Transcriptional Cross Talk within themar-sox-robRegulon in Escherichia coli Is Limited to therobandmarRABOperons

Chubiz, Lon M.; Glekas, George D.; Rao, Chinthalapally V.

doi:10.1128/jb.00680-12

Cited by 45 publications

(68 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Consequently, the lack of MarA-mediated induction of the efflux pumps with 0.5 mM NaSal led to accumulation of ciprofloxacin and enhanced cell elongation in the absence of marA. At higher NaSal concentrations, it is possible that nonmarA-mediated pathways (Tsilibaris et al, 2006;Chubiz et al, 2012), e.g. soxS and rob, may be involved in the lower elongation of DmarA cells with ciprofloxacin.…”

Section: Discussionmentioning

confidence: 99%

Roles of Lon protease and its substrate MarA during sodium salicylate-mediated growth reduction and antibiotic resistance in Escherichia coli

et al. 2016

View full text Add to dashboard Cite

The cellular proteolytic machinery orchestrates protein turnover and regulates several key biological processes. This study addresses the roles of Lon, a major ATP-dependent protease, in modulating the responses of Escherichia coli strain MG1655 to low and high amounts of sodium salicyclate (NaSal), a widely used clinically relevant analgesic. NaSal affects several bacterial responses, including growth and resistance to multiple antibiotics. The loss of lon reduces growth in response to high, but not low, amounts of NaSal. From amongst a panel of Lon substrates, MarA was identified to be the downstream target of Lon. Thus, stabilization of MarA in the absence of lon lowers growth of the strain in the presence of higher amounts of NaSal. The steady-state transcript levels of marA and its target genes, acrA, acrB and tolC, are higher in the Dlon strain compared with the WT strain. Consequently, the resistance to antibiotics, e.g. tetracycline and nalidixic acid, is enhanced in Dlon in a marA-dependent manner. Furthermore, the target genes of MarA, i.e. acrB and tolC, are responsible for NaSal-mediated antibiotic resistance. Studies using atomic force microscopy demonstrated that ciprofloxacin led to greater cell filamentation, which is lower in the Dlon strain due to higher levels of MarA. Overall, this study delineates the roles of Lon protease, its substrate MarA and downstream targets of MarA, e.g. acrB and tolC, during NaSal-mediated growth reduction and antibiotic resistance. The implications of these observations in the adaptation of E. coli under different environmental conditions are discussed.

show abstract

Section: Discussionmentioning

confidence: 99%

Roles of Lon protease and its substrate MarA during sodium salicylate-mediated growth reduction and antibiotic resistance in Escherichia coli

et al. 2016

View full text Add to dashboard Cite

show abstract

“…However, cross talk between the mar and sox systems is limited under physiological conditions. For example, SoxS, when expressed, is not expected to activate marRAB transcription in the absence of salicylate, when MarR still represses the promoter [38]. In the case of the rob and mar systems, the situation is different as salicylate is able to activate marRAB through Rob [38].…”

Section: Mara and The Marrab Operonmentioning

confidence: 99%

“…Once synthesized, SoxS is able to repress its own transcription [60]. MarA and Rob have also been shown to repress soxS expression when ectopically overexpressed [38]. …”

Section: Soxs and Soxrmentioning

confidence: 99%

See 1 more Smart Citation

MarA, SoxS and Rob of Escherichia coli – Global Regulators of Multidrug Resistance, Virulence and Stress Response

Duval¹

2013

Int. J. Biotech. Well. Indus.

118

View full text Add to dashboard Cite

Bacteria have a great capacity for adjusting their metabolism in response to environmental changes by linking extracellular stimuli to the regulation of genes by transcription factors. By working in a co-operative manner, transcription factors provide a rapid response to external threats, allowing the bacteria to survive. This review will focus on transcription factors MarA, SoxS and Rob in Escherichia coli, three members of the AraC family of proteins. These homologous proteins exemplify the ability to respond to multiple threats such as oxidative stress, drugs and toxic compounds, acidic pH, and host antimicrobial peptides. MarA, SoxS and Rob recognize similar DNA sequences in the promoter region of more than 40 regulatory target genes. As their regulons overlap, a finely tuned adaptive response allows E. coli to survive in the presence of different assaults in a co-ordinated manner. These regulators are well conserved amongst Enterobacteriaceae and due to their broad involvement in bacterial adaptation in the host, have recently been explored as targets to develop new anti-virulence agents. The regulators are also being examined for their roles in novel technologies such as biofuel production.

show abstract

“…Together, the three (MarA, SoxS, and Rob) control expression of >80 genes in E. coli (40)(41)(42)(43). While the three systems have their independent inducers and targets, considerable cross talk is known to exist between the Mar, Sox, and Rob systems; however, the precise mechanistic details and physiological significance of these interactions is yet to be fully understood (44)(45)(46).…”

Section: Introductionmentioning

confidence: 98%

Control of MarRAB Operon in Escherichia coli via Autoactivation and Autorepression

Prajapat

Jain

Saini

2015

Biophysical Journal

View full text Add to dashboard Cite

Choice of network topology for gene regulation has been a question of interest for a long time. How do simple and more complex topologies arise? In this work, we analyze the topology of the marRAB operon in Escherichia coli, which is associated with control of expression of genes associated with conferring resistance to low-level antibiotics to the bacterium. Among the 2102 promoters in E. coli, the marRAB promoter is the only one that encodes for an autoactivator and an autorepressor. What advantages does this topology confer to the bacterium? In this work, we demonstrate that, compared to control by a single regulator, the marRAB regulatory arrangement has the least control cost associated with modulating gene expression in response to environmental stimuli. In addition, the presence of dual regulators allows the regulon to exhibit a diverse range of dynamics, a feature that is not observed in genes controlled by a single regulator.

show abstract

Transcriptional Cross Talk within themar-sox-robRegulon in Escherichia coli Is Limited to therobandmarRABOperons

Cited by 45 publications

References 60 publications

Roles of Lon protease and its substrate MarA during sodium salicylate-mediated growth reduction and antibiotic resistance in Escherichia coli

Roles of Lon protease and its substrate MarA during sodium salicylate-mediated growth reduction and antibiotic resistance in Escherichia coli

MarA, SoxS and Rob of Escherichia coli – Global Regulators of Multidrug Resistance, Virulence and Stress Response

Control of MarRAB Operon in Escherichia coli via Autoactivation and Autorepression

Contact Info

Product

Resources

About