Fig. 4

Fig. 4

Osx:mCherry-NTRo cell ablation in the adult medaka fin does not affect rate of regenerative outgrowth. A. Strategy for ablation of osx-positive cells in medaka. Mtz, period of treatment with metronidazole. B, C: Transgenic osx:mCherry-NTRo fin showing osx:mCherry-NTRo expression after DMSO treatment (control; B, C) and Mtz treatment (B′, C′) at 0 dpa and 2 dpa. Scale bars in B, B′, C, C’ = 200 μm. D-L: ph3 and DAPI staining on 20 μm longitudinal fin sections of DMSO-treated (D-G) and Mtz-treated (H-L) osx:mCherry-NTRo fish at 2 dpa. D′, E′ F′: Magnified views of the boxed region in (D). H′, I′, K′: Magnified views of the boxed region in (H). Yellow dotted lines indicate the amputation plane, yellow arrows indicate mCherry/ph3-double positive cells, cyan arrows indicate mCherry-positive, ph3-negative cells. Scale bars in G, F′, L, K’ = 20 μm. M: Number of osx:mCherry-NTRo-expressing cells (300 μm from the amputation plane) is significantly reduced (93.3%) in Mtz treated fish (16.3 ± 6.1) compared to DMSO controls (241.3 ± 15.3) at 2 dpa. Error bars indicate mean ± s.d. Cell count was performed on confocal z-stack images of 20 μm longitudinal sections, n = 8 fin rays (N = 6 fish). N: Lengths of fin regenerates after osx cell ablation. Double transgenic col10a1:nlGFP/osx:mCherry-NTRo (osx:mCherry-NTRo) and osx:mCherry-NTRo negative siblings (control) treated with Mtz show similar rates of fin outgrowth. Data are represented as mean ± SEM. Changes are not significant.