野鸭源新城疫病毒的分离及其F基因的克隆与序列分析

用RT-PCR方法扩增从野鸭体内分离到的3株新城疫病毒(newcastle disease virus,NDV)(JS-1/06/wd、JS-2/06/wd和JS-3/06/wd)F基因,并对其序列进行了测定和分析。结果表明该分离株的F基因长1 662 bp,编码553个氨基酸;F基因裂解位点的氨基酸序列为112R-R-Q-K/R-R-F117,符合NDV强毒株的特征。这些毒株间核苷酸同源性为99.8%~99.9%,与鹅源NDV QY971株和ZJ1株的核苷酸同源性也高达96.7%~97.5%;氨基酸同源性为96.8%~97.5%;而与我国标准强毒株F48E9及疫苗株LaSota的核苷酸同源性分别为86.9%和84.5%;氨基酸同源性分别为94.5%和87.0%。系统发育树分析结果表明,野鸭源NDV与鹅源NDV的遗传关系较近,同属于基因Ⅶ型。

Sequence analysis of F genes of the newcastle disease virus isolates from wild ducks

Fusion(F) genes of three newcastle disease virus(NDV) strains,named as JS-1/06/wd,JS-2/06/wd and JS-3/06/wd,respectively,which were isolated from wild ducks,were sequenced and analyzed.The results showed that the F gene is 1,662 nt in length,and codes 553 amino acids.The deduced amino acid sequences of F protein at the cleavage sites of all the isolates were112R-R-Q-K/R-R-F117,with the characteristics of the virulent NDV strain.These isolates shared 99.8%~99.9% of nucleotide identity with QY971 and ZJ1 strains respectively,which were isolated from Chinese geese.However,they showed only 84.5% and 86.9% of sequence homology with LaSota(vaccine strain) and F48E9(virulent strain),respectively,and the amino acid homologies were 94.5% and 87.0%,respectively.The results indicated that the NDV isolates from wild ducks belong to a same genotype(Ⅶ) as those from geese on the basis of phylogenetic analysis of F genes.It suggested that NDV isolates from wild ducks have a close genetic relationship with those from Chinese geese.