Plasmid pSC101 harbors a recombination site, psi, which is able to resolve plasmid multimers and to substitute for the analogous chromosomal Escherichia coli site dif

Cornet, François; Mortier, I; Patte, Josette; Louarn, Jean-Michel

doi:10.1128/jb.176.11.3188-3195.1994

Cited by 133 publications

(136 citation statements)

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“…1 preferential intramolecular resolution as a full site, its core site is capable of low levels of intermolecular recombination. Therefore, its properties are intermediate between those of cer and dif, as suggested by the experiments of Cornet et al (1994). Intramolecular resolution of a complete psi site, a psi core site and a dif core site is compared in Fig.…”

Section: Resultsmentioning

confidence: 85%

“…However, some sites that show resolution selectivity also have a 6 bp central region (for example, psi and parB). In order to determine what distinguishes these two classes of 6 bp central region sites, we have constructed and analysed recombination sites that are hybrids between either cer and parB, or psi (derived from plasmid pSC101; Cornet et al, 1994) and dif.…”

Section: Introductionmentioning

confidence: 99%

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DNA sequence of recombinase‐binding sites can determine Xer site‐specific recombination outcome

Blake

Ganguly

Sherratt

1997

Molecular Microbiology

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SummaryXer site-specific recombination functions in the stable inheritance of circular plasmids and bacterial chromosomes. Two related recombinases, XerC and XerD, mediate this recombination, which 'undoes' the potential damage of homologous recombination. Xer recombination on natural plasmid sites is preferentially intramolecular, converting plasmid multimers to monomers. In contrast, recombination at the Escherichia coli recombination site, dif, occurs both intermolecularly and intramolecularly, at least when dif is inserted into a multicopy plasmid. Here the DNA sequence features of a family of core recombination sites in which the XerC-and XerD-binding sites, which are separated by 6 bp, were analysed in order to ascertain what determines whether recombination will be preferentially intramolecular, or will occur both within and between molecules. Sequence changes in either the XerC-or XerD-binding site can alter the recombination outcome. Preferential intramolecular recombination between a pair of recombination sites requires additional accessory DNA sequences and accessory recombination proteins and is correlated with reduced affinities of recombinase binding to recombination core sites, reduced XerC-mediated cleavage in vitro, and an apparent increased overall bending in recombinase-core-site complexes.

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Section: Resultsmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

DNA sequence of recombinase‐binding sites can determine Xer site‐specific recombination outcome

Blake

Ganguly

Sherratt

1997

Molecular Microbiology

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“…The dif site was eventually inserted into the tetA locus using pFC72. Cornet et al 1994) inserted into the BamHI site of the polylinker. pLN138 carrying the 2.8-kb BstYI tet fragment from pFC68 cloned in the BamHI site creating the zdc310::tet insertion at position 1563.0. pFC68 carrying the 1597.8-1599.8 EcoRV dif-containing chromosomal fragment (from pBS12; Bejar and Bouch4 1983) cloned into the EcoRV site of the tetA gene.…”

Section: Resultsmentioning

confidence: 99%

Restriction of the activity of the recombination site dif to a small zone of the Escherichia coli chromosome.

Cornet¹,

Patte²,

Louarn³

1996

Genes Dev.

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126

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The recombination site dif is the target on the Escherichia coli chromosome of the site-specific recombinases XerC and XerD. The dif/XerC-D system plays a role during the cell cycle, probably by favoring sister chromosome monomerization or separation. A phenomenon of regional control over dif activity, also analyzed in this issue, is demonstrated here by translocation of dif to a series of loci close to the normal locus. We found that the site is physiologically active only within a narrow zone around its natural position.Competence for dif activity does not depend on the sequence of the normal dif activity zone (DAZ), because ~(diD deletions larger than the DAZ result in Dif + bacteria when dif is reinserted at the junction point. Although dif maps where replication normally terminates, termination of replication is not the elicitor. A strain with a large inversion that places dif and its surrounding region close to oriC remains Dif*, even when a Tus-mutation allows replication to terminate far away from it. Preliminary data suggest the possibility that specialized sequences separate the competent zone from the rest of the chromosome. We suspect that these sequences are members of a set of sequences involved in a polarized process of postreplicative reconstruction of the nucleoid structure. We propose that this reconstruction forces catenation links between sister chromosomes to accumulate within the DAZ, where they eventually favor recombination at d/f.[Key Words." Site-specific recombination; dif site domain of activity; E. coli chromosome organization] Received January 10, 1996; revised version accepted March 20, 1996.The

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“…The modified gene, expressed from the lac promoter, had no detectable effect on cell division. Then the modified chromosomal insert (1,043 bp) was cloned into pFC20, a vector designed for selectable integration of plasmids into the chromosome and excision from it (8). The resulting plasmid tended to lyse cells, and attempts to integrate the modified chromosomal sequence at its locus failed, possibly because vector transcription was allowed to reach sieBЈ or as a result of activation of the excision function of Rac in the integrated plasmid state.…”

Section: Identification Of a Cell Division Inhibition Genementioning

confidence: 99%

Identification of a new inhibitor of essential division gene ftsZ as the kil gene of defective prophage Rac

1996

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A gene function carried by a plasmid, causing arrest of cell division in Escherichia coli, has been identified as the product of a short open reading frame of the prophage Rac, previously designated orfE, expressed only under conditions of prophage induction. Because Rac carries a killing function expressed under conditions of zygotic induction, an orfE-defective Rac ؉ strain was constructed. This strain had lost the killing function, indicating that orfE is kil. Division inhibition by kil was specifically relieved by overexpression of essential division gene ftsZ. The kil gene product acts independently of the min operon, and its effects are increased in conditions of high cyclic AMP (cAMP) receptor protein-cAMP complex levels in the cell. Furthermore, at high levels of expression, kil product distorts the rod shape of the cells. These features distinguish kil-encoded protein from the inhibitory product of gene dicB, which occupies a similar genetic location in Kim (Qin), another defective prophage of Escherichia coli.Three defective lambdoid prophages, Rac, QSRЈ, and Kim (Qin), have been identified in the genome of Escherichia coli K-12 (3, 21). Prophage Kim encodes two division inhibitors, DicB (4) and DicF (25), both expressed from a p L -like promoter under control of an immunity region related to that of phage P22 (1). DicF is a 53-nucleotide-long antisense RNA generated in part by RNase III processing in two regions with extensive secondary structures, R 1-2 and R 3-4 , located upstream and downstream respectively from the dicF gene (12).Southern blot hybridization revealed that a part of the Rac prophage hybridizes specifically to a probe containing dicF and the flanking R 1-2 and R 3-4 sequences (3). The sequence of that part of Rac has been established by Chu et al., and its resemblance to dicF has been confirmed (5). In another study, a fragment of E. coli B which hybridized to a R 1-2 -dicF-R 3-4 probe was cloned and sequenced. This fragment turned out to contain Rac DNA nearly identical to that of K-12 strains. Sequence analysis indicated that the fragment contains the 5Ј part of a gene related to sieB, followed by sequences similar to those of Kim R 1-2 , dicF, and R 3-4 , then by an open reading frame called orfE, and by the 5Ј region of another open reading frame, orfF (11) (Fig. 1).We noticed that the Rac fragment cloned in one orientation under control of P lac in a high-copy-number plasmid yielded a cellular filamentation phenotype under some conditions, suggesting the presence of a cell division inhibition gene. We report the identification and some properties of this gene. We also demonstrate that this gene expresses the killing function of the Rac prophage revealed by the study of Feinstein and Low (13). MATERIALS AND METHODSBacterial strains and media. The bacterial strains used in this study are described in Table 1. The construction of JS1478 is described in detail below. Strains were grown in Luria broth. Solid and soft agar contained 1.5% and 0.9% (wt/vol) agar, respectively. When appr...

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Plasmid pSC101 harbors a recombination site, psi, which is able to resolve plasmid multimers and to substitute for the analogous chromosomal Escherichia coli site dif

Cited by 133 publications

References 24 publications

DNA sequence of recombinase‐binding sites can determine Xer site‐specific recombination outcome

DNA sequence of recombinase‐binding sites can determine Xer site‐specific recombination outcome

Restriction of the activity of the recombination site dif to a small zone of the Escherichia coli chromosome.

Identification of a new inhibitor of essential division gene ftsZ as the kil gene of defective prophage Rac

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