RETINOL-MEDICATED REGULATION OF SPERMATOGENESIS

维生素A已被证明是一种重要的细胞外调节剂 哺乳动物睾丸中生殖细胞的正常发育。 本提案的长期目标是调查 维生素A的一种形式， 调节精子发生的过程。 这将是 通过鉴定视黄醇的靶基因来完成， 睾丸中的调节。 当老鼠被喂食缺乏维生素A的食物时，它们的睾丸 萎缩，生精上皮退化。 这可以 通过腹腔注射视黄醇完全逆转 （Morales和格里斯沃尔德，《内分泌学》，12：432。1987年）。 的 视黄醇诱导的睾丸重新启动精子发生过程， 沿着生精小管以同步的方式进行。 是 假定特异性基因产物和mRNA是在 在支持细胞或 生殖细胞 在这两种情况下， 转录本或新翻译的蛋白质是绝对必要的 在VAD大鼠精子发生的重新启动过程中 睾丸 为了研究视黄醇的功能意义， 在分子水平上诱导睾丸中的mRNA， 从cDNA文库中分离。 具体来说，这将是 通过构建富集的λ cDNA文库来完成， 在未杂交但被视黄醇刺激的序列中。 的 未杂交的序列是单链cDNA，其产生于DNA中。 从视黄醇诱导的细胞中的mRNA的消减杂交， 用来自VAD大鼠睾丸的过量mRNA处理睾丸。 这些克隆的cDNA对于研究 精子发生过程中视黄醇的调节机制。 他们将 进行测序和表征，以确定它们在 睾丸 将研究这些克隆cDNA的表达 在不同的睾丸细胞类型和不同的阶段， 精子发生周期的一部分 此外，这些国家 将研究由视黄醇调节的序列，即， 转录、转录后或翻译。 阐明本 视黄醇对睾丸靶基因作用的分子机制 视黄醇诱导和睾丸组织的调节元件- 特异性将在编码视黄醇的基因中进行研究， 特定蛋白质

Vitamin A has been shown to be an essential extracellular regulator for the normal development of germ cells in the mammalian testis. It is the long term objective of this proposal to Investigate the molecular mechanism by which retinol, a form of Vitamin A, regulates the Process of spermatogenesis. This will be accomplished by identification of target genes for the retinol- modulation in the testis. When rats are fed on a Vitamin A-deficient diet, their testes atrophy and their seminiferous epithelium degenerate. This can be completely reversed by an intraperitoneal injection of retinol (Morales and Griswold, Endocrinology, 12: 432.,1987). The retinol-induced testes reinitiate the spermatogenic process in a synchronized manner all along the seminiferous tubules. It is Presumed that sPecific gene Products and mRNAs are synthesized in direct response to retinol in either the Sertoli cells or in the germinal cells. In either case, the retinol-responsive mRNA transcripts or newly translated proteins are absolutely essential in the reinitiation process of spermatogenesis in the VAD rat testes. In order to investigate the functional significance of the retinol- induced mRNAs in the testes at the molecular level, they will be isolated from a cDNA library. Specifically, this will be accomplished by the construction of a Lambda cDNA library enriched in the unhybridized but retinol-stimulated sequences. The unhybridized sequences are single stranded cDNAs generated in the subtractive hybridization of the mRNAs from the retinol-induced testis with an excess of mRNAs from the VAD rat testes. These cloned cDNAs are essential to investigate the molecular mechanism of retinol regulation during spermatogenesis. They will be sequenced and characterized to identify their function in the testis. The expression of these cloned cDNAs will be investigated in the different testis cell types and during the different stages of the spermatogenic cycle. In addition, the level at which these sequences are regulated by retinol will be investigated, i.e., transcription, post-transcription or translation. To elucidate the molecular mechanism of retinol on testicular target genes, the regulatory elements for the retinol induction and testis tissue- specificity will be investigated in the genes encoding the retinol- specific proteins.