Fig. 4 Correlative light and electron microscopy of myosin II. REF-52 fibroblast was microinjected with smooth muscle myosin II labelled by tetramethylrhodamine and, after light microscopy processed for electron microscopy. (a), fluorescence microscopy of the cell after detergent extraction, gelsolin treatment and glutaraldehyde fixation; (b), enlarged boxed region from (a); Copyright © , electron microscopy of the region shown in (b). Accumulation of myosin II visualized as fluorescent spots in (a) and (b) can be seen in Copyright © as stack-like assemblies of bipolar filaments. Note that brighter areas in a light microscopic image (b) correspond to higher density of myosin filaments visualized by electron microscopy Copyright © . Bars, 0.2 µm