Factor involved in transcription-coupled nucleotide excision repair (TC-NER), a mechanism that rapidly removes RNA polymerase II-blocking lesions from the transcribed strand of active genes (PubMed:22466610, PubMed:22466611, PubMed:22466612). Facilitates the ubiquitination of the elongating form of RNA polymerase II (RNA pol IIo) at DNA damage sites, thereby promoting RNA pol IIo backtracking and access by the TC-NER machinery to lesion sites (PubMed:22466611, PubMed:32142649). Acts by promoting stabilization of ERCC6 by recruiting deubiquitinating enzyme USP7 to TC-NER complexes, preventing UV-induced degradation of ERCC6 by the proteasome (PubMed:22466611, PubMed:22466612). Also facilitates transfer of TFIIH to RNA polymerase II (PubMed:32142649). Not involved in processing oxidative damage (PubMed:22466612).
