Figure 3.

Accumulation of autophagosomes in MLIV fibroblasts. Electron micrographs of control fibroblasts (A) and MLIV fibroblasts (B). Note the accumulation of electron-dense lysosomes and autophagosomes [arrow indicates example similar to that shown in (E)] present in MLIV cells. Scale bars = 2 µm. (C–E). High magnification images of membrane-bound structures with cytoplasmic contents, consistent with autophagosomes, in MLIV fibroblasts. In (D), the arrow indicates a crista in a mitochondrion. The arrowhead indicates an area where the mitochondrial inner and outer membranes and the surrounding double membrane of the autophagosome are clearly seen. Scale bars = 200 nm. (F and G) Characteristic lysosomes in MLIV fibroblasts containing concentric lamellar inclusions. Scale bars = 200 nm. (H) EM images of MLIV fibroblasts showing autolysosomes containing the concentric lamellar inclusions and cytoplasmatic contents. Scale bars = 200 nm.