MitoRCA-seq reveals unbalanced cytocine to thymine transition in Polg mutant mice

Ting Ni, Gang Wei, Ting Shen, Miao Han, Yaru Lian, Haihui Fu, Yan Luo, Yanqin Yang, Jie Liu, Yoshi Wakabayashi, Zheng Li, Toren Finkel, Hong Xu, Jun Zhu

Research output: Contribution to journalArticlepeer-review

Abstract

Mutations in mitochondrial DNA (mtDNA) can lead to a wide range of human diseases. We have developed a deep sequencing strategy, mitoRCA-seq, to detect low-frequency mtDNA point mutations starting with as little as 1ng of total DNA. It employs rolling circle amplification, which enriches the full-length circular mtDNA by either custom mtDNA-specific primers or a commercial kit, and minimizes the contamination of nuclear encoded mitochondrial DNA (Numts). By analyzing the mutation profiles of wild-type and Polg (mitochondrial DNA polymerase γ) mutant mice, we found that mice with the proofreading deficient mtDNA polymerase have a significantly higher mutation load by expanding the number of mutation sites and to a lesser extent by elevating the mutation frequency at existing sites even before the premature aging phenotypes appear. Strikingly, cytocine (C) to thymine (T) transitions are found to be overrepresented in the mtDNA of Polg mutated mice. The C →T transition, compared to other types of mutations, tends to increase the hydrophobicity of the underlying amino acids, and may contribute to the impaired protein function of the Polg mutant mice. Taken together, our findings may provide clues to further investigate the molecular mechanism underlying premature aging phenotype in Polg mutant mice.

Original languageEnglish (US)
Article number12049
JournalScientific Reports
Volume5
DOIs
StatePublished - Jul 27 2015
Externally publishedYes

ASJC Scopus subject areas

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