GATA-BINDING PROTEINS REGULATE TESTICULAR GENE EXPRESSION

本研究项目的长期目标是描绘 参与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，加塔-1因子，一种GATA结合蛋白， 最初被认为是红细胞特异性转录因子， 在调节睾丸细胞核转录中起重要作用。 基因，包括在大肠杆菌中的胰蛋白酶/激活素α-和β-B-亚基基因， MA-10，小鼠Leydig肿瘤细胞系。 我们还证明了 另一种睾丸GATA结合蛋白GAT-4可以选择性地 反式激活激活素/激活素β-B亚基基因。 鉴于 GATA结合蛋白相互作用的机制， 反式激活睾丸基因从未被研究过，在这个 我们建议使用α-和β-B-激活素/激活素， 亚基基因作为mosel系统来研究加塔-1和 加塔-4在控制特定基因表达方面的作用 睾丸 具体目标1是研究 加塔-1相互作用并反式激活大鼠睾丸中的α-谷氨酰胺结合蛋白， 亚基基因在MA-10和大鼠睾丸支持细胞，以检查功能 结构域的加塔-1，并确定蛋白质因子，赋予 加塔-1对α-亚基基因的睾丸特异性反式激活。 具体目标2是比较加塔-1和GATA-2的作用机制。 加塔-4可上调。4.8-kb大鼠胰蛋白酶结合/激活素 β-B亚基基因转录本，以鉴定加塔和GATA样 β-B亚基启动子中负责 睾丸细胞中加塔-1和/或加塔-4因子的反式激活， 并确定加塔-4的相互作用的功能结构域， 反式激活4.8 kb β-B亚基转录物的启动子 并与加塔-1因子进行比较。 具体目标3是 研究加塔的发育和激素调节- 结合蛋白，并与以前的结果进行比较 观察到在Escherichin/激活素α-和β-B-亚基基因。具体 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亚基启动子的蛋白质。 从拟议的研究中获得的观察结果可能会产生一些 关于界定《公约》所涉机制的新资料 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.