摘要
从大鼠精子尾部基因Spag4出发 ,在dbEST数据库中同源搜寻与大鼠Spag4基因编码氨基酸同源性较高的表达序列标签 (ExpressedSequenceTag ,EST) ,找到两个在小鼠精母细胞中表达的ESTs ,BG10 1130和BG10 0 990。通过电子杂交得到 115 5bp的片段 ,包含了小鼠假想基因AK0 0 6 2 2 5的全部序列 ,定位于 2H1 H2 ,其开放阅读框为 87～ 1133bp ,并被RT PCR所证实 ,将该基因命名为小鼠生精相关基因 4 (SpermatogenesisRelatedGene 4 ,SRG4 ,GenBank登录号为AY30 70 77)。SRG4基因推定编码 348个氨基酸 ,有一个coiled coil区 ,可能是一个跨膜蛋白。该基因与人类同源基因TSARG4同源性为 74 % (2 77/374 ) ,与大鼠Spag4同源性为 4 5 % (10 3/22 4 )。多组织RT PCR和Northernblot结果显示 ,SRG4在睾丸中特异性表达。RT PCR结果发现 ,小鼠出生后 2周内 ,SRG4表达量极低 ;3周开始时SRG4大量表达 ,到 4～ 5周时表达量最高。该结果提示 。
Spermatogenesis required lots of genes taking part in this process.In prevision studies,Odf1,Odf2,Sak57,Spag4,Spag5 were identified in mouse and rat sperm tail developing.Two ESTs ,BG101130 and BG100990,which coded amino acid sequences with high homology to rat Spag4,were found from mouse spermatocytes.By electrical hybridization,a 1 155 bp sequence was obtained and named as SRG4(Spermatogenesis Related Gene 4)(GenBank accession number: AY307077),which included the full-length sequence of mouse testis hypothetical gene AK006225.The opening reading frame of SRG4 was 87～1 133 bp,and was proved by RT-PCR in mouse testis.The information analysis showed SRG4 gene was located in 2H1-H2,and the putative protein was 348-amino acid with a coiled-coil region,suggesting SRG4 might function as a transmembrane protein.The homologies of amino acid sequences were 74% between TSARG4 and SRG4 gene and 45% between SRG4 and rat Spag4 gene,respectively.RT-PCR and Northern blot results showed SRG4 gene expressed specifically in mouse testis.Changes of SRG4 expression in mouse different developing stages were observed.The results showed SRG4 gene expressed slightly in two weeks postpartum,and expressed abundantly from three weeks,and reached the top at 4～5 weeks.This indicted SRG4 gene may play an important role in mouse spermatogenesis.
基金
国家重点基础研究发展规划 ( 973 )资助项目 (编号 :G19990 5 5 90 1)~~
