Disease relevance of PZSVs1gp1

• Viral RNA as a potential target for two independent mechanisms of replicase-mediated resistance against cucumber mosaic virus [1].
• Evolution of a quadripartite hybrid virus by interspecific exchange and recombination between replicase components of two related tripartite RNA viruses [2].
• The RNA replicase extracted from Brome mosaic virus (BMV)-infected plants has been used to characterize the cis-acting elements for RNA synthesis and the mechanism of RNA synthesis [3].
• Members of the Bromovirus and Cucumovirus genera have a tRNA-like structure at the 3' end of their genomic RNAs that interacts with the replicase and is required for minus-strand synthesis [4].
• We found that in the absence of a functional replicase, assembled virions contained non-replicating viral RNAs (RNA1 or RNA2 or RNA3 or RNA1 + RNA3 or RNA2 + RNA3) as well as cellular RNAs [5].

High impact information on PZSVs1gp1

• Phosphorylation of cucumber mosaic virus RNA polymerase 2a protein inhibits formation of replicase complex [6].
• Mutations of the key residues in the core promoter reduced replicase binding, but deletions that disrupt the predicted base pairing in the proposed stem retained binding at wild-type levels [7].
• The first posits that the replicase recognizes at least four key nucleotides in the core promoter, followed by an induced fit, wherein some of the nucleotides base pair prior to the initiation of RNA synthesis (S. Adkins and C. C. Kao, Virology 252:1-8, 1998) [7].
• Based on this study, we conclude that the key structural motif in the triloop recognized by the replicase is a solution-exposed, 5'-adenine base in the triloop that is clamped to the stem helix, which is called a clamped adenine motif [8].
• Replication of viral RNA genomes requires the specific interaction between the replicase and the RNA template [4].

Chemical compound and disease context of PZSVs1gp1

• Putative RNA capping activities encoded by brome mosaic virus: methylation and covalent binding of guanylate by replicase protein 1a [9].
• Additional experiments involving coinoculation of either C3/DeltaCP-EGFP or C3/CP:EGFP with heterologous brome mosaic bromovirus (BMV) genomic RNAs 1 and 2 revealed that, in addition to movement protein and CP, viral replicase also influences cell-to-cell spread [10].

Biological context of PZSVs1gp1

• A replicase-driven template-switching model is presented to explain recombination silencing by GC-rich sequences [11].
• Additional transformants have been generated which contain replicase gene constructs designed to determine the role(s) of transgene mRNA and/or protein in resistance [12].
• Nucleotide sequence and infectivity of cucumber mosaic cucumovirus (strain K) RNA2 involved in breakage of replicase-mediated resistance in tobacco [13].
• Replicase-mediated resistance to cucumber mosaic virus in transgenic plants involves suppression of both virus replication in the inoculated leaves and long-distance movement [14].

Anatomical context of PZSVs1gp1

• In barley protoplasts, functional replicase provided by wild-type BMV RNAs 1 and 2 successfully interacted with the CMV 3' end when present on RNA3 and resulted in the proliferation and accumulation of chimeric progeny RNA3 and RNA4 [15].

References