Figure 5.

Expression of fgfr1 and msxC during caudal fin regeneration. fgfr1 is expressed in the regenerating caudal fin blastema. In situ hybridisation on longitudinal sections at 4 days post amputation (dpa) reveal fgfr1 expression in the basal layer of the epidermis and in scleroblasts (A). msxC expression overlaps with thatof fgfr1 in scleroblasts (B) and shows additional expression in the distal blastema (B, G, H). There is no overall clearly visible difference in expression of fgfr1 (C-F) and msxC (G, H) between sword and non-sword regenerates until 7 dpa. At 11 dpa fgfr1 (I) and msxC (J) show higher levels of expression in regenerating sword rays than in non-sword rays, though this difference is more obvious for msxC. White arrowheads indicate expression in scleroblasts, black arrowheads the msxC expression domain in the distal blastema and white arrows the plain of amputation. bl = basal epidermal layer; db = distal blastema; e = epidermis; l = lepidotrichia; m = mesenchyme (4 dpa fgfr1: n = 8; 7 dpa fgfr1: n = 5; 7 dpa msxC: n = 5; 11 dpa fgfr1: n = 5; 11 dpa msxC: n = 4; scale bars: A and B: 100 μm, C-J: 200 μm).