Fig. 3 Organization of actin filaments in the lamellipodia/cell body transition zone. Electron microscopy of wet-cleaved cells with nuclei removed shows actin bundles in the transition zone (top of each panel) and a network of actin filaments at the bottom of the cell body (bottom of each panel). Different amounts of actin filaments remain associated with bottom plasma membrane (a-c). Orientation of actin filaments is random (a, b) or approximately parallel to the transition zone bundle (c). The cell's leading edge is oriented upward in all panels. Bar, 0.1 µm.