Generation of the mito-QC mouse and detection of mitophagy and mitochondrial architecture in vivo. (A) Schematic of gene targeting strategy used to generate the mito-QC mouse model. (B) Representative anti-GFP immunoblot showing expression of the reporter construct in different tissues from heterozygous reporter mice (designated A, B, and C). Ponceau is shown to indicate protein loading. (C) Sections of adult heart isolated from mito-QC littermate mice. Images depict representative heart sections from animals with and without indicated copies of the reporter construct. DAPI nuclear stain shown in blue. Bar, 20 µm. (D) Images of mito-QC heart tissue sections immunolabeled with antibodies to the mitochondrial marker, TOM20. Bar, 5 µm. (E) mito-QC heart tissue sections immunolabeled with antibodies to the lysosomal marker LAMP1. Bar, 5 µm. Arrowheads indicate examples of LAMP1/mCherry-only (GFP-negative) colocalization. (F) Quantification of mCherry-positive mitolysosomes in heart sections obtained from homozygous mito-QC adult littermate mice (n = 4 mice). (G) Quantification of mean mitolysosome size between mito-QC adult littermate mice (n = 4 mice). (H) Quantitation of mean cardiac mitolysosome area in mito-QC adult littermate mice (n = 4 mice). Error bars in F–H depict standard deviation.