Xeroderma Pigmentosum, Complementation Group B (XPB)

The human genes correcting the rodent repair defects are termed excision-repair cross-complementing or ERCC genes. A number appended to the symbol refers to the rodent complementary group that is corrected by the human gene. The human ERCC3 gene product specifically corrects the defect in an early step of the DNA nucleotide excision-repair (NER) pathway of UV-sensitive rodent mutants of complementation group 3. See also ERCC1, ERCC2, ERCC4, ERCC5, and ERCC6, as well as the XRCC1 gene that corrects the x-ray sensitivity of the CHO mutant cell line EM-9. 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 kDa subunit of basal transcription factor 2 (TFIIH) and thus functions in class II transcription.