cis-Acting Elements Required for Efficient Packaging of Brome Mosaic Virus RNA3 in Barley Protoplasts
AUTOR(ES)
Asmira Damayanti, Tri
FONTE
American Society for Microbiology
RESUMO
Brome mosaic virus (BMV) is a positive-sense RNA plant virus, the tripartite genomic RNAs of which are separately packaged into virions. RNA3 is copackaged with subgenomic RNA4. In barley protoplasts coinoculated with RNA1 and RNA2, an RNA3 mutant with a 69-nucleotide (nt) deletion in the 3′-proximal region of the 3a open reading frame (ORF) was very poorly packaged compared with other RNA3 mutants and wild-type RNA3, despite their comparable accumulation in the absence of coat protein. Computer analysis of RNA secondary structure predicted two stem-loop (SL) structures (i.e., SL-I and SL-II) in the 69-nt region. Disruption of SL-II, but not of SL-I, significantly reduced RNA3 packaging. A chimeric BMV RNA3 (B3Cmp), with the BMV 3a ORF replacing that of cucumber mosaic virus (CMV), was packaged negligibly, whereas RNA4 was packaged efficiently. Replacement of the 3′-proximal region of the CMV 3a ORF in B3Cmp with the 3′-proximal region of the BMV 3a ORF significantly improved packaging efficiency, and the disruption of SL-II in the substituted BMV 3a ORF region greatly reduced packaging efficiency. These results suggest that the 3′-proximal region of the BMV 3a ORF, especially SL-II predicted between nt 904 and 933, plays an important role in the packaging of BMV RNA3 in vivo. Furthermore, the efficient packaging of RNA4 without RNA3 in B3Cmp-infected cells implies the presence of an element in the 3a ORF of BMV RNA3 that regulates the copackaging of RNA3 and RNA4.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=224592Documentos Relacionados
- Minimal cis-Acting Elements Required for Adenovirus Genome Packaging
- cis-Acting Elements Important for Retroviral RNA Packaging Specificity
- cis-Acting Sequences Required for Coronavirus Infectious Bronchitis Virus Defective-RNA Replication and Packaging
- Multiple cis-acting sequence elements are required for efficient splicing of simian virus 40 small-t antigen pre-mRNA.
- Packaging of Brome Mosaic Virus RNA3 Is Mediated through a Bipartite Signal