slc4a2b mRNA injection can rescue the phenotype induced by slc4a2b gene deficiency. The Tg(Brn3c:mGFP);slc4a2bmut zebrafish that were injected with Cas9 mRNA and slc4a2b sgRNA had fewer HC clusters (A, B) and fewer HCs in each posterior lateral line neuromast (A, C) compared to controls. However, slc4a2b mRNA injection could rescue the phenotype caused by slc4a2b mutation. *** P < 0.001; ** P < 0.01; ns, no significance.