recX, a new SOS gene that is co-transcribed with the recA gene in Escherichia coli

Pagès, Vincent; Koffel-Schwartz, Nicole; Fuchs, Robert P. P.

doi:10.1016/s1568-7864(02)00217-3

Cited by 66 publications

(54 citation statements)

References 24 publications

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“…But, in agreement with the biochemical data, the number of RecA-GFP foci observed in live cells is higher in recX mutants and lower in both the dinI single and dinI, recX double mutants (13). The expression of both the DinI and RecX proteins is controlled by the LexA repressor (14,15), defining their membership in the SOS regulon. There appears to be a network of proteins that function to regulate RecA filaments in bacterial systems.…”

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confidence: 85%

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The Escherichia coli DinD Protein Modulates RecA Activity by Inhibiting Postsynaptic RecA Filaments

Uranga

Balise

Benally

et al. 2011

Journal of Biological Chemistry

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Escherichia coli dinD is an SOS gene up-regulated in response to DNA damage. We find that the purified DinD protein is a novel inhibitor of RecA-mediated DNA strand exchange activities. Most modulators of RecA protein activity act by controlling the amount of RecA protein bound to single-stranded DNA by affecting either the loading of RecA protein onto DNA or the disassembly of RecA nucleoprotein filaments bound to singlestranded DNA. The DinD protein, however, acts postsynaptically to inhibit RecA during an on-going DNA strand exchange, likely through the disassembly of RecA filaments. DinD protein does not affect RecA single-stranded DNA filaments but efficiently disassembles RecA when bound to two or more DNA strands, effectively halting RecA-mediated branch migration. By utilizing a nonspecific duplex DNA-binding protein, YebG, we show that the DinD effect is not simply due to duplex DNA sequestration. We present a model suggesting that the negative effects of DinD protein are targeted to a specific conformational state of the RecA protein and discuss the potential role of DinD protein in the regulation of recombinational DNA repair.The Escherichia coli SOS response is a coordinately regulated network of genes induced in reaction to heavy or persistent DNA damage (1). The SOS regulon is repressed by the LexA protein, which is inactivated as a repressor upon cellular stress such as heavy DNA damage. The cellular signal for SOS induction is the RecA protein bound to single-stranded DNA (ssDNA). 2RecA is the central DNA recombinase in bacteria and carries out several distinct functions when activated (2). The most appreciated function of RecA is the catalysis of homologous DNA recombination crucial to the generation of genetic diversity. However, based on frequency of use, the primary role of RecA lies in the multiple pathways for the recombinational repair of stalled DNA replication forks. Through much in vitro work, it has become increasingly apparent that the RecA protein is under considerable control by a network of proteins that function to modulate when and where RecA protein binds to DNA (3). The PsiB protein has recently been shown to bind to free RecA protein, effectively inhibiting RecA from nucleating onto ssDNA (4). RecA is also inhibited from nucleating onto ssDNA bound by the single-stranded DNA-binding protein (SSB) (5). The SSB-imposed inhibition is relieved by the action of the RecF, RecO, and RecR proteins (3). Following nucleation, RecA protein protomers assemble into a nucleoprotein filament, extending cooperatively in the 5Ј to 3Ј direction. The RdgC protein can inhibit RecA binding to ssDNA and can interfere with homologous DNA pairing by binding to duplex DNA (6, 7). Some proteins shown to dismantle RecA filaments are known DNA translocases, such as UvrD (8) and PcrA helicases (9). Filament extension can be blocked through the action of the RecX protein (10), whereas the DinI protein antagonizes the function of RecX by stabilizing RecA filaments, inhibiting filament end-dependent disassem...

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confidence: 85%

“…8A. At 7,15, and 30 min, DNA strand exchange is still in progress, as judged by the substrate molecules remaining after deproteinization. By 45 min after the DNA strand exchange reaction is initiated, all linear duplex DNA substrate have been converted to nicked circular dsDNA product.…”

Section: The Dind and Yebg Proteins Are Nonspecific Dna-bindingmentioning

confidence: 99%

The Escherichia coli DinD Protein Modulates RecA Activity by Inhibiting Postsynaptic RecA Filaments

Uranga

Balise

Benally

et al. 2011

Journal of Biological Chemistry

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“…The genes recA, recX, recN, lexA, uvrA, ruvCAB and dnaE2 are well known from the SOS regulons of E. coli and M. tuberculosis Pages et al, 2003;Stohl et al, 2003;Walker, 1984). Additional genes are apparently involved in DNA repair (cg0714, cg1318, cg1319, radA) and the corynebacterial cell division process (divS, ftsK).…”

Section: Verification Of Differential Gene Expression By Rt-pcr and Dmentioning

confidence: 99%

Genetic makeup of the Corynebacterium glutamicum LexA regulon deduced from comparative transcriptomics and in vitro DNA band shift assays

et al. 2009

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The lexA gene of Corynebacterium glutamicum ATCC 13032 was deleted to create the mutant strain C. glutamicum NJ2114, which has an elongated cell morphology and an increased doubling time. To characterize the SOS regulon in C. glutamicum, the transcriptomes of NJ2114 and a DNA-damage-induced wild-type strain were compared with that of a wild-type control using DNA microarray hybridization. The expression data were combined with bioinformatic pattern searches for LexA binding sites, leading to the detection of 46 potential SOS boxes located upstream of differentially expressed transcription units. Binding of a hexahistidyl-tagged LexA protein to 40 double-stranded oligonucleotides containing the potential SOS boxes was demonstrated in vitro by DNA band shift assays. It turned out that LexA binds not only to SOS boxes in the promoteroperator region of upregulated genes, but also to SOS boxes detected upstream of downregulated genes. These results demonstrated that LexA controls directly the expression of at least 48 SOS genes organized in 36 transcription units. The deduced genes encode a variety of physiological functions, many of them involved in DNA repair and survival after DNA damage, but nearly half of them have hitherto unknown functions. Alignment of the LexA binding sites allowed the corynebacterial SOS box consensus sequence TcGAA(a/c)AnnTGTtCGA to be deduced. Furthermore, the common intergenic region of lexA and the differentially expressed divS-nrdR operon, encoding a cell division suppressor and a regulator of deoxyribonucleotide biosynthesis, was characterized in detail. Promoter mapping revealed differences in divS-nrdR expression during SOS response and normal growth conditions. One of the four LexA binding sites detected in the intergenic region is involved in regulating divS-nrdR transcription, whereas the other sites are apparently used for negative autoregulation of lexA expression.

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“…The transcription of mtlB, pncC, recA and recX genes are the same direction (Zhou and Rudd, 2012), although the transcriptional relationship between mtl, pncC, recA and recX was not reported. It has been reported that a transcriptional relationship exists between recA and recX in the SOS response (Pages et al, 2003), suggesting that a recA promoter and its transcription affect recX gene expression. It has also been reported that RecX regulates the RecA function in vitro and in vivo (Drees et al, 2004;Stohl et al, 2003).…”

Section: Discussionmentioning

confidence: 99%

Phenotypic difference between Δ(srl–recA)306 and ΔrecA::Km elucidated by next-generation sequencing combined with a long-PCR system

Suzuki

Kaidow

Meya

et al. 2017

J. Gen. Appl. Microbiol.

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recX, a new SOS gene that is co-transcribed with the recA gene in Escherichia coli

Cited by 66 publications

References 24 publications

The Escherichia coli DinD Protein Modulates RecA Activity by Inhibiting Postsynaptic RecA Filaments

The Escherichia coli DinD Protein Modulates RecA Activity by Inhibiting Postsynaptic RecA Filaments

Genetic makeup of the Corynebacterium glutamicum LexA regulon deduced from comparative transcriptomics and in vitro DNA band shift assays

Phenotypic difference between Δ(<i>srl</i>–<i>recA</i>)<i>306</i> and Δ<i>recA</i>::Km elucidated by next-generation sequencing combined with a long-PCR system

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