The ERCC1 and ERCC4 (XPF) genes and gene products

• ERCC1–XPF is a structure-specific nuclease in several DNA repair pathways.
• ERCC4 encodes the XPF protein which is mutated in xeroderma pigmentosum group F.
• Mutations in ERCC1 and ERCC4 cause several other inherited human syndromes.
• Inhibition of ERCC1–XPF may be valuable in cancer treatment.

The ERCC1 and ERCC4 genes encode the two subunits of the ERCC1–XPF nuclease. This enzyme plays an important role in repair of DNA damage and in maintaining genomic stability. ERCC1–XPF nuclease nicks DNA specifically at junctions between double-stranded and single-stranded DNA, when the single-strand is oriented 5′ to 3′ away from a junction. ERCC1–XPF is a core component of nucleotide excision repair and also plays a role in interstrand crosslink repair, some pathways of double-strand break repair by homologous recombination and end-joining, as a backup enzyme in base excision repair, and in telomere length regulation. In many of these activities, ERCC1–XPF complex cleaves the 3′ tails of DNA intermediates in preparation for further processing. ERCC1–XPF interacts with other proteins including XPA, RPA, SLX4 and TRF2 to perform its functions. Disruption of these interactions or direct targeting of ERCC1–XPF to decrease its DNA repair function might be a useful strategy to increase the sensitivity of cancer cells to some DNA damaging agents. Complete deletion of either ERCC1 or ERCC4 is not compatible with viability in mice or humans. However, mutations in the ERCC1 or ERCC4 genes cause a remarkable array of rare inherited human disorders. These include specific forms of xeroderma pigmentosum, Cockayne syndrome, Fanconi anemia, XFE progeria and cerebro-oculo-facio-skeletal syndrome.