Accession ARO:3000506
Synonym(s)nalB
DefinitionMexR is the repressor of the MexRAB-OprM operon. Mutant forms of mexR result in up-regulation of efflux pump system MexAB-OprM.
AMR Gene Familyresistance-nodulation-cell division (RND) antibiotic efflux pump
Drug Classpeptide antibiotic, diaminopyrimidine antibiotic, penam, sulfonamide antibiotic, tetracycline antibiotic, aminocoumarin antibiotic, triclosan, phenicol antibiotic, aminoglycoside antibiotic, acridine dye, antibacterial free fatty acids, macrolide antibiotic, fluoroquinolone antibiotic, cephalosporin, monobactam, glycylcycline, carbapenem, penem, cephamycin
Resistance Mechanismantibiotic efflux, antibiotic target alteration
Efflux Componentefflux pump complex or subunit conferring antibiotic resistance
Efflux Regulatorprotein(s) and two-component regulatory system modulating antibiotic efflux
Classification59 ontology terms | Show
+ process or component of antibiotic biology or chemistry
+ antibiotic molecule
+ peptide antibiotic [Drug Class]
+ resistance-modifying agents
+ lipopeptide antibiotic
+ beta-lactam antibiotic
+ mechanism of antibiotic resistance
+ diaminopyrimidine antibiotic [Drug Class]
+ beta-lactamase inhibitor
+ penam [Drug Class]
+ antibiotic efflux [Resistance Mechanism]
+ cephem
+ determinant of antibiotic resistance
+ sulfonamide antibiotic [Drug Class]
+ tetracycline antibiotic [Drug Class]
+ polymyxin antibiotic
+ antibiotic without defined classification
+ aminocoumarin antibiotic [Drug Class]
+ triclosan [Drug Class]
+ phenicol antibiotic [Drug Class]
+ sulfamethoxazole [Antibiotic]
+ aminoglycoside antibiotic [Drug Class]
+ amoxicillin [Antibiotic]
+ antibiotic mixture
+ acridine dye [Drug Class]
+ antibacterial free fatty acids [Drug Class]
+ trimethoprim [Antibiotic]
+ colistin
+ macrolide antibiotic [Drug Class]
+ fluoroquinolone antibiotic [Drug Class]
+ clavulanate [Adjuvant]
+ cephalosporin [Drug Class]
+ efflux pump complex or subunit conferring antibiotic resistance [Efflux Component]
+ monobactam [Drug Class]
+ glycylcycline [Drug Class]
+ antibiotic target alteration [Resistance Mechanism]
+ carbapenem [Drug Class]
+ mutation conferring antibiotic resistance
+ tetracycline [Antibiotic]
+ erythromycin [Antibiotic]
+ ceftriaxone [Antibiotic]
+ ampicillin [Antibiotic]
+ colistin B [Antibiotic]
+ penem [Drug Class]
+ meropenem [Antibiotic]
+ colistin A [Antibiotic]
+ resistance-nodulation-cell division (RND) antibiotic efflux pump [AMR Gene Family]
+ ciprofloxacin [Antibiotic]
+ panipenem [Antibiotic]
+ cephamycin [Drug Class]
+ azithromycin [Antibiotic]
+ aztreonam [Antibiotic]
+ ceftazidime [Antibiotic]
+ novobiocin [Antibiotic]
+ trimethoprim-sulfamethoxazole [Antibiotic]
+ amoxicillin-clavulanic acid
+ chloramphenicol [Antibiotic]
+ antibiotic resistant gene variant or mutant
+ MexAB-OprM
Parent Term(s)5 ontology terms | Show
Publications

Wilke MS, et al. 2008. Proc Natl Acad Sci U S A 105(39): 14832-14837. The crystal structure of MexR from Pseudomonas aeruginosa in complex with its antirepressor ArmR. (PMID 18812515)

Chen H, et al. 2010. EMBO Rep 11(9): 685-690. Structural insight into the oxidation-sensing mechanism of the antibiotic resistance of regulator MexR. (PMID 20616806)

Saito K, et al. 2003. J Bacteriol 185(20): 6195-6198. Mutations affecting DNA-binding activity of the MexR repressor of mexR-mexA-mexB-oprM operon expression. (PMID 14526032)

Higgins PG, et al. 2003. Int. J. Antimicrob. Agents 21(5):409-13 Mutations in GyrA, ParC, MexR and NfxB in clinical isolates of Pseudomonas aeruginosa. (PMID 12727072)

Resistomes

Prevalence of MexR among the sequenced genomes, plasmids, and whole-genome shotgun assemblies available at NCBI for 82 important pathogens (see methodological details and complete list of analyzed pathogens). Values reflect percentage of genomes, plasmids, or whole-genome shotgun assemblies that have at least one hit to the AMR detection model. Default view includes percentages calculated based on Perfect plus Strict RGI hits. Select the checkbox to view percentages based on only Perfect matches to AMR reference sequences curated in CARD (note: this excludes resistance via mutation as references in protein variant models are often wild-type, sensitive sequences).

Prevalence: protein overexpression model (view sequences)

SpeciesNCBI ChromosomeNCBI PlasmidNCBI WGS
Acinetobacter baumannii0%0%0.15%
Citrobacter freundii0%0%0%
Enterobacter cloacae0%0%0.22%
Klebsiella oxytoca0%0%0%
Klebsiella pneumoniae0%0%0.02%
Proteus mirabilis0%0%0%
Pseudomonas aeruginosa100%0%99.86%
Show Perfect Only

Prevalence: protein variant model

SpeciesNCBI ChromosomeNCBI PlasmidNCBI WGS
No prevalence data


Detection Models

Model Type: protein overexpression model

Model Definition: This model detects protein overexpression based on the presence of mutations. The detection of the protein without an associated mutation indicates that the protein is likely to be expressed at low or basal levels. The detection of the protein with the mutation indicates that the protein is likely overexpressed. This model reflects how certain proteins are functional with and without mutations. For example, efflux pump subunits and regulators are functional with mutations and without mutations. Without mutations, efflux pump subunits and regulators are usually expressed at a low level. When an efflux pump regulator has a mutation, it can cause the overexpression of the efflux pump it is responsible for regulating, leading to resistance to specific drugs. Protein overexpression models have two parameters: a curated BLASTP cutoff, and a curated set of mutations (single resistance variants, frameshift mutations, indels, etc.) shown clinically to confer resistance. This model type is a combination of the protein homolog and protein variant model. A detected hit can be categorized as Perfect, Strict, or Loose with no mutation(s) or as Strict or Loose with mutation(s).

Legend:

  • discovered in clinical, agricultural, or environmental isolates
  • discovered via laboratory selection experiments


Bit-score Cut-off (blastP): 270

PMID: 14526032L45P I46N L57R L57P T69I I72N L75P L75R R83C R91H R91C H107P
PMID: 12727072N53D

>gb|AAG03813.1|-|mexR [Pseudomonas aeruginosa PAO1]
MNYPVNPDLMPALMAVFQHVRTRIQSELDCQRLDLTPPDVHVLKLIDEQRGLNLQDLGRQ
MCRDKALITRKIRELEGRNLVRRERNPSDQRSFQLFLTDEGLAIHQHAEAIMSRVHDELF
APLTPVEQATLVHLLDQCLAAQPLEDI



>gb|AE004091.2|-|471306-471749|mexR [Pseudomonas aeruginosa PAO1]
ATGAACTACCCCGTGAATCCCGACCTGATGCCCGCGCTGATGGCGGTCTTCCAGCATGTGCGGACGCGCATCCAGAGCGAGCTCGATTGC
CAGCGACTCGACCTGACCCCGCCCGACGTCCATGTATTGAAGCTTATCGACGAACAACGCGGGCTGAACCTGCAGGACCTGGGACGCCAG
ATGTGCCGCGACAAGGCACTGATCACCCGGAAGATCCGCGAGCTGGAGGGAAGAAACCTGGTCCGCCGCGAGCGCAACCCCAGCGACCAG
CGCAGCTTCCAGCTCTTCCTCACCGACGAGGGGCTGGCCATCCACCAGCATGCGGAGGCCATCATGTCACGCGTGCATGACGAGTTGTTT
GCCCCGCTCACCCCGGTGGAACAGGCCACCCTGGTGCATCTCCTCGACCAGTGCCTGGCCGCGCAACCGCTTGAGGATATTTAA


Model Type: protein variant model

Model Definition: The protein variant model is an AMR detection model. Protein variant models are similar to protein homolog models - they detect the presence of a protein sequence based on its similarity to a curated reference sequence, but secondarily search submitted query sequences for curated sets of mutations shown clinically to confer resistance relative to wild-type. This model includes a protein reference sequence, a curated BLASTP cut-off, and mapped resistance variants. Mapped resistance variants may include any or all of: single resistance variants, insertions, deletions, co-dependent resistance variants, nonsense SNPs, and/or frameshift mutations. Protein variant model matches to reference sequences are categorized on two criteria: strict and loose. A strict match has a BLASTP bitscore above the curated BLASTP cutoff value and contains at least one detected mutation from amongst the mapped resistance variants; a loose match has a BLASTP bitscore below the curated BLASTP cutoff value but still contains at least one detected mutation from amongst the mapped resistance variants. Regardless of BLASTP bitscore, if a sequence does not contain one of the mapped resistance variants, it is not considered a match and not detected by the protein variant model.

Legend:

  • discovered in clinical, agricultural, or environmental isolates
  • discovered via laboratory selection experiments


Bit-score Cut-off (blastP): 270

PMID in progress (nonsense): L35STOP

PMID: 14526032L45P I46N L57R L57P T69I I72N L75P L75R R83C R91H R91C H107P
PMID: 12727072N53D

>gb|AAG03813.1|-|mexR [Pseudomonas aeruginosa PAO1]
MNYPVNPDLMPALMAVFQHVRTRIQSELDCQRLDLTPPDVHVLKLIDEQRGLNLQDLGRQMCRDKALITRKIRELEGRNLVRRERNPSDQ
RSFQLFLTDEGLAIHQHAEAIMSRVHDELFAPLTPVEQATLVHLLDQCLAAQPLEDI


>gb|AE004091.2|-|471306-471749|mexR [Pseudomonas aeruginosa PAO1]
ATGAACTACCCCGTGAATCCCGACCTGATGCCCGCGCTGATGGCGGTCTTCCAGCATGTGCGGACGCGCATCCAGAGCGAGCTCGATTGC
CAGCGACTCGACCTGACCCCGCCCGACGTCCATGTATTGAAGCTTATCGACGAACAACGCGGGCTGAACCTGCAGGACCTGGGACGCCAG
ATGTGCCGCGACAAGGCACTGATCACCCGGAAGATCCGCGAGCTGGAGGGAAGAAACCTGGTCCGCCGCGAGCGCAACCCCAGCGACCAG
CGCAGCTTCCAGCTCTTCCTCACCGACGAGGGGCTGGCCATCCACCAGCATGCGGAGGCCATCATGTCACGCGTGCATGACGAGTTGTTT
GCCCCGCTCACCCCGGTGGAACAGGCCACCCTGGTGCATCTCCTCGACCAGTGCCTGGCCGCGCAACCGCTTGAGGATATTTAA