新城疫病毒TS09耐热株HN基因的序列测定与分析

摘要

新城疫病毒TS09耐热株是由V4株经耐热选育得到的新毒株.对其血凝素-神经氨酸酶(Hemagglutinin-Neuraminidase,HN)基因进行序列测定分析.选取GenBank中国内外具有代表性的序列与其进行同源性和系统进化分析.结果表明,氨基酸序列同源性比较中,TS09耐热株与V4株的氨基酸的同源性为96.8%；在核苷酸系统进化树中,V4株位于基因Ⅰ型的分支上,TS09耐热株位于基因Ⅱ型的分支上；耐热株中HN基因中GC含量为47.58%,比不耐热株GC含量高；但比较耐热株和不耐热株HN蛋白的α螺旋,耐热株比不耐热株的HN蛋白在跨膜区和胞外区均多出一个长的α螺旋.同源性和系统进化分析表明TS09耐热株与V4株有很近的亲缘关系；耐热株和不耐热株HN蛋白的GC含量、α-螺旋有很大的差别,这可能与耐热性有一定的关系.%The Newcastle disease virus TS09 heat-resistant strain is a new strain obtained from the V4 strain by heat-resistant breeding. Its hemagglutinin-neuraminidase (HN) gene was sequenced and analyzed. Domestic and international representative sequences in GenBank were selected to analyze the homology and the phyletic evolution with HN gene of TS09 heat-resistant strain. Amino acid homology of the TS09 heat-resistant strains and the V4 strain was 96.8% in the comparison of amino acid homology. In the phylogenetic tree of nucleotide, TS09 heat-resistant strain is on the branch of genetype II and V4 strain is on the branch of genetype I. The GC content in HN gene of TS09 heat-resistant strain is 47.58% that is higher than thermolabile strains. Comparison of the a helixes in the HN protein of heat-resistant strains and thermolabile strains, the heat-resistant strains have two a helixes more than the thermolabile strains,one is in the transmembrane domain and the other one is in the extracellular domain. The similarity and phylogenetic analysis showed that genetic relationship of TS09 heat-resistant strain and V4 strain are very close. GC content and α helixes of HN protein are very different between heat-resistant strains and thermolabile strains,which may representate thermostability.