Gene expression in regenerating and scarring tails of lizard evidences three main key genes (wnt2b, egfl6, and arhgap28) activated during the regulated process of tail regeneration.

Abstract

We have analyzed the expression of key genes orchestrating tail regeneration in lizard under normal and scarring conditions after cauterization. At 1-day post-cauterization (1dpc), the injured blastema contains degenerating epithelial and mesenchymal cells, numerous mast cells, and immune cells. At 3 and 7dpc, a stratified wound epidermis is forming while fibrocytes give rise to a scarring connective tissue. Oncogenes such as wnt2b, egfl6, wnt6, and mycn and the tumor suppressor arhgap28 are much more expressed than other oncogenes (hmga2, rhov, fgf8, fgfr4, tert, shh) and tumor suppressors (apcdd1, p63, rb, fat2, bcl11b) in the normal blastema and at 7dpc. Blastemas at 3dpc feature the lowest upregulation of most genes, likely derived from damage after cauterization. Immunomodulator genes nfatc4 and lef1 are more expressed at 7dpc than in normal blastema and 3dpc suggesting the induction of immune response favoring scarring. Balanced over-expression of oncogenes, tumor suppressor genes, and immune modulator genes determines regulation of cell proliferation (anti-oncogenic), of movement (anti-metastatic), and immunosuppression in the normal blastema. Significant higher expression of oncogenes wnt2b and egfl6 in normal blastema and higher expression of the tumor suppressor arhgap28 in the 7dpc blastema indicate that they are among the key/master genes that determine the regulated regeneration of the tail.