TherecXgene product is involved in the SOS response inHerbaspirillum seropedicae

2003 ◽  
Vol 49 (2) ◽  
pp. 145-150 ◽  
Author(s):  
Carolina W Galvão ◽  
Fábio O Pedrosa ◽  
Emanuel M Souza ◽  
M Geoffrey Yates ◽  
Leda S Chubatsu ◽  
...  
Keyword(s):  
Reca Protein ◽  
Sos Response ◽  
Promoter Sequence ◽  
Transcriptional Analysis ◽  
Reca Gene ◽  
Herbaspirillum Seropedicae ◽  
Transcription Terminator ◽  
Reca Mutant ◽  
Operator Site

The recA and the recX genes of Herbaspirillum seropedicae were sequenced. The recX is located 359 bp downstream from recA. Sequence analysis indicated the presence of a putative operator site overlapping a probable σ70-dependent promoter upstream of recA and a transcription terminator downstream from recX, with no apparent promoter sequence in the intergenic region. Transcriptional analysis using lacZ promoter fusions indicated that recA expression increased three- to fourfold in the presence of methyl methanesulfonate (MMS). The roles of recA and recX genes in the SOS response were determined from studies of chromosomal mutants. The recA mutant showed the highest sensitivity to MMS and UV, and the recX mutant had an intermediate sensitivity, compared with the wild type (SMR1), confirming the essential role of the RecA protein in cell viability in the presence of mutagenic agents and also indicating a role for RecX in the SOS response.Key words: Herbaspirillum seropedicae, recA gene, recX gene, DNA repair, SOS mutagenesis.

scholarly journals Duplication mutation as an SOS response in Escherichia coli: enhanced duplication formation by a constitutively activated RecA.

Genetics ◽  
1989 ◽  
Vol 123 (2) ◽  
pp. 255-260 ◽  
Author(s):  
J Dimpfl ◽  
H Echols
Keyword(s):  
Escherichia Coli ◽  
Point Mutations ◽  
Reca Protein ◽  
Regulatory System ◽  
Sos Response ◽  
Dna Lesions ◽  
Reca Gene ◽  
Sos System ◽  
Constitutive Mutation ◽  
Recombination Pathway

Abstract The SOS response in Escherichia coli involves the induction of a multioperon regulatory system, which copes with the presence of DNA lesions that interfere with DNA replication. Induction depends on activation of the RecA protein to cleave the LexA repressor of SOS operons. In addition to inducible DNA repair, the SOS system produces a large increase in the frequency of point mutations. To examine the possibility that other types of mutations are induced as part of the SOS response, we have studied the production of tandem duplications. To avoid the complications of indirect effects of the DNA lesions, we have activated the SOS response by a constitutive mutation in the recA gene, recA730. The introduction of the recA730 mutation results in an increase in duplications in the range of tenfold or greater, as judged by two different criteria. Based on its genetic requirements, the pathway for induced duplication formation is distinct from the point mutation pathway and also differs from the major normal recombination pathway. The induction of pathways for both duplications and point mutations shows that the SOS system produces a broad mutagenic response. We have suggested previously that many types of mutations might be induced by severe environmental stress, thereby enhancing genetic variation in an endangered population.

scholarly journals Evaluation of the Role of RecA Protein in Plant Virulence with recA Mutants of Xanthomonas campestris pv. campestris

1997 ◽  
Vol 10 (7) ◽  
pp. 911-916 ◽  
Author(s):  
Socorro Martínez ◽  
Jaime Martínez-Salazar ◽  
Alberto Camas ◽  
Rosalba Sánchez ◽  
Gloria Soberón-Chávez
Keyword(s):  
Xanthomonas Campestris ◽  
Genetic Recombination ◽  
Reca Protein ◽  
Reca Gene ◽  
Methyl Methane Sulfonate ◽  
In Trans ◽  
Reca Mutation ◽  
Xanthomonas Campestris Pv Campestris ◽  
Selection Of

Xanthomonas campestris pv. campestris NRRL B1459 recA mutants were isolated by recombination with an interrupted Rhizobium etli recA gene and selection of double recombinants. The mutants were impaired in homologous genetic recombination and in DNA repair as judged by their sensitivity to methyl-methane-sulfonate and to UV irradiation; these defects are complemented in trans by the R. etli recA gene. Virulence of X. campestris pv. campestris NRRL B1459 to cabbage is considerably diminished by the recA mutation. The recA mutation is not correlated with the frequency of occurrence of a genetic rearrangement that affects chemotaxis, plant virulence, and xanthan gum production.

Exposure to sub-inhibitory ciprofloxacin and nitrofurantoin concentrations increases recA gene expression in uropathogenic Escherichia coli: The role of RecA protein as a drug target

2020 ◽  
Vol 146 ◽  
pp. 105268 ◽  
Author(s):  
Ághata Cardoso da Silva Ribeiro ◽  
Willames Marcos Brasileiro da Silva Martins ◽  
Adilson Aderito da Silva ◽  
Ana Cristina Gales ◽  
Daniela Gonçales Galasse Rando ◽  
...  
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Drug Target ◽  
Reca Protein ◽  
Uropathogenic Escherichia Coli ◽  
Reca Gene

Cloning of a recA-like gene from the diazotroph Herbaspirillum seropedicae strain Z78

1993 ◽  
Vol 39 (12) ◽  
pp. 1096-1102 ◽  
Author(s):  
M. B. R. Steffens ◽  
L. U. Rigo ◽  
S. Funayama ◽  
E. M. Souza ◽  
H. B. Machado ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genomic Library ◽  
Reca Gene ◽  
Methyl Methanesulfonate ◽  
Herbaspirillum Seropedicae ◽  
E Coli ◽  
Tn5 Mutagenesis ◽  
Ultraviolet Resistance ◽  
Restriction Sites ◽  
Reca Mutant

A recombinant plasmid, pBMR5, carrying a recA-like gene of Herbaspirillum seropedicae, was isolated from a H. seropedicae genomic library by intergeneric complementation of Escherichia coli recA mutant strain HB101. Quantitative survival experiments showed that pBMR5 restored the ultraviolet radiation and methyl methanesulfonate resistances and recombinational proficiency of this strain. Hybridization studies showed that there is DNA sequence homology between the recA gene of E. coli K12 and that of H. seropedicae. Restriction sites for EcoRI, HindIII, BamHI, and BglII were found in the DNA insert derived from H. seropedicae in pBMR5. A Tn5 insertional mutant of pBMR5, called pBMR26.2, failed to restore recombination proficiency and methyl methanesulfonate and ultraviolet resistance to recA mutants of E. coli.Key words: Herbaspirillum seropedicae, nitrogen fixation, recA-like gene, Tn5 mutagenesis.

scholarly journals Overexpression of the recA Gene Decreases Oral but Not Intraperitoneal Fitness of Salmonella enterica

2010 ◽  
Vol 78 (7) ◽  
pp. 3217-3225 ◽  
Author(s):  
Laura Medina-Ruiz ◽  
Susana Campoy ◽  
Cristina Latasa ◽  
Paula Cardenas ◽  
Juan Carlos Alonso ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Virulent Strain ◽  
Critical Role ◽  
Reca Protein ◽  
Sos Response ◽  
Reca Gene ◽  
Dna Damaging Agents ◽  
Protein Overproduction ◽  
Lexa Binding ◽  
Bacterial Swarming

ABSTRACT Transcription of the Salmonella enterica recA gene is negatively controlled by the LexA protein, the repressor of the SOS response. The introduction of a mutation (recAo6869) in the LexA binding site, in the promoter region of the S. enterica ATCC 14028 recA gene, allowed the analysis of the effect that RecA protein overproduction has on the fitness of this virulent strain. The fitness of orally but not intraperitoneally inoculated recAo6869 cells decreased dramatically. However, the SOS response of this mutant was induced normally, and there was no increase in the sensitivity of the strain toward DNA-damaging agents, bile salts, or alterations in pH. Nevertheless, S. enterica recAo6869 cells were unable to swarm and their capacity to cross the intestinal epithelium was significantly reduced. The swarming deficiency in recAo6869 cells is independent of the flagellar phase. Moreover, swimming activity of the recAo6869 strain was not diminished with respect to the wild type, indicating that the flagellar synthesis is not affected by RecA protein overproduction. In contrast, swarming was recovered in a recAo6869 derivative that overproduced CheW, a protein known to be essential for this function. These data demonstrate that an equilibrium between the intracellular concentrations of RecA and CheW is necessary for swarming in S. enterica. Our results are the first to point out that the SOS response plays a critical role in the prevention of DNA damage by abolishing bacterial swarming in the presence of a genotoxic compound.

scholarly journals Transcriptional and Mutational Analyses of theStreptomyces lividans recX Gene and Its Interference with RecA Activity

2000 ◽  
Vol 182 (14) ◽  
pp. 4005-4011 ◽  
Author(s):  
Silke Vierling ◽  
Tilmann Weber ◽  
Wolfgang Wohlleben ◽  
Günther Muth
Keyword(s):  
Dna Damage ◽  
Reverse Transcriptase ◽  
Colony Size ◽  
Genetic Instability ◽  
Reca Protein ◽  
Gene Replacement ◽  
Transcriptional Analysis ◽  
Recombination Activity ◽  
Extra Copy

ABSTRACT The role of the 20,922-Da RecX protein and its interference with RecA activity were analyzed in Streptomyces lividans. TherecX gene is located 220 bp downstream of recA. Transcriptional analysis by reverse transcriptase PCR demonstrated thatrecX and recA constitute an operon. WhilerecA was transcribed at a basal level even under noninducing conditions, a recA-recX cotranscript was only detectable after induction of recA following DNA damage. The recA-recX cotranscript was less abundant than therecA transcript alone. The recX gene was inactivated by gene replacement. The resulting mutant had a clearly diminished colony size, but was not impaired in recombination activity, genetic instability, and resistance against UV irradiation. Expression of an extra copy of the S. lividans recA gene under control of the thiostrepton-inducible tipA promoter was lethal to the recX mutant, demonstrating that RecX is required to overcome the toxic effects of recA overexpression. Since inactivation of the recX gene did not influence transcription of recA, the putative function of the RecX protein might be the downregulation of RecA activity by interaction with the RecA protein or filament.

Role of Transcriptional Read-Through in PRE Activity in Drosophila melanogaster

Acta Naturae ◽  
2016 ◽  
Vol 8 (2) ◽  
pp. 79-86 ◽  
Author(s):  
P. V. Elizar’ev ◽  
D. V. Lomaev ◽  
D. A. Chetverina ◽  
P. G. Georgiev ◽  
M. M. Erokhin
Keyword(s):  
Dna Sequences ◽  
Cell Types ◽  
Transcription Terminator ◽  
Response Elements ◽  
Polycomb Response Elements ◽  
The Individual ◽  
Multicellular Organisms ◽  
Different Cell Types ◽  
Main Factor

Maintenance of the individual patterns of gene expression in different cell types is required for the differentiation and development of multicellular organisms. Expression of many genes is controlled by Polycomb (PcG) and Trithorax (TrxG) group proteins that act through association with chromatin. PcG/TrxG are assembled on the DNA sequences termed PREs (Polycomb Response Elements), the activity of which can be modulated and switched from repression to activation. In this study, we analyzed the influence of transcriptional read-through on PRE activity switch mediated by the yeast activator GAL4. We show that a transcription terminator inserted between the promoter and PRE doesnt prevent switching of PRE activity from repression to activation. We demonstrate that, independently of PRE orientation, high levels of transcription fail to dislodge PcG/TrxG proteins from PRE in the absence of a terminator. Thus, transcription is not the main factor required for PRE activity switch.

scholarly journals Excision and transposition of Tn5 as an SOS activity in Escherichia coli.

Genetics ◽  
1991 ◽  
Vol 128 (1) ◽  
pp. 45-57 ◽  
Author(s):  
C T Kuan ◽  
S K Liu ◽  
I Tessman
Keyword(s):  
Escherichia Coli ◽  
Binding Site ◽  
Reca Protein ◽  
Precursor Molecule ◽  
Functional Integrity ◽  
Lexa Protein ◽  
Lexa Binding ◽  
Additional Role ◽  
Stimulation Of

Abstract Excision and transposition of the Tn5 element in Escherichia coli ordinarily appear to occur by recA-independent mechanisms. However, recA(Prtc) genes, which encode RecA proteins that are constitutively activated to the protease state, greatly enhanced excision and transposition; both events appeared to occur concomitantly and without destruction of the donor DNA. The recombinase function of the RecA protein was not required. Transposition was accompanied by partial, and occasionally full, restoration of the functional integrity of the gene vacated by the excised Tn5. The stimulation of transposition was inhibited by an uncleavable LexA protein and was strongly enhanced by an additional role of the RecA(Prtc) protein besides its mediation of LexA cleavage. To account for the enhanced transposition, we suggest that (i) there may be a LexA binding site within the promoter for the IS50 transposase, (ii) activated RecA may cleave the IS50 transposition inhibitor, and (iii) the transposase may be formed by RecA cleavage of a precursor molecule.

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