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Generation and Assembly of Virus-Specific Nucleocapsids of the Respiratory Syncytial Virus
Published on: July 27, 2021
An encapsidated viral protein and its role in RNA packaging by a non-enveloped animal RNA virus
Adriano Mendes1, Marli Vlok1, James R Short1
1Department of Biochemistry and Microbiology, Rhodes University, PO Box 94, Grahamstown 6140, South Africa.
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.
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