title: The red clover necrotic mosaic virus capsid protein N-terminal amino acids possess specific RNA binding activity and are required for stable virion assembly.
abstract: The red clover necrotic mosaic virus (RCNMV) bipartite RNA genome is packaged into two virion populations containing either RNA-1 and RNA-2 or multiple copies of RNA-2 only. To understand this distinctive packaging scheme, we investigated the RNA-binding properties of the RCNMV capsid protein (CP). Maltose binding protein-CP fusions exhibited the highest binding affinities for RNA probes containing the RNA-2 trans-activator or the 3' non-coding region from RNA-1. Other viral and non-viral RNA probes displayed CP binding but to a much lower degree. Deletion of the highly basic N-terminal 50 residues abolished CP binding to viral RNA transcripts. In planta studies of select CP deletion mutants within this N-terminal region revealed that it was indispensable for stable virion formation and the region spanning CP residues 5-15 is required for systemic movement. Thus, the N-terminal region of the CP is involved in both producing two virion populations due to its RNA binding properties and virion stability.
authors.affiliation: Department of Agricultural Biotechnology and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Republic of Korea.
authors.forename: Sang-Ho
authors.initials: SH
authors.lastname: Park
authors.forename: Tim L
authors.initials: TL
authors.lastname: Sit
authors.forename: Kook-Hyung
authors.initials: KH
authors.lastname: Kim
authors.forename: Steven A
authors.initials: SA
authors.lastname: Lommel
mesh_terms: D036022:Capsid Proteins / Q000235:genetics / Q000378:metabolism*; D004252:DNA Mutational Analysis; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion; D019183:Tombusviridae / Q000235:genetics / Q000502:physiology*; D014771:Virion / Q000378:metabolism; D019065:Virus Assembly
chemical_list: D036022:Capsid Proteins; D016601:RNA-Binding Proteins
keywords: Co-packaging; RCNMV; RNA–CP interactions; TA; TABS; Virus assembly