FIG. 3.

Effects of glucose, CRP, and cAMP on gapB mRNA level. (A) Primer extension reactions using total RNA extracts were conducted as described in Materials and Methods. E. coli TG1 (lanes 1 and 3), POP4129Δcrp (lanes 2 and 4), and TP2006 (cya) (lanes 5 to 8) were grown at 37°C to mid-log phase in the presence of glucose (lanes 1, 2, 5, and 6) or succinate-glycerol (lanes 3, 4, 7, and 8) as the sole carbon source. cAMP was added to TP2006 cultures at 1 mM (lanes 6 and 8). (B) E. coli TG1 cells transformed with plasmid pPBK500 (lanes 9 and 10) or pPBK500mutCRP (lanes 11 and 12) were grown in M63 medium supplemented with ampicillin and with glucose (lanes 9 and 11) or a succinate-glycerol mixture (lanes 10 and 12) as the sole carbon source. Primer extension reactions were done with 5 μg of total RNA extracts.