鸭Ⅰ型禽副粘病毒YH_(99)V株F基因的克隆和序列分析

Cloning and sequencing of F gene of avian paramyxovirus type 1 strain YH_(99)V isolated from duck

从患病鸭群中分离到一株引起鸭产蛋锐减而不死亡的病毒,经鉴定该病毒属于Ⅰ型禽副粘病毒,命名为YH99V株。以YH99V株的基因组RNA为模板,用RT-PCR一步法扩增出其F基因的cDNA序列,然后将其克隆至pMD18-T载体中,对其进行序列测定。结果表明,所克隆的基因片段长度为1 750 bp,含有1个1 662bp的开放式阅读框架(ORF),编码553个氨基酸。将YH99V株F基因序列和推导的氨基酸序列与国内外新城疫毒株的F基因相应序列比较后发现,它们的核苷酸序列同源性分别在82.7%-99.6%,氨基酸序列同源性为87.2%-99.3%。YH99V株在F蛋白裂解位点区的氨基酸序列与弱毒株在这一区域的序列完全相同,表明为弱毒株。根据F基因的全核苷酸序列,进一步绘制了Ⅰ型禽副粘病毒株F基因的系统发育树。分析结果显示YH99V株与Lasota等参考毒株同属于基因Ⅱ型,表明它们具有较近的亲缘关系。

A strain virus was isolated from duck. It resulted to egg laying drop , but didn＇t cause duck to die. The virus was identified as avian paramyxovirus- 1 and designated as YH99V. Using the viral genome RNA as template, cDNA fragments of F gene of strain YH99V was amplified by one-step RT-PCR, and which was cloned into pMD18-T vector and sequenced. The sequence analysis showed that the nuclotide sequence of the F gene was 1 750 bp, and it contains a single open reading frame（ORF）, which encodes a polypeptide of 553 amino acids. The nucleotide sequence of F gene and the deduced amino acid sequence of F protein of strain YH99V were compared with the published sequences of F gene of NDV strains, and the homology found was between 82.7% - 99.6% in nucleotide sequence, 87.2% - 99.3% in deduced amino acid sequence. The study on cleavage site amino acid sequence deduced from the nucleotide sequence （residues 112- 117） showed that YH99V strain matched to NDV lentogenic strains . Based on alignments of nucleotide sequences of F gene the phylogenetic tree was constructed. The analysis showed that YH99V strain and l_asota reference strain belong to genotype Ⅱ , and indicated that they had a common origin.