Steady-state levels of IS50 transposase mRNA in wt and hfq−cells. (A) Plasmids encoding wt or DAM-Insensitive IS50 transposase genes were transformed into wt (DBH33) or hfq− (DBH16) E. coli strains. Total RNA was isolated from five different clones grown to mid-log phase for each of the indicated strains. Primer extension reactions were multiplexed using 32P-labeled primers complimentary to IS50 transposase (primer oDH230) and lpp (primer oDH390) RNAs. The corresponding cDNAs were analyzed on a 10% sequencing gel. T1 and T2 are defined in Figure 1. Note that transcription of lpp is known to be insensitive to hfq status . (B) Summary of data in (A).