Fig. 5.
A secretin that does not multimerize has no impact on the Psp system.
A. PilQ production is not toxic in Y. enterocolitica psp+ or psp null strains. psp+ (AJD3) and Δpsp (AJD1171) strains containing pVLT35 (− PilQ) or pAJD1806 (+ PilQ) were grown in medium containing 1 mM IPTG. Optical density was measured hourly. B. Anti-His6 (for PilQ-His6) immunoblot analysis of cells grown as in panel A and harvested at the 4 h time point. Ponceau S stain of the PilQ monomer region of the nitrocellulose membrane is shown as a loading control. The region corresponding to the top of the original 4-12% polyacrylamide gradient gel is indicated (any secretin multimers would be slightly below the top). C. PilQ does not induce the Psp response. Φ(pspA-lacZ) operon fusion expression in psp+ strain AJD977 containing pVLT35 (− PilQ) or pAJD1806 (+ PilQ) grown with 1mM IPTG. Error bars represent one positive standard deviation