Differential and zonal regulation of cardiomitophagy during development. (A–C) Representative montage of tile-scan images of E14.5 (A), E17.5 (B), and adult heart (C) sections from mito-QC reporter mice. Arrowheads in B indicate areas of high mitophagy. As images are to scale, and only a representative sample of adult cardiac tissue is depicted in C. Bars, 200 µm. (D) High resolution Airyscan images showing a mitophagic zone (delineated by dotted line) in the E17.5 ventricle Bar, 20 µm. (E) Representative Airyscan image of adult ventricular cardiomyocytes in vivo. Bar, 20 µm. (F) Immunostaining of E17.5 heart sections with anti–activated caspase-3 antibodies. Dotted line highlights high mitophagic zone. Bar, 20 µm. (G) Immunostaining of E17.5 heart sections with anti-Ki67 antibodies. Dotted line highlights high mitophagic zone. Bar, 20 µm.