Nucleotide sequence of the T-DNA region from theA grobacterium tumefaciens octopine Ti plasmid pTi15955

Barker, R. F.; Idler, Ken B.; Thompson, David V.; Kemp, John D.

doi:10.1007/bf01578595

Cited by 406 publications

(284 citation statements)

References 39 publications

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“…Recently, Barker et al (34) determined the entire sequence of the T region of the octopine Ti plasmid pTil5955, which was shown to be highly homologous to pTiB6806 (16). The analyses of the sequence showed that the T region is composed of three distinct domains, TL-DNA, TR-DNA, and the center region of (34), and that the insertion split the T region into two portions, TL-DNA and TR-DNA. The limited homology with IS66 in the TC region may be the result of DNA rearrangements during subsequent evolution, since the frequency of DNA rearrangements, including deletion, inversion, and homologous recombination, in the regions adjacent to transposons is higher than in other DNA regions (35).…”

Section: Discussionmentioning

confidence: 99%

Nucleotide sequence of the insertion sequence found in the T-DNA region of mutant Ti plasmid pTiA66 and distribution of its homologues in octopine Ti plasmid.

Machida¹,

Sakurai²,

Kiyokawa³

et al. 1984

Proc. Natl. Acad. Sci. U.S.A.

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The octopine tumor-inducing (Ti) plasmid pTiA66 has an insertion mutation in its T region (the DNA region incorporated into the plant genome) that results in the slow growth of crown gall tumors. These tumors exhibit hormonal autonomy different from that of the crown gall tumors caused by wild-type Ti plasmids. In the present study, the nucleotide sequences of both the DNA segment inserted into pTiA66 and its target site have been determined. The inserted segment is 2548 base pairs long and has 20-base-pair terminal inverted repeats. An 8-base-pair sequence at the target site is duplicated at both integration junctions. These structural features of the insert suggest that it is a bacterial insertion sequence (IS) element, which we have named IS66. Blot-hybridization analyses using IS66 probes revealed that genomes of octopine Ti plasmids contain at least three sequences homologous to IS66: two homologues are located in the virulence region and one is located between the left-hand (TL-DNA) and right-hand (TR-DNA) portions of T-DNA. The chromosome of Agrobacterium tumefaciens A66 also contains two sequences highly homologous to IS66. These results suggest that the mutant pTiA66 plasmid was generated by translocation of one of the sequences showing homology with IS66 into the T region. The fact that a sequence homologous to IS66 is present between TL-DNA and TR-DNA also suggests that the octopine T region was split into two portions, TL-DNA and TR-DNA, by translocation of IS66 or its relatives. Thus, IS66 may cause genetic and structural variations of the T region and the vir region of the octopine Ti plasmids.Tumor-inducing (Ti) plasmids harbored by oncogenic strains of Agrobacterium tumefaciens cause formation of tumors on dicotyledonous plants, called crown galls (1). Cells isolated from the crown gall tumors are characterized by their unlimited proliferation in medium lacking phytohormones, such as cytokinins and auxins, that are required for the culture of normal plant cells (2). It has been shown that a specific DNA region of the Ti plasmid, called the T-DNA region (Fig. 1), causes tumor formation when transferred into plant chromosomes and that the T-DNA persists in the chromosomes of the tumor cells (3-6). The virulence (vir) region of the Ti plasmid (Fig. 1) is located outside the T region and is also required for tumorigenesis by the Ti plasmid. However, this region is probably not stably maintained in the tumor cells (7-10).The Ti plasmids are classified on the basis of the novel amino acid metabolites, such as octopine or nopaline, whose syntheses are directed by T-DNA genes in the tumor cells (11-15). The octopine T region is composed of twQ DNA segments near each other in the Ti plasmid (16) (Fig. 1), whereas the nopaline T region consists of one contiguous DNA segment (17, 18). The chromosomes of the tumor cells caused by the octopine strain contain either one or two portions of the T region (16). All tumor cells that have been analyzed contained the left portion of T-DNA (TL-DNA) but not all...

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Section: Discussionmentioning

confidence: 99%

Nucleotide sequence of the insertion sequence found in the T-DNA region of mutant Ti plasmid pTiA66 and distribution of its homologues in octopine Ti plasmid.

Machida¹,

Sakurai²,

Kiyokawa³

et al. 1984

Proc. Natl. Acad. Sci. U.S.A.

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“…Both vectors contain translation stop codons in all three reading frames 5' of the cloning sites and therefore allow only transcdptional fusion. A promotedess ipt gene corresponding to bp 8755-9836 of the T-DNA octopine Ti plasmid pTi15955 (Barker et al, 1983) was cloned into the Kpnl/Hind III sites of plasmid pLIRB-I to yield plasmid pBIK (see Figure 1). The iptgene retains 15 bp of its untranslated leader region, the coding sequence of 693 bp, and 373 bp untranslated 3' flanking sequences (Schm011ing et al, 1989).…”

Section: Construction Of Plasmidsmentioning

confidence: 99%

Promoter tagging with a promoterless ipt gene leads to cytokinin‐induced phenotypic variability in transgenic tobacco plants: implications of gene dosage effects

Hewelt

Prinsen

Schell³

et al. 1994

The Plant Journal

108

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“…Sequence data showed that the T-region is flanked by two imperfect direct repeats of 24 bp in the Ti-plasmid (3). Studies on the T-DNA content of different transformed plant tumor lines revealed that the integration of T-DNA into the plant genome often takes place at or near these border repeats (17,24,36,37,44).…”

Section: Introductionmentioning

confidence: 99%

Functional analysis of the Agrobacterium tumefaciens octopine Ti-plasmid left and right T-region border fragments

et al. 1987

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SummaryBorder fragments of the octopine Ti-plasmid were tested for their ability to restore tumorigenicity of an avirulent mutant carrying a deleted right border. It was found that neither introduction of left border fragments nor that of small right border fragments at the position of the deletion resulted in a complete restoration of oncogenicity. However, insertion of a larger right border fragment in the deletion mutant gave fully oncogenic strains. In the latter case sequences to the right side of the right border repeat were found to be responsible for a complete restoration of oncogenicity. Also a left border repeat inserted together with this enhancer sequence fully restored the oncogenicity of the deletion mutant. The enhancer-sequence on itself was not able to mediate the transfer of the T-region to the plant cell. Border fragments inserted in inverted orientation in the deletion mutant were able to mediate the transfer of the T-region to the plant cell, but at a reduced frequency.

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Nucleotide sequence of the T-DNA region from theA grobacterium tumefaciens octopine Ti plasmid pTi15955

Cited by 406 publications

References 39 publications

Nucleotide sequence of the insertion sequence found in the T-DNA region of mutant Ti plasmid pTiA66 and distribution of its homologues in octopine Ti plasmid.

Nucleotide sequence of the insertion sequence found in the T-DNA region of mutant Ti plasmid pTiA66 and distribution of its homologues in octopine Ti plasmid.

Promoter tagging with a promoterless ipt gene leads to cytokinin‐induced phenotypic variability in transgenic tobacco plants: implications of gene dosage effects

Functional analysis of the Agrobacterium tumefaciens octopine Ti-plasmid left and right T-region border fragments

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