<i>pvcA-D</i> gene cluster constitutes an operon in MPAO1.

<p>Confirmation that the <i>pvcA-D</i> gene cluster constitutes an operon was accomplished through a series of RT-PCR experiments using primers that correspond to regions within adjacent genes. <b>A.</b> Order and direction of transcription of <i>pvcABCD</i> on the MPAO1 chromosome is indicated by block arrows. The intergenic region between each pair of genes is shown above and the location of the primers for each pair of genes is marked by the inward-facing arrows below: (1) <i>pvcC-pvcD,</i> solid; (2) <i>pvcB-pvcC</i>, dashed; (3) <i>pvcA-pvcB</i>, dotted. Sizes of the expected products are indicated below the primer locations. <b>B.</b> RNA from MPAO1 grown in LB broth for 16 h was obtained, processed, and reverse transcribed to produce cDNA as described in Materials and Methods. PCR reactions using each pair of primers were run and the products separated on a 1% (w/v) agarose gel and stained with ethidium bromide. (1) 324-bp product from <i>pvcC-pvcD</i>; (2) 556-bp product from <i>pvcB-pvcC</i>; (3) 463-bp product from <i>pvcA-pvcB</i>; (NT) no cDNA template control (Std) molecular size standard.