FIG. 2.

DNA template for in vitro transcription. bp 1 to 27 are from the multiple cloning site of plasmid pBluescript II SK(−) (Stratagene), bp 28 to 135 are from the BamHI fragment containing the short carAB P1 promoter region (see “DNA preparations and site-directed mutagenesis” in Materials and Methods), and bp 136 to 207 are from a PCR-generated DNA that contains the pyrBI attenuator (att). A transcript initiated at promoter P1 and terminated at the end of the pyrBI attenuator contains 96 nucleotides.