半胱氨酸蛋白酶抑制剂家族2相关新基因Rcet3的克隆

目的 利用NCBI中的DDD(数字差异显示)数据库及RT-PCR技术克隆睾丸等组织中特异表达的新基因.方法 利用NCBI中的DDD数据库首先电子克隆了Rcet3基因,并从成年小鼠睾丸组织中利用RT-PCR克隆出Rcet3全长基因,然后测序及序列分析.结果 序列分析显示,Rcet3基因全长cDNA为610bp,含4个外显子,编码一个140个氨基酸残基的蛋白,该蛋白含一个半胱氨酸蛋白酶抑制剂结构域,但缺少半胱氨酸蛋白酶抑制剂关键的作用位点,而这些位点对半胱氨酸蛋白水解酶的抑制作用足重要的.Rcet3在成年老鼠睾丸、附睾和大脑等生殖域中特异表达,睾丸中的表达高于附睾和大脑,Rcet3与半胱氨酸蛋白酶抑制家族2的Cres亚家族具有相似的特征.结论 Rcet3可能是半胱氨酸蛋白酶抑制剂家族2,Cres亚家族中的一个新成员.

Cloning of Rcet3, a novel gene related to family 2 cystatins

OBJECTIVE: To clone the full-length Rcet3 gene, a novel gene related to family 2 cystatins, from mouse testis or other tissues. METHODS: Rcet3 gene was cloned using digital differential display (DDD) and RT-PCR was performed for cloning the full-length Rcet3 gene from adult mouse testis cDNA library with sequence analysis. RESULTS: Rcet3 cDNA was 610 bp in length, consisting of 4 exons to encode a protein with 140 amino acid residues. The encoded protein contained a potential signal peptide and a cystatin domain, but lacked critical consensus site important for cysteine protease inhibition. These characteristics could be seen in the Cres subgroup related to the family 2 cystatains. Rcet3 was specifically expressed in adult mouse testis, epididymis and the cerebrum, but at higher levels in the testis than in the epididymis and cerebrum. CONCLUSION: Rcet3 may be a new member of Cres subgroup of family 2 cystatins.