鸭肝炎病毒新血清型基因组序列分析

Genomic sequence of a new serotype duck hepatitis virus

摘要:

摘 要：【目的】为了揭示鸭肝炎病毒新血清型（DHV-N）G株的演化及其与DHV-1的基因序列差异。【方法】运用RT-PCR结合5'-/3'-RACE策略对DHV-N G株基因组进行扩增，克隆测序后进行序列分析。【结果】DHV-N G株全基因组序列除12 nt poly(A)尾外全长共7774 nt，含有一个大的开放阅读框，编码2251 aa的蛋白前体，其基因组结构：5' UTR-L-VP0-VP3-VP1-2A1-2A2-2B-2C-3A-3B-3C-3D-3'UTR；3'UTR长为366 nt，比1型鸭肝炎病毒C80株多52 nt；VP1蛋白与DHV-1相比发生较大的变异，特别在其第140～221位；其基因组与DHV-1、韩国DHV-N和台湾DHV-N 的同源率分别为72.8%～73.4%、96.3%～96.5%和78.3%。【结论】DHV-N G株基因组结构与DHV-1存在明显差异，DHV-N成员之间DHV-N G株与韩国DHV-N关系更为密切。

Abstract:

Abstract: [Objective] A strain of highly pathogenic duck hepatitis virus was isolated in south China from a Pekin duck flock in 1999. No cross reaction with type 1 and 3 duck hepatitis virus was found by serum neutralization. We suggested the strain should be classified as a new serotype of duck hepatitis virus and named it as DHV-N G strain in our previous study. We wanted to reveal the evolution of this virus in molecular level and gene sequence differences between it and DHV-1 strains.[Methods]We used RT-PCR and 5'-/3'-RACE to amplify the complete genome sequence of DHV-N G strain and compared it with other picornaviruses [Results]The genome of DHV-N G consists of 7774 nucleotides excluding a poly(A) tail of 12 nucleotides. It contains a single large open reading frame encoding a polypeptide of 2251 amino acid residues. The length of 3'UTR of DHV-N G is 366 nucleotides, which is 52 nucleotides longer than that of DHV-1 C80 strain. Significant amino acid variation was found in the protein VP1, especially at the position of 140-221 comparing with DHV-1. The DHV-N G genome shares 72.8%-73.4%, 96.3%-96.5% and 78.3% similarity with DHV-1 strains, Korea’s and Taiwanese DHV-N strains, respectively. [Conclusion]The genome structure of DHV-N G strain is obviously different with that of DHV-1 strains. The homologies of genome among the DHV-N group are variable, therein DHV-N G strain is more homologous with Korea’s strains than with Taiwanese.