FIG. 9.

Demonstration of the expression of abm gene clusters as operons. RT-PCR was performed using primers derived from the 3′ part of one gene (forward primer) and the 5′ part of the following gene (reverse primer), or from intergenic regions between two ORFs. Most of the primers were derived from sequences that were identical in the two gene clusters. The amplified PCR products included the intergenic regions between two ORFs and therefore demonstrate their coordinated transcription into one mRNA product. Positions of the fragments are shown in Fig. 2. Lanes 1 and 12, molecular standards; lane 2, abmA/B(I); lane 3, abmA/B(II); lane 4, abmB/C; lane 5, abmB/D(I); lane 6, abmD/interEF(II); lane 7, interEF/interFG(II); lane 8, abmF/G; lane 9, abmG/H; lane 10, negative control, as indicated in Fig. 2 (nc); lane 11, negative control, without cDNA.