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The genome organization of the broad bean necrosis virus (BBNV)

Lu, X., Yamamoto, S., Tanaka, M., Hibi, T., Namba, S.
Archives of virology 1998 v.143 no.7 pp. 1335-1348
Broad bean necrosis virus, DNA-directed RNA polymerase, Furovirus, Peanut clump virus, Potato mop-top virus, amino acid sequences, capsid, computer analysis, genes, phylogeny, plant viruses, polyacrylamide gel electrophoresis, proteins
The genome of the broad bean necrosis virus Oita-isolate (BBNV-O) [RNAff1 (6.0 kb), RNAff2 (2.8 kb) and RNAff3 (2.4 kb)] was cloned and sequenced. Computer analysis indicates that methyltransferase, helicase and RNA-dependent RNA polymerase (RdRp) motifs are present in RNAff1. The viral capsid protein (CP) cistron is located at the 5′ terminal end of RNAff2 and the Mr of CP (20 K) is close to that determined by SDS-PAGE analysis. An ochre codon (UAA) in the CP cistron is thought to be partially suppressed to produce a large readthrough protein. RNAff3 possesses typical motifs of triple gene block proteins, which are also reported in several other plant viruses. The furovirus genome organization and phylogenetic analysis using RdRp and CP amino acid sequences suggest that BBNV is closely related to potato mop-top virus (PMTV), but is relatively distantly related to other furoviruses. The data also suggest that the genus Furovirus should be separated into several genera: the prototypical genus Furovirus, which excludes the following viruses: the PMTV group including BBNV; the beet necro- tic yellow vein virus (BNYVV) group; and the peanut clump virus (PCV) group.