Wound-induced proliferation is perturbed in Padi2-deficient larvae. (A and C) Representative images of 6 h EdU pulsed larvae in developmental, unwounded (A) or 66 hpw (C) fins. Merged images of EdU (green) and DAPI (white) on the left and single EdU (white) image on the right. (B and D) Quantification of EdU-positive cells in the fin. (E) Number of EdU-positive cells in the fin normalized to corresponding no wound conditions. (F) Representative images of the dorsal half of 6 h EdU-pulsed fins. (G) Quantification of EdU-positive cells within the dorsal region of the fin. All data are from three pooled independent replicates with the lsmeans and SEM reported and P values calculated by ANOVA (no wound, n = 39 +/+, 39 −/−; 66 hpw, n = 47 +/+, 47 −/−). Scale bars, 100 µm. (H) A proposed model depicting how the early wound epithelial calcium flux might activate (dashed arrow) Padi2 to catalyze citrullination events that, either directly or indirectly (left question mark), regulate neutrophil (purple) recruitment to the wound. Concomitantly, wound-dependent Padi2 citrullination of histones (green nuclei) within a subset of cells in the notochord bead (pink) potentially stimulates, through yet to be determined mechanisms (right question mark), regenerative proliferation.