Figure 3.

In vivo homologous recombination experiments. (A) Homologous recombination when scFv 1 has 3′ homology to the display vector and scFv 2 has 5′ homology to the display vector. (B) Homologous recombination when scFv 1 has 5′ homology to the display vector and scFv 2 has 3′ homology to the display vector. (C) Homologous recombination when both scFv 1 and scFv 2 have 5′ and 3′ homology to the display vector. Solid lines indicate a crossover producing chimeric clones that have 5′ homology to scFv 1 and 3′ homology to scFv 2. Dashed lines indicate a crossover to produce chimeric clones with the opposite arrangement. A mixed path of one solid line crossover and one dashed line crossover without crossover between the two scFvs would produce a plasmid without a chimeric gene. (D) Homologous recombination when scFv 1 has 3′ homology to the display vector and scFv 2 is not present. This recombination occurs between the (gly4ser)₃ linker that joins the scFv heavy and light chains and the (gly4ser)₃ linker located immediately 5′ to the the ultimate location of the gene in the display plasmid.