Electron tomograms from mitochondria in WT and FAM92A1-KO U2OS cells

The specimens for ET were chemically fixed and flat embedded. 250-nm-semithick sections were imaged using a Tecnai FEG 20 operating at 200 kV. Images were collected with a 4,000 × 4,000–pixel Ultrascan 4000 charge-coupled device camera at a nominal magnification of 9,600×, providing a 2× binned pixel size of 2.3 nm. The specimens were tilted at 1° intervals using a high-tilt specimen holder between ±60°. Automated acquisition of dual-axis tilt series were performed using SerialEM software. The alignment of tilt series and reconstructions were done with the IMOD software package using 10-nm colloidal gold particles underneath and on top of the sections as fiducial markers. Tomographic reconstructions were segmented and modeled using the Microscopy Image Browser and Amira.