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Presenting Author(s) Nadia Mercader
Abstract Title Proximodistal patterning during limb regeneration.
Full author List Nadia Mercader 1, Elly Tanaka 2, Miguel Torres 1
Text of abstract

After amputation, urodeles regenerate their limbs, faithfully reproducing the pattern corresponding to the missing parts. Positional information regarding the P-D level of amputation can be experimentally reprogrammed. When blastemas from distally amputated limbs are exposed to retinoic acid (RA), they regenerate a whole P-D limb axis 1,2 Furthermore distal blastema cells exposed to RA acid change their distal-specific affinity properties to match that of proximal cells. During limb development, members of the Meis and Pbx family have been identified as determinants of proximal limb regions in both vertebrates and insects3-5. In addition, Meis gene expression has been shown to be positively regulated by retinoic acid during chicken limb development6. We have initiated a molecular analysis of P-D patterning during axolotl limb regeneration by characterizing the regulation, expression and function of Meis and Pbx proteins. Meis expression is restricted to proximal regions of both developing and regenerating axolotl limbs and is ectopically upregulated by RA in both situations. Forced overexpression of Meis and Pbx proteins during regeneration leads to preferential contribution of the transfected cells to proximal regions of the regenerated limb. These results indicate that Meis/Pbx regulate P-D-specific cell affinity, a hallmark of P-D identity. Meis/Pbx are thus effectors of the proximalizing activity of RA during limb regeneration invertebrates.

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3.González-Crespo, S. et al. Nature 394, 196-200 (1998).

4.Capdevila, J., Tsukui, T., Rodriquez Esteban, C., Zappavigna, V. & Izpisua Belmonte, J. C. Mol Cell 4, 839-849 (1999).

5.Mercader, N. et al. Nature 402, 425-429 (1999).

6.Mercader, N. et al. Development 127, 3961-3970 (2000).
Which session is your work most relevant to: Limb regeneration or Limb patterning