Seems to be involved in nucleotide excision repair (NER) of damaged DNA (dark repair mechanism). Involved in repair of UV light, and probably oxidative damage. The UVH1/RAD1-ERCC1/RAD10 complex may act as an endonuclease making DNA incision 5' to the lesion site. In vitro, is implicated in double strand breaks (DSBs) repair and is required for homologous recombination in the presence of non-homologous overhangs. May mediate the induction of a DNA-damage sensitive cell-cycle checkpoint during the G2 phase. Heterodimer with ERCC1/RAD10. Isoform 1 and isoform 2 are widely expressed, predominantly in flowers, meristems and stems. Isoform 3 is detected at low levels. Inactive. Inactive. Belongs to the XPF family.