Suppression of oxidative phosphorylation in mouse embryonic fibroblast cells deficient in apurinic/apyrimidinic endonuclease

Rangaswamy Suganya, Anirban Chakraborty, Sumitra Miriyala, Tapas K. Hazra, Tadahide Izumi

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


The mammalian apurinic/apyrimidinic (AP) endonuclease 1 (APE1) is an essential DNA repair/gene regulatory protein. Decrease of APE1 in cells by inducible shRNA knockdown or by conditional gene knockout caused apoptosis. Here we succeeded in establishing a unique mouse embryonic fibroblast (MEF) line expressing APE1 at a level far lower than those achieved with shRNA knockdown. The cells, named MEFla (MEFlowAPE1), were hypersensitive to methyl methanesulfonate (MMS), and showed little activity for repairing AP-sites and MMS induced DNA damage. While these results were consistent with the essential role of APE1 in repair of AP sites, the MEFla cells grew normally and the basal activation of poly(ADP-ribose) polymerases in MEFla was lower than that in the wild-type MEF (MEFwt), indicating the low DNA damage stress in MEFla under the normal growth condition. Oxidative phosphorylation activity in MEFla was lower than in MEFwt, while the glycolysis rates in MEFla were higher than in MEFwt. In addition, we observed decreased intracellular oxidative stress in MEFla. These results suggest that cells with low APE1 reversibly suppress mitochondrial respiration and thereby reduce DNA damage stress and increases the cell viability.

Original languageEnglish
Pages (from-to)40-48
Number of pages9
JournalDNA Repair
StatePublished - Mar 1 2015

Bibliographical note

Funding Information:
This study was supported by CA098664 ( NCI , T.I.) and NS073976 ( NINDS , T.K.H.) and CA53791 ( NCI , S.M.), and by the Markey Cancer Center Support Grant . The authors thank Dr. S. Mitra and his colleagues at UTMB who generously provided the research environment during the recovery from a natural disaster in 2005. The assistance by Ms. D. Montgomery and Dr. Szczesny, who also provided insight regarding the PPAR involvement, were crucial to the success of this project. We thank Drs. Mitov, Butterfield, and St. Clair for their expert consultancy in the mitochondrial respiration experiments.

Publisher Copyright:
© 2015 Elsevier B.V.


  • AP endonuclease 1
  • DNA repair
  • Endogenous DNA damage
  • Oxidative phosphorylation

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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