RegulonDB RegulonDB 9.3:Regulon Page

LeuO DNA-binding transcriptional dual regulator

Synonyms: LeuO
LeuO is a dual transcriptional regulator that regulates genes involved in leucine biosynthesis [9, 12], genes involved in the utilization of certain β-glucosides [1, 2] and genes encoding LuxR-type transcription factors [11] It is also involved in the bacterial stringent response [13].
LeuO is one of the transcription factors that counteracts H-NS-mediated repression of specific loci [1, 2, 9, 14, 15] Overproduction of LeuO causes the phenotype Bgl+, since LeuO can unsilence the bglGFB operon, which is silenced (phenotypically Bgl ) under laboratory conditions [2]
LeuO is part of the RpoS/H-NS/Hfq/LeuO/DsrA RNA regulatory cascade that controls the bglGFH operon [1]and translation of rpoS, particularly at low temperatures [16, 17].
LeuO belongs to the LysR transcriptional regulator family and contains a helix-turn-helix DNA-binding domain [2, 18] No LeuO consensus binding sequence is known [11].
LeuO activates transcription of the divergent leuLABCD operon [8].
An in vivo genetic selection (SELEX) and phenotype microarray analysis revealed several multidrug resistance genes as targets for LeuO, including acrEF, ygcLKJIH-ygbTF, and mdtNOP (sdsRQP).
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Transcription factor      
TF conformation(s):
Name Conformation Type TF-Effector Interaction Type Apo/Holo Conformation Evidence (Confirmed, Strong, Weak) References
LeuO     nd nd
Evolutionary Family: LysR
Sensing class: Using internal synthesized signals
Connectivity class: Local Regulator
Gene name: leuO
  Genome position: 84368-85312
  Length: 945 bp / 314 aa
Operon name: leuO
TU(s) encoding the TF:
Transcription unit        Promoter

Regulated gene(s) bglB, bglF, bglG, bglJ, cadC, cas1, cas2, casA, casB, casC, casD, casE, dsrA, leuA, leuB, leuC, leuD, leuL, leuO, yjjQ
Multifun term(s) of regulated gene(s) MultiFun Term (List of genes associated to the multifun term)
defense/survival (7)
leucine (6)
carbon compounds (4)
Transcription related (4)
activator (4)
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Regulated operon(s) bglGFB, cadC, casABCDE12, dsrA, leuLABCD, leuO, yjjQ-bglJ
First gene in the operon(s) bglG, bglG, cadC, casA, dsrA, leuL, leuL, leuO, leuO, yjjQ
Simple and complex regulons CRP,Fis,H-NS,LeuO,RcsB-BglJ,StpA
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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
  LeuO activator bglGp nd -149.0 -279.0 bglG, bglF, bglB
3906836 3906856 [BPP], [GEA], [IC] [1], [2], [3]
  LeuO activator bglGp nd -118.0 -248.0 bglG, bglF, bglB
3906805 3906825 [BPP], [GEA], [IC] [1], [2], [3]
  LeuO repressor cadCp Sigma70 nd nd cadC nd nd [GEA] [4]
  LeuO activator casp Sigma70 -110.0 -291.0 casA, casB, casC, casD, casE, cas1, cas2
2884419 2884439 [BPP], [GEA], [IC] [5], [6]
  LeuO activator casp Sigma70 -80.0 -261.0 casA, casB, casC, casD, casE, cas1, cas2
2884389 2884409 [BPP], [GEA], [IC] [5], [6]
  LeuO activator casp Sigma70 21.0 -161.0 casA, casB, casC, casD, casE, cas1, cas2
2884289 2884309 [BPP], [GEA], [IC] [5], [6]
  LeuO activator casp Sigma70 47.0 -135.0 casA, casB, casC, casD, casE, cas1, cas2
2884263 2884283 [BPP], [GEA], [IC] [5], [6]
  LeuO repressor dsrAp Sigma70 nd nd dsrA nd nd [GEA] [7]
  LeuO activator leuLp Sigma70 nd nd leuL, leuA, leuB, leuC, leuD nd nd [GEA] [8]
  LeuO activator leuOp Sigma70 -56.0 -236.0 leuO
84122 84142 [BPP], [GEA], [IC] [9], [10]
  LeuO dual leuOp2 nd -280.0 -344.0 leuO
84014 84034 [BPP], [GEA], [IC] [10]
  LeuO dual leuOp2 nd -254.0 -318.0 leuO
84040 84060 [BPP], [GEA], [IC] [10]
  LeuO dual leuOp2 nd -195.0 -259.0 leuO
84099 84119 [BPP], [GEA], [IC] [10]
  LeuO dual leuOp2 nd -172.0 -236.0 leuO
84122 84142 [BPP], [GEA] [9], [10]
  LeuO activator yjjQp Sigma70 nd nd yjjQ, bglJ nd nd [BPP] [11]

Alignment and PSSM for LeuO TFBSs    

Aligned TFBS of LeuO   

Position weight matrix (PWM).   
A	4	5	4	6	9	1	0	2	7	0	2	3	1	8	2	3	5	8	0
C	1	0	2	0	1	0	1	8	0	4	2	0	0	0	1	1	0	0	0
G	1	0	1	0	0	0	0	0	1	0	4	5	3	1	1	2	1	2	0
T	4	5	3	4	0	9	9	0	2	6	2	2	6	1	6	4	4	0	10

PWM logo   


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


 [BPP] Binding of purified proteins

 [GEA] Gene expression analysis

 [IC] Inferred by curator


 [1] Madhusudan S., Paukner A., Klingen Y., Schnetz K., 2005, Independent regulation of H-NS-mediated silencing of the bgl operon at two levels: upstream by BglJ and LeuO and downstream by DnaKJ., Microbiology. 151(Pt 10):3349-59

 [2] Ueguchi C., Ohta T., Seto C., Suzuki T., Mizuno T., 1998, The leuO gene product has a latent ability to relieve bgl silencing in Escherichia coli., J Bacteriol. 180(1):190-3

 [3] Venkatesh GR., Kembou Koungni FC., Paukner A., Stratmann T., Blissenbach B., Schnetz K., 2010, BglJ-RcsB heterodimers relieve repression of the Escherichia coli bgl operon by H-NS., J Bacteriol. 192(24):6456-64

 [4] Shi X., Bennett GN., 1995, Effects of multicopy LeuO on the expression of the acid-inducible lysine decarboxylase gene in Escherichia coli., J Bacteriol. 177(3):810-4

 [5] Arslan Z., Stratmann T., Wurm R., Wagner R., Schnetz K., Pul U., 2013, RcsB-BglJ-mediated activation of Cascade operon does not induce the maturation of CRISPR RNAs in E. coli K12., RNA Biol. 10(5)

 [6] Westra ER., Pul U., Heidrich N., Jore MM., Lundgren M., Stratmann T., Wurm R., Raine A., Mescher M., Van Heereveld L., Mastop M., Wagner EG., Schnetz K., Van Der Oost J., Wagner R., Brouns SJ., 2010, H-NS-mediated repression of CRISPR-based immunity in Escherichia coli K12 can be relieved by the transcription activator LeuO., Mol Microbiol. 77(6):1380-93

 [7] Repoila F., Gottesman S., 2001, Signal transduction cascade for regulation of RpoS: temperature regulation of DsrA., J Bacteriol. 183(13):4012-23

 [8] Chen CC., Fang M., Majumder A., Wu HY., 2001, A 72-base pair AT-rich DNA sequence element functions as a bacterial gene silencer., J Biol Chem. 276(12):9478-85

 [9] Chen CC., Chou MY., Huang CH., Majumder A., Wu HY., 2005, A cis-spreading nucleoprotein filament is responsible for the gene silencing activity found in the promoter relay mechanism., J Biol Chem. 280(6):5101-12

 [10] Stratmann T., Pul ¿¿., Wurm R., Wagner R., Schnetz K., 2012, RcsB-BglJ activates the Escherichia coli leuO gene, encoding an H-NS antagonist and pleiotropic regulator of virulence determinants., Mol Microbiol. 83(6):1109-23

 [11] Stratmann T., Madhusudan S., Schnetz K., 2008, Regulation of the yjjQ-bglJ operon, encoding LuxR-type transcription factors, and the divergent yjjP gene by H-NS and LeuO., J Bacteriol. 190(3):926-35

 [12] Hertzberg KM., Gemmill R., Jones J., Calvo JM., 1980, Cloning of an EcoRI-generated fragment of the leucine operon of Salmonella typhimurium., Gene. 8(2):135-52

 [13] Majumder A., Fang M., Tsai KJ., Ueguchi C., Mizuno T., Wu HY., 2001, LeuO expression in response to starvation for branched-chain amino acids., J Biol Chem. 276(22):19046-51

 [14] Shimada T., Bridier A., Briandet R., Ishihama A., 2011, Novel roles of LeuO in transcription regulation of E.¿¿¿coli genome: antagonistic interplay with the universal silencer H-NS., Mol Microbiol. 82(2):378-97

 [15] Dillon SC., Espinosa E., Hokamp K., Ussery DW., Casadesus J., Dorman CJ., 2012, LeuO is a global regulator of gene expression in Salmonella enterica serovar Typhimurium., Mol Microbiol. 85(6):1072-89

 [16] Klauck E., Bohringer J., Hengge-Aronis R., 1997, The LysR-like regulator LeuO in Escherichia coli is involved in the translational regulation of rpoS by affecting the expression of the small regulatory DsrA-RNA., Mol Microbiol. 25(3):559-69

 [17] Repoila F., Gottesman S., 2003, Temperature sensing by the dsrA promoter., J Bacteriol. 185(22):6609-14

 [18] Henikoff S., Haughn GW., Calvo JM., Wallace JC., 1988, A large family of bacterial activator proteins., Proc Natl Acad Sci U S A. 85(18):6602-6

 [19] Shimada T., Yamamoto K., Ishihama A., 2009, Involvement of the leucine response transcription factor LeuO in regulation of the genes for sulfa drug efflux., J Bacteriol. 191(14):4562-71