FIG. 7.

Model of lesion bypass mutagenic repair of MMC DNA interstrand cross-links. The first incision step places two nicks on the same strand, flanking the cross-linked base. The gap structure is created by the unwinding of the incised oligonucleotide and subsequently filled in by Pol η and other lesion bypass polymerases. Misincorporation likely occurs when DNA synthesis passes the still cross-linked base. Subsequently, the remaining lesion is repaired by a second round of regular NER reaction. Arrows indicate incisions. Diamonds indicate the positions of potential misincorporations, and dark lines depict repair synthesis patches.