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Complementation between polymerase- and exonuclease-deficient mitochondrial DNA polymerase mutants in genomically engineered flies

Lookup NU author(s): Dr Jim StewartORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Replication errors are the main cause of mitochondrial DNA (mtDNA) mutations and a compelling approach to decrease mutation levels would therefore be to increase the fidelity of the catalytic subunit (POLγA) of the mtDNA polymerase. Here we genomically engineer the tamas locus, encoding fly POLγA, and introduce alleles expressing exonuclease- (exo) and polymerase-deficient (pol) POLγA versions. The exo mutant leads to accumulation of point mutations and linear deletions of mtDNA, whereas pol mutants cause mtDNA depletion. The mutant tamas alleles are developmentally lethal but can complement each other in trans resulting in viable flies with clonally expanded mtDNA mutations. Reconstitution of human mtDNA replication in vitro confirms that replication is a highly dynamic process where POLγA goes on and off the template to allow complementation during proofreading and elongation. The created fly models are valuable tools to study germ line transmission of mtDNA and the pathophysiology of POLγA mutation disease.

Publication metadata

Author(s): Bratic A, Kauppila TES, Macao B, Grönke S, Siibak T, Stewart JB, Baggio F, Dols J, Partridge L, Falkenberg M, Wredenberg A, Larsson NG

Publication type: Article

Publication status: Published

Journal: Nature Communications

Year: 2015

Volume: 6

Online publication date: 10/11/2015

Acceptance date: 06/10/2015

Date deposited: 21/12/2020

ISSN (electronic): 2041-1723

Publisher: Nature Research


DOI: 10.1038/ncomms9808

PubMed id: 26554610


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