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HdfR DNA-binding transcriptional dual regulator

Synonyms: HdfR
Hns-dependent flhDCregulator, HdfR, negatively regulates the expression of the flagellar master operon, flhDC [1]and positively regulates the expression of the gltBD operon [2] H-NS is a direct activator of the flhDC operon and represses transcription of hdfR.
HdfR is a transcriptional regulator that belongs to the LysR family. It consist of two domains, an amino-terminal domain that contains a potential helix-turn-helix DNA-binding motif and a carboxy-terminal domain involved in co-inducer recognition [1, 3] Little is known about the regulatory role of HdfR, and the binding sites for this transcription factor have not yet been determined.
In systematic studies of oligomerization, it was shown that some members of the LysR family, like HdfR, interact with other members of the family to form heterodimers, but the physiological significance of this is unknown [4]
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Transcription factor      
TF conformation(s):
Name Conformation Type TF-Effector Interaction Type Apo/Holo Conformation Evidence (Confirmed, Strong, Weak) References
HdfR     nd nd
Evolutionary Family: LysR
Connectivity class: Local Regulator
Gene name: hdfR
  Genome position: 3947128-3947967
  Length: 840 bp / 279 aa
Operon name: hdfR
TU(s) encoding the TF:
Transcription unit        Promoter

Regulated gene(s) flhC, flhD, gltB, gltD, gltF
Multifun term(s) of regulated gene(s) MultiFun Term (List of genes associated to the multifun term)
operon (3)
flagellum (2)
Transcription related (2)
activator (2)
repressor (2)
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Regulated operon(s) flhDC, gltBDF
First gene in the operon(s) flhD, gltB
Simple and complex regulons AdiY,ArgR,CRP,FNR,Fur,GadE,HdfR,IHF,Lrp,Nac
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
  HdfR repressor flhDp Sigma70 nd nd flhD, flhC nd nd [BPP], [GEA] [1]
  HdfR activator gltBp Sigma70 nd nd gltB, gltD, gltF nd nd [BPP] [2]

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


 [BPP] Binding of purified proteins

 [GEA] Gene expression analysis


 [1] Ko M., Park C., 2000, H-NS-Dependent regulation of flagellar synthesis is mediated by a LysR family protein., J Bacteriol. 182(16):4670-2

 [2] Krin E., Danchin A., Soutourina O., 2010, Decrypting the H-NS-dependent regulatory cascade of acid stress resistance in Escherichia coli., BMC Microbiol. 10:273

 [3] Schell MA., 1993, Molecular biology of the LysR family of transcriptional regulators., Annu Rev Microbiol. 47:597-626

 [4] Knapp GS., Hu JC., 2010, Specificity of the E. coli LysR-type transcriptional regulators., PLoS One. 5(12):e15189