我国水痘-带状疱疹病毒VZV84-7减毒株基因特征研究

目的　建立水痘 带状疱疹病毒 (VZV)毒株的特异性鉴定方法 ,研究我国分离的VZV84 7减毒株(VZV84 7株 )基因特征。方法　利用PCR分别扩增VZV84 7株和Oka株R2和R5可变区基因 ,比较两者串联重复单位拷贝数 ;用PCR结合限制性片段长度多态性 (PCR RFLP)分析VZV84 7株和Oka株基因的BglI、PstI酶切位点突变 ;并对gpI编码区基因进行序列分析。结果　VZV84 7株R2、R5区PCR产物分别为 4 2 5bp和 2 5 5bp ,对应的串联重复单位拷贝数分别为 7和 1;Oka株R2、R5区PCR产物分别为 4 2 5bp和 36 7bp ,对应的串联重复单位拷贝数分别为 7和 2。VZV84 7株基因存在PstI酶切位点 ,而Oka株无PstI酶切位点 ;两者均存在BglI酶切位点。基因序列分析显示 ,VZV84 7株与Oka株在gpI区存在 4个碱基差异 ,并导致 1个编码氨基酸不同 ,氨基酸序列同源性为99 8%。结论　所建立的PCR和PCR RFLP方法简便、特异 ;VZV84 7株的基因特征与Oka株存在一定差异 ,但两株之间gpI编码区氨基酸序列具有较高的同源性

Genetic Characteristrics of VZV84-7,An Attenuated Varicella-Zoster Virus Strain Isolated in China

Objective To establish a specific method for identifying varicella-zoster virus(VZV) strains and analyze the genetic characteristics of VZV84-7,an attenuated VZV strain isolated in China.Methods The R2 and R5 variable region genes of VZV84-7 and Oka strains were amplified by PCR separately,and the copy numbers of tandem repeat units at the two regions were compared.The gene mutations at Bgl I and Pst I sites of the two strains were analyzed by PCR-restriction fragment length polymorphism(PCR-RFLP),and the genes at encoding regions of gp I of the two strains were sequenced.Results VZV84-7 strain had seven copies of tandem repeat units in R2 region at a length of 425 bp and one copy in R5 region at a length of 225 bp. However, Oka strain had seven copies in R2 region at a length of 425 bp and two copies in R5 region at a length of 367 bp. The Bgl I sites existed in both VZV84-7 and Oka strains, but the Pst I site existed only in VZV84-7 strain. Gene sequencing showed the difference in the four bases at gp I regions of the two strains. Though the difference resulted in an amino acid substitution (Gl127→Val), the homogeneity of amino acid sequences of the two strains was 99 8%.Conclusion The established PCR and PCR-RFLP methods for the identification of VZV strains were simple and specific. The genetic characteristics of VZV84-7 strain were different from those of Oka strain, however, the amino acids encoded by gp I genes of the two strains were highly homogenous.