The analysis of the complete genome sequence of swine hepatitis E virus isolate swGX32 / 中华微生物学和免疫学杂志

ABSTRACT

Objective To analyze the complete genome sequence of Guangxi HEV isolate swGX32 and to compare it with other HEV isolates. Methods The overlapping fragments of HEV isolate swGX32 were amplified with reverse-transcription nested polymerase chain reaction (RT-nPCR),and the 5′ and 3′ ends of viral genome were amplified with rapid amplification of cDNA ends (RACE). The PCR products were cloned and sequenced. The sequence and phylogenetic analysis of swGX32 was performed. Results The genome of swGX32 consisted of 7240 nt excluding the polyA tail, with 4 nt overlapping between ORF1 and ORF2. ORF3 is contained in the sequence of ORF2. The complete genome sequence of swGX32 shared identity of 73%-74%, 73%, 74%-75%,83%-94% with HEV genotype 1,2,3 and 4, respectively. Among all these HEV reference sequences, swGX32 showed the highest identity with the human isolate JKO-ChiSai98C (94%). Phylogenetic tree showed that swGX32 belonged to genotype 4 and clustered with JKO-ChiSai98C in the branch of HEV subtype 4a. Conclusion The swine HEV isolate swGX32 is closely related to human strain JKO-ChiSai98C genetically and phylogenetically, which further provides molecular biology evidence of hepatitis E as a zoonosis.