Linear mitochondrial DNA is rapidly degraded by components of the replication machinery

• DOI: 10.1038/s41467-018-04131-w
• Publication Date: 2018-04-24T13:27:59Z
• Authors: Viktoriya Peeva; Daniel Blei; Genevieve Trombly; Sarah Corsi; Maciej J. Szukszto; Pedro Rebelo-Guiomar; Payam A. Gammage; Alexei P. Kudin; Christian Becker; Janine Altmüller; Michal Minczuk; Gábor Zsurka; Wolfram S. Kunz
• Keywords: DNA Replication; 0301 basic medicine; Science; Recombinant Fusion Proteins; DNA, Mitochondrial; Article; Electron Transport Complex IV; 03 medical and health sciences; Humans; DNA Breaks, Double-Stranded; DNA Cleavage; Deoxyribonucleases, Type II Site-Specific; Gene Editing; 0303 health sciences; Base Sequence; Q; DNA Helicases; Genetic Therapy; DNA Polymerase gamma; Mitochondria; Exodeoxyribonucleases; HEK293 Cells; Technology Platforms; CRISPR-Cas Systems

Abstract Emerging gene therapy approaches that aim to eliminate pathogenic mutations of mitochondrial DNA (mtDNA) rely on efficient degradation linearized mtDNA, but the enzymatic machinery performing this task is presently unknown. Here, we show that, in cellular models restriction endonuclease-induced mtDNA double-strand breaks, linear eliminated within hours by exonucleolytic activities. Inactivation 5′-3′exonuclease MGME1, elimination 3′-5′exonuclease activity polymerase POLG introducing p.D274A mutation, or knockdown helicase TWNK leads severe impediment degradation. We do not observe similar effects when inactivating other known nucleases (EXOG, APEX2, ENDOG, FEN1, DNA2, MRE11, RBBP8). Our data suggest rapid performed same responsible for replication, thus proposing novel roles participating enzymes POLG, TWNK, and MGME1.