Fig. 5. Free-floating neural tubes in the transgenic tail buds. Transverse sections of E12.5 wild-type (A) and transgenic tail buds (B,C). In the transgenic tail bud, free-floating tubular structures (B, arrowheads) are formed in place of mesodermal tissues. Immunostaining for tubulin ß 3 confirms the neural nature of the ectopic tubes in the transgenic tail bud (C). (A-C) Dorsal is at the top and ventral is at the bottom. (A,B) Hematoxylin and Eosin staining, (C) Immuno-peroxidase labeling. Bars: 100 µm.