Figure 2.

Recombination by φC31 integrase between attP and attB sites in E. coli DH5α recA⁻. (a) Restriction maps of plasmids used and expected recombinant products. E. coli containing pHS33 and pHS34 encode attP and attB, respectively, and express the φC31 int gene from the tac promoter located within the vector sequences; the vector in each case is a λ defective plasmid, pZMR100. The attB (i) and attP (ii) sites have been placed on compatible plasmids. (b) Restriction analysis by SphI of parental and recombinant products after extraction of plasmid DNA from E. coli. Bands containing recombination products attL and attR are indicated by arrows. In lane 6 the recombinant fragments migrate close together but can be resolved after a longer electrophoresis. In lane 8 the attL recombinant product and linearized pHS34 comigrate. Molecular weight markers (M) are provided by 0.5 μg of 1-kbp ladder (Life Technologies).