Fig.2.
A-C: Dynamic expression of Wnt activity reporter (blue) in developing mouse small intestine (from Kim and Shivdasani, 2007; with permission). A: Embryonic day 16.25; B: Postnatal day 3; C: Postnatal day 20. D, E: Intestinal metamorphosis in Xenopus. (from Ishizuya-Oka and Shi, 2007; with permission). D: Histological section, showing clusters of adult gut progenitors (arrows) attached to the basal surface of degenerating larval gut (arrowhead). E: Adult gut progenitors express Shh (brown; arow).