The VirD2 protein of A. tumefaciens contains a C-terminal bipartite nuclear localization signal: Implications for nuclear uptake of DNA in plant cells

Howard, Elizabeth; Zupan, John R.; Citovsky, Vitaly; Zambryski, Patricia

doi:10.1016/0092-8674(92)90210-4

Cited by 249 publications

(201 citation statements)

References 35 publications

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“…P30 domains required for interaction with plasmodesmata (domain E) and/or binding to p38 (domains F1 and F2, ¢gure 1) may carry such a signal. Similar transport of nucleic acids via a protein import pathway has been proposed for the nuclear import of Agrobacterium T-DNA associated with the bacterial VirD2 and VirE2 proteins (Citovsky et al 1992bHoward et al 1992;Guralnick et al 1996;Zupan et al 1996) and for that of the in£uenza virus genomic RNANP nucleoprotein complexes (O'Neill et al 1995).…”

Section: Possible Mechanisms For Plasmodesmatal Transportmentioning

confidence: 99%

Tobacco mosaic virus: a pioneer to cell–to–cell movement

Citovsky

1999

Phil. Trans. R. Soc. Lond. B

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Cell-to-cell movement of tobacco mosaic virus (TMV) is used to illustrate macromolecular tra¤c through plant intercellular connections, the plasmodesmata. This transport process is mediated by a specialized viral movement protein, P30. In the initially infected cell, P30 is produced by transcription of a subgenomic RNA derived from the invading virus. Presumably, P30 then associates with a certain proportion of the viral RNA molecules, sequestering them from replication and mediating their transport into neighbouring uninfected host cells. This nucleoprotein complex is targeted to plasmodesmata, possibly via interaction with the host cell's cytoskeleton. Prior to passage through a plasmodesma, the plasmodesmatal channel is dilated by the movement protein. It is proposed that targeting of P30-TMV RNA complexes to plasmodesmatal involves binding to a speci¢c cell-wall-associated receptor molecule. This protein, designated p38, also functions as a protein kinase, phosphorylating P30 at its carboxyterminus and minimizing P30-induced interference with plasmodesmatal permeability during viral infection.

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Section: Possible Mechanisms For Plasmodesmatal Transportmentioning

confidence: 99%

Tobacco mosaic virus: a pioneer to cell–to–cell movement

Citovsky

1999

Phil. Trans. R. Soc. Lond. B

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“…In particular, functional plant cell NLSs have been identified in maize in both the anthocyanin regulatory proteins Opaque2 and R (Varagona et al, 1992;Shieh et al, 1993) and the Ac transposase (Boehm et al, 1995), in auxininducible proteins in pea (Abel and Theologis, 1995), and in the GT box-binding transcription factor GT-2 from Arabidopsis (Dehesh et al, 1995). They have also been described in karyophilic proteins encoded by plant pathogens, namely, the NIa protein encoded by tobacco etch virus (Carrington et al, 1991) and the VirD2 and VirE2 proteins encoded by the Ti plasmid of Agrobucterium tumefuciens Howard et al, 1992). Analysis of C1 and R further demonstrate that a11 three consensus NLSs are used in plants (Hicks et al, 1995).…”

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confidence: 97%

A Viral Movement Protein as a Nuclear Shuttle (The Geminivirus BR1 Movement Protein Contains Domains Essential for Interaction with BL1 and Nuclear Localization)

1996

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For the nuclear replicating bipartite geminiviruses such as squash leaf curl to systemically infect the host requires the active participation of two virus-encoded movement proteins, BR1 and BL1. These act in a cooperative manner to transport the viral singlestranded DNA genome from its site of replication in the nucleus to the cell periphery (A.A. Sanderfoot, S.C. Lazarowitz [1995] Plant Cell 7: 1185-1194). We have proposed that BR1 functions as a nuclear shuttle protein, transporting the viral single-stranded DNA to and from the nucleus as a complex that is recognized by BL1 for movement to adjacent cells. To further investigate this, we expressed BR1 mutants known to affect viral infectivity in Spodoptera frugiperda insect cells and Nicotiana tabacum L. cv Xanthi protoplasts and found these to be defective in either their nuclear targeting or their ability to be redirected to the cell periphery when co-expressed with BL1. Translational fusions to p-glucuronidase and alanine-scanning mutagenesis further demonstrated that the C-terminal 86 amino acids of BR1 contains a domain(s) essential for i t s interaction with B L I and identified two nuclear localization signals within the N-terminal 113 residues of BR1. These nuclear localization signals were precisely located within distinct 16-and 22-peptide segments of BR1. These studies support and extend our model for squash leaf curl virus movement, showing that BR1 has a domain structure, with an N-terminal region required for nuclear targeting and a C-terminal region required for i t s interaction with BL1. Department of Microbiology, University of lllinois 23Regulated trafficking across the nuclear membrane is an essential component of many signal transduction pathways in eukaryotic cells and a fundamental aspect of infection by animal and plant viruses that replicate in the nucleus. The transport of proteins across the nuclear membrane is an energy-requiring process mediated by proteins associated with nuclear pore complexes (Newmeyer and Forbes, 1988). Although nuclear pores have an effective size-exclusion limit of approximately 60 kD, proteins smaller than this appear not to diffuse efficiently across the nuclear membrane (reviewed by Silver, 1991). Karyophilic proteins contain NLSs, short basic regions of approximately 10 to 20 amino acids (reviewed

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“…VirD2 consists of an N-terminal relaxase domain and a large domain of unknown function (DUF) that is less conserved between different VirD2 proteins (Howard et al, 1992;van Kregten et al, 2009). To investigate whether the relaxase domain or the DUF was responsible for the interaction with histones, BiFC experiments were performed with VirD2-204…”

Section: Resultsmentioning

confidence: 99%

Interaction of the Agrobacterium tumefaciens virulence protein VirD2 with histones

et al. 2015

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Agrobacterium tumefaciens is a Gram-negative soil bacterium that genetically transforms plants and, under laboratory conditions, also transforms non-plant organisms, such as fungi and yeasts. During the transformation process a piece of ssDNA (T-strand) is transferred into the host cells via a type IV secretion system. The VirD2 relaxase protein, which is covalently attached at the 59 end of the T-strand through Tyr29, mediates nuclear entry as it contains a nuclear localization sequence. How the T-strand reaches the chromatin and becomes integrated in the chromosomal DNA is still far from clear. Here, we investigated whether VirD2 binds to histone proteins in the yeast Saccharomyces cerevisiae. Using immobilized GFP-VirD2 and in vitro synthesized His 6 -tagged S. cerevisiae proteins, interactions between VirD2 and the histones H2A, H2B, H3 and H4 were revealed. In vivo, these interactions were confirmed by bimolecular fluorescence complementation experiments. After co-cultivation of Agrobacterium strains expressing VirD2 tagged with a fragment of the yellow fluorescent protein analogue Venus with yeast strains expressing histone H2A or H2B tagged with the complementary part of Venus, fluorescence was detected in dot-shaped structures in the recipient yeast cells. The results indicated that VirD2 was transferred from Agrobacterium to yeast cells and that it interacted with histones in the host cell, and thus may help direct the T-DNA (transferred DNA) to the chromatin as a prelude to integration into the host chromosomal DNA.

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The VirD2 protein of A. tumefaciens contains a C-terminal bipartite nuclear localization signal: Implications for nuclear uptake of DNA in plant cells

Cited by 249 publications

References 35 publications

Tobacco mosaic virus: a pioneer to cell–to–cell movement

Tobacco mosaic virus: a pioneer to cell–to–cell movement

A Viral Movement Protein as a Nuclear Shuttle (The Geminivirus BR1 Movement Protein Contains Domains Essential for Interaction with BL1 and Nuclear Localization)

Interaction of the Agrobacterium tumefaciens virulence protein VirD2 with histones

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