Rescue of PKD2-associated zebrafish phenotypes by PKD2 gate mutants. a Representative zebrafish embryos showing different severities in tail curling induced by PKD2 MO knockdown. Normal (no curvature), Moderate (significant curvature, <90°), Substantial (90°–180°), and Severe (>180°). b Averaged percentages of embryos with Normal, Moderate, Substantial and Severe tail curling at 3dpf. Embryos were co-injected with 2.5 ng PKD2 MO together with none or 100 pg mRNAs of WT or mutant PKD2, as indicated. Ctrl, uninjected embryos. Data were from three independent experiments with the indicated total numbers of embryos. Statistic significance was determined by the χ² test. NS, no significance; *P < 0.05; **P < 0.01. PKD2 F604P mutant serves as a positive control. c Water-injected (Normal) and PKD2 MO-injected (Cyst) zebrafish embyros at 3 dpf showing curly tail and pronephric cyst formation (arrows) which is confirmed by a histologic section that also displayed dilated pronephric tubules (asterisks). G, glomerulus; Pt/Pd, pronephric tubule/duct; Nc, notochord. d Averaged percentages of embryos exhibiting pronephric cysts under the same conditions as those in b. Data are presented as mean ± SEM. Statistic significance was determined by Student’s t-test. NS, no significance; **P < 0.01; ***P < 0.001