Isolation and characterization of sperm associated genes

我们从减去的cDNA文库中克隆了单倍体生殖细胞特异性cDNA，该文库是通过从35日龄小鼠睾丸的cDNA中减去17日龄小鼠睾丸（在单倍体生殖细胞发育之前）的mRNA产生的。详细的mRNA表达分析表明，克隆cdna对应的基因在生殖细胞的所有分化阶段、特定分化阶段或单倍体生殖细胞发育的特定阶段均有特异性表达。所有这些基因的表达都受到发育控制。生殖细胞特异性基因编码的产物包括在细胞稳态方面发挥各种作用的蛋白质。特别是，一些蛋白质代表了以前已知的能量代谢酶的生殖细胞特异性同工酶。我们还分离了单倍体特异性基因的基因组DNA，并在基因启动子区域鉴定了许多对转录至关重要的调控基序。其中一个基序，环AMP反应元件，存在于几个睾丸特异性基因的启动子区域，被认为在功能上很重要。然而，haspin基因启动子区域不包含CRE基序。同样，在单倍体生殖细胞中特异性表达的MMP-28 （Illman et al. 2001）、激素敏感脂肪酶（Blaise et al. 2001）、ldhc（Jethanandani and Goldberg 2001）、SP-10（Reddi et al. 1999）基因的启动子区域也不包含CRE基元。这些发现表明存在不同的单倍体生殖细胞特异性调节蛋白，特异性调节单倍体生殖细胞特异性基因的表达。在这里，我们描述了我们在生殖细胞特异性基因和基因产物方面的最新发现，并讨论了我们的方法与生殖细胞分化机制研究的相关性。

We have cloned haploid germ-cell-specific cDNAs from a subtracted cDNA library that was generated by subtracting the mRNA of 17-day-old mouse testes (before haploid germ cells develop) from the cDNA of 35-day-old mouse testes. Detailed mRNA expression analysis revealed that the genes corresponding to the cloned cDNAs were exclusively expressed in germ cells at all steps of differentiation, at specific steps of differentiation, or at specific steps in the development of haploid germ cells. The expression of all of these genes was developmentally controlled. The products of germ-cell-specific genes encoded products included proteins of all sorts of roles in aspect of cellular homeostasis. Particularly, some proteins represented germ-cell-specific isozymes of previously known enzymes in energy metabolism. We also isolated the genomic DNA of haploid-specific genes and identified a number of regulatory motifs in the gene-promoter regions that were essential for transcription. One of these motifs, the cyclic AMP response element, was present in the promoter regions of several testis-specific genes, and was deemed to be functionally important. However, the haspin gene-promoter region did not contain a CRE motif. Similarly, the promoter regions of the MMP-28 (Illman et al. 2001), Hormone-sensitive lipase (Blaise et al. 2001), ldhc(Jethanandani and Goldberg 2001), SP-10(Reddi et al. 1999) genes which were specifically expressed in haploid germ cells, did not contain CRE motifs. These findings suggest the existence of different haploid germ-cell-specific regulatory proteins that specifically regulate the expression of haploid germ-cell-specific genes. Here, we describe our recent findings regarding germ-cell-specific genes and gene, products, and we discuss the relevance of our approaches to the study of germ cell differentiation mechanisms.