title: Serology-enabled discovery of genetically diverse hepaciviruses in a new host.
abstract: Genetic and biological characterization of new hepaciviruses infecting animals contributes to our understanding of the ultimate origins of hepatitis C virus (HCV) infection in humans and dramatically enhances our ability to study its pathogenesis using tractable animal models. Animal homologs of HCV include a recently discovered canine hepacivirus (CHV) and GB virus B (GBV-B), both viruses with largely undetermined natural host ranges. Here we used a versatile serology-based approach to determine the natural host of the only known nonprimate hepacivirus (NPHV), CHV, which is also the closest phylogenetic relative of HCV. Recombinant protein expressed from the helicase domain of CHV NS3 was used as antigen in the luciferase immunoprecipitation system (LIPS) assay to screen several nonprimate animal species. Thirty-six samples from 103 horses were immunoreactive, and viral genomic RNA was present in 8 of the 36 seropositive animals and none of the seronegative animals. Complete genome sequences of these 8 genetically diverse NPHVs showed 14% (range, 6.4% to 17.2%) nucleotide sequence divergence, with most changes occurring at synonymous sites. RNA secondary structure prediction of the 383-base 5' untranslated region of NPHV was refined and extended through mapping of polymorphic sites to unpaired regions or (semi)covariant pairings. Similar approaches were adopted to delineate extensive RNA secondary structures in the coding region of the genome, predicted to form 27 regularly spaced, thermodynamically stable stem-loops. Together, these findings suggest a promising new nonprimate animal model and provide a database that will aid creation of functional NPHV cDNA clones and other novel tools for hepacivirus studies.
authors.affiliation: Neurobiology and Pain Therapeutics Section, Laboratory of Sensory Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Burbelo
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Dubovi
authors.forename: Peter
authors.initials: P
authors.lastname: Simmonds
authors.forename: Jan L
authors.initials: JL
authors.lastname: Medina
authors.forename: Jose A
authors.initials: JA
authors.lastname: Henriquez
authors.forename: Nischay
authors.initials: N
authors.lastname: Mishra
authors.forename: Jason
authors.initials: J
authors.lastname: Wagner
authors.forename: Rafal
authors.initials: R
authors.lastname: Tokarz
authors.forename: John M
authors.initials: JM
authors.lastname: Cullen
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Iadarola
authors.forename: Charles M
authors.initials: CM
authors.lastname: Rice
authors.forename: W Ian
authors.initials: WI
authors.lastname: Lipkin
authors.forename: Amit
authors.initials: A
authors.lastname: Kapoor
mesh_terms: D020121:5' Untranslated Regions; D000818:Animals; D000956:Antigens, Viral / Q000235:genetics; D016174:Hepacivirus / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D006526:Hepatitis C / Q000276:immunology / Q000662:veterinary*; D018937:Hepatitis C Antibodies / Q000097:blood*; D006734:Horse Diseases / Q000821:virology*; D006736:Horses; D058507:Host Specificity; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012367:RNA, Viral / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D020121:5' Untranslated Regions; D000956:Antigens, Viral; D018937:Hepatitis C Antibodies; D012367:RNA, Viral; D011994:Recombinant Proteins