蓝舌病病毒血清1型野毒株及疫苗株S10基因差异

Genetics Diversity of S10 Gene Segment Between China Field Strain of Serotype Ⅰ and Vaccine Strain of Bluetongue Virus

蓝舌病病毒血清型 1型是主要致病血清型之一。为明确其流行规律的分子生物学基础 ,采用 RT- PCR扩增和序列测定技术分析了 15株野毒株及 1株弱毒疫苗株的 S10全基因片段 ,并对其核苷酸和氨基酸差异进行了比较。所有毒株 S10基因核苷酸长度均为 82 2 bp,含有 2个起始密码子 (核苷酸 2 0～ 2 2和 5 9～ 6 1)和 1个终止子 (核苷酸 70 7～70 9) ,预测编码 2种蛋白 (NS3和 NS3A)。不同毒株间 S10基因核苷酸差异为 0～ 138个 (同源性 10 0 %～ 82 %) ,NS3/NS3A蛋白氨基酸差异为 0～ 15个 (同源性 10 0 %～ 93%)。基于 S10基因序列分析 ,可将蓝舌病病毒野毒株及疫苗株分为 2个基因群 :12株野毒株及 1株疫苗株为基因 群 ,3株野毒株与澳大利亚 型毒株属于基因 群 ,两群间的核苷酸同源性为 79%。各基因群在地域分布及宿主来源上未发现有明显的特征性。基因群与毒株分离年代、对 BHK- 2 1细胞毒力等特征关系亦不明显。

Serotype Ⅰ bluetongue virus(BTV) is a major cause of ruminant bluetongue disease in China.In order to investigate the molecular epidemiology of BTV in the country 15 Chinese isolates and 1 vaccine strain were analyzed phylogenetically based on sequence comparison of S10 gene.In consequence the S10 gene of all 16 strains comprise 822 nucleotides with two inframe initiate codens(nucleotide 20-22 and 59-61) and one stop coden(707-709),encoding two proteins,NS3 and NS3A.The differences found in S10 gene fragment among all tested isolates were 0 to 138 nucleotides,showing the identity of 82% to 100%,while the NS3/NS3A region showed a minor genetic diversity among the isolates(0 to 15 amino acids distinct).S10 gene-based phylogenetical analysis showed that these 15 isolates,along with the vaccine strain,were segregated into two distinct genetic groups.The vaccine strain and 12 field isolates were classified into group Ⅱ,while the other 3 isolates and Australian BTV1NS3 into group Ⅰ.This grouping is independent of geographical origin,host species and the year of isolation.