Dataset Information

Campylobacter gene regulation in C. jejuni

ABSTRACT: The pathogenic bacterium Campylobacter jejuni is the leading cause of bacterial foodborne gastroenteritis worldwide yet it does not grow in the aerobic environment. The paralogues RrpA and RrpB which are members of MarR family of DNA binding proteins have been shown to be important for the survival of C. jejuni under aerobic and redox stress. We report that RrpA is a positive regulator of mdaB, encoding a flavin-dependent quinone reductase. MdaB confers protection to the cell from redox stress mediated by structurally diverse quinones. RrpB negatively regulates the expression of nfrA (Cj1555c), a flavin reductase. NfrA reduces riboflavin at a much higher rate than flavin mononucleotide (FMN),suggesting exogenous free flavins are the natural substrate. Enzymatic activity of MdaB and NfrA towards their substrates revealed both reductases preferred NADPH as an electron donor. DNA-binding and post translational modification analyses showed that the mechanism of RrpA and RrpB DNA binding is likely a cysteine-based redox switch. Complete genome sequences analysis indicated that MdaB is predominant in Campylobacter spp. and the related Helicobacter spp., whilst NfrA is more often found in C. jejuni strains. Quinones and flavins are antimicrobial redox cycling agents secreted by a wide range of cell-types that can form damaging superoxide by one-electron reactions. We propose that MdaB and NfrA production allows a two-electron reduction mechanism to the less toxic quinol forms. These enzymes thus aid the survival and persistence of C. jejuni in the face of toxic compounds from competing microbes.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Campylobacter Jejuni

SUBMITTER: Steven Lynham

LAB HEAD: Fauzy Nasher

PROVIDER: PXD028910 | Pride | 2021-11-03

REPOSITORIES: Pride

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Publications

MdaB and NfrA, Two Novel Reductases Important in the Survival and Persistence of the Major Enteropathogen Campylobacter jejuni.

Nasher Fauzy F Taylor Aidan J AJ Elmi Abdi A Lehri Burhan B Ijaz Umer Z UZ Baker Dave D Goram Richard R Lynham Steven S Singh Dipali D Stabler Richard R Kelly David J DJ Gundogdu Ozan O Wren Brendan W BW

Journal of bacteriology 20211004 1

The paralogues RrpA and RrpB, which are members of the MarR family of DNA binding proteins, are important for the survival of the global bacterial foodborne pathogen Campylobacter jejuni under redox stress. We report that RrpA is a positive regulator of mdaB, encoding a flavin-dependent quinone reductase that contributes to the protection from redox stress mediated by structurally diverse quinones, while RrpB negatively regulates the expression of cj1555c (renamed nfrA for N ...[more]

PMID: 34606373

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Project description:Campylobacter, a major foodborne pathogen, is increasingly resistant to macrolide antibibotics. Previous findings suggeted that development of macrolide resistance in campylobacter requires a multi-step process, but the molecular mechanisms involved in the process are not known. In our study, multiple series of macrolide-resistant C. jejuni mutants were selected in vitro by stepwise exposure of C. jejuni NCTC11168 to increasing concentrations of erythromycin and tylosin. A set of the selected resistance were subjected to microarray and the the global transcriptional profile was analyzed. In this sery, DNA microarray was used to compare the gene expression profiles of macrolide resistant strains (68E1, 68E8 and 68E64) with its parent wild-type strain NCTC11168. The assay identified a small number of genes that showed significant changes (q-value<0.1) in expression in the low-level macrolide resistant strain 68E1, while a large number of gene showing significant changes in intermedia-level resistant stran 68E8 and high-level resistant strain 68 E64. The up-regulated genes in the resistant strains are involved in miscellaneous periplasmic proteins, efflux protienand putative aminotransferase, while the majority of the down-regulated genes are involved in electron transport,lipoprotein, heat shock protein and unknown function proteins. These findings suggest that there is not much change in low-level macrolide resistant C. jejuni strain. The over-expression of efflux pump and periplasmic protein was involved in the development of resistance to macrolide in C. jejuni. Keywords: macrolide resistant C. jejuni selected from NCTC 11168 step-wise selection. The design utilized an available two color microarray slide for the entire transcriptome of Campylobacter jejuni. Four hybridizations were performed each with independently extracted samples of either macrolide susceptible C. jejuni NCTC11168 cDNA samples or macrolide resistant C.jejuni cDNA samples. A dye swap was utilized to help minimize dye dependent bias. Thus, there were four biological replicates of each sample.

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	PR599_FN1_1-_1__RrpA_Control.msf	Msf
	PR599_FN1_1.mgf	Mgf
	PR599_FN1_1_RrpA_Control.raw	Raw
	PR599_FN1_3-_1_.mzML	Mzml