Figure 4

Col2a1a knockdown mimicked the characteristic features of human Stickler syndrome in zebrafish. A lissamine-tagged antisense MO targeting the promoter region (prMO) of col2a1a was injected into TgBAC(col2a1a::EGFP) and Tg(sox10::EGFP) embryos at the single-cell stage. Lateral FL microscopy images (A) show the loss of GFP reporter expression driven by the col2a1a promoter in TgBAC(col2a1a::EGFP) transgenic fish (lower right panel) compared with uninjected and standard control (std ctrl) MO-injected embryos (upper right and middle panels, respectively). Quantification of this effect showed a significant loss of expression (B). MO-injected Sox10-positive transgenic zebrafish embryos showed skeletal defects, including scoliosis (upper right panel, dashed black line, (C)) and significantly shortened body length (D), measured perpendicular to the spine from the tip of the epiphysis to the area above the urogenital opening (white dashed arrow (inset, D), delayed neural crest-derived jaw development (white arrowhead, upper right panel and black asterisk, lower right-most panel, (C)), and significantly smaller bulging eyes (solid and dashed circles, (C,E)), as measured along the anterior–posterior (a-p; inset, E) and dorsal-ventral (d-v; inset, E) axes, compared with uninjected and std ctrl MO-injected embryos at 48 and 72 hpf (left and middle panels, (C–E)). *, p-value ≤ 0.05; **, p-value ≤ 0.001.