FIG. 2.

In vitro transcription of candidate C. trachomatis T3S promoters. (A) Transcription of 10 candidate promoters with chlamydial σ⁶⁶ RNA polymerase. The promoter for each operon is indicated by the name or the open reading frame number of its first gene. The promoters for the CT663, CT665, and CT863 operons are abbreviated as 663, 665, and 863, respectively. (B) Three late T3S promoters were not transcribed by chlamydial σ²⁸ RNA polymerase. The hctB promoter is a known σ²⁸-regulated promoter that was used as a positive control (33).