传染性法氏囊病病毒BC6/85株全基因组克隆及其序列分析

Sequence Analysis of the Complete Genome of IBDV BC6 /85

以传染性法氏囊病病毒（IBDV）BC6／85株基因组RNA为模板，采用RT—PCR方法扩增并克隆了IBDVBC6／85株基因组全长eDNA。序列测定结果表明：A节段全长共3260个核苷酸，与IM株的同源性最高为97．4％，与其他血清I型毒株的核苷酸同源性介于91．2％～97．1％；B节段有2827个核苷酸，与IM株同源性最高为98．6％，与其他毒株的核苷酸同源性为88．7％～98．6％。通过对编码的氨基酸序列进行分析，发现BC6／85株有21个特有氨基酸，其中15个位于多聚蛋白VP2—4—3。系统进化树分析表明，BC6／85株与经典毒株、弱毒株和变异株的关系较近，而与超强毒株相对较远。

The full - length of double segments of the infectious bursal disease virus （strain BC6/85 ） was amplified by RT -PCR and sequenced. The results showed that segment A contained 3260 bp, compared with other IBDV strains, BC6/85 segment A shared 91. 2% -97. 4% homology at nucleotide level, segment B contained 2827 bp,which shared 88.7% -98.6% homology. The analysis of deduced amino acid sequences indicated that IBDV BC6/85 strain had 21 specific residues. Phylogenetic tree analysis indicated BC6/85 was more closely related to the attenuated, classical and variant IBDV than those of very virulent IBDV strains.