FIG. 1.

Mapping the transcription start sites of the selected Salmonella serovar Typhimurium pag genes. Primer extension products were generated after reverse transcription of total RNA isolated from mid-exponential-phase 14028s (wild-type) or MS7953s (phoP) cells grown in N-minimal medium, pH 7.5, with 8 μM MgCl₂. As negative control, a primer extension reaction was carried out without addition of RNA (−). The primer extension products were run on a 6% polyacrylamide sequencing gel against dideoxy sequencing reactions primed with the same primer. The sequences spanning the transcription start sites are shown, and the transcription start sites are boldfaced.