Asymmetric regeneration dynamics in zebrafish pectoral fins

Appendage amputation in regeneration-capable systems results in the full re-formation of lost tissue and cell populations. Despite an appreciation of this phenomenon in a select number of organisms, there is still much to quantitatively understand about the tissue growth dynamics during limb regeneration. To address these gaps in knowledge, we developed novel methods that enable longitudinal, quantitative imaging of zebrafish pectoral fin regeneration and uncovered a persistent spatial asymmetry in growth dynamics between anterior and posterior regions of the regenerating fin. Spatiotemporally resolved transcriptomics suggests differential anteroposterior regulation of the Mitogen-activated protein kinase (MAPK) and Wnt signaling pathways in pectoral fins. This asymmetry was also detected using quantitative imaging of biosensors reporting canonical Wnt and Erk pathway activity. In addition to known static spatially asymmetric genes, bulk transcriptomic analysis uncovered a large subset of genes with temporally asymmetric peaks in expression levels between anterior and posterior regions of the fin across regeneration timepoints, suggesting a global differential regulation of the regenerative program. Taken together, our results establish pectoral fins as a platform for quantitative analyses of appendage regeneration, and they identify persistent spatial asymmetries in growth, gene expression, and signaling activity during regeneration.