Capture of somatic mtDNA point mutations with severe effects on oxidative phosphorylation in synaptosome cybrid clones from human brain

Abstract

Mitochondrial DNA (mtDNA) is replicated throughout life in postmitotic cells, resulting in higher levels of somatic mutation than in nuclear genes. However, controversy remains as to the importance of low-level mtDNA somatic mutants in cancerous and normal human tissues. To capture somatic mtDNA mutations for functional analysis, we generated synaptosome cybrids from synaptic endings isolated from fresh hippocampus and cortex brain biopsies. We analyzed the whole mtDNA genome from 120 cybrid clones derived from four individual donors by chemical cleavage of mismatch and Sanger sequencing, scanning around two million base pairs. Seventeen different somatic point mutations were identified, inc..