猪、鼠、羊补体C3d分子cDNA的克隆及序列分析

Cloning and sequences analysis of the complement C3d cDNA of porcine,mouse and sheep

为比较不同动物的补体C3d基因序列,本研究参考已报道的人、鼠、牛的C3d基因序列设计引物,分别从小鼠、猪、羊的肝脏组织中扩增获得鼠、猪、羊的补体C3d基因。以鼠、猪、羊的肝脏中提取总RNA为模板,通过RT-PCR扩增出C3d分子的cDNA克隆到pMDl8-T载体中,转化大肠杆菌,经酶切鉴定后进行序列测定,并利用生物信息学工具软件对3种C3d蛋白的理化和生物学性质进行分析。鼠C3d基因与人、猪、羊C3d基因的同源性分别为83%、82%、81%,牛和羊C3d基因的同源性为94%。鼠、猪、羊的补体C3d分子与受体CR2结合的功能区同源性很高,只有个别位置氨基酸发生了突变,可能具有相同的结构和功能。

The C3d gene from mouse, porcine and sheep were amplified from total RNA by RT-PCR using primes designed according to C3d gene sequences of human, mouse and cattle. The cDNA fragments were cloned and sequenced. Bioinformatics analyses showed that the C3d of mouse had a sequence similarity of 83 %, 82 %and 81% at the amino acid level with human, porcine and sheep C3d respectively, and the C3d of sheep shared 94 % similarity with cattle. The complement receptor2 （CR2）- binding site on C3d of mouse, porcine and sheep was highly conserved, suggesting these receptor binding regions have consistent structure and function.