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Exonuclease of human DNA polymerase gamma disengages its strand displacement function.

ABSTRACT: Pol ?, 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 ? efficiently gap-fills except when the gap is only a single nucleotide. Although wild-type Pol ? has very limited ability for strand displacement DNA synthesis, exo(-) (3'-5' exonuclease-deficient) Pol ? 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 ?A alone, even when exo(-), is unable to synthesize by strand displacement, making this the only known reaction of Pol ? holoenzyme that has an absolute requirement for the accessory subunit Pol ?B.

SUBMITTER: He Q

PROVIDER: S-EPMC5017585 | biostudies-literature | 2013 Nov

REPOSITORIES: biostudies-literature

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Exonuclease of human DNA polymerase gamma disengages its strand displacement function.

He Quan Q Shumate Christie K CK White Mark A MA Molineux Ian J IJ Yin Y Whitney YW

Mitochondrion 20130830 6

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 ...[more]

PMID: 23993955

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