Data from: Screen for mitochondrial DNA copy-number maintenance genes reveals essential role for ATP synthase

The machinery of mitochondrial DNA (mtDNA) maintenance is only partially
characterized and is of wide interest due to its involvement in disease.
To identify novel components of this machinery, plus other cellular
pathways required for mtDNA viability, we implemented a genome-wide RNAi
screen in Drosophila S2 cells, assaying for loss of fluorescence of mtDNA
nucleoids stained with the DNA-intercalating agent PicoGreen. In addition
to previously characterized components of the mtDNA replication and
transcription machineries, positives included many proteins of the
cytosolic proteasome and ribosome (but not the mitoribosome), three
proteins involved in vesicle transport, some other factors involved in
mitochondrial biogenesis or nuclear gene expression, > 30 mainly
uncharacterized proteins and most subunits of ATP synthase (but no other
OXPHOS complex). ATP synthase knockdown precipitated a burst of
mitochondrial ROS production, followed by copy number depletion involving
increased mitochondrial turnover, not dependent on the canonical autophagy
machinery. Our findings will inform future studies of the apparatus and
regulation of mtDNA maintenance, and the role of mitochondrial
bioenergetics and signaling in modulating mtDNA copy number.