STAGE SPECIFIC GERM CELL/SERTOLI CELL INTERACTIONS

有相当多的证据表明，在正常，成熟的睾丸，发展 雄配子与周围的支持细胞相互作用， 相互作用对于精子发生是必不可少的。在大鼠中，一个结果是 这些相互作用是支持细胞表达特定的基因， 生精上皮细胞周期的特定阶段。是 提出这些基因的产物调节生殖细胞的发育 存在于这些阶段或其他重要的睾丸功能。到 研究阶段特异性基因表达支持细胞，我们有 专注于环蛋白-2，半胱氨酸蛋白酶的前酶形式， 组织蛋白酶L这种蛋白质由V-VIII期的支持细胞分泌 小管最近发表的结果提出了三种不同的体内 该蛋白在大鼠睾丸中的功能：[1]降解残留的 被支持细胞吞噬的身体，阻止了 生殖细胞特异性抗原进入一般生理 环境[2]压实之间粘合剂功能的分裂 精子细胞和支持细胞在第六阶段小管，促进 精子细胞向小管内腔的运动。[3]刺激 睾丸间质细胞分泌睾酮。第一个具体的实验 目的测试，在体内，这些建议的功能。第二个具体目标 检查是否CP-2/组织蛋白酶L mRNA的阶段特异性表达， 支持细胞也存在于人类、兔子、野猪和公牛中。等 在其他物种中的表达表明，我们提出的研究， 啮齿类动物适用于这些物种，在未来可能会提供 人类特发性生育的原因。本申请还 提出定义调节阶段的分子机制- CP-2/Cathepsin L基因的特异性转录。我们有 先前证明，随着周期阶段的进展， 生殖细胞依次触发阻遏、去阻遏（或丧失）， 阻遏）、刺激和再阻遏该基因的转录。 生殖细胞的这种调节可以通过增强子和 我们在CP中发现的阻遏和去阻遏区域， 2/组织蛋白酶L基因。因此，我们建议确定顺式作用 这些区域中的元件结合特定的反式作用因子， 特定阶段的方式。我们还建议通过研究小鼠来确定 携带特异性CP-2/组织蛋白酶L-β-半乳糖苷酶转基因， 这些区域负责阶段特异性基因转录。 这些研究的结果将开始阐明 阶段特异性生殖细胞-支持细胞相互作用。

There is considerable evidence that in normal, mature testes, developing male gametes interact with surrounding Sertoli cells and that these interactions are essential for spermatogenesis. In rats, one result of these interactions is the expression by Sertoli cells of specific genes at particular stages of the cycle of the seminiferous epithelium. It is proposed that these genes' products regulate the development of germ cells present in those stages or other important testis functions. To investigate stage-specific gene expression by Sertoli cells, we have focused on Cyclic Protein-2, the pro-enzyme form of the cysteine protease, Cathepsin L. This protein is secreted by Sertoli cells within stage V-VIII tubules. Recent and published results propose three different in vivo functions for this protein in rat testes: [1] Degradation of residual bodies that have been engulfed by Sertoli cells, preventing the release of the germ cell-specific antigens into the general physiological environment. [2] Cleavage of adhesive functions between compacted spermatids and Sertoli cells in stage VI tubules, facilitating the movement of spermatids towards the lumen of the tubule. [3] Stimulation of testosterone secretion by Leydig cells. Experiments in the first specific aim test, in vivo, these proposed functions. The second specific aim examines whether the stage-specific expression of CP-2/Cathepsin L mRNA by Sertoli cells also occurs in humans, rabbits, boar and bulls. Such expression in other species would indicate that our proposed studies in rodents are applicable to those species and in the future might provide insight into causes of human idiopathic fertility. This application also proposes to define the molecular mechanisms which regulate the stage- specific transcription of the gene encoding CP-2/Cathepsin L. We have previously demonstrated that with progression of the stages of the cycle, germ cells sequentially trigger the repression, derepression (or loss of repression), stimulation and re-repression of transcription of this gene. Such regulation by germ cells may be mediated by an enhancer and by repressor and derepressor regions that we have identified in the CP- 2/Cathepsin L gene. We, therefore, propose to identify the cis-acting elements in these regions which bind specific transacting factors in a stage-specific manner. We also propose to determine, by studying mice carrying specific CP-2/Cathepsin L-beta-galactosidase transgenes, whether these regions are responsible for stage-specific gene transcription. Results from these studies will begin to elucidate the molecular basis for a stage-specific germ cell-Sertoli cell interaction.