Fig. 1

Zebrafish pegasus is broadly expressed during embryonic development. (A) Alternate splicing of zebrafish pegasus. The exon–intron structure of three alternatively spliced variants (1–3) of pegasus identified through ESTs. Coding and non-coding regions are displayed as thick or thin lines, respectively, with spliced introns shown with dashed lines. (B) Expression analysis of pegasus using RT-PCR. Total RNA was extracted from 4 cell, 24 hpf, 48 hpf, 72 hpf and 7 dpf embryos, as well as adult fish, and incubated in the presence of reverse transcriptase (RT), except for a control (24 hpf) sample in which the RT was omitted (RT-). PCR was performed on these samples using primers specific for pegasus and β-actin, as indicated. (C–T) Spatio-temporal expression of pegasus during embryogenesis. Zebrafish embryos at 1.25 hpf (C–D), 4 hpf (E–F), 6 hpf (G–H), 14 hpf (I–J), 24 hpf (K–L), 48 hpf (M–N), 72 hpf (O–Q) and 7 dpf (R–T) were analysed by whole-mount in situ hybridisation (WISH) using either antisense (AS: C, E, G, I, K, M, O, Q, R, and T) or sense (S: D, F, H, J, L, N, P, and S) probes specific for the pegasus gene, as indicated. Panels Q and T represent sectioned WISH embryos stained with Fast Red. The dashed lines in panel I and J indicate the position of the developing embryo. Expression of pegasus is evident by purple staining in the following labelled structures: b—body; di—diencephalon; le—lens; ep—epiphysis; fb—forebrain; fi—fin; g—gut; gcl—ganglion cell layer; h—head; hb—hindbrain; i—intestine; ir—iris; mc—mandibular cartilage; oc—optic chiasm; ov—otic vesicle; p—pancreas (exocrine); s—sphere stage embryo; t—tectum; th—thymus; and 8c—8 cell embryo.