title: The carboxy-terminal two-thirds of the cowpea chlorotic mottle bromovirus capsid protein is incapable of virion formation yet supports systemic movement.
abstract: Previous investigations into recombination in cowpea chlorotic mottle bromovirus (CCMV) resulted in the recovery of an unusual recombinant virus, 3-57, which caused a symptomless infection of cowpeas but formed no detectable virions. Sequence analysis of cDNA clones derived from 3-57 determined that mutations near the 5' terminus of the capsid protein gene introduced an early translational termination codon. Further mutations introduced a new in-frame start codon that allowed translation of the 3' two-thirds of the capsid protein gene. Based on the mutations observed in 3-57, wild-type CCMV clones were modified to determine if the carboxyl two-thirds of the capsid protein functions independently of the complete protein in long-distance movement. Analysis of these mutants determined that while virion formation is not required for systemic infection, the carboxy-terminal two-thirds of the capsid protein is both required and sufficient for systemic movement of viral RNA. This indicates that the CCMV capsid protein is multifunctional, with a distinct long-distance movement function in addition to its role in virion formation.
authors.affiliation: Genetics Program, Michigan State University, East Lansing 48824, USA.
authors.forename: W L
authors.initials: WL
authors.lastname: Schneider
authors.forename: A E
authors.initials: AE
authors.lastname: Greene
authors.forename: R F
authors.initials: RF
authors.lastname: Allison
mesh_terms: D017795:Bromovirus / Q000235:genetics / Q000254:growth & development*; D002213:Capsid / Q000737:chemistry*; D004252:DNA Mutational Analysis; D007887:Fabaceae / Q000382:microbiology; D015967:Gene Expression Regulation, Viral; D005814:Genes, Viral; D053830:Plant Viral Movement Proteins; D010946:Plants, Medicinal; D010947:Plants, Toxic; D012333:RNA, Messenger / Q000235:genetics; D014026:Nicotiana; D014764:Viral Proteins / Q000737:chemistry*; D015678:Viral Structural Proteins / Q000235:genetics; D014771:Virion / Q000648:ultrastructure*
chemical_list: D053830:Plant Viral Movement Proteins; D012333:RNA, Messenger; D014764:Viral Proteins; D015678:Viral Structural Proteins