DNA helicase and DNA-dependent ATPase; role in DNA repair and checkpoint recovery, timely commitment to meiotic recombination and the MI to MII transition; blocks trinucleotide repeat expansion; disassembles Rad51p nucleoprotein filaments during meiotic recombination; stimulates Mus81p-Mms4p endonuclease activity; delays abscission in the presence of chromatin bridges to prevent chromosome breakage during cytokinesis; ATP hydrolysis activity inhibited by Dmc1p; functional homolog of human RTEL1