title: Characterization of neuraminidase-resistant mutants derived from rotavirus porcine strain OSU.
abstract: Infection by some rotavirus strains requires the presence of sialic acid on the cell surface, its infectivity being reduced in cells treated with neuraminidase. A neuraminidase treatment-resistant mutant was isolated from the porcine rotavirus strain OSU. In reassortant strains, the neuraminidase-resistant phenotype segregated with the gene coding for VP4. The mutant retained its capacity to bind to sialic acid. The VP4 sequence of the mutant differed from that of the parental OSU strain in an Asp-to-Asn substitution at position 100. Neutralization escape mutants selected from an OSU neuraminidase-sensitive clone by monoclonal antibodies that failed to recognize the neuraminidase-resistant mutant strain carried the same mutation at position 100 and were also neuraminidase resistant. Neuraminidase sensitivity was restored when the mutation at position 100 was compensated for by a second mutation (Gln to Arg) at position 125. Molecular mechanics simulations suggest that the neuraminidase-resistant phenotype associated with mutation of OSU residue 100 from Asp to Asn reflects the conformational changes of the sialic acid cleft that accompany sialic acid binding.
authors.affiliation: Centro de Microbiología y Biología Celular, Instituto Venezolano de Investigaciones Científicas, Apartado postal 21827, Caracas 1020-A, Venezuela.
authors.forename: José Agustín
authors.initials: JA
authors.lastname: López
authors.forename: Antonio José
authors.initials: AJ
authors.lastname: Maldonado
authors.forename: Marlene
authors.initials: M
authors.lastname: Gerder
authors.forename: José
authors.initials: J
authors.lastname: Abanero
authors.forename: Juan
authors.initials: J
authors.lastname: Murgich
authors.forename: Flor H
authors.initials: FH
authors.lastname: Pujol
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Liprandi
authors.forename: Juan Ernesto
authors.initials: JE
authors.lastname: Ludert
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D036022:Capsid Proteins / Q000737:chemistry / Q000502:physiology; D002460:Cell Line; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D009439:Neuraminidase / Q000494:pharmacology*; D011487:Protein Conformation; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D012401:Rotavirus / Q000737:chemistry / Q000235:genetics*; D013552:Swine / Q000821:virology*; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D036022:Capsid Proteins; D016601:RNA-Binding Proteins; C060339:VP4 protein, Rotavirus; D017361:Viral Nonstructural Proteins; C079234:NS35 protein, rotavirus; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid