FIG 5.
Truncations of RsiP lead to constitutive σP activation. To determine if RasP was required for ampicillin-inducible PsigP-lacZ expression, we assayed β-galactosidase activity of B. thuringiensis with transcriptional fusion PsigP-lacZ and different rsiP truncation mutants (WT, THE2549; RsiP1–220, THE2602; RsiP1–80, THE2628; RsiP1–61, THE2637; RsiP1–16, THE2642) and a ΔrasP deletion (WT, EBT140; RsiP1–220, EBT116; RsiP1–80, EBT148; RsiP1–61, EBT133; RsiP1–16, THE2605). Cells were grown overnight at 30°C, subcultured in LB, and grown to an OD600 of ∼0.8 before being incubated with cefoxitin (5 μg/ml) for 1 h. The experiment was performed in triplicate, and standard deviations are represented by error bars.