Mitochondrial DNA haplotypes induce differential patterns of DNA methylation that result in differential chromosomal gene expression patterns

Mitochondrial DNA (mtDNA) haplotypes are associated with phenotypes and disease. To understand how mtDNA haplotypes induce these characteristics, we used four embryonic stem cell lines that have the same set of chromosomes but possess different mtDNA haplotypes. We show that mtDNA haplotypes influence changes in chromosomal gene expression and affinity for nuclear-encoded mtDNA replication factors to modulate mtDNA copy number, two events that act synchronously during differentiation. Global DNA methylation analysis showed that each haplotype induces distinct DNA methylation patterns, which, when modulated by DNA demethylation agents resulted in skewed gene expression patterns that highlight the effectiveness of the new DNA methylation patterns established by each haplotype. The haplotypes differentially regulate α-ketoglutarate, a metabolite from the TCA cycle that modulates the TET family of proteins, which catalyse the transition from 5-methylcytosine (DNA methylation) to 5-hydroxymethylcytosine (DNA demethylation). Our outcomes show a direct link between mtDNA haplotypes and DNA methylation profiles. 4 different mouse ES cell lines, distinguished by their mtDNA genome. 3 biological replicates of each cell line.