FIGURE 3

Craniofacial phenotype characterization in chd7 ^sr5 mutants. (A) Viscerocranium morphology. The viscerocranium was dissected out from the Alcian blue and Alizarin red costained WT, chd7 ^sr5, and MZchd7 ^sr5 mutants with or without heart edema at 7 dpf. Yellow arrowheads indicate the reduction in the IV ceratobranchial; black asterisks mark the defects in the teeth; red asterisks mark the abnormalities in the basihyal. (B) Quantification of the different types of the morphology of basihyal in WT, chd7 ^sr5, and MZchd7 ^sr5. (WT: n = 16; chd7 ^sr5 : n = 16; MZchd7 ^sr5 : n = 15). The statistical analysis was performed using the chi-square test. (C) Schematic of the viscerocranium cartilage at 7 dpf. bb, basibranchial; bh, basihyal; cb, ceratobranchial; ch, ceratohyal; hb, hypobranchial; hs, hyosymplectic; ih, interhyal; m, Meckel’s; and pq, palatoquadrate. (D) Quantification of the length of I to V ceratobranchials in WT, chd7 ^sr5, and MZchd7 ^sr5 . (WT: n = 24; chd7 ^sr5 : n = 20; MZchd7 ^sr5 : n = 23). The statistical significance was performed using the ordinary one-way ANOVA test. (E) Quantification of different types of the morphology of the IV ceratobranchial. (n = 22 for each group). The statistical analysis was performed using the chi-square test. (F) High-magnification image shows that chondrocyte stacking is disrupted in chd7 ^sr5 mutants, and severely disorganized stacking has been found in MZchd7 ^sr5 mutants. (G) Schematic of chondrocytes’ stacking measurement. (H) Angles of three neighbor chondrocytes in I and II ceratobranchials. Each number indicates a different fish. (n = 6 for each group). The significance was calculated between different groups. chd7 ^sr5 mutants have mild disorganization in the chondrocyte arrangement, but MZchd7 ^sr5 mutants have more severe defects in the chondrocytes. The statistical analysis was performed using the ordinary one-way ANOVA test. (I) Alizarin red-stained teeth are reduced in chd7 ^sr5 mutants at 7 dpf. Nearly 50% of MZchd7 ^sr5 fish have defects in teeth number. (WT: n = 23; chd7 ^sr5 : n = 20; MZchd7 ^sr5 : n = 38). The statistical significance was performed using the chi-square test. ns: p ≥ 0.05, *: p < 0.05, **: p < 0.01, ***: p < 0.001, and ****: p < 0.0001.