The accessory subunit of human DNA polymerase γ is required for mitochondrial DNA maintenance and is able to stabilize the catalytic subunit

Mitochondrion. 2020 Jul:53:133-139. doi: 10.1016/j.mito.2020.05.008. Epub 2020 May 26.

Abstract

Human DNA polymerase γ (POLG) is a mitochondria-specific replicative DNA polymerase consisting of a single catalytic subunit, POLGα, and a dimeric accessory subunit, POLGβ. To gain a deeper understanding of the role of POLGβ, we knocked out this protein in cultured human cybrid cells and established numerous knockout clones. POLGβ-knockout clones presented a clear phenotype of mitochondrial DNA loss, indicating that POLGβ is necessary for mitochondrial DNA replication. Moreover, POLGβ-knockout cells showed a severe decrease in POLGα levels and acute suppression of POLGβ expression efficiently down-regulated POLGα levels. These results suggest that, in addition to its role as the processivity factor of POLG, POLGβ acts as a POLGα stabilizer, an important role for POLGβ in mitochondrial DNA maintenance.

Keywords: Cybrid cells; DNA polymerase γ; Mitochondrial DNA; MtDNA replication; POLGβ.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA Polymerase gamma / chemistry
  • DNA Polymerase gamma / genetics
  • DNA Polymerase gamma / metabolism*
  • DNA, Mitochondrial / chemistry
  • DNA, Mitochondrial / genetics*
  • DNA-Directed DNA Polymerase / chemistry
  • DNA-Directed DNA Polymerase / genetics
  • DNA-Directed DNA Polymerase / metabolism*
  • Enzyme Stability
  • Gene Expression Regulation, Enzymologic
  • Gene Knockout Techniques
  • HeLa Cells
  • Humans
  • Mitochondria / genetics*
  • Phenotype

Substances

  • DNA, Mitochondrial
  • DNA Polymerase gamma
  • DNA-Directed DNA Polymerase
  • POLG protein, human
  • POLG2 protein, human