Replication of alfamo- and ilarviruses: role of the coat protein.
In the family Bromoviridae, a mixture of the three genomic RNAs of bromo-, cucumo-, and oleaviruses is infectious as such, whereas the RNAs of alfamo- and ilarviruses require binding of a few molecules of coat protein (CP) to the 3' end to initiate infection. Most studies on the early function of CP have been done on the alfamovirus Alfalfa mosaic virus (AMV). The 3' 112 nucleotides of AMV RNAs can adopt two different conformations. One conformer consists of a tRNA-like structure that, together with an upstream hairpin, is required for minus-strand promoter activity. The other conformer consists of four hairpins interspersed by AUGC-sequences and represents a strong binding site for CP. Binding of CP to this conformer enhances the translational efficiency of viral RNAs in vivo 40-fold and blocks viral minus-strand RNA synthesis in vitro. AMV CP is proposed to initiate infection by mimicking the function of the poly(A)-binding protein.
Bol
John F
JF
Institute of Biology, Gorlaeus Laboratories, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands. j.bol@chem.leidenuniv.nl
D019178:Alfamovirus / Q000235:genetics / Q000502:physiology*; D036022:Capsid Proteins / Q000235:genetics / Q000378:metabolism*; D015967:Gene Expression Regulation, Viral; D016679:Genome, Viral; D019179:Ilarvirus / Q000235:genetics / Q000502:physiology*; D010935:Plant Diseases / Q000821:virology; D014779:Virus Replication
D036022:Capsid Proteins