FIG. 2.

Expression of actII-ORF4 mRNA in J1501 (abs⁺), C542 (absA), C120 (absB), and C430 (absA disruption). RNA was isolated from PGA plate-grown cultures at the times indicated and used for S1 nuclease protection analyses. The size markers (SM) used were as described in the legend to Fig. 1. The probes used for actII-ORF4 and glk were the same as for Fig. 1. “FLP actII-ORF4” indicates the position of full-length probe; transcriptional readthrough from the upstream promoter for actII-ORF3 likely contributes to the signal as well (19, 25). This signal intensity varied from experiment to experiment but, when present, followed the same kinetics as the labeled actII-ORF4.