Additional file 3: of Mechanosensory organ regeneration in zebrafish depends on a population of multipotent progenitor cells kept latent by Schwann cells

Temporary loss of MBP expression in caudally located SCs after L3 electroablation. tg(foxd3:GFP; brn3c:GFP) larvae 3 dpf were injured at the L3 neuromast and fixed at different time points. Expression of Brn3c:GFP was used as an indicator to locate the L3 neuromast. Fixed control and injured larvae were processed by immunohistochemistry to analyze MBP and GFP expression. (A, B) White arrowheads show MBP signal in 4 dpf control larvae and 24 hpi in injured larvae (only rostral to L3). The yellow arrowhead in B shows the loss of MBP expression in the caudal zone with respect to the injury site. (C–N) Double transgenic larvae tg(foxd3:GFP; brn3c:GFP) were processed in order to describe, by immunodetection, the time course of MBP expression in the vicinity of L3 in control larvae (C–H) vs injured larvae (I–N). MBP expression by itself is shown in monocolor (C, E, G, I, K, M), while MBP expression (red) merged with the FoxD3 expression (green) is shown in color (D, F, H, J, L, N). In control larvae, there is continuous expression of MBP from 3 to 5 dpf. The arrowhead in C shows the localization of the L3 neuromast. In injured larvae, the expression of MBP is fragmented after 3 hpi (white arrowhead in I), disappears after 24 hpi caudal to L3 (yellow arrowhead in K), and reappears after 48 hpi (M). Note that, despite the transient loss of the differentiation marker, SCs revealed by the presence of GFP are present throughout the regeneration process (J, L, and N). The asterisk in I and J indicates the site where injury was made. Scale bar A, B: 200 μm, C–N: 50 μm. (TIF 6575 kb)