VirB/D4-Dependent Protein Translocation from
            <i>Agrobacterium</i>
            into Plant Cells

Vergunst, Annette C.; Schrammeijer, Barbara; Dulk‐Ras, Amke den; Vlaam, Clementine M. T. de; Regensburg-Tuïnk, Tonny; Hooykaas, Paul J. J.

doi:10.1126/science.290.5493.979

Cited by 355 publications

(360 citation statements)

References 18 publications

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“…39). Of further interest, VirD4 was shown to interact with the carboxy-terminal region of VirE2, adding to evidence that SECRETION SIGNALS are localized at the carboxyl termini of VirE2 and other protein substrates of the VirB/D4 T4S system [39][40][41][42] .…”

Section: The Hexameric Coupling Protein: a Substrate-recruitment Factmentioning

confidence: 99%

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The versatile bacterial type IV secretion systems

Cascales¹,

Christie²

2003

Nat Rev Microbiol

589

559

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Bacteria use type IV secretion systems for two fundamental objectives related to pathogenesisgenetic exchange and the delivery of effector molecules to eukaryotic target cells. Whereas gene acquisition is an important adaptive mechanism that enables pathogens to cope with a changing environment during invasion of the host, interactions between effector and host molecules can suppress defence mechanisms, facilitate intracellular growth and even induce the synthesis of nutrients that are beneficial to bacterial colonization. Rapid progress has been made towards defining the structures and functions of type IV secretion machines, identifying the effector molecules, and elucidating the mechanisms by which the translocated effectors subvert eukaryotic cellular processes during infection. The year 2003 marks the fiftieth anniversary of the first description of a TYPE IV SECRETION (T4S)SYSTEM: the CONJUGATION apparatus of the F plasmid 1 . This is a dynamic bacterial surface organelle, the activities of which are now known to include the contact-dependent delivery of DNA to bacterial recipients and the assembly and retraction of a conjugal PILUS 2 . In the past decade, reports describing systems that are ancestrally related to the F-transfer system and other conjugation machines have emerged. Instead of mediating DNA transfer between bacteria, these systems deliver DNA or protein substrates, known as effectors, to eukaryotic target cells during infection [3][4][5] . More recently, several new T4S systems have been described that are also ancestrally related to the conjugation machines, but these systems mediate the exchange of DNA with the extracellular milieu [6][7][8] . Collectively, this diversity of function in the face of a common ancestry makes the T4S machines attractive subjects for comparative studies that explore the dynamics of organelle assembly and action. Additionally, from a medical perspective, it is of enormous interest to develop a detailed understanding of how the inter-kingdom transfer of type IV effector molecules contributes to pathogenesis. This review will summarize the recent advances in our knowledge of T4S, NIH Public Access Author ManuscriptNat Rev Microbiol. Author manuscript; available in PMC 2013 December 27. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscriptwith an emphasis on machine structure and function, and the activities of effectors after translocation into the eukaryotic host. The T4S familyThis fascinatingly versatile translocation family can be classified into three subfamilies, each of which contributes in unique ways to pathogenesis ( Fig. 1; Table 1). The largest subfamily, the conjugation systems, are found in most species of Gram-negative and Grampositive bacteria. These systems mediate DNA transfer both within and between phylogenetically diverse species, and some systems even deliver DNA to fungi, plants and human cells 2,9-13 . Conjugation is an important contributor to genome plasticity, and therefore bacterial fitness under changing en...

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Section: The Hexameric Coupling Protein: a Substrate-recruitment Factmentioning

confidence: 99%

“…42) and VirF (REF. 40). Whereas VirE2 interacts with the T-strand VirD2 particle to form the so-called T-complex, VirE3 and VirF participate in largely unspecified ways to promote infection of certain plant species.…”

Section: A Tumefaciens T-dna and Effector Protein Transfermentioning

confidence: 99%

The versatile bacterial type IV secretion systems

Cascales¹,

Christie²

2003

Nat Rev Microbiol

589

559

View full text Add to dashboard Cite

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“…This indicates that substrate recognition by the CP primarily occurs via interactions with protein components of the transfer-competent protein/DNA-intermediate. By analogy, the CP of A. tumefaciens, VirD4, interacts with the protein substrate VirE2 (Atmakuri et al, 2003), which is secreted into plant cells independent of T-DNA transfer (Vergunst et al, 2000). The interaction is mediated by the C-terminal domain of VirE2 (Atmakuri et al, 2003).…”

Section: Cp (Vird4): the Cytoplasmic Gate To The Secretion Channelmentioning

confidence: 99%

“…The interaction is mediated by the C-terminal domain of VirE2 (Atmakuri et al, 2003). The C-termini of several T4SS-translocated substrates have been identiWed as the signals mediating secretion by their associated secretion systems (Nagai et al, 2005;Schulein et al, 2005;Simone et al, 2001;Vergunst et al, 2000Vergunst et al, , 2003Vergunst et al, , 2005. It therefore seems probable that substrate recognition by the CPs, as a general rule, occurs via speciWc interactions between the CPs and the C-termini of their associated substrates.…”

Section: Cp (Vird4): the Cytoplasmic Gate To The Secretion Channelmentioning

confidence: 99%

“…Finally, other type IV secretion systems, which are ancestrally related to the conjugative Mpf/CP machinery, are found to secrete protein substrates without any indication for concomitant DNA transfer (Cascales and Christie, 2003;Schröder et al, 2005). The existence of a C-terminal signal mediating translocation of dedicated T4SS protein substrates has been discovered in three diVerent T4SS: the VirB/VirD4 systems of B. henselae and A. tumefaciens, and the Dot/Icm system of L. pneumophila (Atmakuri et al, 2003;Nagai et al, 2005;Schulein et al, 2005;Simone et al, 2001;Vergunst et al, 2000Vergunst et al, , 2003Vergunst et al, , 2005. Evidence is accumulating that these secretion systems have evolved from conjugation systems and that the C-terminal secretion signal of their secreted protein substrates originates from a relaxase ancestor (Schulein et al, 2005).…”

Section: Conjugative Relaxases: Dna Carrier Proteins Secreted By the mentioning

confidence: 99%

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The mating pair formation system of conjugative plasmids—A versatile secretion machinery for transfer of proteins and DNA

Schröder

Lanka

2005

Plasmid

187

146

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The mating pair formation (Mpf) system functions as a secretion machinery for intercellular DNA transfer during bacterial conjugation. The components of the Mpf system, comprising a minimal set of 10 conserved proteins, form a membrane-spanning protein complex and a surface-exposed sex pilus, which both serve to establish intimate physical contacts with a recipient bacterium. To function as a DNA secretion apparatus the Mpf complex additionally requires the coupling protein (CP). The CP interacts with the DNA substrate and couples it to the secretion pore formed by the Mpf system. Mpf/CP conjugation systems belong to the family of type IV secretion systems (T4SS), which also includes DNA-uptake and -release systems, as well as eVector protein translocation systems of bacterial pathogens such as Agrobacterium tumefaciens (VirB/VirD4) and Helicobacter pylori (Cag). The increased eVorts to unravel the molecular mechanisms of type IV secretion have largely advanced our current understanding of the Mpf/CP system of bacterial conjugation systems. It has become apparent that proteins coupled to DNA rather than DNA itself are the actively transported substrates during bacterial conjugation. We here present a uniWed and updated view of the functioning and the molecular architecture of the Mpf/CP machinery. 

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Plant Transformation

Hooykaas¹

2010

Encyclopedia of Life Sciences

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The genetic constitution of plants can be altered in the laboratory by a process called transformation, whereby a segment of DNA ( deoxyribonucleic acid ) is introduced that becomes inserted in one of the plant chromosomes. Several methods to accomplish plant transformation have been devised. In all these methods, single cells are transformed and thereafter regenerated into complete, fertile plants by tissue culture procedures. Some of the transformation methods can only be applied to protoplasts (cells from which the walls have been removed). Nowadays, particle bombardment and the natural vector Agrobacterium tumefaciens are preferred because they can also cope with whole plant tissues such as roots and leaves, which are easier to handle, more stable and require less of the lengthy steps that are required for plant regeneration. Transgenes are integrated at random positions in the plant genome, but procedures for targeted integration become more and more efficient. Key concepts: Transgenic plants are plants derived from cells in which genes (often of nonplant origin) have been stably introduced by transformation to give the plant a new and useful trait. Transgenic plants can be obtained after transformation of single cells and the subsequent regeneration into complete, fertile plants by tissue culture protocols. Transformed plant cells can be identified by their ability to grow on selective media containing an antibiotic or a herbicide as transformation vectors contain selection genes conferring such properties. Novel functions are expressed in transformed plant cells if the coding regions are surrounded by promoter and terminator regions that are recognized by the plant transcription machinery. The most preferred methods for plant transformation use either the particle gun or the natural transformation system of Agrobacterium tumefaciens , as they can cope with cells present in whole plants or tissues. Agrobacterium tumefaciens can be disarmed by deletion of the onc ‐genes that are naturally present between the 25‐bp repeats of the T‐DNA. Any gene introduced between these repeats is translocated into plant cells by Agrobacterium tumefaciens. Transformed cells with a single copy of the transgene usually show higher and more stable expression than multicopy lines, in which expression may suffer from posttranscriptional gene silencing. (T)‐DNA integration in plant cells occurs at random sites in the genome by nonhomologous end‐joining and related backup pathways. Targeted integration of transgenes can be accomplished in plant cells by using either a site‐specific recombination system (e.g. Cre‐ lox ) or by homology‐directed integration in combination with a site‐specific nuclease (e.g. a zinc‐finger nuclease). Agrobacterium tumefaciens ‐mediated transformation can be applied not only in dicotyledonous plants, but also in monocots such as cereals and in yeasts and fungi. The T‐DNA can be used as a mutagen causing insertion mutations. Libraries of Arabidopsis thaliana T‐DNA transformants are in use now in mutant screens to identify insertion mutations in genes of interest (reverse genetics).

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VirB/D4-Dependent Protein Translocation from Agrobacterium into Plant Cells

Cited by 355 publications

References 18 publications

The versatile bacterial type IV secretion systems

The versatile bacterial type IV secretion systems

The mating pair formation system of conjugative plasmids—A versatile secretion machinery for transfer of proteins and DNA

Plant Transformation

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