Legend:
The nucleotide excision repair pathway involves several different disorders including xeroderma pigmentosum, Cockayne syndrome and trichothiodystrophy and at least eleven genes. After DNA damage is induced by UV, there are two routes to recognition of the damage and formation of the repair complex. In transcription-coupled repair proteins defective in Cockayne syndrome A (CSA; ERCC8) and Cockayne syndrome B (CSB; ERCC6) recognize the DNA lesion where transcription may be stalled. In global genomic repair, the XPC and HR23 proteins recognize the lesions with a possible role for XPE. A complex including TFIIH is formed at the lesion and the two helicases XPB and XPD unwind the DNA in the neighborhood of the lesion. These XPB and XPA are also defective in most cases of trichothiodystrophy. Another component of TFIIH, TFB5 has been recently implicated in trichothiodystrophy type A. XPA may be required for recruitment of additional components to the repair complex. The endonucleases XPF/ERCC1 and XPG then cleave damaged region. The gap is subsequently filled by DNA polymerases δ and ε followed by ligation. Lastly, defects in bypass repair synthesis of UV damage are caused by DNA polymerase η and lead to the variant form of XP. The diagram was adapted from the references listed below. By clicking on the symbol for the clinical disorder or enzymatic step in the diagram or the table, the list of the samples and the mutations in these samples appears. By clicking on the Gene Symbol a list of samples with characterized mutations appears.
References:
Sancar et al. Molecular mechanisms of mammalian DNA repair and the DNA damage checkpoints. Annu. Rev. Biochem. 73:39-85 (2004).
Abstract
Costa et al. The eukaryotic nucleotide excision repair pathway. Biochimie 85: 1083-1099 (2003).
Abstract
Masters, J.R.W. and Köberle, B. Curing metastatic cancer: lessons from testicular germ-cell tumours. Nature Rev. Cancer 3: 517-525 (2003).
Abstract
Friedberg, E.C. How nucleotide excision repair protects against cancer. Nature Rev. Cancer 1: 232-33 (2001).
Abstract
|