Fig. 6. Sox17 and ß-catenin co-operate to transcribe endodermal genes. Embryos were injected at the 2-cell stage with Sox17ß mRNA (20 pg, 60 pg, 180 pg) either with or without co-injection of RNA encoding a stabilized ß-catenin (pt-ß-catenin, 100 pg) (Yost et al., 1996). At blastula stage, animal cap tissue was explanted and cultured for 3-4 hours until gastrula stage when it was assayed by real-time RT-PCR for the expression of Sox17 target genes. The histograms show the relative expression levels normalized to the loading control ODC. Plakoglobin (Plako) is control gene that is neither a target of Sox17 nor ß-catenin.