Toggle Main Menu Toggle Search

Open Access padlockePrints

Simultaneous DNA and RNA Mapping of Somatic Mitochondrial Mutations across Diverse Human Cancers

Lookup NU author(s): Dr Jim StewartORCiD



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


Somatic mutations in the nuclear genome are required for tumor formation, but the functional consequences of somatic mitochondrial DNA (mtDNA) mutations are less understood. Here we identify somatic mtDNA mutations across 527 tumors and 14 cancer types, using an approach that takes advantage of evidence from both genomic and transcriptomic sequencing. We find that there is selective pressure against deleterious coding mutations, supporting that functional mitochondria are required in tumor cells, and also observe a strong mutational strand bias, compatible with endogenous replication-coupled errors as the major source of mutations. Interestingly, while allelic ratios in general were consistent in RNA compared to DNA, some mutations in tRNAs displayed strong allelic imbalances caused by accumulation of unprocessed tRNA precursors. The effect was explained by altered secondary structure, demonstrating that correct tRNA folding is a major determinant for processing of polycistronic mitochondrial transcripts. Additionally, the data suggest that tRNA clusters are preferably processed in the 3′ to 5′ direction. Our study gives insights into mtDNA function in cancer and answers questions regarding mitochondrial tRNA biogenesis that are difficult to address in controlled experimental systems.

Publication metadata

Author(s): Stewart JB, Alaei-Mahabadi B, Sabarinathan R, Samuelsson T, Gorodkin J, Gustafsson CM, Larsson E

Publication type: Article

Publication status: Published

Journal: PLoS Genetics

Year: 2015

Volume: 11

Issue: 3

Online publication date: 30/06/2015

Acceptance date: 03/06/2015

Date deposited: 21/12/2020

ISSN (print): 1553-7390

ISSN (electronic): 1553-7404

Publisher: Public Library of Science


DOI: 10.1371/journal.pgen.1005333

PubMed id: 26125550


Altmetrics provided by Altmetric