Fig. 4. Dense bodies, M-lines and fibrous organelles. (A) Schematic showing the localization and arrangement of dense bodies and M-lines in C. elegans body wall muscle and fibrous organelles in the epidermis. (Adapted from Mackinnon et al., 2002.) (B) Dense bodies (arrows) and M-lines (arrowheads), visualized with PAT-4–YFP. (Adapted from Mackinnon et al., 2002.) Bar, 5 µm. (C) Fibrous organelles, visualized by MUA-3 staining. Fibrous organelles are shown in regions of epidermal cell contact with body wall muscle (1) and the ALM touch neuron (2). Gaps in fibrous organelles are seen where nerves pass between the epidermis and muscle (3). The image in (b) is an enlargement of (a). (Adapted from Bercher et al., 2001.) Bars, 10 µm.