This entry represents a structural domain found in several DNA repair nucleases, such as Rad1, XPF and crossover junction endonucleases EME1 and Mus81 [, ]. The XPF/Rad1/Mus81-dependent nuclease family specifically cleaves branched structures generated during DNA repair, replication, and recombination, and is essential for maintaining genome stability. The nuclease domain architecture exhibits remarkable similarity to those of restriction endonucleases.
This family includes Rad10 from budding yeasts, Swi10 from fission yeasts and ERCC-1 from animals andplants. All proteins in this family for which functions are known are components in a multiprotein endonuclease complex (usually made up of Rad1 and Rad10 homologues). This complex is used primarily for nucleotide excision repair but also for some aspects of recombination repair. In budding yeast, Rad10 works as a heterodimer with Rad1, and is involved in nucleotide excision repair of DNA damaged with UV light, bulky adducts or cross-linking agents. The complex forms an endonuclease which specifically degrades single-stranded DNA [].ERCC1 and XPF (xeroderma pigmentosum group F-complementing protein) are two structure-specific endonucleases of a class of seven containing an ERCC4 domain. Together they form an obligate complex that functions primarily in nucleotide excision repair (NER), a versatile pathway able to detect and remove a variety of DNA lesions induced by UV light and environmental carcinogens, and secondarily in DNA inter-strand cross-link repair and telomere maintenance. This domain in fact binds simultaneously to both XPF and single-stranded DNA; this ternary complex explains the important role of Ercc1 in targeting its catalytic XPF partner to the NER pre-incision complex [].
