EXPRESSION OF PREPROENKEPHALIN LIKE MRNA IN THE TESTIS

阿片肽前体，脑啡肽原，由多个 睾丸内的细胞类型，包括睾丸体细胞， 生精细胞 在睾丸上也发现了阿片受体 细胞，表明前脑啡肽产物作为旁分泌 介导对精子发生重要的局部相互作用的因子。 在 此外，PI最近的发现表明， 生精细胞也储存在成熟精子的顶体中， 在顶体反应中释放出来。 因此， 脑啡肽原在受精过程中也有睾丸外的作用 过程 在大鼠和小鼠生精细胞中， 存在的，从生殖细胞特异性启动子产生， 发展规律。 转基因小鼠模型已经被 在大鼠的控制下， 脑啡肽原生殖细胞启动子。 转基因适当表达 在小鼠生精细胞中以发育正确的方式。 这 因此，系统作为一个有用的模型来阐明细胞类型， 精子发生过程中的阶段依赖性转录调控。 的 该建议的具体目标是：（1）确定顺式作用元件 在前脑啡肽原生殖细胞启动子中使用转基因小鼠， 体外DNA结合分析;（2）表征反式作用 与生殖细胞内的调节元件相互作用的因子 启动子;和（3）克隆这些生殖细胞反式激活因子。 的 最终目的是了解反式作用因子的调节 活动有助于在活动的阶段依赖性的变化， 脑啡肽原生殖细胞启动子。

The opioid peptide precursor, proenkephalin, is expressed by multiple cell types within the testis, including testicular somatic cells and spermatogenic cells. Opioid receptors are also found on testicular cells, indicating that proenkephalin products function as paracrine factors mediating local interactions important for spermatogenesis. In addition, recent findings by the PI have shown that peptides derived from spermatogenic cells are also stored in the acrosome of mature sperm and are released during the acrosome reaction. It is therefore possible that proenkephalin also has an extratesticular role during the fertilization process. In rat and mouse spermatogenic cells, novel proenkephalin mRNAs are present that are generated from a germ cell-specific promoter in a developmentally regulated manner. A transgenic mouse model has been developed using a reporter gene under the control of the rat proenkephalin germ cell promoter. Transgenes are appropriately expressed in mouse spermatogenic cells in a developmentally correct manner. This system thus serves as a useful model to elucidate cell-type and stage-dependent transcriptional regulation during spermatogenesis. The specific aims of this proposal are: (1) to identify cis-acting elements within the proenkephalin germ cell promoter using transgenic mice and in vitro DNA binding a analysis; (2) to characterize the trans-acting factors that interact with regulatory elements within this germ cell promoter; and (3) to clone these germ cell trans-activators. The ultimate goal is to understand how regulation of trans-acting factor activity contributes to the stage-dependent variation in activity of the proenkephalin germ cell promoter.