Embryonic stem cells lacking the epigenetic regulator Cfp1 are hypersensitive to DNA-damaging agents and exhibit decreased Ape1/Ref-1 protein expression and endonuclease activity

Courtney M. Tate, Melissa L. Fishel, Julianne L. Holleran, Merrill J. Egorin, David G. Skalnik

Research output: Contribution to journalArticle

3 Scopus citations


Modulation of chromatin structure plays an important role in the recruitment and function of DNA repair proteins. CXXC finger protein 1 (Cfp1), encoded by the CXXC1 gene, is essential for mammalian development and is an important regulator of chromatin structure. Murine embryonic stem (ES) cells lacking Cfp1 (CXXC1-/-) are viable but demonstrate a dramatic decrease in cytosine methylation, altered histone methylation, and an inability to differentiate. We find that ES cells lacking Cfp1 are hypersensitive to a variety of DNA-damaging agents. In addition, CXXC1-/- ES cells accumulate more DNA damage and exhibit decreased protein expression and endonuclease activity of AP endonuclease (Ape1/Ref-1), an enzyme involved in DNA base excision repair. Expression in CXXC1-/- ES cells of either the amino half of Cfp1 (amino acids 1-367) or the carboxyl half of Cfp1 (amino acids 361-656) restores normal Ape1/Ref-1 protein expression and rescues the hypersensitivity to DNA-damaging agents, demonstrating that Cfp1 contains redundant functional domains. Furthermore, retention of either the DNA-binding activity of Cfp1 or interaction with the Setd1A and Setd1B histone H3-Lys4 methyltransferase complexes is required to restore normal sensitivity of CXXC1-/- ES cells to DNA-damaging agents. These results implicate Cfp1 as a regulator of DNA repair processes.

Original languageEnglish (US)
Pages (from-to)1411-1423
Number of pages13
JournalDNA Repair
Issue number12
StatePublished - Dec 3 2009



  • Ape1/Ref-1
  • Cfp1
  • Chromatin
  • DNA damaging agents
  • Epigenetic regulation

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this