Quasispecies sequence analyses of envelope protein E1/E2 coding genes from four Chinese HCV patients and identification of a novel insertion mutation of HCV / 病毒学报

ABSTRACT

This paper investigated the envelope protein E1/E2 quasispecies genetic characterization of 4 HCV positive sera (Genotype 1b: 274, 366, 383; Genotype 2a: 283) in China. Nucleotide acid was extracted and glycoprotein E1/E2 (191-764aa) coding genes were obtained by RT-PCR, positive clones were randomly selected for sequencing. The phylogenetic relationships and the homology of nucleotide and amino acid were analyzed based on E1/E2 coding genes, and some vital functional regions of E1/E2 were characterized. A total of 43 sequences (274: 10; 283: 12; 366: 13; 383: 8) were obtained showing high genetic heterogeneity in HVR1 and HVR2 regions, while sequences of the neutralizing epitopes, transmembrane domain I, II and N-terminal ectodomain were comparatively conservative. Single base (C) insertion mutation at nt1279 ( E1 region, aa313), resulting in a mutated E1 coding protein (beginning at aa 313) and interruption at N terminus (aa 398) of HVR1 region of E2, was dominant quasispecies sequence(11/12) found in serum 283 . This is the first report on E1/E2 quasispecies in Chinese HCV patients and this novel pattern of insertion mutation provides important information for further study on HCV pathogenesis and immune evasion.