Alfalfa mosaic virus RNA3 mutants do not replicate in transgenic plants expressing RNA3-specific genes

Dore, Jean-Michel; Dun, Cees M.P. Van; Pinck, L.; Bol, John F.

doi:10.1099/0022-1317-72-2-253

Cited by 17 publications

(5 citation statements)

References 24 publications

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“…In the case of alfalfa mosaic virus (AMV), a 32K protein, designated P3, appears to be involved in viral cell-to-cell spread (Dore et al, 1991). In this context, we have investigated the symplastic transport of fluorescent dyes to estimate the gating capacity of plasmodesmata putatively modified in transformed plants expressing P3.…”

mentioning

confidence: 99%

Effect of the alfalfa mosaic virus movement protein expressed in transgenic plants on the permeability of plasmodesmata

Poirson

Giovane²,

Berna³

et al. 1993

Journal of General Virology

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confidence: 99%

Effect of the alfalfa mosaic virus movement protein expressed in transgenic plants on the permeability of plasmodesmata

Poirson

Giovane²,

Berna³

et al. 1993

Journal of General Virology

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“…Alfalfa mosaic virus (AMV) and ilarviruses provide an interesting model system in which to study RNA-protein interactions because the viral coat protein (CP) has multiple roles in the viral life cycle, not all of which are completely understood. In addition to virion assembly (21,44) the viral CP has roles in cell-to-cell movement (12,43), infectivity (6,23), and translation (28,29).…”

mentioning

confidence: 99%

Coat Protein Activation of Alfalfa Mosaic Virus Replication Is Concentration Dependent

Guogas

Laforest

Gehrke

2005

J Virol

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Alfalfa mosaic virus (AMV) and ilarvirusRNA-protein interactions play important roles in a variety of biological processes and are of particular importance in the life cycle of positive-strand RNA viruses, where the genomic RNA serves as the template for protein synthesis and replication. Alfalfa mosaic virus (AMV) and ilarviruses provide an interesting model system in which to study RNA-protein interactions because the viral coat protein (CP) has multiple roles in the viral life cycle, not all of which are completely understood. In addition to virion assembly (21, 44) the viral CP has roles in cell-to-cell movement (12, 43), infectivity (6, 23), and translation (28,29).Most bromoviruses have a tRNA-like structure (TLS) on the 3Ј end of the RNA genome. The TLS has been found to be important for recruiting the viral replicase (8, 13). Conversely, AMV and ilarviruses lack a canonical CCA 3Ј end common to the TLS and further require the presence of their own viral CP to initiate replication (6). It has been shown that CP binds specifically to the 3Ј untranslated region found on all three AMV genomic RNAs as well as the subgenomic RNA4 (5, 22, 24). Genomic RNA1 and -2 encode proteins with replicase functions (33). RNA3 is dicistronic, encoding the viral movement protein (MP) and CP. Only the upstream open reading frame, encoding the viral MP, is translated from genomic RNA3. The viral CP is translated from a subgenomic RNA4, which is generated by the internal initiation of transcription from minus-strand RNA3. In vitro-transcribed RNA4 (CP mRNA) can substitute for CP in the activation of replication when inoculated with the genomic RNAs into tobacco protoplasts (46).It was first proposed by Houwing and Jaspars that an RNA conformational change accompanies CP binding to the 3Ј ends of the genomic RNAs and thereby presents a recognition signal for replicase binding (20). Results from circular dichroism analyses and native polyacrylamide gel electrophoresis experiments support the idea that the 3Ј untranslated region (UTR) of AMV RNA3 and -4 undergoes a conformational change upon binding amino-terminal CP peptides (3). Further investigation of this RNA-protein interaction revealed a 26-aminoacid RNA binding motif in the N terminus of the CP that is sufficient to activate replication in mesophyll protoplasts (3,39). A minimal CP binding site was also identified at the terminal 39 nucleotides of the AMV 3Ј UTR (1, 17). While it is known that the genomic RNAs are not infectious in the absence of CP (6, 47), it is unclear how CP initiates infection or how it influences ongoing replication.Several models have been proposed to explain the genome activation phenomenon. The interaction of CP with the genomic RNA 3Ј UTR may serve to protect the RNAs from degradation (30); however, AMV genomic RNAs have been shown to be stable for several hours when inoculated into protoplasts in the absence of CP or polymerase (19). Olsthoorn et al. (31) described the conformational switch model, wherein the protein-free 3Ј UTR assumes a pseu...

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“…It could be that the function of C P in regulating the balance betw een plus-and m inusstrand R N A synthesis is dose-dependent and is dis turbed only at higher levels of CP such as are obtained in the M onsanto CP plants. T h e Leiden C P plants could be infected with A1MV RNAs 1, 2 and 3 b u t did not com plem ent infection w hen the C P gene in R N A 3 in this inoculum was defective (Dore 1991;. A pparently, C P produced by these plants is able to carry out the early function of C P in genom e ac ti vation but is not sufficient to perform one of the later functions of this proteins.…”

Section: Discussionmentioning

confidence: 97%

Complementation and disruption of viral processes in transgenic plants

Bol

Brederode

Neeleman

et al. 1993

Phil. Trans. R. Soc. Lond. B

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RNAs 1 and 2 of alfalfa mosaic virus (AIMV) encode the replicase genes P1 and P2, respectively, whereas RNA 3 encodes the movem ent protein and the viral coat protein (CP). To investigate the mechanism of cross-protection, tobacco plants were transformed with wild-type and mutant DNA copies of the AIMV CP gene and the two replicase genes P1 and P2. Expression of wild-type CP at relatively low levels resulted in a resistance against infection with AIMV virus particles whereas at higher expression levels CP protected against infection with either AIMV particles or RNAs. Plants transformed with a mutant AIMV CP gene were not resistant to the wild-type virus but were resistant to AIMV with the same mutation in the CP gene. Transformation of plants with the wild-type P1 gene (P1 plants), P2 gene (P2 plants) or both these genes (P12 plants) did not result in resistance to AIMV. Instead, these plants could be infected with an inoculum lacking the gene(s) that was (were) integrated in the plant genome. Infection of non-transgenic plants, P1 plants or P2 plants with a mixture of AIMV genomic RNAs requires the presence of CP in the inoculum but P12 plants could be infected with RNA3 without any requirement for CP in the inoculum. Infection conditions in which 355 promoter/AlMV cDNA fusions were present in the inoculum instead of in the plant genome were used to shed light on the early function of CP. Finally, plants were transformed with P2 genes with mutations in the GDD-motif. A number of these transgenic lines showed a high level of resistance to AIMV.

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Alfalfa mosaic virus RNA3 mutants do not replicate in transgenic plants expressing RNA3-specific genes

Cited by 17 publications

References 24 publications

Effect of the alfalfa mosaic virus movement protein expressed in transgenic plants on the permeability of plasmodesmata

Effect of the alfalfa mosaic virus movement protein expressed in transgenic plants on the permeability of plasmodesmata

Coat Protein Activation of Alfalfa Mosaic Virus Replication Is Concentration Dependent

Complementation and disruption of viral processes in transgenic plants

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