Publications

rapid mapping of transposon insertion and deletion mutations in the large ti-plasmids of agrobacterium tumefaciens.	a procedure is presented, that has allowed the rapid assignment of transposon tn1 and tn7 insertion sites in the large (130 md) nopaline ti-plasmid ptic58, to specific restriction enzyme fragments. total bacterial dna is isolated from agrobacterium tumefaciens strain c58 mutants that carry a transposon in their ti-plasmid, and digested with an appropriate restriction endonuclease. the fragments are separated on an agarose gel, denatured and transferred to nitrocellulose filters. these are hybrid ...	1979	231764
molecular cloning of overlapping segments of the nopaline ti-plasmid ptic58 as a means to restriction endonuclease mapping.		1980	6100893
the functional organization of the nopaline a. tumefaciens plasmid ptic58.		1980	6100894
a general method for the transfer of cloned genes to plant cells.	this paper describes a method for the transfer to plant cells of any cloned gene, regardless of its termini or internal restriction enzyme cleavage sites. a broad host-range intermediate vector, pgv1117, was constructed containing hindiii-23, a right-end t-region fragment of the nopaline plasmid ptic58. using in vivo protection by ecori methylase and ecori linker ligation, a fragment of rabbit chromosomal dna, carrying the beta-globin gene, was inserted into plasmid pgv1117. following transmissi ...	1983	6628995
broad-host-range agrocin of agrobacterium tumefaciens.	eighteen strains of agrobacterium tumefaciens isolated from crown galls were tested for agrocin production. of six agrocin-producing strains, one (d286) produced a broad-host-range agrocin active against strains carrying nopaline, octopine, and agropine type ti plasmids. sensitivity to agrocin d286 was found to map in the 11- to 18-megadalton region of the nopaline ti plasmid ptic58. the agrocin was partially purified, and its physical characteristics were consistent with its being a nucleotide, ...	1983	16346290
design and development of amplifiable broad-host-range cloning vectors: analysis of the vir region of agrobacterium tumefaciens plasmid ptic58.	the construction of a set of new plasmids that are suitable as general cloning vectors in escherichia coli and agrobacterium tumefaciens is described. plasmid pucd2 is amplifiable in e. coli, replicates in a wide range of gram-negative hosts and contains a number of useful restriction endonuclear cleavage sites and antibiotic resistance genes. this includes unique sites for kpni, saci, sacii, psti, clai, sali, ecorv, and pvuii and the genes for resistance to kanamycin, tetracycline, ampicillin, ...	1984	6095350
transfer of the octopine t-dna segment to plant cells mediated by different types of agrobacterium tumor- or root-inducing plasmids: generality of virulence systems.	genetic complementation studies demonstrated that the transfer to plant cells of the octopine t-dna, entirely present as the only part of the tumor-inducing (ti) plasmid on the plasmid pal1050, was effected by the virulence systems from related plasmids, viz. the nopaline ti plasmid ptic58, the limited host range plasmid ptiag57, and the root-inducing (ri) plasmid pri1855. rhizobium symbiosis plasmids were not capable of effecting the introduction of pal1050 into plant cells.	1984	6715283
genetic analysis of integration mediated by single t-dna borders.	transformation of plant cells by the t-dna of the ti plasmid of agrobacterium tumefaciens depends in part upon a sequence adjacent to the right t-dna end. when this sequence is absent, the t-dna is almost avirulent; when it is present, dna between it and the left t-dna border region becomes integrated in plants. to investigate further this process of dna transfer and integration, we introduced the right border region and the nopaline synthase (nos) gene of plasmid ptic58 into a variety of new po ...	1985	3968034
analysis of agrobacterium tumefaciens plasmid ptic58 replication region with a novel high-copy-number derivative.	the origin of replication, ori, of the nopaline tumor-inducing plasmid, ptic58, mapped in a region that shares sequence homology with octopine plasmids ptiach5 and ptib6. within this region, the minimum amount of dna necessary for maintaining autonomous replication was a 2.6-kilobase region, which also comprised the incompatibility function inc. ptic58 derivatives containing inc were incompatible with agrobacterium tumefaciens plasmids ptic58, ptid1439, ptiach5, pti15955, and ptia5 and were comp ...	1985	3972769
regulation of ti plasmid virulence genes by a chromosomal locus of agrobacterium tumefaciens.	we isolated a mutant strain of agrobacterium tumefaciens, designated ros, that has a pleiotropic phenotype which includes elevated levels of expression of certain genes in the virulence (vir) region of tumor-inducing plasmid ptic58. this mutant and others were isolated by fusing the promoter of the vir bak gene to a promoterless gene (cat) that encodes chloramphenicol acetyltransferase and then selecting for increased expression of cat in a. tumefaciens. the ros mutation is chromosomal in nature ...	1985	4055699
tumour genes in plants: t-dna encoded cytokinin biosynthesis.	gene 4 from the t-region of ti plasmids is responsible for cytokinin effects in crown gall cells; we investigated whether it codes for an enzyme of hormone biosynthesis. in a first set of experiments, gene 4 from octopine plasmid ptiach5 and nopaline plasmid ptic58 was expressed in escherichia coli, and the gene products were identified by reaction with antiserum raised against a decapeptide derived from the dna sequence of the gene. extracts from cells expressing the gene contained high isopent ...	1985	15938044
a 3.6-kbp segment from the vir region of ti plasmids contains genes responsible for border-sequence-directed production of t region circles in e. coli.	the vir region of ti plasmids is responsible for the transfer of the t region from agrobacteria to plant cells; previous experiments suggested that formation of independent t region dna circles is one step in this process. to study this step in escherichia coli, we developed a binary vector system. one plasmid (= substrate) contains correctly oriented right and left borders from octopine plasmid ptiach5. a gene with a counterselectable function (galk) was cloned between these borders. the galk g ...	1986	15966100
[conjugation transfer of the bireplicon plasmid pspa044 into rhizobiaceae bacteria].	we have demonstrated the possibility of hybrid plasmid pspa044 conjugative transfer from e. coli cells into different rhizobium species. the bireplicon plasmid, constructed earlier in our laboratory, consisting of pbr325 and hindiii fragment 13 of the nopaline plasmid ptic58 was mobilized for transfer by the helper plasmid prk2013 with the frequency about 10(-4). we conclude the hybrid plasmid pspa044 to be able to replicate stably in rhizobiaceae cells.	1986	3540635
location of the right boundary of the virulence region on agrobacterium tumefaciens plasmid ptic58 and a host-specifying gene next to the boundary.	the right boundary of the virulence (vir) region of the nopaline plasmid ptic58 of agrobacterium tumefaciens was determined by transposon insertion, cartridge emplacement, and deletion mutagenesis. genetic complementation with mutant and wild-type alleles led to the identification of the vire locus at the right boundary, which was located about 6 kilobases from the left border of the segment of dna that is transferred into the plant genome. vire is 2.0 kilobases long and encodes at least one pro ...	1986	3019998
nucleotide sequence of the virg locus of the agrobacterium tumefaciens plasmid ptic58.	the nucleotide sequence of the virg locus of the nopaline type plasmid ptic58 of agrobacterium tumefaciens has been determined. it contains an open reading frame (orf) of 759 nucleotides and has 77% homology to the virg sequences of octopine type plasmids. differences between the sequences of the two types of ti plasmids in the region of virg are located predominantly outside the orf. the amino acid sequences inferred from the two virg genes show 80% homology to each other and each shows the sam ...	1987	3448462
regulation of the vir genes of agrobacterium tumefaciens plasmid ptic58.	the virulence (vir) region of ptic58 was screened for promoter activities by using gene fusions to a promoterless lux operon in the broad-host-range vector pucd615. active vir fragments contained the strongly acetosyringone-inducible promoters of virb, virc, vird, and vire and the weakly inducible promoters of vira and virg. identical induction patterns were obtained with freshly sliced carrot disks, suggesting that an inducer is released after plant tissue is wounded. optimal conditions for vir ...	1987	2822665
characterization of the vire locus of agrobacterium tumefaciens plasmid ptic58.	the vire locus that is responsible for the efficiency of infection by agrobacterium tumefaciens (t. hirooka and c. kado, j. bacteriol. 168:237-243, 1986) is located next to the right boundary of the virulence (vir) region of the nopaline plasmid ptic58. this locus is very similar to the vire locus of octopine type ti plasmids on the basis of nucleotide and amino acid sequence comparisons as well as genetic complementation analyses. the nucleotide sequence of vire revealed three open reading fram ...	1987	3549694
molecular characterization of the virc genes of the ti plasmid.	the virc (formerly bak) complementation group of the nopaline-type ti plasmid ptic58 encodes two proteins, virc1 and virc2. according to the primary structure of the polypeptides predicted by the nucleotide sequence, virc1 is composed of 231 amino acids with a total molecular mass of 25.5 kilodaltons, and virc2 is composed of 202 amino acids with a molecular mass of 22.1 kilodaltons. the ptic58 virc1 and virc2 polypeptides are equal in length to virc1 and virc2 of the octopine-type plasmid ptia6 ...	1987	3584058
characterization and mapping of the agrocinopine-agrocin 84 locus on the nopaline ti plasmid ptic58.	overlapping segments of ptic58 inserted into cosmid vectors were used to characterize the agrocinopine-agrocin 84 locus from the nopaline/agrocinopine a and b agrobacterium tumefaciens strain c58. all of the clones conferring agrocin 84 sensitivity on agrobacteria also conferred uptake of agrocin 84 and agrocinopines a and b. transposon tn3-hoho1 insertion mutations of one such clone were generated that simultaneously abolished agrocin 84 sensitivity and transport of agrocinopines a and b and ag ...	1988	2832379
transfer of the ti plasmid from agrobacterium tumefaciens into escherichia coli cells.	we have screened strains of agrobacterium tumefaciens for spontaneous mutants showing constitutive transfer of the nopaline ti plasmid ptic58 during conjugation. the ti plasmid derivatives obtained could be transferred not only to a. tumefaciens but also to e. coli cells. the ti plasmid cannot survive as a freely replicating plasmid in e. coli, but it can occasionally integrate into the e. coli chromosome. however, insertion in tandem of plasmids carrying fd replication origins (pfd plasmids) in ...	1988	3049936
characterization of conjugal transfer functions of agrobacterium tumefaciens ti plasmid ptic58.	physical characterization of 13 transposon tn5 insertions within the agrocinopine-independent, transfer-constitutive ti plasmid ptic58trac identified three separate loci essential for conjugation of this nopaline/agrocinopine a + b-type ti plasmid. complementation analysis with relevant subcloned dnas indicated that the three physically separated blocks of conjugal genes constitute distinct complementation groups. two independent tn5 insertions within the wild-type, agrocinopine-dependent, repre ...	1989	2551885
virg of agrobacterium tumefaciens plasmid ptic58 encodes a dna-binding protein.	virulence genes of the agrobacterium tumefaciens ti plasmid are positively regulated by the products of vira and virg. to study the dna-binding properties of the virg protein, a translational fusion between virg and the trpe gene of escherichia coli was constructed, and antiserum was raised against the encoded fusion protein. using this antiserum, a protein of mr congruent to 29,000, a size similar to that calculated from the virg nucleotide sequence, was detected in an e. coli strain harbouring ...	1989	2664419
agrobacterium-mediated plant transformation by novel mini-t vectors in conjunction with a high-copy vir region helper plasmid.	a new binary vector system for agrobacterium-mediated plant transformation was developed. a set of four mini-t vectors comprised of t-dna border sequences from nopaline-type ti-plasmid ptic58 flanking a chimaeric hygromycin-resistance gene for selection of transformants and up to eight unique restriction sites for cloning foreign dna was constructed on a broad-host replicon containing the oriv of plasmid psa. in two of the constructs these multiple cloning sites are flanked by a strong promoter ...	1990	2103448
overexpression of vird1 and vird2 genes in agrobacterium tumefaciens enhances t-complex formation and plant transformation.	the vird1 and vird2 proteins encoded by an inducible locus of the virulence (vir) region of the agrobacterium tumefaciens ti plasmid are required for site-specific nicking at t-dna border sites. we have determined the nucleotide sequence of a 3.6-kilobase-pair fragment carrying the vird locus from nopaline ti plasmid ptic58. in contrast to the previous report (hagiya et al., proc. natl. acad. sci. usa 82:2669-2673, 1985), we found that the first three open reading frames were capable of encoding ...	1990	2165478
vird2 gene product from the nopaline plasmid ptic58 has at least two activities required for virulence.	virulence genes vird1 and vird2 are required for t-dna processing in agrobacterium tumefaciens. the regions within vird2 contributing to t-dna processing and virulence were investigated. some insertional mutations in vird2 prevented t-dna border endonucleolytic cleavage and produced an avirulent phenotype. however, a non-polar insertion immediately after bp 684 of the 1344 bp open reading frame of vird2 did not inhibit endonucleolytic cleavage but still caused a loss of virulence. this suggested ...	1990	2263456
agrobacterium plasmids encode structurally and functionally different loci for catabolism of agrocinopine-type opines.	agrobacterium tumefaciens strains c58, t37, k827 and j73, a. rhizogenes strains a4 and 15834, and a. radiobacter strain k299 were all susceptible to agrocin 84 and this sensitivity was enhanced in each case by addition of agrocinopines a and b. analysis of transconjugants showed that sensitivity of strain a4 to agrocin 84 was encoded by para4a and not by the rhizogenic plasmid, pria4. the acc region of the a. tumefaciens nopaline-type ti plasmid ptic58, contained on the recombinant plasmid pthh2 ...	1990	2270086
phenotypically normal transgenic t-cyt tobacco plants as a model for the investigation of plant gene expression in response to phytohormonal stress.	the tumour-inducing t-dna gene 4 (t-cyt gene) of the nopaline ti plasmid ptic58 was cloned and introduced into tobacco cells by leaf disc transformation using agrobacterium plasmid vectors. tobacco shoots exposed to elevated cytokinin levels were unable to develop roots and lacked apical dominance. using exogenously applied phytohormone manipulations we were able to regenerate morphologically normal transgenic tobacco plants which differed in endogenous cytokinin levels from normal untransformed ...	1991	1912501
the orit region of the agrobacterium tumefaciens ti plasmid ptic58 shares dna sequence identity with the transfer origins of rsf1010 and rk2/rp4 and with t-region borders.	ti plasmids of agrobacterium tumefaciens are conjugal elements whose transfer is induced by certain opines secreted from crown galls. on transmissible plasmids, dna transfer initiates within a cis-acting site, the origin of conjugal transfer, or orit. we have localized an orit on the a. tumefaciens plasmid ptic58 to a region containing the conjugal transfer loci trai and traii and acc, which is the locus encoding catabolism of the two conjugal opines, agrocinopines a and b. the smallest function ...	1992	1400174
physical map of the vitopine ti plasmid ptis4.	within the agrobacterium vitis group the vitopine strains represent a special subclass. vitopine bacteria carry ti plasmids with little or no homology with the well-characterized t-dnas of agrobacterium tumefaciens or agrobacterium rhizogenes. the 262-kb ti plasmid of the vitopine strain s4 was cloned and mapped. homology studies with the octopine ti plasmid ptiach5, the nopaline ti plasmid ptic58, and the agropine/mannopine ri plasmid prihri identified several regions of homology. the origin of ...	1992	1409971
opine catabolism and conjugal transfer of the nopaline ti plasmid ptic58 are coordinately regulated by a single repressor.	the ti plasmids of agrobacterium tumefaciens are conjugal elements whose transfer is strongly repressed. transfer is induced by the conjugal opines, a group of unique carbon compounds synthesized in crown gall tumors. the opines also induce ti plasmid-encoded genes required by the bacteria for opine catabolism. we have cloned and sequenced a gene from the ti plasmid ptic58, whose product mediates the opine-dependent regulation of conjugal transfer and catabolism of the conjugal opines, agrocinop ...	1992	1731335
functional and mutated agrocinopine synthase genes on octopine t-dnas.	agrocinopine synthase genes have so far been detected only on the agrobacterium tumefaciens nopaline ti plasmid ptic58 and on the a. rhizogenes ri plasmid pria4. the ta region of the octopine/cucumopine (o/c) a. vitis ti plasmid ptitm4 strongly resembles the tl dna of biotype i octopine ti plasmids. in addition, it carries an intact and functional agrocinopine synthase gene close to its left border. ta/tl sequence comparison shows that the biotype i tl region still carries a 5'-deleted acs gene, ...	1993	8324252
genetic analysis of the agrocinopine catabolic region of agrobacterium tumefaciens ti plasmid ptic58, which encodes genes required for opine and agrocin 84 transport.	the acc region, subcloned from ptic58 of classical nopaline and agrocinopine a and b agrobacterium tumefaciens c58, allowed agrobacteria to grow using agrocinopine b as the sole source of carbon and energy. acc is approximately 6 kb in size. it consists of at least five genes, acca through acce, as defined by complementation analysis using subcloned fragments and transposon insertion mutations of acc carried on different plasmids within the same cell. all five regions are required for agrocin 84 ...	1993	8366042
characterization of a nopaline-induced gene for a 40 kda protein in the nopaline catabolic (noc) region of ti plasmid ptic58.	the nopaline catabolic region (noc) in ti plasmid ptic58 codes for functions in the utilization of nopaline. the enzymes are identified, except for a 40 kda protein (40k gene). the sequence reveals a polypeptide with no homology to other known proteins, except for similarities in two out of three motifs characteristic for d-isomer specific 2-hydroxyacid dehydrogenases.	1993	8373810
the ti plasmid from the wide host range agrobacterium vitis strain tm4: map and homology with other ti plasmids.	the octopine/cucumopine (o/c) strains of agrobacterium vitis are divided into limited (lhr) and wide host range (whr) strains. we present here the first map of a ti plasmid from a whr o/c strain, tm4. ptitm4 (252 kb) has homology with the octopine ti plasmid ptiach5, the nopaline plasmid ptic58, and the ri plasmid prihri. approximately 155 kb of ptitm4 is homologous with the lhr o/c ti plasmids ptiab3 and ptiag57, the remaining part is ptitm4-specific. our data suggest that the evolution of the ...	1993	8469721
agrobacterium vitis nopaline ti plasmid ptiab4: relationship to other ti plasmids and t-dna structure.	the ti plasmid of the agrobacterium vitis nopaline-type strain ab4 was subcloned and mapped. several regions of the 157 kb ti plasmid are similar or identical to parts of the a. vitis octopine/cucumopine (o/c)-type ti plasmids, and other regions are homologous to the nopaline-type ti plasmid ptic58. the t-dna of ptiab4 is a chimaeric structure of recent origin: the left part is 99.2% homologous to the left part of the ta-dna of the o/c-type ti plasmids, while the right part is 97.1% homologous t ...	1994	7808399
natural instability of agrobacterium vitis ti plasmid due to unusual duplication of a 2.3-kb dna fragment.	the octopine/cucumopine (o/c) ti plasmids of agrobacterium vitis carry two t regions, ta and tb. the ta region resembles the octopine tl region. the tb region contains the auxin synthesis genes tb-iaam and tb-iaah and the cucumopine synthesis gene cus. within the group of o/c isolates, strains 2608 and 2641 are closely related. however, 2641 lacks the tb region. the restriction maps of pti2608 and pti2641 were established and showed that the tb deletion resulted from intramolecular recombination ...	1994	8012038
trai, a luxi homologue, is responsible for production of conjugation factor, the ti plasmid n-acylhomoserine lactone autoinducer.	conjugal transfer of the nopaline-type agrobacterium ti plasmid ptic58 is regulated by a transcriptional activator, trar, and a diffusible signal molecule, conjugation factor (cf). cf is a member of a family of substituted homoserine lactones (hsls) that act as coinducers for regulating gene expression in diverse gram-negative bacteria by a mechanism called autoinduction. in vibrio fischeri hsl production is conferred by the luxi gene. homologues of this gene are responsible for hsl production b ...	1994	8197112
a new regulatory element modulates homoserine lactone-mediated autoinduction of ti plasmid conjugal transfer.	conjugal transfer of the agrobacterium tumefaciens nopaline-type ti plasmid ptic58 is induced by agrocinopines a and b, opines secreted by crown gall tumors induced by the bacterium. this regulation functions through the transcriptional repressor, accr. however, actual transcription of the tra genes is regulated by autoinduction through the activator trar and the substituted homoserine lactone second messenger, agrobacterium autoinducer (aai). we have identified a new regulatory element that mod ...	1995	7814335
the octopine-type ti plasmid ptia6 of agrobacterium tumefaciens contains a gene homologous to the chromosomal virulence gene acvb.	although the majority of genes required for the transfer of t-dna from agrobacterium tumefaciens to plant nuclei are located on the ti plasmid, some chromosomal genes, including the recently described acvb gene, are also required. we show that acvb shows 50% identity with the product of an open reading frame, designated virj, that is found between the vira and virb genes in the octopine-type ti plasmid ptia6. this reading frame is not found in the nopaline-type ti plasmid ptic58. acvb is require ...	1995	7860597
effect of the m-ecorii methyltransferase-encoding gene on the phenotype of nicotiana tabacum transgenic cells.	the ecorii dna methyltransferase (m-ecorii; mtase) modifies a cytosine in the dna sequence ccwgg which contains a cng methylation motif characteristic of plant dna. the gene (ecoriim) encoding this mtase has been cloned into the t-dna of the wild-type agrobacterium ti-plasmid ptic58 downstream from the plant expression nopaline synthase-encoding gene promoter. nicotiana tabacum cells have been transformed with agrobacterium tumefaciens harbouring this recombinant ti-plasmid. the primary transfor ...	1995	7607509
the tra region of the nopaline-type ti plasmid is a chimera with elements related to the transfer systems of rsf1010, rp4, and f.	the ti plasmids of agrobacterium tumefaciens encode two transfer systems. one mediates the translocation of the t-dna from the bacterium to a plant cell, while the other is responsible for the conjugal transfer of the entire ti plasmid from one bacterium to another. the determinants responsible for conjugal transfer map to two regions, tra and trb, of the nopaline-type ti plasmid ptic58. by using transposon mutagenesis with tn3hoho1, we localized the tra determinants to an 8.5-kb region that als ...	1996	8763953
the conjugal transfer system of agrobacterium tumefaciens octopine-type ti plasmids is closely related to the transfer system of an incp plasmid and distantly related to ti plasmid vir genes.	we have determined the dna sequences of two unlinked regions of octopine-type ti plasmids that contain genes required for conjugal transfer. both regions previously were shown to contain sequences that hybridize with tra genes of the nopaline-type ti plasmid ptic58. one gene cluster (designated tra) contains a functional orit site and is probably required for conjugal dna processing, while the other gene cluster (designated trb) probably directs the synthesis of a conjugal pilus and mating pore. ...	1996	8763954
ti plasmid conjugation is independent of vir: reconstitution of the tra functions from ptic58 as a binary system.	two regions of the nopaline-type ti plasmid ptic58 are important for conjugal transfer of this element to recipient bacteria. these two regions were cloned into two independent replicons to produce a binary transfer system. for one region, orit/tra, we constructed two derivatives, pfrtra and pdctra-5. each contains the orit site and the two flanking, divergently transcribed tra operons that encode the dna processing functions associated with the relaxosome. these two plasmids also carry trar, wh ...	1997	9023214
characterization of the acc operon from the nopaline-type ti plasmid ptic58, which encodes utilization of agrocinopines a and b and susceptibility to agrocin 84.	the acc locus from the ti plasmid ptic58 confers utilization of and chemotaxis toward agrocinopines a and b (a+b), as well as susceptibility to a highly specific antiagrobacterial antibiotic, agrocin 84. dna sequence analyses revealed that acc is composed of eight open reading frames, accr and acca through accg. previous work showed that accr encodes the repressor which regulates this locus, and acca codes for the periplasmic binding protein of the agrocinopine transport system (s. beck von bodm ...	1997	9393724
conjugal transfer but not quorum-dependent tra gene induction of ptic58 requires a solid surface.	donors of agrobacterium tumefaciens harboring a transfer-constitutive derivative of the nopaline-type ti plasmid ptic58 transferred this element at frequencies 3 to 4 orders of magnitude higher in matings conducted on solid surfaces than in those conducted in liquid medium. however, as measured with a lacz reporter fusion, the tra genes of the wild-type ti plasmid were inducible by opines to indistinguishable levels on solid and in liquid medium. donors induced in liquid transferred the ti plasm ...	1999	10347084
hierarchical gene regulatory systems arising from fortuitous gene associations: controlling quorum sensing by the opine regulon in agrobacterium.	conjugation of the agrobacterium ti plasmid ptic58 is regulated by a hierarchy involving induction by the opines agrocinopines a and b and a quorum-sensing system. regulation by the opines is mediated by the repressor accr, while quorum sensing is effected by the transcriptional activator trar and its ligand, the acyl-homoserine lactone signal molecule agrobacterium autoinducer (aai). these last two elements combine to activate expression of the tra system at high population densities. sequence ...	1999	10361309
modulating quorum sensing by antiactivation: tram interacts with trar to inhibit activation of ti plasmid conjugal transfer genes.	conjugal transfer of the ti plasmid ptic58 is regulated by a quorum-sensing system involving the transcriptional activator trar and the acyl homoserine lactone autoinducer n-(3-oxo-octanoyl)-l-homoserine lactone (aai). activation of tra gene expression by trar and aai is inhibited by tram, an 11 kda protein also coded for by the ti plasmid. previous studies suggested that tram interferes with trar activity by directly interacting with the activator protein. using the yeast two-hybrid system, con ...	1999	10564472
the replicator of the nopaline-type ti plasmid ptic58 is a member of the repabc family and is influenced by the trar-dependent quorum-sensing regulatory system.	the replicator (rep) of the nopaline-type ti plasmid ptic58 is located adjacent to the trb operon of this conjugal element. previous genetic studies of this region (d. r. gallie, m. hagiya, and c. i. kado, j. bacteriol. 161:1034-1041, 1985) identified functions involved in partitioning, origin of replication and incompatibility, and copy number control. in this study, we determined the nucleotide sequence of a 6,146-bp segment that encompasses the rep locus of ptic58. the region contained four f ...	2000	10613878
the right end of the vir region of an octopine-type ti plasmid contains four new members of the vir regulon that are not essential for pathogenesis.	we sequenced the vird-vire, vire-virf, and virf-t-dna intergenic regions of an octopine ti plasmid. four newly described genes were induced by the vir gene inducer acetosyringone, two of which are conserved in the nopaline-type ti plasmid ptic58. one gene resembles a family of phosphatase genes. each of these genes is dispensable for tumorigenesis.	2000	10692388
identification of a chromosomal tra-like region in agrobacterium tumefaciens.	the vird4 gene is one of the virulence genes present on the ptic58 plasmid of agrobacterium tumefaciens. unexpectedly, we found that a pti-free a. tumefaciens strain carried a protein of similar size to the plasmid-encoded vird4 protein which reacted with vird4-specific antibodies. this suggested that this strain may contain a homologue of the vird4 protein. a chromosomal fragment encoding a protein of similar sequence to vird4 was isolated and a 7.8 kilobase region surrounding the gene encoding ...	2002	11919722
novel toxin-antitoxin system composed of serine protease and aaa-atpase homologues determines the high level of stability and incompatibility of the tumor-inducing plasmid ptic58.	stability of plant tumor-inducing (ti) plasmids differs among strains. a high level of stability prevents basic and applied studies including the development of useful strains. the nopaline type ti plasmid ptic58 significantly reduces the transconjugant efficiency for incoming incompatible plasmids relative to the other type, such as octopine-type plasmids. in this study we identified a region that increases the incompatibility and stability of the plasmid. this region was located on a 4.3-kbp s ...	2009	19447904
agrobacterium tumefaciens type iv secretion protein virb3 is an inner membrane protein and requires virb4, virb7, and virb8 for stabilization.	agrobacterium tumefaciens virb proteins assemble a type iv secretion apparatus and a t-pilus for secretion of dna and proteins into plant cells. the pilin-like protein virb3, a membrane protein of unknown topology, is required for the assembly of the t-pilus and for t-dna secretion. using phoa and green fluorescent protein (gfp) as periplasmic and cytoplasmic reporters, respectively, we demonstrate that virb3 contains two membrane-spanning domains and that both the n and c termini of the protein ...	2010	20348257