A genome wide screening for mitochondrial fission factors

Whether mitochondrial fission players other than the core effector dynamin related protein 1 (Drp1) and its known adaptors and regulators exist is unclear. We performed a high content imaging screening of ~19,000 genes to identify positive regulators of mitochondrial fission in mouse embryonic fibroblasts (MEFs) lacking the fusion factor Optic Atrophy 1 (Opa1) and human fibroblasts carrying the inactivating OPA1S545R mutation. We identified 1,748 genes that when ablated restore mitochondrial elongation in Opa1-/- MEFs and 1,292 in OPA1S545R fibroblasts. The former list was enriched in genes participating in actin regulation or encoding for mitochondrial proteins, including known fission effectors. By intersecting the results obtained in mouse and human fibroblasts, we identified 68 conserved hits, including dystrobrevin-α (DTNA), an intermediate filament scaffold. DTNA and the mouse hit cysteine string protein α (CSPα), a co-chaperone for dynamin-1 oligomerization and vesicle fission were retrieved on mitochondria associated membranes and their ablation caused mitochondrial elongation also in fusion proficient cells. Our screening identifies genes with roles in muscle disease and neuron biology as regulators of mitochondrial fission.