FIG 1.
(A) Physical map of the sps operon of B. subtilis. Positions of the σK and the putative σE promoter are indicated as reported previously (5). DNA regions fused to the lacZ gene of E. coli also are indicated. (B) Expression of an spsA::lacZ transcriptional fusion during sporulation in an otherwise wild-type strain (closed squares), a gerE null mutant strain (gray circles), a gerR null mutant strain (gray triangles), and a strain not producing an active sigK (open squares). (C) Expression of an spsG::lacZ transcriptional fusion in a mutant deleted of the promoter and the first gene of the sps operon (white squares) or in an otherwise wild-type (black squares) strain. Samples were collected at various times after the onset of sporulation. Enzyme activity is expressed in Miller units. Data are the means from three independent experiments performed with spores prepared independently.