Analysis of aaxABC expression in C. trachomatis L2/434. Part A shows a map of the putative CTL0626-CTL0628 operon, comprising the aaxABC gene cluster. Both intragenic regions (bars 1–3 shown in red) and intergenic regions (bars A-D shown in blue) were amplified by RT-PCR. Part B shows PCR amplification products for the intergenic regions identified in part A using either cDNA, prepared from 24 h cultures of C. trachomatis L2/434, or chromosomal DNA as a template. Part C shows the PCR amplification products for the constitutively expressed hsp60 gene, using cDNA prepared from uninfected cells (mock) or C. trachomatis L2-infected cells harvested at the indicated hours post infection (hpi). Control reactions were performed using DNA (left lanes) or omitting reverse transcriptase (-RT) prior to PCR analysis. Part D shows gene-specific RT-PCR products to semi-quantitatively assess transcript levels during the course of infection. The numbered reactions correspond to the regions shown in part A. Control DNA reactions are shown in the left-hand lanes of each section, next to mock infection controls. Marker lanes (M) shows bands corresponding to 0.25, 0.50, 0.75 or 1.0 kbp DNA standards, as indicated. All PCR products were separated on 1.5% agarose electrophoresis gels and stained using ethidium bromide. The images were cropped, inverted and adjusted for contrast and brightness using Photoshop CS3 software (Adobe).