Regulation of the activities of African cassava mosaic virus promoters by the AC1, AC2, and AC3 gene products

Haley, Ann; Zhan, Xi; Richardson, Kim; Head, Kylie; Morris, Bret A.M.

doi:10.1016/0042-6822(92)90551-y

Cited by 92 publications

(72 citation statements)

References 16 publications

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“…Both the TGMV and ACMV AL2 gene products are transactivators that are necessary for the efficient expression of virion-sense, ARI(CP) and BR1 genes (Sunter & Bisaro, 1991Haley et al, 1992). The BL1 and BR1 ORFs encode proteins necessary for systemic infection by bipartite geminiviruses and may perform distinct and independent functions involved in viral DNA movement (Noueiry et al, 1994).…”

Section: Resultsmentioning

confidence: 99%

Mutational analysis of potato yellow mosaic geminivirus

Sung

Coutts²

1995

Journal of General Virology

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Mutations have been inserted into the virion and complementary sense ORFs encoding proteins with MrS in excess of 9 kDa of both DNA A and DNA B of potato yellow mosaic geminivirus (PYMV). Wild-type and mutant monomeric clones were tested for their ability to replicate, produce PYMV-specific DNA, spread and cause symptoms in Nicotiana benthamiana plants following biolistic inoculation. Dimeric clones of the DNA A mutants were also investigated by agroinoculation of leaf discs. In contrast to N. benthamiana plants agroinoculated with PYMV DNA A, in which the wild-type DNA A component was capable of limited independent replication and spread, both excised DNA A and B components were required for DNA replication and symptom development in plants inoculated by the biolistic method. Mixtures of both genomic components were also infectious for potato plants following biolistic inoculation. Mutations in ORFs ALl, AL2, BR1 and BLl resulted in clones incapable of infecting N. benthamiana plants. However, the AL2 mutation, but not the ALl mutation, allowed viral DNA replication in leaf discs. Mutations to both the ARI and AL30RFs produced clones which were infectious in plants but showed a considerable delay in the production of attenuated symptoms as compared to wild-type infections. Mutating the AL30RF dramatically reduced viral DNA replication in both whole plants and leaf discs. Mutations to the AL40RF produced clones which were as infectious for both N. benthamiana and potato plants as the wild-type clones. Our results are compared with those from mutagenesis studies on related bipartite geminiviruses.

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Section: Resultsmentioning

confidence: 99%

Mutational analysis of potato yellow mosaic geminivirus

Sung

Coutts²

1995

Journal of General Virology

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“…down-regulation of transcription of the ALI ORF. Indeed such down-regulation has recently been demonstrated [23]. (ii) The putative helicase activity of the AL1 protein can then unwind the region containing the origin of replication.…”

Section: Discussionmentioning

confidence: 99%

TGMV replication protein AL1 preferentially binds to single‐stranded DNA from the common region

et al. 1993

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The AL1 protein of tomato golden mosaic virus (TGMV) is encoded by the viral DNA and has been shown to be essential for viral DNA replication. We have over-expressed the AL1 open reading frame in E. coli and purified the protein from bacterial extracts to near homogeneity. Using various different techniques we have studied the interaction of the AL1 protein with DNA. The AL1 protein is able to bind to DNA containing the common region of the viral genome, which can be demonstrated by photochemical cross-linking. Binding is 4-fold stronger to single-stranded than to double-stranded DNA. Antibodies against the AL1 protein can be used to precipitate the protein-DNA complex. The binding to single-and double-stranded DNA is specifically to the common region since a DNA fragment unrelated to TGMV is not shifted in a gel retardation assay.

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“…A function has yet to be assigned to the overlapping gene, A V2, and neither virion-sense gene is required for systemic infection of Nicotiana benthamiana (Stanley & Townsend, 1986;Etessami et al, 1989). Of the four overlapping complementary-sense genes, AC1 is essential for viral DNA replication (Brough et al, 1988;Elmer et al, 1988;Etessami et al, 1991), AC2 transactivates the expression of coat protein and DNA B genes (Haley et al, 1992; and AC3 is required for normal levels of viral DNA replication (Sunter et al, 1990;Etessami et al, 1991;Morris et al, 1991). No function has been assigned to * Author for correspondence.…”

Section: Introductionmentioning

confidence: 99%