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. 2000 Aug 1;14(15):1971–1982.

Figure 7.

Figure 7

Figure 7

Figure 7

Different RecE/RecT and Redα/Redβ recombination mechanisms revealed by different substrates. (A) Relative recombination efficiencies achieved using RecE/RecT (ET) or Redα/Redβ (βα) expression constructs in either JC5547 or JC5519 as indicated, as a function of homology region length, are shown. Linear molecules, which were generated to contain homology regions of variable length at their ends, were allowed to recombine with a prelinearized target generated by restriction digestion. Recombination efficiencies from one experiment are shown relative to the maximum recombination efficiency of B, which was set to 1. Recombination efficiencies are thus presented as relative and are not directly comparable to those shown in previous figures. The experiment was repeated twice, producing similar results. (█) 5547ET; (○) 5519ET; (●) 5547βα; (□) 5519βα. (B) Same as A, except that the target was left intact. The maximum absolute recombination efficiency found was arbitrarily set to 1, and all other recombination efficiencies were related to this maximum. Recombination efficiencies from one experiment are shown. The experiment was repeated five times, producing similar results. The experiments shown in A and B were done in parallel with the same batches of competent cells and PCR fragments. Colony numbers observed in these experiments were adjusted to relative recombination efficiencies by relating to the maximums obtained in B, which were set to 1. (█) 5547ET; (○) 5519ET; (●) 5547βα; (□) 5519βα. (C) Recombination efficiencies in the presence of the indicated expression constructs in JC5519 using two linear molecules, both of which were preresected in vitro using T7 gene six exonuclease. Data from one representative experiment is shown, in which pools of preresected molecules (which shared 400 nucleotide homology regions and were generated using six different incubation conditions with T7 gene 6 exonuclease) were recombined. C, no exogenous protein expressed; β, expression of Redβ only; βα, coexpression of Redβ and Redα; T, expression of RecT only; ET, coexpression of RecE and RecT. Recombination efficiencies are shown relative to the maximum of B.