14.15-14.30 Can Aztekin
Unlike mammals, Xenopus laevis tadpoles have a high regenerative potential. Here, we performed single-cell RNA sequencing over an extended time course following tail amputation to characterize the regenerative response. By comparing naturally-occurring regeneration-competent and -incompetent tadpoles, we identified a previously unrecognized cell type that we term the regeneration-organizing cell (ROC). ROCs are present in the epidermis during normal tail development, and specifically relocalise to the amputation plane of regeneration-competent tadpoles, forming the wound epidermis. Genetic ablation or manual removal of ROCs blocks regeneration, whereas grafting ROCs containing-tissues induce ectopic outgrowths in early embryos. Transcriptional profiling revealed that ROCs secrete ligands associated with key regenerative pathways, thereby signaling to proximal progenitors to increase their proliferation and reconstitute lost tissue. Overall, our comprehensive analysis of cell types in the Xenopus tail reveals the central cellular mechanism through which ROCs form the wound epidermis and ensure successful regeneration.