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Large-scale Production of Recombinant RNAs on a Circular Scaffold Using a Viroid-derived System in Escherichia coli
Published on: November 30, 2018
Replication mechanisms of circular ssDNA plant viruses and their potential implication in viral gene expression
Mélia Bonnamy1,2, Stéphane Blanc1, Yannis Michalakis2
1PHIM, Univ Montpellier, IRD, CIRAD, INRAE, Institut Agro , Montpellier, France.
Abstract:
The replication of members of the two circular single-stranded DNA (ssDNA) virus families Geminiviridae and Nanoviridae, the only ssDNA viruses infecting plants, is believed to be processed by rolling-circle replication (RCR) and recombination-dependent replication (RDR) mechanisms. RCR is a ubiquitous replication mode for circular ssDNA viruses and involves a virus-encoded Replication-associated protein (Rep) which fulfills multiple functions in the replication mechanism. Two key genomic elements have been identified for RCR in Geminiviridae and Nanoviridae: (i) short iterative sequences called iterons which determine the specific recognition of the viral DNA by the Rep and (ii) a sequence enabling the formation of a stem-loop structure which contains a conserved motif and constitutes the origin of replication. In addition, studies in Geminiviridae provided evidence for a second replication mode, RDR, which has also been documented in some double-stranded DNA viruses. Here, we provide a synthesis of the current understanding of the two presumed replication modes of Geminiviridae and Nanoviridae, and we identify knowledge gaps and discuss the possibility that these replication mechanisms could regulate viral gene expression through modulation of gene copy number.
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