MtDNA specific fluorescent probe uncovering mitochondrial nucleoids dynamics during programmed cell death under super-resolution nanoscopy

Mitochondrial nucleoids or mitochondrial DNA (mtDNA) encodes for a variety of enzymes and proteins that are essential for oxidative phosphorylation, mitochondrial fussion/fission and apoptotic processes. However, visulization of mtDNA dynamics in response to external stumili has not yet been achieved. Herein, we developed a fluorescent probe, named BDP, that is capable of specifically bind to mtDNA in vitro and in living cells, without interfering mitochondrial functions. Its large Stokes-Shift and red-emission tail render its suitability for stimulated emission depletion (STED) visulization of mtDNA dynamics in living cells. We sucessfully demonstrated for the first time how apoptotic induced anti-cancer drug could impact on mitochondrial nucleoids, and the morphology evolution of mtDNA from segmentation to dispersion was recorded, in a single mitochondria at nanoscale.