Fig. 4

Cell proliferation in late larval development of S. californicum. All: anterior up; blue = Hoechst, green = EdU; scale bar is 100 um. Schematics of ventral (A), dorsal (D), and medial (G) views with key structures labeled. EdU staining with maximum intensity projection ventral (B), dorsal (E), and medial (H) sections. B late larva ventral surface, C inset of (B), highlights ventral posterior epidermis and ciliary band E late larva dorsal surface, F inset of (E) highlights dorsal cord, marked by white asterisk, H late larva medial section, arrowheads highlight regions that will give rise to protocoel, mesocoel, and metacoel. I inset of lateral view of late larva medial section, arrowhead highlights gill bars. J protocoel, mesoderm that will form the proboscis, K mesocoel, mesoderm that will form the collar, L metacoel, mesoderm that will form the trunk. M, N distribution of anti-histone H3 (phospho S10) and EdU positive cells in ciliary bands, magenta = pHH3.3, grey = acetylated tubulin