Nucleotide sequence and evolutionary relationships of cucumber mosaic virus (CMV) strains: CMV RNA 3

A procedure based on the polymerase chain reaction (PCR) has been developed to classify cucumber mosaic cucumovirus (CMV) isolates accurately into two subgroups. Two CMV-specific primers that flank the CMV capsid protein gene were used to amplify a DNA fragment of approximately 870 bp. Restriction enzyme analysis of this fragment produces distinct restriction patterns that assign the CMV isolate into one of two subgroups. These two restriction groups correlate with the previously established CMV subgroupings; this PCR-based method may provide a simple alternative to the serological assays used for typing CMV isolates.

Section: Discussionmentioning

confidence: 99%

Differentiation of cucumber mosaic virus isolates using the polymerase chain reaction

Rizos

Gunn²,

Pares³

et al. 1992

“…The amino acid sequence of the 3a protein deduced from the nucleotide sequence of RNA 3 from CMV-24 (Vaquero et al, 1996) is identical to that of the 3a protein of CMV-Fny (Owen et al, 1990). Complementation studies using the Fny strain showed that deletion of 43 aa from the C terminus of the 3a protein did not affect the ability of the virus to infect nontransformed tobacco plants (Kaplan et al, 1995).…”

mentioning

confidence: 99%

Mapping of the RNA-binding domain of the cucumber mosaic virus movement protein.

Vaquero

Liao

Nähring

et al. 1997

A series of in-frame deletion mutants was used to identify a domain within the 3a protein of cucumber mosaic virus (CMV) that is required for RNA-binding activity. Deletions in the 3a gene were generated by PCR and restriction digestion, and the resulting mutated 3a sequences were cloned either in pT7-7 or in pGEX-5X3 expression vectors. The mutated 3a proteins or fusions with glutathione S-transferase (GST) were expressed in E. coli, purified, and their nucleic acid-binding activities analysed by photochemical UV cross-linking assays using digoxigenin-UTP-labelled RNA probes. Comparative analyses of seven mutated 3a proteins obtained from inclusion bodies and eight GST fusion proteins revealed that there is an RNA-binding domain located between amino acids 174 and 233. This RNA-binding domain is able to bind single-stranded RNA out of the context of the complete 3a movement protein and is highly conserved within both subgroups of CMV.

“…The amino acid sequence of the CMV-24 3a protein, as deduced from the nucleotide sequence, is identical to that from CMV-Fny (Owen et al, 1990). The accumulation of the 3a protein in leaf tissue from transgenic plants was assessed by Western immunoblot hybridization, using a polyclonal rabbit antiserum raised against purified E. coli-expressed CMV-24 3a protein (unpublished results).…”

mentioning

confidence: 99%

The 3a Protein from Cucumber Mosaic Virus Increases the Gating Capacity of Plasmodesmata in Transgenic Tobacco Plants

Vaquero¹,

Turner

Demangeat³

et al. 1994

The 3a protein, encoded by RNA 3 of cucumber mosaic virus (CMV), is the putative movement protein of viral progeny in infected plants. An analysis of transgenic tobacco plants constitutively expressing the CMV 3a protein showed that the protein is accumulated in leaves at every stage of development. In fully expanded leaves the protein is immunodetectable mostly in a cell-wallenriched fraction. Dye-coupling experiments using fluorescent-dextran probes were performed on fully expanded leaves to study the modifying effect of CMV 3a protein on the gating capacity of plasmodesmata. Movement of fluorescein-isothiocyanate-labelled dextran with a mean molecular mass of 10000 Da, and an approximate Stokes' radius of 2-3 nm, was detected between cells of the 3a protein transgenic plants, but not in the control plants. These results are consistent with the idea that the CMV 3a protein is involved in the modification of plasmodesmata and, therefore, in the cell-to-cell spread of the virus.