title: Nopaline-type Ti plasmid of Agrobacterium encodes a VirF-like functional F-box protein.
abstract: During Agrobacterium-mediated genetic transformation of plants, several bacterial virulence (Vir) proteins are translocated into the host cell to facilitate infection. One of the most important of such translocated factors is VirF, an F-box protein produced by octopine strains of Agrobacterium, which presumably facilitates proteasomal uncoating of the invading T-DNA from its associated proteins. The presence of VirF also is thought to be involved in differences in host specificity between octopine and nopaline strains of Agrobacterium, with the current dogma being that no functional VirF is encoded by nopaline strains. Here, we show that a protein with homology to octopine VirF is encoded by the Ti plasmid of the nopaline C58 strain of Agrobacterium. This protein, C58VirF, possesses the hallmarks of functional F-box proteins: it contains an active F-box domain and specifically interacts, via its F-box domain, with SKP1-like (ASK) protein components of the plant ubiquitin/proteasome system. Thus, our data suggest that nopaline strains of Agrobacterium have evolved to encode a functional F-box protein VirF.
authors.affiliation: Stony Brook University, Department of Biochemistry and Cell Biology, Stony Brook, NY 11794-5215, USA.
authors.forename: Benoît
authors.initials: B
authors.lastname: Lacroix
authors.affiliation: Stony Brook University, Department of Biochemistry and Cell Biology, Stony Brook, NY 11794-5215, USA.
authors.forename: Vitaly
authors.initials: V
authors.lastname: Citovsky
mesh_terms: D060054:Agrobacterium / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D001120:Arginine / Q000031:analogs & derivatives / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D044783:F-Box Proteins / Q000235:genetics* / Q000378:metabolism; D050835:Interferon Regulatory Factors / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D010802:Phylogeny; D036741:Plant Tumor-Inducing Plasmids / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism; D014764:Viral Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D044783:F-Box Proteins; D050835:Interferon Regulatory Factors; D008164:Luminescent Proteins; D014764:Viral Proteins; D037521:Virulence Factors; C413486:viral interferon regulatory factors; C008666:nopaline; C005394:octopine; D001120:Arginine