Behavior of a cross-linked attachment site: testing the role of branch migration in site-specific recombination.
Integrative recombination of bacteriophage lambda requires perfect homology between partners over a short segment of DNA, the overlap region, that separates the positions of top and bottom strand exchange. We constructed a specific cross-link between complementary strands in the overlap region of one partner, using a method designed to introduce minimal distortion of DNA. The modified attachment site could initiate recombination, forming a Holliday junction, but could not resolve this junction so as to complete the recombination. This demonstrates that the ability of complementary base-pairs to dissociate is important for overlap region function and strongly supports the view that branch migration across this region is the way homology is sensed during integrative recombination.
Cowart
M
M
Department of Chemistry, Pennsylvania State University, University Park 16802.
Benkovic
S J
SJ
Nash
H A
HA
D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism; D010582:Bacteriophage lambda / Q000235:genetics*; D001482:Base Composition; D001483:Base Sequence; D001665:Binding Sites; D004278:DNA, Superhelical / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D034982:Integration Host Factors; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010957:Plasmids; D011995:Recombination, Genetic
D001426:Bacterial Proteins; D004278:DNA, Superhelical; D004279:DNA, Viral; D034982:Integration Host Factors