title: Phylogenetic inference of the porcine Rotavirus A origin of the human G1 VP7 gene.
abstract: Rotavirus A (RVA) is an important cause of acute gastroenteritis in children worldwide. The most common VP7 genotype of human RVA is G1, but G1 is rarely detected in porcine strains. To understand the evolutionary relationships between human and porcine G1 VP7 genes, we sequenced the VP7 genes of three Japanese G1 porcine strains; the first two (PRV2, S80B) were isolated in 1980 and the third (Kyusyu-14) was isolated in 2001. Then, we performed phylogenetic and in-silico structural analyses. All three VP7 sequences clustered into lineage VI, and the mean nucleotide sequence identity between any pair of porcine G1 VP7 sequences belonging to lineage VI was 91.9%. In contrast, the mean nucleotide sequence identity between any pair of human G1 VP7 sequences belonging to lineages I-V was 95.5%. While the mean nucleotide sequence identity between any pair of porcine lineage VI strain and human lineage I-V strain was 85.4%, the VP7 genes of PRV2 and a rare porcine-like human G1P[6] strain (AU19) were 98% identical, strengthening the porcine RVA origin of AU19. The phylogenetic tree suggests that human G1 VP7 genes originated from porcine G1 VP7 genes. The time of their most recent common ancestor was estimated to be 1948, and human and porcine RVA strains evolved along independent pathways. In-silico structural analyses identified 7 amino acid residues within the known neutralisation epitopes that show differences in electric charges and shape between different porcine and human G1 strains. When compared with much divergent porcine G1 VP7 lineages, monophyletic, less divergent human G1 VP7 lineages support the hypothesis that all human G1 VP7 genes included in this study originated from a rare event of a porcine RVA transmitting to humans that was followed by successful adaptation to the human host. By contrast, AU19 represents interspecies transmission that terminated in dead-end infection.
authors.affiliation: Department of Hygiene and Molecular Epidemiology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan; Department of Virology, National Institute of Hygiene and Epidemiology, Hanoi, Vietnam.
authors.forename: Loan Phuong
authors.initials: LP
authors.lastname: Do
authors.affiliation: Department of Hygiene and Molecular Epidemiology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan; Centre for Bioinformatics and Molecular Medicine, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Toyoko
authors.initials: T
authors.lastname: Nakagomi
authors.affiliation: Centre for Bioinformatics and Molecular Medicine, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Otaki
authors.affiliation: Department of Hygiene and Molecular Epidemiology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Chantal Ama
authors.initials: CA
authors.lastname: Agbemabiese
authors.affiliation: Department of Hygiene and Molecular Epidemiology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan; Centre for Bioinformatics and Molecular Medicine, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan. Electronic address: onakagom@nagasaki-u.ac.jp.
authors.forename: Osamu
authors.initials: O
authors.lastname: Nakagomi
authors.affiliation: Dairy Hygiene Research Division, Hokkaido Research Station, National Institute of Animal Health, Sapporo, Hokkaido, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsunemitsu
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000737:chemistry / Q000235:genetics*; D036022:Capsid Proteins / Q000737:chemistry / Q000235:genetics*; D019295:Computational Biology / Q000379:methods; D019143:Evolution, Molecular; D006801:Humans; D008958:Models, Molecular; D009154:Mutation; D010802:Phylogeny; D011487:Protein Conformation; D012401:Rotavirus / Q000145:classification* / Q000235:genetics*; D012400:Rotavirus Infections / Q000635:transmission / Q000821:virology*; D017422:Sequence Analysis, DNA; D013552:Swine; D013553:Swine Diseases / Q000821:virology*
chemical_list: D000956:Antigens, Viral; D036022:Capsid Proteins; C050779:VP7 protein, Rotavirus
keywords: Evolution; G1; Interspecies transmission; Rotavirus; VP7 gene