FIG. 7.

Model for nucleotide excision repair with nucleosomal substrate. Damage in the nucleosome is recognized by XPA and RPA. The binding of XPC and TFIIH leads to open-complex formation. Brackets indicate that there might be nucleosome disassembly or movement at this stage although direct experimental evidence for these events is lacking. XPG and XPF-ERCC1 are recruited to the complex, and XPC leaves the complex. The damage-containing oligonucleotide is excised by dual incision mediated by XPG and XPF-ERCC1. Repair synthesis, ligation, and nucleosome reassembly occur in a coupled series of reactions (2, 42). Circle, histone; asterisk, DNA damage; gray half-arrow, repair synthesis.