The UV-damaged DNA binding protein mediates efficient targeting of the nucleotide excision repair complex to UV-induced photo lesions

DNA Repair (Amst). 2005 May 2;4(5):571-82. doi: 10.1016/j.dnarep.2005.01.001.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Nucleus / radiation effects
  • DNA / genetics
  • DNA / metabolism*
  • DNA / radiation effects*
  • DNA Damage / genetics
  • DNA Damage / radiation effects*
  • DNA Repair*
  • DNA-Binding Proteins / deficiency
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Dimerization
  • Fibroblasts / drug effects
  • Fibroblasts / radiation effects
  • Humans
  • Photochemistry
  • Pyrimidine Dimers*
  • Ultraviolet Rays
  • Xeroderma Pigmentosum Group A Protein
  • Xeroderma Pigmentosum* / genetics
  • Xeroderma Pigmentosum* / metabolism
  • Xeroderma Pigmentosum* / pathology

Substances

  • DNA-Binding Proteins
  • Ddb1 protein, mouse
  • Pyrimidine Dimers
  • XPA protein, human
  • Xeroderma Pigmentosum Group A Protein
  • Xpc protein, mouse
  • pyrimidine-pyrimidone dimer
  • XPC protein, human
  • DNA