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MtlR DNA-binding transcriptional repressor

Synonyms: MtlR
The transcriptional activator MtlR, for Mannitol Rrgulator, is capable of controlling its own synthesis [1]and it controls the transcription of the operon involved in mannitol utilization [1] MtlR in the presence of just mannitol produces derepression of the mtlADR operon, but when glucose is present in the medium, this operon is a target of catabolite repression (through CRP), independent of MtlR [1] MtlA takes up exogenous mannitol, releasing the phosphate ester, mannitol-1-P, into the cell cytoplasm, but it is not clear which of the two metabolites is the inducer of MtlR [1].
To repress transcription, MtlR recognizes DNA-binding sites that overlap the initiation site for transcription of the mtlADR operon, preventing RNA polymerase binding [1] but no consensus sequence has been identified.
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Transcription factor      
TF conformation(s):
Name Conformation Type TF-Effector Interaction Type Apo/Holo Conformation Evidence (Confirmed, Strong, Weak) References
MtlR     nd nd
Evolutionary Family: MtlR
Sensing class: External sensing using transported metabolites
Connectivity class: Local Regulator
Gene name: mtlR
  Genome position: 3775572-3776159
  Length: 588 bp / 195 aa
Operon name: mtlADR
TU(s) encoding the TF:
Transcription unit        Promoter

Regulated gene(s) mtlA, mtlD, mtlR
Multifun term(s) of regulated gene(s) MultiFun Term (List of genes associated to the multifun term)
carbon compounds (3)
Phosphotransferase Systems (PEP-dependent PTS) (1)
membrane (1)
Transcription related (1)
repressor (1)
Regulated operon(s) mtlADR
First gene in the operon(s) mtlA
Simple and complex regulons CRP,Cra,Fis,MtlR
Simple and complex regulatory phrases Regulatory phrase (List of promoters regulated by the phrase)

Transcription factor binding sites (TFBSs) arrangements       

  Functional conformation Function Promoter Sigma factor Central Rel-Pos Distance to first Gene Genes Sequence LeftPos RightPos Evidence (Confirmed, Strong, Weak) References
  MtlR repressor mtlAp Sigma70 nd nd mtlA, mtlD, mtlR nd nd [GEA] [1]

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


 [GEA] Gene expression analysis


 [1] Figge RM., Ramseier TM., Saier MH., 1994, The mannitol repressor (MtlR) of Escherichia coli., J Bacteriol. 176(3):840-7

 [2] Tan K., Borovilos M., Zhou M., Horer S., Clancy S., Moy S., Volkart LL., Sassoon J., Baumann U., Joachimiak A., 2009, The Mannitol Operon Repressor MtlR Belongs to a New Class of Transcription Regulators in Bacteria., J Biol Chem

 [3] Bateman A., Coin L., Durbin R., Finn RD., Hollich V., Griffiths-Jones S., Khanna A., Marshall M., Moxon S., Sonnhammer EL., Studholme DJ., Yeats C., Eddy SR., 2004, The Pfam protein families database., Nucleic Acids Res. 32(Database issue):D138-41