Flap endonuclease GEN homolog 1 (Gen1)

Endonuclease which resolves Holliday junctions (HJs) from the introduction of symmetrically related cuts throughout the intersection point, to produce nicked duplex products in which the nicks can be readily ligated. Four-way DNA intermediates, also called Holliday junctions, are formed through homologous recombination and DNA repair, and their resolution is necessary for proper chromosome segregation.

Cleaves HJs by a nick and counter-nick mechanism involving double coordinated incisions that lead to the formation of ligatable nicked duplex solutions. Cleavage of the first strand is rate limiting, while second strand cleavage is rapid.