Fig. 8

Zebrafish alx1 protects craniofacial and ocular lineages against ethanol toxicity. Embryos derived from wildtype, alx1^uw2016, or alx1^uw2016/+ parents were exposed to 0.5% ethanol from 6 hpf until 48 hpf and examined for craniofacial and ocular abnormalities at 5 dpf. (A-C) Embryos were stained with Alcian Blue to visualize anterior neurocranium (ANC) chondrocytes. Examples of normal ANC morphology (A) in an ethanol-treated wildtype larva, mildly dysmorphic median ANC in an ethanol-treated alx1^uw2016 mutant (B), and severely abrogated ANC with missing median element in an ethanol-treated alx1^uw2016 mutant. (D) Ethanol exposure does not increase penetrance of craniofacial defects in wildtype (n.s., not significant; P=0.2424) whereas it increases in progeny from alx1×alx1/+ (*P=0.0237). Compared to untreated or treated wildtype, craniofacial defects are more penetrant in untreated or progeny from alx1×alx1/+ (**P=0.0066, ****, P<0.0001), respectively. Fisher's exact test was used to measure statistical significance (three trials for wildtype and two trials for alx1×alx1/+). (E-G) Embryos were exposed to ethanol and examined for ocular anomalies at 5 dpf. (E) A representative 5 dpf wildtype larva with normal ocular morphology. (F) Misshapen eye in a representative alx1 homozygote. (G) Ethanol exposure increases penetrance of ocular abnormalities in wildtype (*P=0.0448) and in alx1^uw2016 mutants (***P=0.0005). Compared to wildtype, abnormal ocular phenotype is more penetrant in both untreated alx1 mutants (***P=0.0003) and in ethanol-treated ones (****P<0.0001). Fisher's exact test was used to measure statistical significance (one trial for wildtype and two trials for alx1 mutants). (H-J) Three representative alx1^uw2016 adults exposed to 0.5% ethanol from 6 hpf until 48 hpf and raised to adulthood (2 months of age) exhibit unilateral ocular anomalies. (K) Penetrance of ocular defects increased following embryonic exposure to ethanol but did not rise to significance (n.s., P=0.1022. Fisher's exact test, one trial). (A-C) dissected ANC preparations, anterior to the top. (E,F) lateral views, anterior to the left. H and H′ are different sides of the same fish, as are I and I′, and J and J′, shown in lateral view. mANC: median ANC.