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RelB DNA-binding transcriptional repressor

Synonyms: RelB
RelB is a DNA-binding transcriptional regulator which belongs to the ribbon-helix-helix (RHH) family of transcription factors [2]and it is an antitoxin that prevents the lethal action of the toxin [3] RelB is part of the relBE-hokD operon, which specifies a toxin-antitoxin system, and it is autoregulated by its own products, RelB and RelE [2, 3, 4] On the other hand, relE encodes a cytotoxin that is lethal or inhibitory to host cells [3] and it also encodes a cofactor that enhances the repressor activity of RelB [2, 3, 4] The relBE-hokD operon is induced upon entering nutritional starvation conditions, such as the stringent response or acid starvation [5] while the level of RelB antitoxin is reduced as a result of Lon-dependent proteolysis.
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Transcription factor      
TF conformation(s):
Name Conformation Type TF-Effector Interaction Type Apo/Holo Conformation Evidence (Confirmed, Strong, Weak) References
RelB Functional   [APPH] [1]
Evolutionary Family: RelB, RelE
Connectivity class: Local Regulator
Gene name: relB
  Genome position: 1645633-1645872
  Length: 240 bp / 79 aa
Operon name: relBE-hokD
TU(s) encoding the TF:
Transcription unit        Promoter
Gene name: relE
  Genome position: 1645346-1645633
  Length: 288 bp / 95 aa
Operon name: relBE-hokD
TU(s) encoding the TF:
Transcription unit        Promoter

Regulated gene(s) hokD, relB, relE
Multifun term(s) of regulated gene(s) MultiFun Term (List of genes associated to the multifun term)
RNA degradation (2)
translation attenuation and efficiency (2)
cell killing (2)
prophage genes and phage related functions (1)
Transcription related (1)
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Regulated operon(s) relBE-hokD
First gene in the operon(s) relB
Simple and complex regulons RelB,RelB-RelE
Simple and complex regulatory phrases Regulatory phrase (List of promoters regulated by the phrase)

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 (Confirmed, Strong, Weak) References
  RelB repressor relBp Sigma70 1.5 -30.5 relB, relE, hokD
1645897 1645908 [BPP], [GEA], [HIBSCS] [2]
  RelB repressor relBp Sigma70 13.5 -18.5 relB, relE, hokD
1645885 1645896 [BPP], [GEA], [HIBSCS] [2]

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


 [APPH] Assay of protein purified to homogeneity

 [BPP] Binding of purified proteins

 [GEA] Gene expression analysis

 [HIBSCS] Human inference based on similarity to consensus sequences


 [1] Hindermann W., Mentzel T., Katenkamp D., 1999, [Tyrosine-rich crystalloids in a myoepithelioma of the minor salivary glands in the smooth palate]., Pathologe 20(5):288-91

 [2] Li GY., Zhang Y., Inouye M., Ikura M., 2008, Structural mechanism of transcriptional autorepression of the Escherichia coli RelB/RelE antitoxin/toxin module., J Mol Biol 380(1):107-19

 [3] Gotfredsen M., Gerdes K., 1998, The Escherichia coli relBE genes belong to a new toxin-antitoxin gene family., Mol Microbiol 29(4):1065-76

 [4] Galvani C., Terry J., Ishiguro EE., 2001, Purification of the RelB and RelE proteins of Escherichia coli: RelE binds to RelB and to ribosomes., J Bacteriol 183(8):2700-3

 [5] Christensen SK., Mikkelsen M., Pedersen K., Gerdes K., 2001, RelE, a global inhibitor of translation, is activated during nutritional stress., Proc Natl Acad Sci U S A 98(25):14328-33

 [6] Overgaard M., Borch J., Gerdes K., 2009, RelB and RelE of Escherichia coli Form a Tight Complex That Represses Transcription via the Ribbon-Helix-Helix Motif in RelB., J Mol Biol

 [7] Bech FW., Jorgensen ST., Diderichsen B., Karlstrom OH., 1985, Sequence of the relB transcription unit from Escherichia coli and identification of the relB gene., EMBO J 4(4):1059-66