Endonuclease which resolves Holliday junctions by the introduction of symmetrically related cuts across the junction point, to produce nicked duplex products in which the nicks can be readily ligated. Four-way DNA intermediates, also known as Holliday junctions, are formed during homologous recombination and DNA repair, and their resolution is necessary for proper chromosome segregation. Involved in DNA-damage repair in vegetative cells. Predominantly nuclear in G1-arrested cells, but cytoplasmically localized after release from G1 arrest. Present with 131 molecules/cell in log phase SD medium. Belongs to the XPG/RAD2 endonuclease family. GEN subfamily.