title: An encapsidated viral protein and its role in RNA packaging by a non-enveloped animal RNA virus.
abstract: Alphatetraviruses are small (+) ssRNA viruses with non-enveloped, icosahedral, T=4 particles that assemble from 240 copies of a single capsid protein precursor. This study is focused on the mechanisms underlying selection and packaging of genomic vRNAs by Helicoverpa armigera stunt virus. We demonstrate that the viral protein, p17, is packaged at low levels (between 4 and 8 copies per capsid) raising the possibility of icosahedral asymmetry in wild-type particles. p17 promotes packaging of vRNA2 by virus-like particles (VLPs) generated from plasmid-expressed vRNA2. The 5' and 3' UTRs of RNA2 are not required for encapsidation. VLPs produced by recombinant baculoviruses package vRNA2 at detectable levels even in the absence of p17 and apparently excluding baculoviral transcripts. This suggests a role for p17 in vRNA selectivity. This is one of few examples of the packaging of a minor non-structural protein by (+) ssRNA animal viruses.
authors.affiliation: Department of Biochemistry and Microbiology, Rhodes University, PO Box 94, Grahamstown 6140, South Africa.
authors.forename: Adriano
authors.initials: A
authors.lastname: Mendes
authors.affiliation: Department of Biochemistry and Microbiology, Rhodes University, PO Box 94, Grahamstown 6140, South Africa.
authors.forename: Marli
authors.initials: M
authors.lastname: Vlok
authors.affiliation: Department of Biochemistry and Microbiology, Rhodes University, PO Box 94, Grahamstown 6140, South Africa.
authors.forename: James R
authors.initials: JR
authors.lastname: Short
authors.affiliation: Department of Biochemistry and Microbiology, Rhodes University, PO Box 94, Grahamstown 6140, South Africa.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Matsui
authors.affiliation: Department of Biochemistry and Microbiology, Rhodes University, PO Box 94, Grahamstown 6140, South Africa. Electronic address: r.dorrington@ru.ac.za.
authors.forename: Rosemary A
authors.initials: RA
authors.lastname: Dorrington
mesh_terms: D000818:Animals; D002213:Capsid / Q000378:metabolism; D007304:Insect Viruses / Q000235:genetics / Q000502:physiology*; D007915:Lepidoptera / Q000821:virology*; D012328:RNA Viruses / Q000235:genetics / Q000502:physiology*; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism; D019065:Virus Assembly
chemical_list: D012367:RNA, Viral; D014764:Viral Proteins
keywords: Alphatetraviridae; RNA packaging; Virus-like particles; p17 Encapsidation