Disease relevance of TAVs2gp2

• The 2b protein of cucumoviruses has a role in promoting the cell-to-cell movement of pseudorecombinant viruses [1].
• Examination of published viral RNA sequences revealed the conservation of ORF 2b in all of the four other cucumoviruses sequenced to date; however, it is absent from the rest of the Bromoviridae [2].
• Polyclonal antibodies raised against a 2b fusion protein expressed in Escherichia coli specifically detected the 2b gene product in Q-CMV-infected cucumber plants by Western immunoblotting [2].

High impact information on TAVs2gp2

• We recently demonstrated that a previously undescribed gene (2b) encoded by RNA 2 of the tripartite RNA genome of CMV is required for systemic virus spread and disease induction in its hosts [3].
• As CMV and the hybrid virus accumulated to a similar level in the infected tobacco protoplasts, the observed synergistic responses most likely resulted from an increased efficacy of the hybrid virus in systemic spread in host plants provided by the TAV 2b protein [3].
• The 2b gene rather than the overlapping open reading frame encoding the C-terminal 41 amino acids of 2a protein of the corresponding virus was found to be essential for promoting infection of the pseudorecombinant viruses in planta [1].
• By contrast, the 2b genes of both TAV and a hypervirulent strain of CMV (WAII-CMV) were found to affect the virulence of the pseudorecombinant viruses but not the levels of viral RNA accumulation [1].

References