E2F regulates DDB2: consequences for DNA repair in Rb-deficient cells

S. Prost, P. Lu, H. Caldwell, D. Harrison

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

DDB2, a gene mutated in XPE patients, is involved in global genomic repair especially the repair of cyclobutane pyrimidine dimers (CPDs), and is regulated by p53 in human cells. We show that DDB2 is expressed in mouse tissues and demonstrate, using primary mouse epithelial cells, that mouse DDB2 is regulated by E2F transcription factors. Retinoblastoma (Rb), a tumor suppressor critical for the control of cell cycle progression, regulates E2F activity. Using Cre-Lox technology to delete Rb in primary mouse hepatocytes, we show that DDB2 gene expression increases, leading to elevated DDB2 protein levels. Furthermore, we show that endogenous E2F1 and E2F3 bind to DDB2 promoter and that treatment with E2F1-antisense or E2F1-small interfering RNA (siRNA) decreases DDB2 transcription, demonstrating that E2F1 is a transcriptional regulator for DDB2. This has consequences for global genomic repair: in Rb-null cells, where E2F activity is elevated, global DNA repair is increased and removal of CPDs is more efficient than in wild-type cells. Treatment with DDB2-siRNA decreases DDB2 expression and abolishes the repair phenotype of Rb-null cells. In summary, these results identify a new regulatory pathway for DDB2 by E2F, which does not require but is potentiated by p53, and demonstrate that DDB2 is involved in global repair in mouse epithelial cells.

Original languageEnglish
Pages (from-to)3572-3581
Number of pages10
JournalOncogene
Volume26
Issue number24
DOIs
Publication statusPublished - May 2007

Keywords

  • DDB2
  • Retinoblastoma
  • E2F
  • Transcription factor
  • Hepatocytes
  • DNA repair
  • Nucleotide excision-repair
  • Cyclobutane pyrimidine dimers
  • Binding-protein
  • In-vivo
  • Transcription factors
  • UV-irradiation
  • Gene-product
  • Mouse cells
  • Wild-type
  • p53

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