系统发生分析发现牛病毒性腹泻病病毒新基因亚型  

A New Gene Subtype of BVDV-1 from ZM-95,a Pig-isdated train

作　　者：徐兴然[1] 肖昌[1] 梁龙[2] 余兴龙[1] 张青婵[1] 涂长春[1] 

机构地区：[1]解放军军事医学科学院军事兽医研究所 [2]解放军军事医学科学院生物工程研究所,北京100071

出　　处：《中国病毒学》2005年第6期626-631,共6页Virologica Sinica

基　　金：国家"973"计划资助课题(No.G1999011905)。

摘　　要：本研究对我国首次分离获得的牛源牛病毒性腹泻病毒(BVDV)毒株Changchun 184(CC-184)和猪源牛病毒 性腹泻病毒ZM-95进行了遗传衍化关系研究。选择主要抗原E2基因为研究对象,首先应用RT-PCR及套式PCR 克隆得到CC-184和ZM-95的E2片段,通过序列测定发现CC-184和ZM-95 E2基因长度分别为1,122bp和1, 125bp,各自编码374和375个氨基酸残基。核酸序列同源性比较和系统发生分析表明2株病毒均属于BVDV-1, CC-184与Osloss亲缘关系最近,都属于已有的b基因亚型,其E2基因同源性达91．8％。而ZM-95的E2基因有 一个特征性的变异区,包含一个密码子序列插入,这一变异区编码了一段有别于其他瘟病毒的五肽氨基酸序列 HYKKK。结果还表明ZM-95与BVDV-1现有的5个基因亚型的亲缘关系均较远,E2基因同源性最高(与Oregon c24v)只有72．4％。而BVDV-1亚型内毒株间的同源性大于85％,亚型间的同源性在69％～75％之间,充分说明 ZM-95是BVDV-1中一个新发现的基因亚型。通常认为猪源BVDV来源于牛,应该与牛源BVDV有十分近的遗 传关系,但是本研究发现ZM-95与其他已知牛源BVDV较低的基因同源性说明猪源BVDV还具有独立的遗传衍 化与传播来源的可能性。Two earlier Chinese isolates of bovine viral diarrhea virus, bovine CC-184 and pig ZM- 95 were phylogenetically analyzed. The E2 gene encoding a major antigenic was obtained by reverse transcription polymerase chain reaction （RT-PCR） and nest-PCR. Sequencing results showed that the E2 genes of CC-184 and ZM-95 are 1122 and 1125 nucleotides in length, encoding 374 and 375 amino acids, respectively. Sequence comparison and phylogenetic analyses demonstrated that both isolates fall into the BVDV-1 group and distant from other Pestiviruses such as BVDV-2, Border disease virus （BDV）and Classical swine fever virus （CSFV）. The E2 gene of CC-184 had the highest identity （91.8%） with its homologue in the Osloss strain. However, the E2 gene of ZM-95 is significantly divergent from other known Pestiviruses, with the highest sequence identity of 72.4% to strain Oregon c24v. Furthermore, isolate ZM-95 addressed significant evolution distance compared with the other established subgroups of BVDV-1, as indicated by phylogenetic analysis. Taking together with the fact that within BVDV-1 group sequences share at least 85% homology in the subgroup and 69%-75% between different subgroups, we suggested that the ZM-95 form a new subgroup, subgroup F. In addition, the E2 gene of ZM-95 possesses a characteristic variable region, which contains an insertion and encodes unique amino acid residues HYKKK. The low sequence identity with other BVDV-1 strains indicate that ZM-95 likely had an independent evolutional pathway, and a unique transmission mechanism.

关 键 词：猪源 BVDV E2 基因 系统发生 新基因亚型 

分 类 号：S852.653[农业科学—基础兽医学]