Characterization of the bovine Cα gene
Characterization of the bovine Cα gene
复制标题
牛 Cα 基因的表征
DOI：
--
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
L. Hammarström
中科院分区：
文献类型：
--
作者：
W. Brown;H. Rabbani;J. Butler;L. Hammarström
本文报道了牛 Cα 基因的完整基因组序列。基因组序列是从 Cα 噬菌体克隆获得的，该克隆是从基因组 EMBL4 噬菌体载体库中克隆的。 Cα 序列之前已表达为嵌合抗体，并使用 IgA 特异性抗体鉴定为 IgA。通过将基因组序列与通过逆转录聚合酶链式反应 (RT-PCR) 从脾脏获得的表达牛 Cα 序列进行比较来确定内含子/外显子边界。使用基因组印迹和五种不同的限制性酶对 50 份瑞典牛基因组 DNA 样本进行分析，未能检测到多态性的证据。然而，Brown Swiss DNA 的 PstI 消化显示出限制性片段长度多态性 (RFLP)，表明至少存在两种牛 IgA 等位基因变体。将推导的牛 IgA 氨基酸序列与其他物种可用的序列进行比较表明，与猪（另一种偶蹄类动物）的同源性最高。这是除人类 IgA1 和 IgA2 之外的所有哺乳动物 IgA 观察到的最高同源性。牛 IgA 与兔 IgA3 和 IgA4 共享，在第 282 位有一个额外的 N 联糖基化位点。然而，集体数据表明，牛与猪和啮齿动物一样，与兔不同，该物种的 IgA 编码基因只有一个基因座。
The complete genomic sequence of a bovine Cα gene is reported here. The genomic sequence was obtained from a Cα phage clone that had been cloned from a genomic EMBL4 phage vector library. The Cα sequence had previously been expressed as a chimeric antibody and identified as IgA using IgA‐specific antibodies. Intron/exon boundaries were determined by comparison of the genomic sequence with an expressed bovine Cα sequence obtained from spleen by reverse transcription‐polymerase chain reaction (RT‐PCR). Analysis of 50 Swedish bovine genomic DNA samples using genomic blots and five different restriction enzymes failed to detect evidence of polymorphism. However, PstI digests of Brown Swiss DNA showed a restriction fragment length polymorphism (RFLP), suggesting that at least two allelic variants of bovine IgA exist. Comparison of the deduced amino acid sequence of bovine IgA with sequences available for other species indicated that the highest homology was with that of swine, another artiodactyl. This was the highest homology observed for all mammalian IgA compared except for that between IgA1 and IgA2 in humans. Bovine IgA shares with rabbit IgA3 and IgA4, an additional N‐linked glycosylation site at position 282. However, the collective data indicate that cattle are like swine and rodents and unlike rabbits in having a single locus of the gene encoding IgA of this species.