ROSA ^Kaleidoscope mice express correctly localized fusion proteins across cell types. (A) Primary cell culture from dissociated P7 CMV-Cre; ROSA^{Kaleidoscope/+} lungs, showing colocalization of each fusion protein with markers of their expected subcellular structures: Lamp2 for lysosomes, Tomm20 for mitochondria, β-Tubulin for microtubules. An escaper of CMV-Cre recombination is outlined with dashes. Scale: 10 μm. (B) A survey of cell types and tissues from CMV-Cre; ROSA^{Kaleidoscope/+} mice at P28, except for the inner ear at P5 to avoid calcification. Lysosomes range in size from 10 to 1 μm characteristic of cell types in the decreasing order of hepatocytes, lung alveolar type 2 (AT2) cells, hair cells, skeletal muscle cells, and lung alveolar type 1 (AT1) cells. In the skeletal muscle, microtubules perpendicularly bundle actomyosin fibers, whereas lysosomes and mitochondria align with and fit between actomyosin fibers. Additional lysosomes surround the nuclei (asterisk). Arrow, unrecombined hair cell; n, neuronal cell; s, satellite cell. Scale: 10 μm.