FIG. 6.

RT-PCR analysis of the effect of disruptions in rteA and rteB on transcription of rteC. Transcription of rteC from strain BT4007 was determined from RNA preparations made from cells grown with tetracycline (Tc) or without Tc (+Tc and-Tc, respectively) are shown in the first two sets of lanes. Reactions in which reverse transcriptase was added or not (+ or −, respectively) are also shown. Note that mRNA is detected both in cells grown with and without Tc because regulation of the tetQ-rteA-rteB operon, which controls expression of rteC, is at the level of translation rather than transcription (37). The third and fourth sets of lanes show the effect of insertions in tetQ (ΩtetQ) or rteA (ΩrteA) on mRNA from cells grown in the absence of Tc. Both of these insertions are polar on rteB, which is part of the tetQ-rteA-rteB operon. The expected location of the 670-bp rteC product is indicated by an arrow at the right.