Disease relevance of abrB

• The abrB gene of Bacillus subtilis is believed to encode a repressor that controls the expression of genes involved in starvation-induced processes such as sporulation and the production of antibiotics and degradative enzymes [1].
• Expression of AbrB, a transition state regulator from Bacillus subtilis, is growth phase dependent in a manner resembling that of Fis, the nucleoid binding protein from Escherichia coli [2].
• Molecular characterization of the transition state regulator AbrB from Bacillus stearothermophilus [3].

High impact information on abrB

• These findings reinforce the hypothesis that AbrB represses gene expression through its direct interaction with the transcription initiation regions of genes under its control [1].
• AbrB protein was also observed to bind to the tycA gene within a region between the transcription start site and the tycA coding sequence as well as to a region containing the putative tycA promoter [1].
• Spo0A binds to specific DNA sequences (0A boxes), and two such boxes are found downstream of the tandem promoters for the abrB gene [4].
• The regulated expression of this operon by Spo0A-P is mediated indirectly through the transition state regulator AbrB and is manifest only during growth on solid medium [5].
• In fact, purified AbrB protein bound to a portion of the dciA promoter region, protecting it against DNase I digestion [6].

Biological context of abrB

• The abrupt reduction of abrB transcript level during the early period of the growth cycle is effected by the phosphorylated form of the response regulator Spo0p3and to a lesser extent by negative autoregulation [2].
• The dependence on the spo0A gene product could be entirely bypassed by an abrB suppressor mutation, which caused tycA-lacZ to be transcribed constitutively at all stages of growth [7].
• We hypothesize therefore that AbrB, like Fis, is a nucleoid binding protein [2].
• The global regulators AbrB, Abh, and SpoVT are paralogous proteins showing their most extensive sequence homologies in the DNA-binding amino-terminal regions (about 50 residues) [8].
• The Bacillus subtilis global transition-state regulator AbrB specifically recognizes over 60 different DNA regulatory regions of genes expressed during cellular response to suboptimal environments [9].

Associations of abrB with chemical compounds

• Expression of dciA in growing cells was also repressed independently by glucose and by a mixture of amino acids; neither of these effects was mediated by AbrB [6].

References