| |
FIG. 1. Whole-mount in situ hybridization with fgf-2 mRNA (A) and fgf-8 mRNA antisense probes (L, M). (A) Normal hindlimbs from larvae at stages 52, 55, and 57, respectively. (A and B) At stage 52 and 55, fgf-2 mRNA expression is detectable in whole the limb, but a distal to proximal gradient of the fgf-2 expression pattern is visible. (C) At stage 57, a low level of fgf-2 mRNA is observed only at level of the distal autopodium (toes). (D) Regenerating hindlimbs amputated through the tarsalia and denervated, stage 52. (D and E) Three and five days after operation, respectively. A high level of fgf-2 mRNA expression is observed both in the stump and in the regeneration blastema. Red lines indicate the approximate amputation level. (F) Longitudinal section of the same blastema in E. fgf-2 mRNA is confined to mesenchymal cells in the stump and in the regeneration blastema (arrowheads). In the procartilaginous skeleton of the stump (arrow), fgf-2 mRNA is undetectable. The line marks the approximate boundary between the stump and regeneration blastema. (G) Hindlimbs amputated through the tarsalia, stage 57. (G) Three days after amputation and sham-denervation: fgf-2 mRNA expression is evident only in the most distal part of the stump in close proximity to the amputation surface. (H) Nine days after amputation and sham-denervation: fgf-2 mRNA is undetectable both in the stump and in the blastema (arrow). (I) Nine days after amputation and denervation. No blastema is present and fgf-2 mRNA is undetectable in the stumped limb. (L and M) fgf-8 expression in hindlimbs of stage 52 larvae. In the normal limb (L), fgf-8 is expressed in the distal epidermis. In the regenerating limb (M), fixed 4 days after amputation, fgf-8 is expressed in the apical epithelial cap covering the regeneration blastema. rb, regeneration blastema; st, stump. Scale bar, 500 ﰁm. |
