Fig. 3

Effects of retinoic acid (RA) signaling alterations on the development of amphioxus. (a-f) Early amphioxus (Branchiostoma lanceolatum) larvae at 60 h of development with anterior to the left and the dorsal side up are shown as maximal projections of confocal microscopy scans displaying auto-fluorescence (in red) and Hoechst nuclear staining (in cyan). Magnifications of the tail region are boxed, with anterior to the left and the dorsal side up. Scale bars are 100 μm for the larvae and 50 μm for the magnified tail fins. (g) Tail fin length measurements following pharmacological treatments. The length of the tail fin of B. lanceolatum larvae at 60 h of development was measured, as indicated in the schematics. The graph shows the tail fin lengths ± standard deviation, with n = 15, for the different treatment conditions indicated. Tail fin lengths that are significantly different from the DMSO control are indicated as “*”, for a cutoff value of p = 0,005, and as “**”, for a cutoff value of p = 0,001. (h-o) Rootletin expression in the tail fin of early B. lanceolatum larvae at 60 h of development, with anterior to the left and the dorsal side up. Arrowheads in (h, m-o) indicate expression in lateral ectodermal cells. Pharmacological treatments are as indicated. Scale bars are 100 μm