaction between these two cell types. The recent studies on inhibin have opened a new field for studying the regulation of reproductive physiology. Inhibin peptides synthesized by Sertoli cells were shown to modulate Leydig cell steroidogenesis in addition to their well-know function of regulating pituitary FSH secretion. Thus, inhibin is also considered to be an important regulator of spermatogenesis. In addition, POMC-derived peptides are important paracrine modulators of Sertoli cell function and inhibin production. These new observations suggest that the expression of inhibin genes in Sertoli cells and the expression POMC gene in Leydig and germ cells may be regulated by each other. We therefore propose to use inhibin and POMC as model systems to study the intratesticular regulation of gene expression in Sertoli, Leydig, and germ cells. The information on the structure of POMC gene and its regulation in the testis have been accumulated in the past years. However, the expressions of inhibin genes and their regulations in the Sertoli cells have not been well studied. Our first specific aim is to characterize the structure of mRNAs coding for inhibin subunits in rat testis. Secondly, we will investigate the in vitro differential regulation of inhibin subunit gene expression in rat Sertoli cell primary cultures by factors know to affect Sertoli cell functions, by paracrine regulators (POMC-derived peptides and Leydig cell proteins), or by cellular interactions. We will further investigate whether the above modulators affect the gene transcription or the mRNA stability. Using this information we will then investigate the intratesticular regulation of inhibin gene expression in animal systems under the influence of Leydig and/or germ cell functions or of POMC gene modulation, affected by pituitary hormones, androgens, or different stages of germ cells (Specific Aim A.3). finally, we will identify regulatory DNA elements, the promotor/regulatory regions and hormone-responsive elements, that are responsible for inhibin alpha-subunit gene transcription, and determine the molecular mechanism involved in the tissue-specific altered transcription of POMC gene in rat testis (Specific Aim A.4). The information we will obtain from these studies will facilitate our understanding of the intragonadal control of male reproduction.