牛病毒性腹泻病毒P125基因重要区的比较与分析

Comparison of the Main Region within P125 Gene of Bovine Viral Diarrhea Virus

根据牛病毒性腹泻病毒（ＢＶＤＶ）ＮＡＤＬ株的序列，以计算机辅助设计，化学合成１对引物（Ｗ１／Ｗ２）；应用ＲＴ－ＰＣＲ对国内不同地区分离的４株ＢＶＤＶ的Ｐ１２５基因外源序列插入区进行了扩增，并将扩增的片段进行克隆和序列测定，同时以ＤＮＡＳＩＳ和ＰＲＯＳＩＳ计算机软件将测定的核苷酸序列及推导的氨基酸序列进行比较分析。结果证实，国内分离的４株ＢＶＤＶ在这一区域中既没有外源序列的插入，也没有基因重组、基因重排或基因缺失，但存在某些核苷酸和氨基酸的替换，表明病毒的致细胞病变作用除与外源序列的插入、基因重组、基因重排或基因缺失有关外，可能还存在其他机制。核苷酸序列的同源性及系统树分析的结果表明，国内的ＢＶＤＶ毒株存在Ｉａ和Ｉｂ２个基因亚型。

The foreign sequence insertion region within P125 gene of three cytopathic (cp) strains (184, H and D) and one noncytopathic (ncp) strain (Yak) of bovine viral diarrhea virus were amplified by the reverse transcription polymerase chain reaction (RT PCR), cloned and sequenced. The results confirmed that the three cp strains possess neither any insertion nor gene rearrangement, gene recombination, gene deletion in the inserting region of the P125 gene as observed in many other cp strains. However some nucleotide and amino acid substitutions were found in the region analysed. Following the sequence homology, as well as phylogenic analysis, the 4 strains of BVDV could be divided into two subgenotypic groups, the Ia and the Ib. The mean homology between strains of these two groups was 76.7/83.2% for the nucleotide/amino acid sequnces, while it was 79.9/89.4% and 90.0/86.7% within group Ia and Ib respectively.