Neutrophil accumulation in the mydgf mutant is dependent on the HIF-1α pathway. (A) Schematic representation of HIF-1α activation in neutrophils. Pathway activation results in neutrophil persistence and survival and is characterized by increased expression of phd3. HIF-1α pathway activation can be blocked at the level of transcription factor nuclear binding using arnt-1 morpholino. Illustration was created at www.biorender.com. (B)phd3 expression in pooled tail fin tissue collect from WT larvae, either unwounded or 3 h following tail transection (Tt) or thermal injury (burn), measured by RT-qPCR. Data comprise three (burn) to five (Tt) independent replicates performed in technical triplicates and normalized to mydgf expression in unwounded tails and to ef1α. n = 50 tails per condition per independent replicate. *, P < 0.05. Fold changes in gene expression were compared with the normalized value of 1 using one-sample t tests. (C and D) Representative images (C) and quantification (D) of the number of mCherry-labeled neutrophils at the wound in WT and mydgf^−/− larvae, with control or arnt-1 morpholino, at 1 and 6 hpw after Tt; three or four independent replicates with n = 46 +/+ control mo, 33 +/+ arnt-1 mo, 50 −/− control mo, and 38 −/− arnt-1 mo at 1 hpw and 54 +/+ control mo, 38 +/+ arnt-1 mo, 68 −/− control mo, and 73 −/− arnt-1 mo at 6 hpw; scale bar = 100 µm. Data are expressed as mean with 95% CI; each symbol represents one larva, and different colors represent independent replicates. *, P < 0.05; **, P < 0.01. P values were calculated by ANOVA with Tukey’s multiple comparisons.