Resolution of synthetic Holliday structures by an extract of human cells.
Virtually all models for recombination between homologous DNA sequences invoke a branched intermediate known as a Holliday structure. The terminal steps of recombination are postulated to involve a specific cleavage through the four-way junction of a Holliday structure, in a process known as resolution. We have constructed a synthetic Holliday structure in which the position of the junction of the DNA duplexes can branch migrate through approximately 185 bp. Using this structure, we have found that a component of a cytoplasmic extract of Hela cells is capable of cleaving the central junction of the substrate in a manner consistent with resolution. The activity requires a divalent cation but does not require an exogenous energy source. This is the first reported resolution activity from a mammalian source.
Waldman
A S
AS
Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06510.
Liskay
R M
RM
D002467:Cell Nucleus / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004247:DNA / Q000235:genetics*; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D008957:Models, Genetic; D009838:Oligodeoxyribonucleotides / Q000378:metabolism; D011995:Recombination, Genetic
D009838:Oligodeoxyribonucleotides; D004247:DNA