Exonuclease of human DNA polymerase gamma disengages its strand displacement function

Quan He, Christie K. Shumate, Mark A. White, Ian J. Molineux, Y. Whitney Yin

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Pol γ, the only DNA polymerase found in human mitochondria, functions in both mtDNA repair and replication. During mtDNA base-excision repair, gaps are created after damaged base excision. Here we show that Pol γ efficiently gap-fills except when the gap is only a single nucleotide. Although wild-type Pol γ has very limited ability for strand displacement DNA synthesis, exo- (3'-5' exonuclease-deficient) Pol γ has significantly high activity and rapidly unwinds downstream DNA, synthesizing DNA at a rate comparable to that of the wild-type enzyme on a primer-template. The catalytic subunit Pol γA alone, even when exo-, is unable to synthesize by strand displacement, making this the only known reaction of Pol γ holoenzyme that has an absolute requirement for the accessory subunit Pol γB.

Original languageEnglish (US)
Pages (from-to)592-601
Number of pages10
Issue number6
StatePublished - Nov 2013


  • DNA repair and replication
  • Molecular motor
  • Strand displacement

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology
  • Cell Biology


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