Rapid and random turnover of mitochondrial DNA in rat hepatocytes of primary culture

Yoichiro Kai, Chihiro Takamatsu, Kentaro Tokuda, Mayumi Okamoto, Kazuo Irita, Shosuke Takahashi

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)


It is known that mitochondrial DNA (mtDNA) replication is independent of the cell cycle. Even in post-mitotic cells in which nuclear DNA replication has ceased, mtDNA is believed to still be replicating. Here, we investigated the turnover rate of mtDNA in primary rat hepatocytes, which are quiescent cells. Southwestern blot analysis using 5-bromo-2′-deoxyuridine (BrdU) was employed to estimate the activity of full-length mtDNA replication and to determine efficient doses of replication inhibitors. Southern blot analysis showed that a two-day treatment with 20 mM 2′,3′-dideoxycytidine and 0.2 μg/ml ethidium bromide caused a 37% reduction in the amount of mtDNA, indicating that the hepatocytes had a considerably high rate of turnover of mtDNA. Further, pulse-chase analysis using Southwestern analysis showed that the amount of newly synthesized mtDNA labeled with BrdU declined to 60% of the basal level within two days. Because the rate of reduction of the new mtDNA was very similar to the overall turnover rate described above, it appears that degrading mtDNA molecules were randomly chosen. Thus, we demonstrated that there is highly active and random turnover of mtDNA in hepatocytes.

Original languageEnglish
Pages (from-to)299-304
Number of pages6
Issue number6
Publication statusPublished - Dec 2006

All Science Journal Classification (ASJC) codes

  • Molecular Medicine
  • Molecular Biology
  • Cell Biology


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