A, UCSC browser image showing RNA-seq reads (pink vertical histograms) at the zic3 locus (in blue; tall boxes - exons; half-height boxes - UTRs; lines - introns; arrowheads - direction of transcription). B, RT-PCR detection of zic3 transcripts in zebrafish embryo. Portion of image showing expression at 1 hpf to 3 hpf was enhanced to show weak band at 3 hpf. C, D and E, zic3 expression in 4 hpf, 6 hpf, and 8 hpf embryos. Lateral view, dorsal to the right. C′, D′ and E′, animal pole view. F, G, zic3 expression in wild-type and gfp in SqET33 embryos at 24 hpf. F′, G′, dorsal view. Note the absence of gfp expression from the olfactory bulb and presomitic mesoderm domains of the wild-type zic3 expression (arrows). H–H″, GFP expression in live SqET33 embryos at 24 hpf. H, dorsal view, H′, frontal view, H″, lateral view.