FGF signalling and blastema growth during amphibian tail regeneration

Urodeles amphibians can regenerate their tails, including spinal cord and g anglia, as adults. The cellular and molecular mechanisms underlying tail re generation, and particularly recruitment of neural progenitors and the init iation of their division have yet to be fully elucidated. We have studied t he role of FGF2 in this process and found that FGF2 is important both for r egeneration of the spinal cord and of the mesenchymal tissues of the tail s tump, as indicated by its up-regulation in the blastema and in ependymal ce lls and by the fact that FGF2-soaked beads increase blastema growth as comp ared to controls. We have also studied the expression of Pleurodeles Sox1 i n regenerating tails, as members of this gene family have been shown to be upstream of FGF signalling in other systems. We show by RT-PCR analysis tha t this gene is expressed at low levels in normal tail, suggesting that its presence in the adult newt tail may be causally related to its high regener ative capability. Furthermore, this gene is significantly up-regulated foll owing tail amputation indicating that it plays an important role during tai l regeneration.