The AraC transcriptional activators

Martin, Robert G.; Rosner, Judah L.

doi:10.1016/s1369-5274(00)00178-8

Cited by 210 publications

(230 citation statements)

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“…36 The YdeO protein is involved in transcriptional activation of the gadE gene coding for a protein that regulates gadABC (Figure 4). 36,46 YdeO belongs to the AraC-XylS family of bacterial transcriptional regulators known to activate acid resistance 36,47,48 and repress virulence. 49 We investigated the contribution of the MdtEF multi-drug efflux pump in YdeO-induced acid resistance, but MdtEF is not essential for acid resistance of E. coli.…”

Section: Discussionmentioning

confidence: 99%

Role of the AraC–XylS family regulator YdeO in multi-drug resistance of Escherichia coli

et al. 2009

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Multi-drug efflux pumps contribute to the resistance of Escherichia coli to many antibiotics and biocides. In this study, we report that the AraC-XylS family regulator YdeO increases the multi-drug resistance of E. coli through activation of the MdtEF efflux pump. Screening of random fragments of genomic DNA for their ability to increase b-lactam resistance led to the isolation of a plasmid containing ydeO, which codes for the regulator of acid resistance. When overexpressed, ydeO significantly increased the resistance of the E. coli strain to oxacillin, cloxacillin, nafcillin, erythromycin, rhodamine 6G and sodium dodecyl sulfate. The increase in drug resistance caused by ydeO overexpression was completely suppressed by deleting the multifunctional outer membrane channel gene tolC. TolC interacts with different drug efflux pumps. Quantitative real-time PCR showed that YdeO activated only mdtEF expression and none of the other drug efflux pumps in E. coli. Deletion of mdtEF completely suppressed the YdeO-mediated multi-drug resistance. YdeO enhances the MdtEF-dependent drug efflux activity in E. coli. Our results indicate that the YdeO regulator, in addition to its role in acid resistance, increases the multi-drug resistance of E. coli by activating the MdtEF multi-drug efflux pump. Keywords: drug efflux pump; Escherichia coli; MdtEF; multidrug resistance; YdeO INTRODUCTION Multi-drug efflux pumps cause serious problems in cancer chemotherapy and in the treatment of bacterial infections. Bacterial drug resistance is often associated with multi-drug efflux pumps that decrease drug accumulation in the cell. 1,2 Bacterial multi-drug efflux pumps are classified into five families on the basis of sequence similarity: major facilitator, resistance-nodulation-cell division (RND), small multi-drug resistance, multidrug and toxic compound extrusion, and ATP-binding cassette. [3][4][5] Of these, RND family efflux pumps play major roles in both intrinsic and elevated resistance of Gram-negative bacteria to a wide range of compounds, including b-lactams. 1,6-12 RND efflux pumps require two other proteins to function: a membrane fusion protein and an outer membrane protein.Many drug efflux pumps in Escherichia coli need TolC to function. [12][13][14][15] TolC is responsible for resistance to various antibiotics, including b-lactams, 12 quinolones 16 and macrolides. 17 Bacterial genome sequencing enables us to trace drug-resistance genes. [18][19][20] There are many putative and proven drug efflux pumps in the E. coli genome, and we have identified earlier 20 functional drug efflux pumps. 9,20 As many such efflux pumps have overlapping substrate spectra, 9 it is intriguing that bacteria, with their economically organized genomes, harbor such large sets of multi-drug efflux genes.

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Section: Discussionmentioning

confidence: 99%

Role of the AraC–XylS family regulator YdeO in multi-drug resistance of Escherichia coli

et al. 2009

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“…Expression levels of transcription factors (Martin & Rosner, 2001). The MarA-SoxS-Rob regulon is involved in antibiotic resistance, superoxide resistance and tolerance to organic solvents.…”

Section: Expression Levels Of Tfs Under Aerobic Conditionsmentioning

confidence: 99%

“…The MarA-SoxS-Rob regulon is involved in antibiotic resistance, superoxide resistance and tolerance to organic solvents. Many genes involved in response to external stresses are activated by all three TFs, each responding to different signals: superoxides for SoxS, aromatic weak acids such as salicylate for MarA, and bile salts and dipyridyl for Rob (Demple, 1996;Martin & Rosner, 2001). Although SoxS is induced in the lag phase of cell growth, both MarA and Rob are not induced ( Table 1), indicating that SoxS plays a unique role in the initial stage of cell growth.…”

Section: Expression Levels Of Tfs Under Aerobic Conditionsmentioning

confidence: 99%

Expression levels of transcription factors in Escherichia coli: growth phase- and growth condition-dependent variation of 90 regulators from six families

Watanabe

Ishihama

2014

Microbiology

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The expression pattern of the genome in Escherichia coli is controlled by regulating the utilization of a limited number of RNA polymerases between a total of 4600 genes on its genome. The distribution pattern of RNA polymerase on the genome changes after two steps of protein-protein interaction with seven sigma subunits and about 300 transcription factors (TFs). Based on a systematic search for the regulation target promoters recognized by each TF, we propose two novel concepts: each TF regulates a number of target promoters; and each promoter is regulated by many TFs. In parallel, attempts have been made to determine the intracellular concentrations of all TFs using two systems: quantitative immunoblot analysis using TF-specific antibodies; and reporter assay of TF promoter activities. The direct measurement of TF protein level has so far been published for a set of 60 regulators with known functions. This study describes the determination of growth phase-dependent expression levels of 90 TFs using the reporter assay system. The translational fusion vector was constructed from the TF promoter sequence including an N-terminal proximal TF segment and the reporter GFP. At the beginning of cell growth, highlevel expression was observed only for a small number of TFs. In the exponential phase, approximately 80 % TFs are expressed, but the expressed TF species change upon transfer to the stationary phase. Significant changes in the pattern of TF expression were observed between aerobic and anaerobic conditions. The list of intracellular levels of TFs provides further understanding to the transcription regulation of the E. coli genome under various stressful conditions. INTRODUCTIONSingle-cell bacteria are directly exposed to frequently changing environments in nature and thus carry sophisticated genetic systems for adaptation to environmental changes (Ishihama, 2010(Ishihama, , 2012Yamamoto, 2014). On the basis of the complete genome sequence of several model Escherichia coli strains, the whole set of about 4600 genes has been predicted to exist in E. coli K-12 (Hayashi et al., 2006;Riley et al., 2006). In growing E. coli cells under laboratory culture conditions, only one-quarter to one-third of the genes on its genome are expressed, the others remaining silent. The majority of these uncharacterized silent genes must be expressed and utilized for adaptation and survival of E. coli under stressful conditions. Thus, even for this well-characterized model organism, the gene functions remain unidentified or unpredicted for approximately one-quarter because expression conditions of these silent genes have not yet been established.As the total number of RNA polymerases (RNAPs) in E. coli K-12 is less than the total number of genes on its genome (Ishihama, 2000), we proposed a model in which the change in genome transcription pattern takes place mainly through controlling the utilization of this limited number of transcription apparatuses between 4600 genes on the genome (Ishihama, 2010(Ishihama, , 2012. Two groups of reg...

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“…The three remaining IVI antigens identified were a putative right-origin binding (ROB) protein (YPO0456), a putative aminotransferase, NifS (YPO2138), and YPO1673, a high-molecular-weight (107 kDa) hypothetical inner-membrane protein. The ROB protein is a cytoplasmic protein, classified within the AraC family of bacterial transcriptional activators linked to stress responses (Martin and Rosner, 2001). The aminotransferase NifS belongs to the class-V pyridoxal-phosphate-dependent aminotransferase family and plays a vital role in nonheme iron and inorganic sulfide complex formation (Johnson et al, 2005).…”

Section: Western Blot Analyses Of Plasmid-encoded Virulence Factorsmentioning

confidence: 99%

Antigenic Profiling of Yersinia Pestis Infection in the Wyoming Coyote (Canis Latrans)

Vernati

Rocke

Little

et al. 2011

Journal of Wildlife Diseases

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ABSTRACT:Although Yersinia pestis is classified as a ''high-virulence'' pathogen, some host species are variably susceptible to disease. Coyotes (Canis latrans) exhibit mild, if any, symptoms during infection, but antibody production occurs postinfection. This immune response has been reported to be against the F1 capsule, although little subsequent characterization has been conducted. To further define the nature of coyote humoral immunity to plague, qualitative serology was conducted to assess the antiplague antibody repertoire. Humoral responses to six plasmidencoded Y. pestis virulence factors were first examined. Of 20 individual immune coyotes, 90% were reactive to at least one other antigen in the panel other than F1. The frequency of reactivity to low calcium response plasmid (pLcr)-encoded Yersinia protein kinase A (YpkA) and Yersinia outer protein D (YopD) was significantly greater than that previously observed in a murine model for plague. Additionally, both V antigen and plasminogen activator were reactive with over half of the serum samples tested. Reactivity to F1 was markedly less frequent in coyotes (35%). Twenty previously tested antibody-negative samples were also examined. While the majority were negative across the panel, 15% were positive for 1-3 non-F1 antigens. In vivo-induced antigen technology employed to identify novel chromosomal genes of Y. pestis that are up-regulated during infection resulted in the identification of five proteins, including a flagellar component (FliP) that was uniquely reactive with the coyote serum compared with immune serum from two other host species. Collectively, these data suggest that humoral immunity to pLcr-encoded antigens and the pesticin plasmid (pPst)-encoded Pla antigen may be relevant to plague resistance in coyotes. The serologic profile of Y. pestis chromosomal antigens up-regulated in vivo specific to C. latrans may provide insight into the differences in the pathogen-host responses during Y. pestis infection.

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The AraC transcriptional activators

Cited by 210 publications

References 42 publications

Role of the AraC–XylS family regulator YdeO in multi-drug resistance of Escherichia coli

Role of the AraC–XylS family regulator YdeO in multi-drug resistance of Escherichia coli

Expression levels of transcription factors in Escherichia coli: growth phase- and growth condition-dependent variation of 90 regulators from six families

Antigenic Profiling of Yersinia Pestis Infection in the Wyoming Coyote (Canis Latrans)

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