摘要
以传染性法氏囊病病毒(IBDN)中国毒株CJ-801bkf的基因组A片段dsRMA为模板,经反向转录和PCR扩增,克隆了保护性抗原VP2cDNA基因。经Sanger法测序,确定了VP2cDNA基因有1484个核苷酸,推测了VP2氨基酸的顺序,与已报导的6株IBDV毒株CuI、PBG98、52/70、002-73、STC和VariantE的VP2区做了比较,证明:克隆的CJ-801bkfVP2cDNA基因是全长的,含有正确的起始密码子ATG;CJ-801bkf与毒株Cul和pBG98同源性最高;CJ-801bkfVP2高可变区内两个亲水区的氨基酸顺序与CuI、PBG98、52/70、002-73和STC完全相同;7肽区内第三个丝氨酸残基则变异为精氨酸。这些结果提示,中国CJ-801bkf毒株应属标准血清I型IBDV弱毒株。
ouble -stranded RNA of genomic segment A of the Chinese IBDV strain CJ -801bkf wasused as template to produce double0stranded cDNA by reverse-transcription.The cDNA genecoding for the host -protective antigen VP2 was amplified by polymerase chain reaction (PCR)and cloned . The nucleotide sequencing of the expected VP2 gene of 148bp was determined by Sanger’s DNA sequencing method ,and hence the amino acid sequence was deduced .The full-length cDNA gene of CJ0801bkf strain contains its initiation codon (ATG).Both the nucleotide sequence and amino acid sequence were compared with six published sequences of VP2 gene of IBDV strains including CuI ,pBG98,52/70,002-73,STC and variant E. It was shown that the CJ-801bkf strain was most closely related to the low -pathogenic strain CuI and non -pathogenic strain pBG98.Within the two hydrophilic regions of the variable region of VP2 ,in which the main antigenic sites might reside,the amino acid sequence were wholle conserved among all strains. However,in CJ-801bkf as well as in CuI and pBG98, a substitution from serine to arginine occurred in the heptapeptide which might be responsible for the pathogenicity of IBDV strains. These suggested that the Chinese CJ- 801bkf strain is a standard serotype I strain and has low pathogenicity
出处
《病毒学报》
CAS
CSCD
北大核心
1995年第3期234-241,共8页
Chinese Journal of Virology
基金
国家自然科学基金