Fig. 1

Myotome organization in the regenerating tail of the axolotl. a–d. Photomicrographs of regenerating CAGGS:GFP transgenic axolotl tails. Myotomes are visible because CAGGS:GFP is strongly expressed in muscle tissue. Regenerating tails 13, 15, 17 and 19 days post-amputation at 4th myotome posterior to the cloaca (proximal cut). a. Lack of organized muscle tissue at day 13. b. Onset of myotome formation at day 15. c. Clearly countable myotomes at day 17. White lines demarcate some of the intermyotome regions. d. More myotomes formed by day 19. Scale bars, 2,5 mm