RT-PCR analysis of cidABC expression. RNA was isolated from S. aureus over a 12-h time course experiment and subjected to RT-PCR analysis using primers that detect cidABC and gyrA transcription (labeled cidABC RT+ and gyrA RT+, respectively). The time points (in hours) when RNA was collected are indicated above each lane, and the sizes of the RT-PCR products are shown to the left of the gels. Control reactions (labeled cidABC RT- and gyrA RT-), lacking RT enzyme, failed to generate RT-PCR products, indicating the absence of contaminating genomic DNA.