Mice
The K14-Snail Tg mouse was generated by digesting the pcDNA3-mm Snail-HA plasmid (G. de Herreros, Universitat Pompeu, Fabra, Barcelona, Spain) with BamHI and NotI and subcloned into the K14 vector [49]. The linearized construct was injected into the nucleus of embryos from CD1 mice. The K14-Smad 2 Tg mouse was reported in Ito et al., 2001. The TGF-β2 knockout (KO) mouse was described in [34]. The shh KO mouse [38] and TOPGal mouse [20] have previously been reported.