FIG. 2.

Effects of amino acid substitutions in sigH on spoIIA, citGp2, and spoVG promoter activities. B. subtilis JH642 (wild-type sigH) (circles), EUC97Q1 (sigHQ201A) (squares), and EUC97R1 (sigHR205A) (triangles) containing the spoIIA (A), citGp2 (B), or spoVG (C) promoter-lacZ fusions were grown in DSM liquid medium. Samples were taken from cultures growing at mid-log phase (T1), at the end of exponential growth (T0), and at 1-h intervals after the onset of stationary phase (T1 to T4) and were then assayed for β-galactosidase (βgal) activity (11). An independent transductant from each strain was assayed for β-galactosidase activity and found to express essentially the same levels of activity as those shown (data not shown).