中国农业科学 ›› 2005, Vol. 38 ›› Issue (08): 1669-1674 .

• 畜牧.兽医.资源昆虫 • 上一篇    下一篇

猪戊型肝炎病毒新疆株swCH25全基因序列的分析

马勋,陆承平   

  1. 南京农业大学农业部动物疫病诊断与免疫重点开放实验室
  • 收稿日期:2004-05-11 修回日期:1900-01-01 出版日期:2005-08-10 发布日期:2005-08-10
  • 通讯作者: 陆承平

Analysis of the Complete Genome of a Strain swCH25 of Swine Hepatitis E Virus Isolated from Xinjiang

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  1. 南京农业大学农业部动物疫病诊断与免疫重点开放实验室
  • Received:2004-05-11 Revised:1900-01-01 Online:2005-08-10 Published:2005-08-10

摘要: 设计18对PCR引物分片段扩增猪戊型肝炎病毒新疆分离株swCH25全基因,对两末端采用末端快速扩增方法(RACE)进行扩增,扩增产物克隆到pMD18-T载体并测序。用DNAstar软件进行序列同源性分析,PHYLIP软件绘制基因进化树,在全基因序列的基础上比较猪HEV与其它HEV基因型的差异和人源HEV的关系。结果显示swCH25全序列除去3′poly(A)尾,由7 243个核苷酸组成,ORF 1~3分别编码含1070,674和114个氨基酸的蛋白质。全基因序列与HEVⅠ、Ⅱ和Ⅲ型同源性73.5%~75.7%,与Ⅳ型的同源性为83.5%~89.8%,其中与Ⅳ型中国人源T1株最高,达89.8%。ORF1与Ⅰ~Ⅲ和Ⅳ型的核苷酸同源性分别为71.6%~74%和82.3%~89.4%,氨基酸同源性为80.7%~86.1%和94.3%~96.0%;ORF2与Ⅰ~Ⅲ和Ⅳ型的核苷酸同源性分别为78.4%~81.3%和87.1%~90.9%,氨基酸同源性为89.7%~93.8%和97.2%~98.2%;ORF3与Ⅰ~Ⅲ和Ⅳ型的核苷酸同源性分别为84.4%~87.3%和95.4%~96.8%,氨基酸同源性为74.8%~83.2%和93.8%~97.4%,基因进化树显示swCH25与基因Ⅳ型人源T1株最接近,在同一分支上。swCH25株是国内第一个测出全基因序列的猪戊型肝炎病毒。

关键词: 戊型肝炎病毒, 基因型

Abstract: To analyze the full length sequence of swCH25, isolated from a pig fecal sample in Xinjiang in 2001, eight overlapping fragments of swCH25 genomes were amplified with reverse transcription nested polymerase chain reaction (RT-nPCR) and the 5′ and 3′ ends were amplified with RACE. The PCR products were cloned into pMD18-T Vector and sequenced. The result showed that its genome consisted of 7 243 nt excluding the poly(A)tail, and contained three ORFs(ORFs1-3) that encoded proteins of 1 707, 674 and 114aa. Sequence analysis revealed that the overall nucleotide sequence identity of swCH25 was 73.5%-75.7% and 83.5%-89.8% with HEV genotypeⅠ-Ⅲ and Ⅳ, respectively. Compared with HEV genotypesⅠ-Ⅲ and Ⅳ,the ORF1 of swCH25 shared 71.6%-74% and 82.3%-89.4% sequence identity at nucleotide level and 80.7%-86.1% and 94.3%-96% identity at amino acid level, the ORF2 shared 78.4%-81.3% and 87.1%-90.9% sequence identity at nucleotide level and 89.7%-93.8% and 97.2%-98.2% identity at amino acid level and the ORF3 shared 84.4%-87.3% and 95.4-96.8% sequence identity at nucleotide level and 74.8%-83.2% and 93.8%-97.4% identity at amino acid level. The phylogenetic tree constructed based on the full genomic sequence confirmed that swCH25 belong to genotype Ⅳ and were most closely related to T1, a prototype human HEV strain of genotype Ⅳ isolated from patients with acute hepatitis in China. This finding further supports the notion that the hepatitis E is a zoonosis.

Key words: Hepatitis E virus, Genotype