Fig. 1

Differential expression of dystrobrevin and dystrophin genes in early stages. (A) EST frequencies of the dystrobrevin and dystrophin genes from human, mouse and zebrafish as a percentage of total dystrophin and dystrobrevin family ESTs of each species. (B) Semi-quantitative RT-PCR for mRNA samples from 16 hpf (14s), 24 hpf, 3d and 5d to the genes: dmd, dp116, utrn, G-utrn, drp2, dtna, dtnb, dtng and dytn normalized to β-actin. (C–V) In situ mRNA hybridisation for dmd (C–E), dtng (F-I), utrn (J), R-utrn (K–P), dtna (Q and R), dtnb (S and T) and drp2 (U and V) in dorsal flatmounts, anterior to top (C, F-H, J, K, Q, S, U), lateral flatmounts, anterior to left (E, I, O, P, R, T, V), lateral flatmounts, anterior to top, dorsal to right (D, L, N) or transverse sections, dorsal to top (C′, E′, F′, H′, I′, M, O′, R′, T′, V′) (C–E). Dtng mRNA is expressed strongly in the hindbrain (red arrowheads, C) and in the notochord at 13s (arrows in C and C′) but is restricted to the posterior notochord by 22s (D, arrow). At 24 hpf, no notochord expression is detected and transcripts are localised to somite borders (E and E′). F–I. Dmd is expressed strongly in the axial region at tb and 5s stage (F, F′, G). By 13s, dmd is strong in the chordo-neural hinge (arrow in H) and is expressed in the floor plate (H′, white arrowhead) and the hypochord (H′, green arrowhead). Weak dmd expression is detected in somite cells (H, yellow arrowheads). At 24 hpf, dmd transcripts are detected only in the myotome concentrated at somite borders (I,I&prime). J–O. Utrn (J) and R-utrn (K–O) are expressed in the pronephric duct from around 13s to 24 hpf (arrowheads). At 22s and 24 hpf expression is noted at muscle fibre ends at somite borders. Smo embryos lacking slow cells have similar expression in muscle and pronephric duct (P). Note the expression in the lateral line primordia (blue arrowhead). (Q and R) At 13s, dtna mRNA shows a diffuse widespread signal (Q and Q′). No specific expression is detected at 24 hpf in the somite area (R and R′). (S-V) Little specific dtnb expression (S and S′) or drp2 (U and U′) was found at 13s and at the somitic area at 24 hpf (dtnb: T and T&prime& drp2: V and V′).