Genetic diversity of the VP1 gene of duck hepatitis virus type I (DHV-I) isolates from southeast China is related to isolate attenuation

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• 作者：Guangqing Liu ; Fei Wang ; Zheng Ni ; Tao Yun ; Bin Yu ; Jionggang Huang ; Jianping Chen
• 关键词：Duck hepatitis virus type I ; DHV-I ; Phylogenetic tree ; VP1
• 刊名：Virus Research
• 出版年：2008
• 出版时间：October 2008
• 年：2008
• 卷：137
• 期：1
• 页码：137-141
• 全文大小：304 K

文摘

The complete sequence of an isolate (ZJ-V) of Duck hepatitis virus I (DHV-I), originally taken from the field in southeast China was determined. It was 7691 nucleotides long and had 5′- and 3′-terminal non-coding regions of 626 and 315 nucleotides, respectively. The poly(A) tail contained at least 22 residues and the single open reading frame encoded a polypeptide of 2249 amino acids. The VP1 gene was also sequenced from nine southeast China field isolates and three attenuated DHV-I vaccine strains. In phylogenetic analysis of the isolates and other published sequences, attenuated and tissue-adapted isolates (including ZJ-V) clustered as genotypes significantly different from the field isolates that had not been passaged in chicken/duck embryos. There were two consistent amino acid substitutions (E₁₂₉ → V₁₂₉ and A₁₄₂ → S₁₄₂) between all the field isolates and all the tissue-adapted ones. The carboxyl terminal region was generally the most variable and here the four attenuated Chinese isolates showed six consistent differences from the field isolates (S₁₈₁ → L₁₈₁, H₁₈₃K₁₈₄ → R₁₈₃G₁₈₄₁, N₁₉₃ → D₁₉₃, E₂₀₅ → K₂₀₅, R₂₁₇ → K₂₁₇, N₂₃₅ → D₂₃₅). It seems likely that at least some of these differences result from mutations leading to isolate attenuation.