Genes rcsC and rcsB form a two-component system in which rcsC encodes the sensor element and rcsB the regulator. In Escherichia coli, the system positively regulates the expression of the capsule operon, cps, and of the cell division gene ftsZ. We report the identification of the promoter and of the sequences required for rcsB-dependent stimulation of ftsZ expression. The promoter, ftsA1p, located in the ftsQ coding sequence, co-regulates ftsA and ftsZ. The sequences required for rcsB activity are immediately adjacent to this promoter.