Identification and genetic characterization of a minor norovirus genotype, GIX.1[GII.P15], from China

BMC Genom Data. 2022 Jul 6;23(1):50. doi: 10.1186/s12863-022-01066-6.

Abstract

Background: Human noroviruses, single-stranded RNA viruses in the family Caliciviridae, are a leading cause of nonbacterial acute gastroenteritis in people of all ages worldwide. Despite three decades of genomic sequencing and epidemiological norovirus studies, full-length genome analyses of the non-epidemic or minor norovirus genotypes are rare and genomic regions other than ORF2 and 3'-end of ORF1 have been largely understudied, which hampers a better understanding of the evolutionary mechanisms of emergence of new strains. In this study, we detected a rare norovirus genotype, GIX.1[GII.P15], in a vomit sample of a 60 year old woman with acute gastroenteritis using Raji cells and sequenced the complete genome.

Results: Using electron microscopy, a morphology of spherical and lace-like appearance of norovirus virus particles with a diameter of approximately 30 nm were observed. Phylogenetic analysis of VP1 and the RdRp region indicated that the KMN1 strain could be genotyped as GIX.1[GII.P15]. In addition, the VP1 region of KMN1 strain had 94.15% ± 3.54% percent nucleotide identity (PNI) compared to 26 genomic sequences available in GenBank, indicating a higher degree similarity between KMN1 and other GIX.1[GII.P15] strains. Further analysis of the full genome sequence of KMN1 strain showed that a total of 96 nucleotide substitutions (63 in ORF1, 25 in ORF2, and 8 in ORF3) were found across the genome compared with the consensus sequence of GIX.1[GII.P15] genome, and 6 substitutions caused amino acid changes (4 in ORF1, 1 in ORF2, and 1 in ORF3). However, only one nucleotide substitution results in the amino acid change (P302S) in the VP1 protein and the site was located near one of the predicted conformational B epitopes on the dimer structure.

Conclusions: The genomic information of the new GIX.1[GII.P15] strain KMN1, which was identified in Kunming, China could provide helpful insights for the study of the genetic evolution of the virus.

Keywords: Full-length genome; GIX.1[GII.P15]; Norovirus; Phylogenetic analysis.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / genetics
  • Caliciviridae Infections* / epidemiology
  • Female
  • Gastroenteritis* / genetics
  • Genome, Viral / genetics
  • Genotype
  • Humans
  • Middle Aged
  • Norovirus* / genetics
  • Nucleotides
  • Phylogeny

Substances

  • Amino Acids
  • Nucleotides