Ribonucleotides incorporated by the yeast mitochondrial DNA polymerase are not repaired

• DOI: 10.1073/pnas.1713085114
• Publication Date: 2017-11-06T20:20:31Z
• Authors: Paulina H. Wanrooij; Martin K. M. Engq...; Josefin M. E. For...; Clara Navarrete; Anna Karin Nilsson; Juhan Sedman; Sjoerd Wanrooij; Anders R. Clausen; Andrei Chabes
• Keywords: Ribonucleotide

Incorporation of ribonucleotides into DNA during genome replication is a significant source genomic instability. The frequency in determined by deoxyribonucleoside triphosphate/ribonucleoside triphosphate (dNTP/rNTP) ratios, the ability polymerases to discriminate against ribonucleotides, and capacity repair mechanisms remove incorporated ribonucleotides. To simultaneously compare how nuclear mitochondrial genomes incorporate we challenged these processes changing balance cellular dNTPs. Using collection yeast strains with altered dNTP pools, discovered an inverse relationship between concentration individual dNTPs amount corresponding DNA, while ribonucleotide pattern was only absence excision repair. Our analysis uncovers major differences two provides concrete evidence that mitochondria lack for removal mtDNA polymerase. Furthermore, as cytosolic pool imbalances were transmitted equally well nucleus mitochondria, our results support view pools frequent exchange.