This domain is found in AbrB from Bacillus subtilis. The product of the abrB gene is an ambiactive repressor and activator of the transcription of genes expressed during the transition state between vegetative growth and the onset of stationary phase and sporulation (PUBMED:2504584). AbrB is thought to interact directly with the transcription initiation regions of genes under its control (PUBMED:8755877). AbrB contains a helix-turn-helix structure, but this domain ends before the helix-turn-helix begins (PUBMED:1908787). The product of the B. subtilis gene spoVT is another member of this family and is also a transcriptional regulator (PUBMED:8755877). DNA-binding activity in this AbrB homologue requires hexamerisation (PUBMED:10978510). Another family member has been isolated from the Sulfolobus solfataricus and has been identified as a homologue of bacterial repressor-like proteins. The Escherichia coli family member SohA or Prl1F appears to be bifunctional and is able to regulate its own expression as well as relieve the export block imposed by high-level synthesis of beta-galactosidase hybrid proteins (PUBMED:2152898).
The SpoVT-AbrB domain is a DNA-binding domain found in a large protein superfamily [ (PUBMED:16223496) (PUBMED:15939023) ], which includes:
Bacterial antibiotic resistance protein B (AbrB), a transition-state regulator.
Bacterial SpoVT, a late sporulation factor that modulates forespore-specific sigma G-dependent transcription.
Bacterial PrlF, an antitoxin component of a toxin-antitoxin (TA) module.
Bacterial transcription factors (antitoxins) of plasmid maintenance systems (VapB, MvpT, VppA,VagC, PemI, MazE, ChpS).
Bacterial transcriptional regulator MraZ, involved in the expression of the division and cell wall (dcw) cluster. It contains two copies of the SpoVT-AbrB domain.
Bacterial endoribonuclease SymE.
Sulfolobus solfataricus repressor-like proteins SSo7c3 and SSo7c4.
The SpoVT-AbrB domain contains four beta strands and one alpha helix and can be described as a pair of beta hairpins linked by the alpha helix [ (PUBMED:16223496) (PUBMED:15939023) ].
Molecular characterization of the transition state regulator AbrB fromBacillus stearothermophilus.
Biochim Biophys Acta. 2000; 1493: 82-90
Display abstract
The Bacillus subtilis transition state regulator AbrB(su) is a DNA-bindingprotein that acts on several genes either as activator, repressor, orpreventer. However, among genes under its control, neither common bindingsites could be identified nor could the structural features of this broadand specific interaction be elucidated. Attempts to elucidate theseinteresting features by crystallizing AbrB(su) have failed so far.Therefore, to solve this problem, we focused in this work on identifyingan AbrB(su) homologue from Bacillus stearothermophilus. Using a novelmethod, the entire abrB(st) gene of B. stearothermophilus was cloned andsequenced. The gene encodes a 95 amino acid protein that shows 77%identity and 85% similarity to the mesophilic B. subtilis protein. Acalmodulin binding peptide-tagged fusion of the thermophilic gene wasconstructed for overexpression and efficient affinity column purificationof the AbrB(st) protein. The purified protein showed, after removal of thetag, an oligomerization behavior through hexamer formation that isessential for its DNA binding activity.
A compartmentalized regulator of developmental gene expression in Bacillussubtilis.
J Bacteriol. 1996; 178: 4500-7
Display abstract
We have identified a new Bacillus subtilis gene, spoVT, whose gene productis homologous to the transcriptional regulator AbrB and serves as aregulator of E sigmaG-controlled gene expression. SpoVT acts bothpositively and negatively in controlling sigmaG-dependent gene expression,providing an additional level of refinement to forespore gene regulationand feedback control of spoIIIG expression.
Mutant analysis of interaction of the Bacillus subtilis transcriptionregulator AbrB with the antibiotic biosynthesis gene tycA.
FEBS Lett. 1991; 287: 153-6
Display abstract
The AbrB protein of B. subtilis represses the transcription of variouspostexponentially expressed genes, such as the antibiotic biosynthesisgene tycA. Recently, we have shown that ArbB binds to the tycA promoterregion at two A + T-rich sites; the 'promoter site' (-60 to -35) and the'leader site' (+169 to +231). In this study we demonstrate that aPtyc-lacZ fusion missing the leader region is constitutively expressed inwild-type B. subtilis cells and in B. subtilis cells carrying spoOA orabrB mutations. We also show that substitution mutations within therecently reported potential helix-turn-helix DNA binding motif of AbrB didnot affect its specific DNA binding ability.
Increased expression of the bifunctional protein PrlF suppressesoverproduction lethality associated with exported beta-galactosidasehybrid proteins in Escherichia coli.
J Bacteriol. 1990; 172: 185-92
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We have cloned and determined the nucleotide sequence of the prlF gene. Anopen reading frame predicting a 111-amino-acid protein (Mr 12,351) with anacidic carboxy terminus was identified. The DNA sequence preceding thisopen reading frame revealed a putative promoter and a ribosome-bindingsite. The nucleotide sequence of the prlF1 mutation revealed a 7-base-pairduplication resulting in a slightly smaller predicted gene product of Mr12,009 that lacked the acidic carboxy terminus. Maxicell analysis of prlFand prlF1 subclones identified peptides of sizes similar to thosepredicted by the nucleotide sequences. The prlF sequence was shown to beexpressed in vivo by both maxicell analysis and construction of aprlF-lacZ fusion. Two kanamycin resistance insertions within the prlF openreading frame were introduced into the chromosome, replacing the wild-typegene. In contrast to the prlF1 mutation, these insertions had nodetectable effect on cell growth or on the beta-galactosidase activity ormaltose sensitivity (two sensitive indicators of hybrid protein export)conferred by the lamB-lacZ42-1 gene fusion. Overproduction of thewild-type prlF gene product from a plasmid carrying an active hybridpromoter, however, conferred a prlF1 phenotype. In addition, both theprlF1 mutation and both kanamycin resistance insertions increased thebeta-galactosidase activity of a prlF-lacZ fusion. These results suggestthat prlF is autoregulated and that overproduction of the prlF geneproduct increases the export efficiency of beta-galactosidase hybridproteins from the cytoplasm.
AbrB, a regulator of gene expression in Bacillus, interacts with thetranscription initiation regions of a sporulation gene and an antibioticbiosynthesis gene.
Proc Natl Acad Sci U S A. 1989; 86: 8457-61
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The abrB gene of Bacillus subtilis is believed to encode a repressor thatcontrols the expression of genes involved in starvation-induced processessuch as sporulation and the production of antibiotics and degradativeenzymes. Two such genes, spoVG, a sporulation gene of B. subtilis, andtycA, which encodes tyrocidine synthetase I of the tyrocidine biosyntheticpathway in Bacillus brevis, are negatively regulated by abrB in B.subtilis. To examine the role of abrB in the repression of genetranscription, the AbrB protein was purified and then tested for itsability to bind to spoVG and tycA promoter DNA. In a gel mobility shiftexperiment, AbrB was found to bind to a DNA fragment containing thesequence from -95 to +61 of spoVG. AbrB protein exhibited reduced affinityfor DNA of two mutant forms of the spoVG promoter that had been shown tobe insensitive to abrB-dependent repression in vivo. These studies showedthat an upstream A + T-rich sequence from -37 to -95 was required foroptimal AbrB binding. AbrB protein was also observed to bind to the tycAgene within a region between the transcription start site and the tycAcoding sequence as well as to a region containing the putative tycApromoter. These findings reinforce the hypothesis that AbrB represses geneexpression through its direct interaction with the transcriptioninitiation regions of genes under its control.
The transition state transcription regulator abrB of Bacillus subtilis isa DNA binding protein.
EMBO J. 1989; 8: 1615-21
Display abstract
The product of the abrB gene of Bacillus subtilis is an ambiactiverepressor and activator of the transcription of genes expressed during thetransition state between vegetative growth and the onset of stationaryphase and sporulation. Purified AbrB protein binds specifically in ahighly co-operative fashion to fragments of DNA containing the promotersit affects. DNase I footprints of the binding regions in these promotersrevealed large protected areas of 50-120 nucleotides or more depending onthe promoter. Methylation protection experiments gave protected guanineresidues on only one face of the DNA helix. A consensus sequence could bededuced around these guanine residues that was not found aroundnon-protected guanine residues in the footprint region. The resultssuggested that stationary phase functions and sporulation are repressedduring active growth by AbrB and other transition state regulators bybinding to the affected promoters in a concentration-dependent manner.
