Sakiya Yamamoto

eLife Assessment This fundamental work by Yamamoto and colleagues advances our understanding of how positional information is coordinated between axes during limb outgrowth and patterning. They provide convincing evidence that the dorsal-ventral axis feeds into anterior-posterior signaling, and identify the responsible molecules by combining transplantations with molecular manipulations. This work will be of broad interest to regeneration, tissue engineering, and evolutionary biologists.

Abstract Axolotls (Ambystoma mexicanum) exhibit a remarkable ability to regenerate limbs after amputation. Classical experiments have suggested that the integration of four positional cues—dorsal, ventral, anterior, and posterior—within a regenerating blastema is necessary for accurate limb pattern formation. However, the molecular basis underlying this integration has remained largely unknown.

CONFLICT OF INTEREST STATEMENT We have no competing interests. Supporting Information Filename Description dgd70005-sup-0001-FigureS1.jpgJPEG image, 304.6 KB FIGURE S1. Representative measurements of dermis sublayer thickness in axolotl skin at different body sizes (13, 17, and 22 cm). The vertical lines represent the total dermis thickness and its sublayers, with st. Baladachinum shown in green, st. Spongiousum in yellow, and st. Comppactum in magenta.