FIG. 3.

phoP1 and phoR1 are in the same operon. (a) Strategy used to study the coexpression of the two genes. (b) RT-PCR experiment. Lane 1, DNA molecular size markers VIII (Roche); the sizes in base pairs of only two of the fragments are represented. Lanes 2 to 4, PCR products obtained with primers RTP1F and RTP1R using total RNA as a template (lane 2) and cDNAs prepared with RTP1C (lane 3) and P1E3RC (lane 4). Lanes 5 and 6, PCR products obtained with primers P1E15U and P1E15R using as templates total RNA and cDNA synthesized with P1E3RC, respectively.