南阳黄牛TLR2基因扩增及序列分析

根据GenBank中发表的牛TLR2基因序列设计引物,通过PCR方法对南阳黄牛的TLR2基因进行分段扩增并测序,拼接后得到包含TLR2完整编码区以及5′端和3′端非编码区的2399bp的全序列。序列分析结果表明,南阳黄牛TLR2基因开放阅读框全长2 355bp,共编码784个氨基酸。南阳黄牛的TLR2基因编码区与荷斯坦牛的相比发生了16个碱基突变,其中9个发生在胞外区,2个发生在跨膜区,5个发生在胞内区,没有引起氨基酸的改变。与GenBank已发表的其他动物TLR2基因参考序列进行比较,结果显示南阳黄牛与荷斯坦牛、野牛、水牛、山羊、绵羊、猪、大猩猩和人的同源性分别为99.3%、99.3%、98.0%、96.3%、95.5%、85.4%、83.2%和83.1%。TLR2N末端存在信号肽且可能在21位氨基酸处存在裂解位点,蛋白分子结构预测TLR2蛋白含1个跨膜结构域。

Amplification and Sequence Analysis of TLR2 Gene in Nanyang Cattle

The TLR2 gene in Nanyang yellow cattle was segmentally amplificated by polymerase chain reaction(PCR).Primers were designed according to the TLR2 gene sequence of bovines in GenBank.The complete sequence of 2355 bp,containing the complete coding region of TLR2,5′-and 3′-non-coding region,were obtained.The sequence analysis showed that the TLR2 gene in Nanyang cattle contains ORF of 2 355 bp in length and in total,codes for 784 amino acids.Compared with the TLR2 gene of Holstein cows,16 bases of coding region in Nanyang yellow cattle changed,of which 9 happened in the extracellular region,2 in the trans-membrane region,and 5 in the intracellular region with no amino acid reaction.Compared with conferential TLR2 gene sequences of other animals published in GenBank,the homologies of Nanyang yellow cattle and Holstein cows,bison,buffalo,goats,sheep,pigs,gorillas and humans are up to 99.3%,99.3%,98.0%,96.3%,95.5%,85.4%,83.2%and 83.1%,respectively.There are signal peptides at the N end of TLR2 and probably schizolysis sites at the 21st amino acid position,and the protein molecular structure predicts that the TLR2 protein contains one trans-membrane structure region.