FIG. 4.

Ultrastructural analysis of mitochondria in rat fibroblasts. Left, quantitation of the types of cells found in fibroblasts. A total of 10 individual cells each from log-phase-growing myc^+/+, myc^−/−, and myc^−/− + Myc cells were classified and are shown as the percentage displaying N, I, or A morphology. Right, electron micrographs of three major morphological categories: N, abundant, normal mitochondrial sections; I, fewer, normal mitochondrial sections; A, dramatic loss of mitochondrial sections with increased lysosome-like organelles. The lower panels are higher magnifications of the upper panels.