In vitro transcription of C. trachomatis rRNA P1 templates with C. trachomatis RNAP (A) or E. coli RNAP (B). The rRNA P1 templates contained the wild-type (wt) sequence (lane 1), a substitution of wild-type A at −23 with a C (lane 2), G (lane 3), or T (lane 4), or a substitution of wild-type A at −24 with a C (lane 5), G (lane 6), or T (lane 7). The shorter control transcript was transcribed by SP6 RNAP.