Mitochondrial respiration protects against oxygen-associated DNA damage

Ho Joong Sung, Wenzhe Ma, Ping Yuan Wang, James Hynes, Tomas C. O'Riordan, Christian A. Combs, J. Philip McCoy, Fred Bunz, Ju Gyeong Kang, Paul M. Hwang

Research output: Contribution to journalArticlepeer-review

74 Scopus citations


Oxygen is not only required for oxidative phosphorylation but also serves as the essential substrate for the formation of reactive oxygen species (ROS), which is implicated in ageing and tumorigenesis. Although the mitochondrion is known for its bioenergetic function, the symbiotic theory originally proposed that it provided protection against the toxicity of increasing oxygen in the primordial atmosphere. Using human cells lacking Synthesis of Cytochrome c Oxidase 2 (SCO2-/-), we have tested the oxygen toxicity hypothesis. These cells are oxidative phosphorylation defective and glycolysis dependent; they exhibit increased viability under hypoxia and feature an inverted growth response to oxygen compared with wild-type cells. SCO2-/- cells have increased intracellular oxygen and nicotinamide adenine dinucleotide (NADH) levels, which result in increased ROS and oxidative DNA damage. Using this isogenic cell line, we have revealed the genotoxicity of ambient oxygen. Our study highlights the importance of mitochondrial respiration both for bioenergetic benefits and for maintaining genomic stability in an oxygen-rich environment.

Original languageEnglish (US)
Article number5
JournalNature communications
Issue number1
StatePublished - 2010

ASJC Scopus subject areas

  • General Chemistry
  • General Biochemistry, Genetics and Molecular Biology
  • General Physics and Astronomy


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