Figure 3

Schematic illustration of TS-HR. In E. coli, linear DNA was digested by the Redα 5'→3' exonuclease, resulting in the generation of 3' single-stranded tails. Homologous recombination of the V gene strands and the TS-vector, which is mediated by the long overlapping sequences (~50 bp), proceeds by 3' end extension from P1 and P2 (route I). However, homologous recombination of the mock DNA strands and the TS-vector is inefficient because of their short overlapping sequences (route III). Homologous recombination of the TS-vector and the V gene, which is mediated through the long overlapping sequences (~50 bp), proceeds by 3' end extension from VT1 and VT2 (route II). However, homologous recombination of the TS vector and the mock DNA does not occur because strand extension from VT1 and VT2 is blocked by 3' end mismatches (route IV).