猫冠状病毒的全基因测序与遗传进化分析

The Whole Genomic Sequencing and Genetic Evolution Analysis of A Feline Coronavirus Strain

为了解猫传染性腹膜炎病毒(FIPV)的基因组特征和遗传变异情况。本试验利用RT-PCR方法从患病猫组织中鉴定出1株Ⅰ型FIPV病毒,通过RT-PCR扩增18个片段的目的基因,连接到p CE-TA克隆载体后测序,对测序结果进行拼接获得FIPV NJ-20-a株的全基因序列,对获得的全基因序列和编码区序列以往毒株进行同源性分析,并构建S基因系统进化树。结果显示NJ-20-a株与以往毒株同源性较低,新分离毒株基因组变异较大,通过编码区序列同源性分析发现S基因和3a、3b、3c基因是变异的主要区域,S基因系统进化树发现NJ-20-a株处于Ⅰ型FIPV分支内的单独分支,与以往毒株进化差异较大,表明猫冠状病毒在不同地域遗传进化过程中差异较大。本研究通过对FIPV NJ-20-a毒株进行全基因测序和分析,为猫冠状病毒的分子生物学研究和流行性学的调查提供了一定基础。

To understand the genomic characteristics and genetic variation of Feline infectious peritonitis virus(FIPV),the type I FIPV strain NJ-20-a was isolated from diseased feline tissues by RT-PCR in the present study.The target genes of 18 fragments were amplified by RT-PCR and then the amplified products were cloned into pCE-TA vector.After sequencing,the whole genomic sequence of FIPV NJ-20-a strain was obtained by splicing.The whole genomic and coding region sequences were compared with previous strains for analyzing their homology and constructing the S gene phylogenetic tree.The results showed that the homology of NJ-20-a strain and previous strains was lower,indicating this novel FIPV strain NJ-20-a experienced significantly variation.Analysis of coding region sequences also showed that the S gene and 3a,3b and 3c genes were the main regions of variation.The phylogenetic analysis of the S gene showed that FIPV NJ-20-a strain belonged to a separate branch of type I FIPV branch,which was quite different from previous strains.In conclusion,these results indicated that there were great differences in the genetic evolution of feline coronavirus in different regions.This study provided a basis for molecular biology and epidemic investigation of feline coronavirus by sequencing and analyzing the whole genome of FIPV NJ-20-a strain.