Predicted to enable 3' overhang single-stranded DNA endodeoxyribonuclease activity. Involved in double-strand break repair via homologous recombination and double-strand break repair via nonhomologous end joining. Is expressed in brain. Human ortholog(s) of this gene implicated in Lynch syndrome and mismatch repair cancer syndrome. Orthologous to human ASTE1 (asteroid homolog 1).