[Appearance and distribution of retinoic acid in the limb regeneration of Cynops orientalis].
Urodeles are the unique vertebrate which can regenerate their limbs in larvae and adult. The pattern formation of blastema cells in the limb regeneration is a central problem. Many evidence have been established to support the hypothesis that RA may be the morphogen in limb development. The limb development and regeneration are so similar morphogenetic processes that we suspect RA may also play an important role in the latter process. In order to give an answer to this question, we tested the limbs in different stages of regeneration with the specific antibody prepared against RA. The results indicated that RA appeared on day six and arrived its peak on day eight after amputation. During this time, the dedifferentiation of the stump is proceeding to the strongest degree and the distribution of RA showed a posterior-anterior gradient. If the stump is treated with RA for 24 hours at this stage, proximal distal duplication of the regenerate can be induced. These results and the fact that the close connection between apical epidermal cap and mesenchymal cells and abundant RA outside the epidermal cells suggest that RA may play an important role in the establishment of positional information of the blastema.
Shanghai Institute of Cell Biology, Academia Sinica.
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D000818:Animals; D012038:Regeneration; D012454:Salamandra / Q000378:metabolism / Q000502:physiology; D014212:Tretinoin / Q000378:metabolism*
D014212:Tretinoin