Resolution of Holliday structures by endonuclease VII as observed in interactions with cruciform DNA.

Abstract

Exchange of genetic material during general genetic recombination is accomplished through a series of molecular events that are described in two fundamental models (Holliday 1964; Meselson and Radding 1975). An intrinsic part of each model is the formation of the Holliday structure. The structure consists of two aligned homologous double-stranded DNA molecules that, at some point, exchange strands of the same polarity. Because of branch migration, the structure can move away from its original site of formation before it is resolved into either patch or splice recombinants (Fig. 1). The existence of Holliday structures and their role in general genetic recombination has been demonstrated physically in a number of prokaryotic and eukaryotic systems (for review, see Dressler and Potter 1982). Remarkable progress has been made in understanding some of the enzymatic reactions leading to the formation of Holliday structures (West et al. 1983; for review, see Radding 1982). In contrast,...