鸡传染性支气管炎病毒广西株N基因的克隆与序列分析

Cloning and Sequence Analysis on N Gene of an Infectious Bronchitis Virus Guangxi Isolate

参照Gen Bank中鸡传染性支气管炎病毒（IBV）的核酸序列设计了1对引物,利用RT-PCR扩增了1个广西分离株的N基因cDNA片段,并将其克隆到p MDl8-T载体中。序列分析结果表明,N基因序列全长为1 230 bp,编码1条409个氨基酸组成的多肽;分离株与国内外IBV参考毒株相比,核苷酸同源性为83.8%~99.9%,氨基酸同源性为88.4%~99.6%;分离株与LX4株、BJ株关系较近,与疫苗株处于不同的进化分支,亲缘关系较远,是新的IBV变异株。

One pair of primers for amplifying the N gene of IBV based on the sequence in GenBank was designed. The cDNA fragments of N gene of IBV strain isolated from Guangxi province were amplified by RT-PCR, then the amplified fragments were cloned into pMD18-T vector and the recombinant plasmids were sequenced. The results showed that the N gene from all of the IBV isolates consisted of 1230 bp, coding for 409 amino acid. Compared with that of the other published IBV N genes, the homology of nucleotide and amino acid sequence of the isolate were 83.8%-99.9% and 88.4%-99.6% respectively. The isolate strain was closely related to LX4 and BJ and had relatively distant phylogentic relationship with the immune strain which was grouped in other clade. These results suggested that the isolate was a new variant of IBV.