Figure 4

B56α and B56γ are differentially expressed during early Xenopus development. RNA was purified from Xenopus laevis embryos at the indicated stages, and real time RT-PCR was carried out. A standard curve was done from stage 32 embryos, and signals were normalized to that stage. A. B56α is expressed at approximately 45% of the stage 32 value prior to MBT, at approximately 10% of the stage 32 value during gastrula and neurula stages, and its expression gradually increases to its highest expression level during organogenesis. B. The expression level of B56ε is relatively unchanged from the egg to stage 32. C. The expression level of B56γ is highest during organogenesis and is approximately 25% of that value during earlier stages (unfertilized egg to stage 19). D. The mixed-isoform B56δ/γ transcript is expressed at moderate levels until organogenesis (dark blue bars), while B56γ/γ is not significantly expressed until neurulation (light blue bars); both B56δ/γ and B56γ/γ display increased expression during organogenesis. E. A dose response curve of real time RT-PCR amplification data shows that B56α, B56γ, and B56ε primer pairs are isoform specific. Input plasmid DNA concentrations are plotted against their concentration calculated from the amplification of the correct primer pair/template combination.