牛1gG高亲和力受体的分子克隆及序列分析

报道编码牛 Ig G高亲和力受体 ( bovine Ig G Fc receptor I,bo FcγR )的全长序列 .从牛肺巨噬细胞 c DNA文库中克隆的该片段全长 1 .4kb,其中的 ORF为 1 0 50 bp,共编码包括信号肽、胞外域、穿膜区和胞内区在内的 349个氨基酸 ,含有 5个潜在的 N-连接糖基化位点 .与人和鼠的 Ig G高亲和力受体 ( hu FcγR 和 mo FcγR )相比 ,其核苷酸同源性分别为 80 %和 69% ,氨基酸同源性分别为 66%和 55% .研究表明 ,人、牛和鼠的 3种 Ig G高亲和力受体的单体 Ig G结合域高度保守

Molecular Cloning and Sequence Analysis of High Affinity Fc Receptor for Bovine IgG

Receptor I for the Fc region of immunoglobulin G (FcγRⅠ) is a member of superfamily with high affinity to IgG and mediates antibody dependent cellular cytotoxicity and immune complex clearance.A cDNA encoding bovine high affinity Fc receptor was cloned and sequenced.The full length cDNA sequence was 1050 bp with a short 5′ end and long 3′ end untranslated regions,which encoded for 349 amino acids and contained the signal peptide,extracellular region with 3 Ig like domains,transmembrane and intracytoplasmic domain.Five potential N linked glycosylation sites were recognized in this sequence.Compared with the sequences of human and mouse FcγRⅠ,the homologies of nucleotide sequences were 80% and 69% and homologies of deduced amino acid sequences were 66% and 55% respectively.It is shown that the sequences of monomeric IgG binding domain of FcγRⅠ in the three species are highly conserved.