Immunohistochemical and western blot analysis suggest that the soluble forms of FGF1-2 and FGFR1-2 sustain tail regeneration in the lizard

Fibroblast Growth Factors 1-2 (FGF1-2) stimulate tail regeneration in lizards and therefore the distribution of their receptors, FGFR1-2, in the regenerating tail of the lizard. Podarcis muralis has been studied using immunofluorescence and western blotting. Immunoreactive protein bands at 15-16 kDa for FGF1-2 in addition to those at 50-65 kDa are detected in the regenerating epidermis, but weak bands at 35, 45 and 50 kDa appear from the regenerating connective tissues. Strongly immunolabeled bands for FGFR1 at 32, 60, and 80 kDa and less intense for FGFR2 only appear in the regenerating tail. In normal tail epidermis and dermis, higher MW forms are present at 80 and 115-140 kDa, respectively, but they disappear in the regenerating epidermis and dermis where low MW forms of FGFR1-2 are found at 50-70 kDa. Immunolocalization confirms that most FGFR1-2 are present in the wound epidermis, Apical Epidermal Peg, ependymal tube while immunolabeling lowers in regenerating muscles, blastema cells, cartilage and connectives tissues. The likely release of FGFs from the Apical Epidermal Peg and ependyma and the presence of their receptors in these tissues may determine the autocrine stimulation of proliferation and a paracrine stimulation of the blastema cells through their FGF Receptors.