Additional file 10: of Mechanosensory organ regeneration in zebrafish depends on a population of multipotent progenitor cells kept latent by Schwann cells

Copper sulfate treatment does not affect SCs or INCs. (A, B) 72 hpf tg(foxd3:GFP) transgenic larvae (SCs labeled with GFP) were treated for 2 h with 100 μM CuSO4 and imaged 1, 24, and 48 hpt; sibling control fish were left untreated. (A) An arbitrary area of the trunk above the anus was defined (encompassing the width of about three somites) and the “Measure Tool” of ImageJ was used to assign arbitrary units for mean green fluorescence intensity. (B) The graph shows data for control (Co) and copper-treated (CuSO4) fish at the three selected times. While mean values are significantly different between the developmental stages, control fish vs CuSO4-treated fish (control 1, 24, 48 h n =12, 14, 11 respectively and 1, 24, 48 hpt n =13, 17, 11 respectively) at equivalent ages were not significantly different (ns) (P < 0.05). (C) Double transgenic tg(cxcr4:mCherry; et20:GFP) larvae at 3 dpf were treated for 2 h with 100 μM CuSO4 and imaged 48 and 72 hpt. Two larvae are shown at both time points. Note that only secondary lateral line neuromasts (LII) are seen because the copper treatment at day 3 permanently ablates all primary neuromasts. In the bottom three rows, sibling fish were treated in the same way but, after the copper solution was washed out, 5 μM AG1478 was added to the medium and the fish were imaged 48 or 72 hours later; three larvae are shown at both time points. Note that supernumerary neuromasts appear in these animals (compare with two larvae in top half), indicating that INCs are not affected by copper treatment and retain their progenitor potential. (PDF 1994 kb)