Figure 7.
SEM reveals that axons are enveloped by basal cells and surrounded by an electron-dense material at 78 hpf. SEM images of the wild-type zebrafish epidermis at 78 hpf. P, peridermal cell; B, basal cell; BM, basement membrane; asterisks indicate axons. A: An axon enveloped within a basal skin cell, with an electron-dense substance surrounding the axon membrane. B: An axon located between two basal cells, with an electron-dense substance between the axon and skin cell membranes. C: Arrow points to a longitudinal section of an axon. Note the microtubules, distinct axon membrane, and envelopment by basal cell membranes (arrowheads). D: An axon bundle (arrow) located beneath the skin, just dorsal to the eye; this may be a mix of trigeminal and lateral line sensory axons. Two of the axons are myelinated (arrowheads). Asterisk indicates a putative axon shown in longitudinal section, extending through the BM into the epidermis. Scale bars = 0.2 μm in A–C; 1 μm in D.
