ERCC3 is an ATP-dependent DNA helicase that functions in nucleotide excision repair and complements xeroderma pigmentosum group B mutations. It also is the 89 kD subunit of basal transcription factor 2 (TFIIH) and thus functions in class II transcription.Synonyms: BTF2-p89, Basic transcription factor 2 89 kDa subunit, DNA excision repair protein ERCC-3, DNA repair protein complementing XP-B cells, ERCC-3, TFIIH 89 kDa subunit, TFIIH basal transcription factor complex helicase XPB subunit, XPB, XPBC, Xeroderma pigmentosum group B-complementing protein