Fig. 3

Functional Assessment of Rare Nonsynonymous Variants in MEIS1 by In Vivo Complementation in Zebrafish Embryos

(A) Location and frequency of nonsynonymous MEIS1 variants examined in zebrafish. Variants found in case subjects are given above the gene, those found in control subjects below. The short, canonical isoform 1 of MEIS1 is given in dark gray (ENST00000272369); the additional amino acids in the longer isoform 2 in light gray (ENST00000398506).

(B) At 72 hpf, zebrafish larvae were stained as whole mounts using an antibody against acetylated tubulin and the size of the optic tecta was measured for phenotypic read out. Control, morpholino injection, and rescue by human WT mRNA are shown in the upper panels. The lower panels illustrate the effects of different alleles tested.

(C) Quantification of optic tectum area in zebrafish larvae at 72 hpf (n = at least 51 per genotype). Benign alleles show a significant difference with regard to the MO injection, hypomorphic alleles a significant difference with regard to both the MO injection and the rescue (MO plus WT) injection, and null alleles are significantly different from the rescue only. Asterisks denote significance levels as determined by Student’s t test. Color of asterisks as follows: blue, MO versus control; green, rescue versus MO; black, allele versus MO; red, allele versus WT rescue. Abbreviations are as follows: MO, morpholino; WT, wild-type. Error bars represent standard deviations across all examined embryos.