Structure and stability of transposon 5-mediated cointegrates

Hirschel, Bernard; Galas, David J.; Berg, Douglas E.; Chandler, Michaël

doi:10.1016/0022-2836(82)90101-2

Cited by 22 publications

(12 citation statements)

References 21 publications

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“…The formation of the cointegrate could be a secondary event in which the original copy of Tn5-KS, on pBR322, recombines, using the homologous recombination system, with a copy ofthe element that has been tranposed onto pOX38. The results of Isberg and Syvanen (12) and of our previous study (13) in which we used a pOX38::Tn5 derivative to mediate formation ofcointegrate molecules with pBR322 argue against the possibility, however. Of the 23 independent cointegrates we analyzed (formed in a recA+ background) 9 were mediated by IS50-R and none by IS50-L-i.…”

Section: Resuljtsmentioning

confidence: 78%

“…capable of fusing replicons. In contrast to cointegrate structures generated by the first class, those generated by Tn9 (11) and Tn5 - (12,13) are quite stable. The stability of the cointegrates, together with the observation that cointegrate structures are, formed at a frequency lower than the transposition frequency in a recA-host (ref.…”

mentioning

confidence: 73%

“…Our experiments with the 9-base-pair repeating element Tn9 (IS1) have shown that in the absence of recA function this element is capable of forming cointegrates at a frequency comparable to that oftransposition (not more than 10-fold less) rather than the 100-fold difference we observe with Tn5 (11). We think it likely, therefore, that Tn5 is somewhat different in its transposition properties from Tn9, even though the cointegrates it forms are as stable as those formed by Tn9/IS1 (13).…”

Section: Resuljtsmentioning

confidence: 92%

“…Neither pOX38 nor pBR322 carries any known transposable elements, and transfer of pBR322 by pOX38 is an extremely rare event (see below). Introduction of a transposable element into either of the replicons, however, results in an increase of several orders of magnitude in the frequency of transfer of pBR322 by pOX38 (11,13,26,28 Cointegrates between pOX38 and pBR322 are known to have an increased mating efficiency compared to pOX38 (11,13,30 Fig. 2 shows restriction enzyme digests of several ofthese.…”

Section: Resuljtsmentioning

confidence: 99%

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Cointegrate formation by Tn5, but not transposition, is dependent on recA.

Hirschel¹,

Galas²,

Chandler³

1982

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

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We have studied the effect of the recA-dependent homologous recombination system of Escherichia coli on both Tn5-mediated cointegrate formation and Tn5 transposition. We demonstrate here that, whereas transposition of Tn5 is independent of the recA gene product (as has been shown by other workers), Tn5-mediated cointegrate formation is strongly dependent on recA. The structures of both the simple transpositionproducts and the cointegrates formed in a recA-background seem to be the same as those produced in a recA' background. These results provide strong evidence that Tn5 does not transpose via an obligate cointegrate intermediate and suggest that the recA effect on cointegrate formation is exerted during the process oftransposition.Transposable genetic elements are capable of insertion into many distinct nonhomologous sites in the genomes of bacteria and phage. In addition, they are known to promote the fusion of replicons (cointegrate formation) and the formation of deletions and inversions of DNA (for recent reviews see refs. 1 and 2). It has been thought that most, ifnot all, ofthe recombination events induced by transposable elements are independent of homology-requiring recombination systems, first because the recombination events are between nonhomologous sequences, and second because transposition itself and several other transposition-related processes appear to occur with equal facility in wild-type cells and cells deficient in the recA gene product (3,4). [An exception to this recA independence has recently been reported for the transposition of Tn903 from phage A to the Escherichia coli chromosome (5).]Galas and Chandler (6) have proposed that transposable elements in bacteria can be largely classified into two groups. Certain elements, including Tn3 and y8 (TnlOOO), generate 5-basepair repeats in the target DNA on insertion and appear to form unstable cointegrates as obligate intermediates in transposition. These cointegrates consist of donor and recipient replicons delimited by two directly repeated copies of the transposable element. This class of element encodes a site-specific recombination system that promotes recombination between the two directly repeated copies of the element (resolution of the cointegrate), and generates, on recombination, a copy of the donor and a copy of the recipient replicon, now also carrying the transposon (7-10).The second class ofelement, which includes Tn5, Tn9, TnlO, and Tn9O3, can be considered compound elements because they are composed of a region of DNA encoding an antibiotic resistance determinant flanked by two elements that are themselves independently transposable. Elements in this class generate 9-base-pair repeats in the target DNA on insertion. They are also. capable of fusing replicons. In contrast to cointegrate structures generated by the first class, those generated by Tn9 (11) and Tn5 -(12, 13) are quite stable. The stability of the cointegrates, together with the observation that cointegrate structures are, formed at a frequency lower ...

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Section: Resuljtsmentioning

confidence: 78%

mentioning

confidence: 73%

Section: Resuljtsmentioning

confidence: 92%

Section: Resuljtsmentioning

confidence: 99%

See 2 more Smart Citations

Cointegrate formation by Tn5, but not transposition, is dependent on recA.

Hirschel¹,

Galas²,

Chandler³

1982

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

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“…1A). Tn5 contains two nearly identical insertion sequences (ISS0) surrounding a 2.7-kilobase central region that encodes the antibiotic resistance genes (1,6,7,11,12,15 TnS, into pRZ5202. Assays of RNA polymerase-binding sites (10) in two of these clones indicated the presence of the NPTII promoter (Fig.…”

mentioning

confidence: 99%

Transposition of IS50L activates downstream genes

Kendrick

Reznikoff

1988

J Bacteriol

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A transposition system constructed to detect the transposition of TnS to a site upstream of the lacZ gene has revealed that transposition of ISSOL can activate downstream genes. Expression is apparently mediated by the NPTII promoter. Transposase produced either by 'SSOR or by the suppressed S150L catalyzed transposition of ISSOL.Transposon TnS is a composite transposable element that encodes resistance to kanamycin, streptomycin, and bleomycin (2,3,12) (Fig. 1A). Tn5 contains two nearly identical insertion sequences (ISS0) surrounding a 2.7-kilobase central region that encodes the antibiotic resistance genes (1,6,7,11,12,15 TnS, into pRZ5202. Assays of RNA polymerase-binding sites (10) in two of these clones indicated the presence of the NPTII promoter (Fig. 2), which showed that it was IS50L rather than IS50R which had been inserted upstream of the lacZ gene. Dideoxynucleotide sequencing (17)

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Mechanisms of Transposition in Bacteria

Berg

1985

Plasmids in Bacteria

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Structure and stability of transposon 5-mediated cointegrates

Cited by 22 publications

References 21 publications

Cointegrate formation by Tn5, but not transposition, is dependent on recA.

Cointegrate formation by Tn5, but not transposition, is dependent on recA.

Transposition of IS50L activates downstream genes

Mechanisms of Transposition in Bacteria

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