GATA-BINDING PROTEINS REGULATE TESTICULAR GENE EXPRESSION

这项研究项目的长期目标是勾勒出 涉及控制雄性生殖的分子机制。一 我们最近取得的主要进展之一是提供了第一个 有证据表明，GATA-1因子是一种GATA结合蛋白，它是 最初被认为是一种红系细胞特异性转录因子， 在调节睾丸转录方面起着重要作用 包括抑制素/激活素α和βB亚单位基因在内的基因 MA-10，小鼠间质瘤细胞系。我们还展示了 另一种睾丸GATA结合蛋白GAT-4可以选择性地 反式激活抑制素/激活素β-B亚单位基因。有鉴于此 GATA结合蛋白(S)相互作用的机制 反式激活睾丸基因从未被研究过，在这里 应用我们建议使用抑制素/激活素α-和β-B- 亚基基因作为Mosel系统研究GATA-1和GATA-1的作用 GATA-4对肿瘤细胞中特定基因表达的调控 睾丸。具体目标1是研究通过什么机制 GATA-1相互作用并反式激活大鼠睾丸抑制素α- 在MA-10和大鼠支持细胞中检测亚单位基因的功能 GATA-1的结构域，并鉴定与GATA-1相关的蛋白质因子 GATA-1对睾丸特异性α亚基基因的反式激活。 具体目标2是比较GATA-1和GATA-1 GATA-4上调启动子。4.8kb的大鼠抑制素/激活素 β-B亚单位基因转录本，用于鉴定GATA和GATA样蛋白 β-B亚单位启动子中的序列，负责 GATA-1和/或GATA-4因子对睾丸细胞的反式激活， 并确定GATA-4相互作用和 反式激活4.8 kbβ-B亚单位转录本的启动子 并与GATA-1因子进行比较。具体目标3是 研究GATA-2的发育和激素调节 大鼠睾丸中的结合蛋白及其与以前的比较 在抑制素/激活素α和βB亚单位基因中观察到。特定的 目的4是分离和鉴定新的睾丸GATA结合 反式激活α和/或β-B亚单位启动子的蛋白质(S)。 从拟议的研究中获得的观察结果可能会产生一些 关于划定 睾丸生理学的控制。

The long-term goal of this research project is to delineate the molecular mechanisms involved in controlling male reproduction. One of the major advances we have made recently is to provide the first evidence that GATA-1 factor, a GATA-binding protein which was originally considered as an erythroid cell-specific transcription factor, plays an important role in regulating the transcription of testicular genes including inhibin/activin alpha- and beta-B-subunit genes in MA-10, a mouse Leydig tumor cell line. We also demonstrated that another testicular GATA-binding protein, GAT-4, can selectively transactivate inhibin/activin beta-B-subunit gene. In view that the mechanisms by which GATA-binding protein(s) interacts and transactivates testicular genes have never been investigated, in this application we propose to use inhibin/activin alpha- and beta-B- subunit genes as mosel systems to study the actions of GATA-1 and GATA-4 on the control of the expression of specific genes in the testis. Specific Aim 1 is to investigate the mechanisms by which GATA-1 interacts and transactivates the testicular rat inhibin alpha- subunit gene in MA-10 and rat Sertoli cells, to examine the functional domains of GATA-1, and to identify protein factors that confer the testis-specific transactivaion of the alpha-subunit gene by GATA-1. Specific Aim 2 is to compare the mechanisms by which GATA-1 and GATA-4 upregulate the promoter for. the 4.8-kb rat inhibin/activin beta-B-subunit gene transcript, to identify the GATA and GATA-like sequences in the beta-B-subunit promoter that are responsible for the transactivation by GATA-1 and/or GATA-4 factor in testicular cells, and to determine the functional domains of GATA-4 that interact and transactivate the promoter for the 4.8-kb beta-B-subunit transcript and compare with those of GATA-1 factor. Specific Aim 3 is to investigate the developmental and hormonal regulation of GATA- binding proteins in rat testis and compare to those previously observed in inhibin/activin alpha- and beta-B-subunit genes. Specific Aim 4 is to isolate and characterize new testicular GATA-binding protein(s) that transactivates alpha- and/or beta-B-subunit promoters. The observations obtained from the proposed studies may yield some new information on the delineation of the mechanisms involved in the controls of testicular physiology.