To interrogate the role of Top3a in mtDNA replication progression, we studied the interaction of mitochondrial Top3a with known mitochondrial DNA maintenance proteins using proximity labeling proteomics. For this experiment, FlpIN-TRex 293 cell line expressing mitochondrial Top3a tagged with BioID2 were used. FlpIN-TRex 293 cell line expressing mitochondria-targeted BioID2 protein served as a control.