Fig. 1

Maternal rest is required for proper FBMN migration. (A) PCR genotyping of mating crosses to produce rest zygotic and maternal–zygotic (MZ) mutant embryos. The rest^sbu29 allele introduces a 7 bp deletion resulting in a smaller PCR product (red arrowhead). Homozygous mutant females (red box) produced eggs lacking maternal rest transcript. (B–F) Average intensity projection confocal images (dorsal views) of Tg(islet1:GFP); rest^sbu29 mutant embryos at 48 hpf, immunolabeled with EphA4a to allow visualization of r5 (red). Scale bar=20 µm. Decreasing levels of rest from B to F correlate with increasing disruption in FBMN migration. (B′–F′) Pie charts represent the average number of FBMNs counted in r4 (black), r5 (checkered), and r6 (white) as a percentage of total FBMNs in rest mutant embryos. The total number of FBMNs was not significantly different in embryos of different genotypes. (G) Statistical analysis of FBMN migration in rest^sbu29 mutants. The percentages of FBMNs that fully migrate to r6 (white) were compared using unpaired t test. Parentheses indicate number of embryos analyzed per group. Mean±SEM; ^*P<0.05; ^**P<0.01; ^***P<0.001; ^****P<0.0001; n.s.=not significant. (H and I) Tg(islet1:GFP) embryos co-injected with both splice- and translation-blocking morpholinos targeted against Rest recapitulate the MZrest^sbu29/sbu29 mutant phenotype at 48 hpf. Scale bar=20 µm. (J and K) MZrest^sbu29/sbu29 FBMNs fail to reach r6 at 72 hpf, indicating that the mutant phenotype is not merely a consequence of developmental delay.