【摘要】 根据传染性法氏囊病病毒 (IBDV)VP2基因cDNA序列 ,在VP2基因高变区设计一对引物 ,用RT_PCR方法扩增IBDV分离株JS3和JS4。将扩增片段克隆后以双脱氧链末端终止法测定核苷酸序列。JS3和JS4的同源性最高达 98% ,与已发表的vvIBDV、IBDV变异株、IBDV经典株及IBDV弱毒株核苷酸序列的同源性在 92 %～ 98%之间。根据IBDV的大ORF推导出该片段编码蛋白的氨基酸序列 ,JS3和JS4的同源性最高达 97% ,与上述其它病毒的同源性在 91 %～ 97%之间 ;七肽区的氨基酸序列 ,在强毒株完全相同 ,而在弱毒株有一个丝氨酸突变成了其它氨基酸。更多还原

【Abstract】 According to the published cDNA sequences of infectious bursal disease viruses(IBDV),a pair of primers to variable region of VP2 gene were designed for cDNA synthesis and PCR amplification of two different isolates JS3 and JS4 of IBDV.The amplified fragments by RT_PCR technique were cloned,and sequenced by the sanger dideoxy_mediated chain_termination method.The homology of the sequences of JS3 and JS4 was 98%.The identity of JS3 and JS4 with vvIBDV,variant IBDV,classical IBDV and attenuated IBDV published in GenBank databases ranged from 92% to 98%. The homology of the deduced amino acid sequences based on the ORF of JS3 and JS4 was 97%.The identity of JS3 and JS4 with above strains varied from 91% to 97%.The heptapeptide of IBDV was highly conserved in virulent strains,but mutated in attenuated strains.更多还原