IBDV中国超强毒株Harbin-1基因组B节段的克隆和序列分析

Cloning and Sequence Analysis of Segment B of Harbin-1,A Chinese Very Virulent Strain of Infectious Bursal Disease Virus

给SPF鸡人工接种鸡传染性法氏囊病病毒中国超强毒株Harbin_1,用LiCl分级沉淀方法从法氏囊组织纯化病毒基因组dsRNA ,通过RT_PCR分两段扩增获得B节段的cDNA片段Ph12与pb34。将pb12与pb34分别克隆到pGEM_T载体上测序 ,然后进行序列分析。对各毒株VP1序列进行同源性分析而得出的系统树表明Harbin_1与超强毒株IL3、HK4 6、UK6 6 1和OKYM之间的亲缘关系较其它毒株更近 ,但强弱毒株之间没有明显的界限。在Harbin_1B节段序列中没有发现上述超强毒株所独有的

Double_strand RNA of viral genome was purified by LICl gradient precipitation,after bursa was harvested from SPF chicken which had been inoculated with Harbin_1 strain,a Chinese vvIBDV.cDNA fragments pb12 and pb34 were obtained by RT_PCR and then cloned into pGEM_T,respectively.After sequencing these fragments,we compared deduced amino acid sequences of segment B of eleven strains.Although phylogenetic tree from VP1 genes of eleven strains indicated that the Harbin_1 was more similar to vvIBEV IL3,HK46,UK661 and OKYM than other strains,the results from sequence analysis of segment B showed that no distinct differences among strains of various virulence.The seven residues specific for vvIBDV was not found in VP1 sequence of Harbin_1.