Fig.7

A model for tail regeneration at stage 61 by T3. In wild type animals at metamorphic climax stage 61, T3 peaks and liganded T3 receptors (TRs) recruit coactivator complexes to activate gene transcription responsible for tail resorption and inhibit tail regeneration, including inhibition of the initiation of the regeneration after amputation and preventing subsequent patterning and outgrowth. In TRDKO tadpoles, the activation of these genes by T3 is absent, thus preventing tail resorption and allowing the tail to retain regenerative ability. RXR, 9-cis-retinoic acid receptor. TRE, T3 response element. The white dash lines indicate amputation sites. Scale bar: 8.7 mm