Wnt-1 immunodetection in the regenerating tail of lizard suggests it is involved in the proliferation and distal growth of the blastema

Abstract

Lizard tail regeneration depends from growth of the apical tip and autonomous regeneration of a new spinal cord, cartilaginous tube and muscles. The presence of embryonic signaling pathways is likely involved and we have focused on immunolocalization of Wnt1 protein in regenerating tissues, a protein promoting proliferation and tumorigenesis. Western blot indicates some immunoreactive bands in the expected range at 46 and 33kDa in the regenerating tail. Immunolocalization indicates that Wnt1 is prevalently detected in the apical wound epidermis, blastema, and ependyma ampulla of the regenerating tail while it lowers in other tissues of more proximal regions close to the original tail stump. Although a gradient for Wnt1 was not detected, the higher immunofluorescence present in the apical region of the blastema and around the regenerating spinal cord indicates that the protein could be secreted from the apical wound epidermis and the ependyma and might influence cell proliferation in the blastema, the distal-most growing center of the new tail. The present observations suggest the involvement of the Wnt pathway to direct the process of tail regeneration in lizard. The stimulation of proliferation of epidermal and mesenchymal cells in the apical blastema by Wnt proteins remains to be experimentally validated.