MINICELL-FORMING MUTANTS OF ESCHERICHIA-COLI - SUPPRESSION OF BOTH DICB-DEPENDENT AND MIND-DEPENDENT DIVISION INHIBITION BY INACTIVATION OF THE MINC GENE-PRODUCT

We have determined the nucleotide sequence of the minB operon of 10 min mutants of Escherichia coli, characterized by impaired inhibition of polar divisions. These mutants were either sensitive or resistant to the division inhibitor DicB. All the mutations were found to lie in minC or minD, confirming the requirement of both gene products in the process of inhibition of polar sites. Mutations conferring resistance to inhibitor DicB were found exclusively in minC. In agreement with de Boer et al. (P.A.J. de Boer, R.E. Crosseley, and L.I. Rothfield, Proc. Natl. Acad. Sci. USA 87:1129-1133, 1990), these results provide evidence that, in addition to promoting division inhibition with MinD, protein MinC acts in concert with DicB to inhibit division by a second, MinD-independent process.