Fig. 5. Wnt signalling marks the exit from pluripotency.

(A) Fluorescence profile of mES cells cultured in serum+LIF that express an mCherry reporter of transcriptionally active β-catenin (Ferrer-Vaquer et al., 2010). The proportion of cells in each of the gates is shown. (B) Gene expression in cells sorted for expression of mCherry using the gates shown in panel A. The two populations were assessed for their expression of markers of pluripotency (Rex1, Nanog, Oct4 and Sox2), epiblast differentiation (Fgf5), primitive streak and its derivatives (T/Bra, Mixl1, Eomes and Gata4) and neural differentiation (Sox1 and Zfp521) using qPCR. Each bar shows the log₂ value of the ratio of gene expression in mCherry high cells versus mCherry low cells. All values were first normalised to Ppia expression. Error bars above and below each bar represent the standard deviation of the mean of 3 or more qPCR replicates. Axin2, a direct transcriptional target of β-catenin signalling, was also measured in both populations and, as expected, was only expressed in the mCherry high population. Increased levels of β-catenin-mediated transcription are associated with loss of pluripotency gene expression and upregulation of markers of multiple opposing lineages.