Mitochondrial DNA (mtDNA) heteroplasmies are associated with various diseases but the transmission of heteroplasmy from mtDNA to mitochondrial RNA (mtRNA) remains unclear. We compared heteroplasmies in mtRNA from 446 human B-lymphoblastoid cell lines to their corresponding mtDNA using deep sequencing data from two independent studies. We observed 2786 heteroplasmies presenting in both DNA and RNA at 1% frequency cutoff. Among them, the frequencies of 2427 (87.1%) heteroplasmies were highly consistent (less than 5% frequency difference) between DNA and RNA. To validate these frequency consistencies, we isolated DNA and RNA simultaneously from GM12282 cell line used in those two sequencing studies, and resequenced its heteroplasmy sites. Interestingly, we also observed the rapid changes of heteroplasmy frequencies during 4 weeks of the cell culture: the frequencies at Day 14 increased by >25% than those at Day 0. However, the heteroplasmy frequencies from the same time point were highly consistent. In summary, our analysis on public data together with
Mitochondrial DNA (mtDNA) is known to play a critical role in cellular functions. However, the fluorescent probe enantio-selectively targeting live-cell mtDNA is rare. We recently found that the well-known DNA ‘light-switch’ [Ru(phen)2dppz]Cl2 can image nuclear DNA in live-cells with chlorophenolic counter-anions via forming lipophilic ion-pairing complex. Interestingly, after washing with fresh-medium, [Ru(phen)2dppz]Cl2 was found to re-localize from nucleus to mitochondria via ABC transporter proteins. Intriguingly, the two enantiomers of [Ru(phen)2dppz]Cl2 were found to bind enantio-selectively with mtDNA in live-cells not only by super-resolution optical microscopy techniques (SIM, STED), but also by biochemical methods (mitochondrial membrane staining with Tomo20-dronpa). Using [Ru(phen)2dppz]Cl2 as the new mtDNA probe, we further found that each mitochondrion containing 1–8 mtDNA molecules are distributed throughout the entire mitochondrial matrix, and there are more nucleoids near nucleus. More interestingly, we found enantio-selective apoptotic cell death was induced by the two enantiomers by prolonged visible light irradiation, and in-situ self-monitoring apoptosis process can be achieved by using the unique ‘photo-triggered nuclear translocation’ property of the Ru complex. This is the first report on enantio-selective targeting and super-resolution imaging of live-cell mtDNA by a chiral Ru complex via formation and dissociation of ion-pairing complex with suitable counter-anions.
more » « less- PAR ID:
- 10473092
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Nucleic Acids Research
- Volume:
- 51
- Issue:
- 22
- ISSN:
- 0305-1048
- Format(s):
- Medium: X Size: p. 11981-11998
- Size(s):
- p. 11981-11998
- Sponsoring Org:
- National Science Foundation
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Abstract in vitro study indicates that the heteroplasmies in DNA can be transcribed into RNA with high fidelity. Meanwhile, the observed rapid-changing heteroplasmy frequency can potentially disturb cell functions, which could be an overlooked confounding factor in cell line related studies. -
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