The UV-damaged DNA binding protein mediates efficient targeting of the nucleotide excision repair complex to UV-induced photo lesions.
Previous studies point to the XPC-hHR23B complex as the principal initiator of global genome nucleotide excision repair (NER) pathway, responsible for the repair of UV-induced cyclobutane pyrimidine dimers (CPD) and 6-4 photoproducts (6-4PP) in human cells. However, the UV-damaged DNA binding protein (UV-DDB) has also been proposed as a damage recognition factor involved in repair of UV-photoproducts, especially CPD. Here, we show in human XP-E cells (UV-DDB deficient) that the incision complex formation at UV-induced lesions was severely diminished in locally damaged nuclear spots. Repair kinetics of CPD and 6-4PP in locally and globally UV-irradiated normal human and XP-E cells demonstrate that UV-DDB can mediate efficient targeting of XPC-hHR23B and other NER factors to 6-4PP. The data is consistent with a mechanism in which UV-DDB forms a stable complex when bound to a 6-4PP, allowing subsequent repair proteins--starting with XPC-hHR23B--to accumulate, and verify the lesion, resulting in efficient 6-4PP repair. These findings suggest that (i) UV-DDB accelerates repair of 6-4PP, and at later time points also CPD, (ii) the fraction of 6-4PP that can be bound by UV-DDB is limited due to its low cellular quantity and fast UV dependent degradation, and (iii) in the absence of UV-DDB a slow XPC-hHR23B dependent pathway is capable to repair 6-4PP, and to some extent also CPD.
Moser
Jill
J
Department of Toxicogenetics, Leiden University Medical Center, Wassenaarseweg 72, 2333 AL Leiden, The Netherlands.
Volker
Marcel
M
Kool
Hanneke
H
Alekseev
Sergei
S
Vrieling
Harry
H
Yasui
Akira
A
van Zeeland
Albert A
AA
Mullenders
Leon H F
LH
D002467:Cell Nucleus / Q000528:radiation effects; D004247:DNA / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*; D004249:DNA Damage / Q000235:genetics / Q000528:radiation effects*; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D019281:Dimerization; D005347:Fibroblasts / Q000187:drug effects / Q000528:radiation effects; D006801:Humans; D010777:Photochemistry; D011740:Pyrimidine Dimers; D014466:Ultraviolet Rays; D014983:Xeroderma Pigmentosum / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D051760:Xeroderma Pigmentosum Group A Protein
D004268:DNA-Binding Proteins; C490415:Ddb1 protein, mouse; D011740:Pyrimidine Dimers; C497314:XPA protein, human; D051760:Xeroderma Pigmentosum Group A Protein; C501002:Xpc protein, mouse; C058406:pyrimidine-pyrimidone dimer; C086984:XPC protein, human; D004247:DNA