Zebrafish ryr mRNA can be detected from very early developmental stages through to adulthood. (a) Temporal expression pattern of zebrafish ryrs using end-point PCR analysis and isoform specific primers. Total RNA was isolated from different developmental stages, as indicated, and reverse transcribed. 1.5 μg of cDNA was synthesised and isoform specific primers for ryr1a, ryr1b, ryr2a, ryr2b and ryr3 used. Numbers in the right panel indicate the molecular mass of PCR products. β-actin was used as an internal control. The figure shows a representative result of replicates from at least three experiments. (b) Expression of zebrafish ryr2a and ryr2b in the brain (BR) and body (BO) of a 3 months old adult zebrafish. β-actin was used as an internal control. Numbers in the right panel indicate the molecular mass of RT-PCR products. (c) Maternal expression of ryr3 mRNA was observed as staining (arrows) within the dividing cells of 2-2.25 hpf embryos (64 and 128-cell stage). The specificity of the signal is compared to the ryr3 sense probes.