一株基因Ⅱ型新城疫病毒的分离及基因组分析

Genomic analysis of a genotype Ⅱ Newcastle disease virus isolated from chicken

本研究从2008山东表现神经症状的某新城疫疫苗免疫鸡群中分离到一株病毒。通过鸡红细胞凝集试验和血凝抑制试验,表明为新城疫病毒,将其命名为ck/CH/LSD/08-29。根据GenBank上登录的新城疫病毒基因组序列,设计14对引物经过RT-PCR扩增病毒感染的尿囊液,同时应用3'-RACE和5'-RACE技术,扩增得到该病毒全部基因组序列。结果表明,该毒株基因组由15186个核苷酸序列组成,编码6种结构蛋白,在RNA上的顺序依次为3'-NP-P-M-F-HN-L-5'。F基因裂解位点处的氨基酸序列为112R-R-Q-K-R-F117,符合强毒株氨基酸序列特点。通过F基因裂解位点附近高变区389个核苷酸序列构建遗传进化树,证明该毒株在分类地位上属于基因Ⅱ型。此外,病毒感染SPF鸡试验证明ck/CH/LSD/08-29毒株属于强毒嗜神经型毒株,能引起SPF鸡高致死率。

In this study,a Newcastle virus （designated as ck/CH/LSD/08-29） was isolated from chick flock immunized with NDV vaccine which exhibited neurological symptom in Shandong province in China in 2008. Twenty of 80 day-old SPF chicks were infected with 106.4EID50 of the virus and all chicks died within 7 days,exhibited neurological signs. The whole genome was cloned by RT-PCR and sequenced including 3＇-and 5＇-terminals. The results showed that the isolate was constituted by 15 186 nt,and composed of 6 structure protein genes. The cleavage motif of F protein was 112R-R-Q-K-R-F117 which was the characteristic of velogenic strain. The evolution analysis of the 389 nt sequence including the cleavage site of F gene shown that the virus was belonged to genotype Ⅱ.