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

The regulation of abrB gene expression in Bacillus subtilis was analyzed to determine the biochemical activity of the transition state regulator AbrB during microbial growth. The levels of abrB messenger RNA (mRNA) in Bacillus subtilis increased during the lag phase and early logarithmic phase of the growth cycle of Bacillus subtilis. However, abrB mRNA was reduced to undetectable levels before the mid-exponential phase of the growth cycle. Furthermore, the maximal level of AbrB nucleoid binding protein correlated with the maximal transcript level.