Fig. 3. Expression of ryanodine receptors in embryo. (A) Phylogenetic tree of vertebrate RyR family members based on a ClustalW generated alignment of zebrafish RyR3 (CAI11683), chicken RyR3 (Q90985), human RyR3 (Q15413), mouse RyR1 (Q80X16), human RyR1 (P21817), mouse RyR2 (Q9ERN6) and human RyR2 (Q5VWP1). (B) Sequence alignment of the divergent region showing: *, identical residues;:, conservative residues;., semi-conservative residues. (C) Dorsal view of a 10 somite embryo showing expression of zfRyR3 in adaxial muscle pioneer cells of newly formed somites (arrows) and both adaxial and paraxial (arrowhead) cells of more mature somites. Anterior is to the top. (D) Transverse 15 micron section through the trunk of a 32 hpf embryo stained for zfRyR3 expression (blue). (E) Transverse 15 micron section through the trunk of a 32 hpf embryo stained with the pan muscle myosin antibody (brown) and for zfRyR3 expression (blue). Expression is detected throughout the myotome. Immunostaining in embryos aged (F) 20 hpf and (G) 24 hpf with 34C antibody (red) revealed ryanodine receptor clusters from 20 hpf onwards (arrows). Immunostaining using 34C antibody in (H) wild type and (I) nic1 zebrafish embryos at 48 hpf. Bars 10 µm.