Figure 5

Pathways of global genome nuclear excision repair (GG-NER) and transcription-coupled nuclear excision repair (TC-NER). Cancer genes involved in the two subpathways as documented in 'cancer gene census' are marked by red stars. In GG-NER, damage, such as ultraviolet-induced cyclobutane pyrimidine dimers (CPD) or 6-4 photoproducts (6-4 PP), is recognized by proteins, including the XPE (DDB2) and XPC gene products. In TC-NER, the lesion appears to block the progress of RNA polymerase II in a process involving the CSA and CSB gene products. Following initial damage recognition, the two subpathways converge. The XPB (ERCC3) and XPD (ERCC2) helicases unwind the region surrounding the lesion, along with the XPA and XPG (ERCC5) gene products and replication protein A (RPA). (The graph was obtained from the KEGG Pathway database [52], and only part of it is shown here.)