Figure 1.

PCR primers and strategy for modification of the merB gene. Two PCR primers were used to add synthetic flanking sequences to the merB gene that have elements necessary for bacterial and plant expression. The sense primer, MerB5′S, contained restriction endonuclease cloning sites, a TAA stop codon, bacterial (SD) and plant (PT) translation signals, an ATG start codon, and the first 18 nt of the merB coding sequence to prime the forward PCR reaction. The antisense primer, merB3′N, contained cloning sites, and 21 nt of anticodon sequence (covering the last seven merB codons) used to prime the reverse PCR reaction.