Additional characterization of CCDC51 CRISPRi cells. (A) AlphaFold2-generated predicted structures with annotations of predicted MTS, TM domains (TM1 and TM2), and coiled-coil domains shown for yeast Mdm33 (left) and human CCDC51 (right). Note that the orientation of TM2 is likely reversed. (B and C) Representative single-plane confocal images are shown of control (top) and CCDC51 CRISPRi cells (bottom) that were fixed and immunolabeled for HSP60 and (B) Drp1 or (C) MFF. (D) Single-plane confocal images are shown at the indicated time intervals of control (top) or CCDC51 CRISPRi (bottom) cells expressing GFP-Sec61β and stained with MitoTracker Red. (E) Single-plane confocal time-lapse images at the indicated intervals are shown of CCDC51 CRISPRi cells expressing mCherry-OMP25 and mito-HaloTag/JF646. Arrows mark sites of resolution and reformation of lamellar mitochondria (top row), an example of formation of a lamellar mitochondrion via apparent fusion (middle row), and an example of fission of a lamellar mitochondrion (bottom row). See also Videos 1, 2, and 3. (F) Representative maximum intensity projection confocal images are shown of control (top) and CCDC51 (bottom) CRISPRi cells fixed and immunolabeled for HSP60 and dsDNA. Insets at the right correspond to the indicated dashed boxes. Scale bars: (B–D) 5 µm; (E) 3 µm; and (F) 15 µm (3 µm in inset).