Chen L, Sato M, Inoko H, Kimura M
Department of Molecular Life Science, School of Medicine, Tokai University, Kanagawa, Japan.
Biochem Biophys Res Commun. 1997 Nov 17;240(2):261-8. doi: 10.1006/bbrc.1997.7647.
In an effort to examine the molecular basis of spermatogenesis, we isolated two types of novel cDNA clones specifically expressed in mouse testes. Type A cDNA (2,071 nucleotides) is predicted to encode 347 amino acid residues, whereas type B cDNA (1,536 nucleotides) has a deletion of 535 bp from nucleotides 1,206 to 1,740 of type A cDNA, probably due to alternative splicing. This deletion causes a frame shift of the putative open reading frame at the C-terminal portion of type A cDNA to encode 366 amino acid residues. Northern blot analysis using adult ICR organs demonstrated that both types of mRNAs were specifically expressed in testis, although type B mRNA was more abundant than type A mRNA. RT-PCR analysis revealed that these two mRNAs were also expressed in immature testes at 1, 5, 11, 16 and 24 days after birth. In situ hybridization analysis of adult ICR testes demonstrated that these two mRNAs were expressed in spermatogonia, Sertoli cells and Leydig cells. In the W/ WV mouse testis which lacks c-kit activity and spermatogonia, but contains Sertoli and Leydig cells, both mRNAs were found to be expressed in the latter two types of cells. We therefore termed these novel clones tsec-1, testis-specifically expressed cDNAs-1. The protein products of tsec-1 may play an important role in mammalian spermatogenesis.
为了研究精子发生的分子基础，我们分离出了两种在小鼠睾丸中特异性表达的新型cDNA克隆。A型cDNA（2071个核苷酸）预计编码347个氨基酸残基，而B型cDNA（1536个核苷酸）从A型cDNA的第1206至1740个核苷酸处缺失了535 bp，这可能是由于选择性剪接所致。这种缺失导致A型cDNA C端部分推定的开放阅读框发生移码，从而编码366个氨基酸残基。使用成年ICR器官进行的Northern印迹分析表明，两种mRNA均在睾丸中特异性表达，尽管B型mRNA比A型mRNA更丰富。RT-PCR分析显示，这两种mRNA在出生后1、5、11、16和24天的未成熟睾丸中也有表达。对成年ICR睾丸进行的原位杂交分析表明，这两种mRNA在精原细胞、支持细胞和间质细胞中表达。在缺乏c-kit活性和精原细胞但含有支持细胞和间质细胞的W/WV小鼠睾丸中，发现这两种mRNA在后两种细胞类型中表达。因此，我们将这些新型克隆命名为tsec-1，即睾丸特异性表达cDNA-1。tsec-1的蛋白质产物可能在哺乳动物精子发生中发挥重要作用。
