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ComR DNA-binding transcriptional repressor

Synonyms: ComR-Cu+, ComR
Summary:
ComR is a member of the TetR family of transcriptional repressors and has been implicated in the the response of E. coli K-12 to copper. In in vitro experiments, ComR binds to a 60 bp promotor region upstream of the comC gene [1] but is released in the presence of copper, silver or gold. Expression of comC is dramatically increased (approx 270 fold) in a comR negative strain upon exposure to 3mM copper. comR knockout mutants have lower cytoplasmic copper levels compared to the wild type when exposed to copper [1]. Expression of comR is not affected by copper [1]. Genome-wide ComR binding sites were determined in vivo in M9 glucose minimal medium by chromatin immunoprecipitation assays (ChIP-exo) 34428301]|. Review: [2].


Transcription factor      
TF conformation(s):
Name Conformation Type TF-Effector Interaction Type Apo/Holo Conformation Evidence Confidence level (C: Confirmed, S: Strong, W: Weak) References
ComR Functional   Apo nd nd nd
ComR-Cu+ Non-Functional   Holo nd nd nd
Evolutionary Family: TetR/AcrR
TFBs length: 19
TFBs symmetry: inverted-repeat
Connectivity class: Local Regulator
Gene name: comR
  Genome position: 1168200-1168832
  Length: 633 bp / 210 aa
Operon name: comR
TU(s) encoding the TF:
Transcription unit        Promoter
comR
comRp


Regulon       
Regulated gene(s) bhsA
Multifun term(s) of regulated gene(s)
adaptations (1)
Regulated operon(s) bhsA
First gene in the operon(s) bhsA
Simple and complex regulons CRP,ComR
Simple and complex regulatory phrases Regulatory phrase (List of promoters regulated by the phrase)
[ComR,-](1)


Transcription factor regulation    


Transcription factor binding sites (TFBSs) arrangements
      

  Functional conformation Function Promoter Sigma factor Central Rel-Pos Distance to first Gene Genes Sequence LeftPos RightPos Evidence Confidence level (C: Confirmed, S: Strong, W: Weak) References
  ComR repressor bhsAp Sigma24 nd nd bhsA
nd
 nd nd [EXP-IEP-GENE-EXPRESSION-ANALYSIS], [EXP-IDA-BINDING-OF-PURIFIED-PROTEINS] S [1], [1]


Evolutionary conservation of regulatory elements    
     Note: Evolutionary conservation of regulatory interactions and promoters is limited to gammaproteobacteria.
Promoter-target gene evolutionary conservation


Evidence    

 [EXP-IEP-GENE-EXPRESSION-ANALYSIS] Gene expression analysis

 [EXP-IDA-BINDING-OF-PURIFIED-PROTEINS] Binding of purified proteins


Reference(s)    

 [1] Mermod M., Magnani D., Solioz M., Stoyanov JV., 2012, The copper-inducible ComR (YcfQ) repressor regulates expression of ComC (YcfR), which affects copper permeability of the outer membrane of Escherichia coli., Biometals 25(1):33-43

 [2] Rademacher C, Masepohl B, 2012, Copper-responsive gene regulation in bacteria., Microbiology (Reading), 158(Pt 10):2451 10.1099/mic.0.058487-0


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