FIG. 2.
Effect of bypassing the phosphorelay on sigE-lacZ expression. The rvtA11 mutation was introduced into wild-type cells (PY79 [●]), sigK (spoIVCB23) mutant cells (BK556 [○]), and spoIVCBΔ19 cells that produce ςK earlier than normal (BZ48 [▵]). The resulting strains were lysogenized with phage SPβ::sigE-lacZ, and expression of lacZ during development was analyzed as described in Materials and Methods. In each of two separate experiments, the β-galactosidase specific activities were normalized to the average maximum specific activity in two or three isolates containing the rvtA11 mutation in the wild-type background (typically 70 U). Points on the graph are averages of the normalized values (five determinations), and error bars show 1 standard deviation of the data.