auts2 zebrafish knockdown phenotype. (A) At 48 hours post-fertilization (hpf), fish injected with a 5 bp mismatch auts2 morpholino (MO) control have a similar morphology to wild type fish, whereas fish injected with a corresponding translational MO display a stunted developmental phenotype that includes a smaller head, eyes, body, and fins. (B) At 48 hpf, HuC–GFP fish injected with a 5 bp mismatch auts2 control MO display normal levels of developing neurons in the brain, whereas translational MO injected fish display less developing neurons in the cerebellum (ce), optic tectum (ot), and retina (ret). (C) At 120 hpf, fish injected with an auts2 splicing MO and stained with Alcian blue show a significant reduction in the distance between the Meckel (Mk) and ceratohyal cartilages (ch) (shown as a red line) compared to controls, indicating a reduced lower-jaw size. Panels (A, B) adapted from [17], (C) adapted from [26].