PROTEINS THAT PARTICIPATE IN NUCLEOTIDE EXCISION-REPAIR OF DNA IN MAMMALIAN-CELLS

The most versatile strategy for repair of damage to DNA, and the main process for repair of UV-induced damage, is nucleotide excision repair. In mammalian cells, the complete mechanism involves more than 20 polypeptides, and defects in many of these are associated with various forms of inherited disorders in humans. The syndrome xeroderma pigmentosum (XP) is associated with mutagen hypersensitivity and increased cancer frequency, and studies of the nucleotide excision repair defect in this disease have been particularly informative. Many of the XP proteins are now being characterized. XPA binds to DNA, with a preference for damaged base pairs. XPC activity is part of a protein complex with single-stranded DNA binding activity. The XPG protein is a nuclease.