Figure 6.

TAp73 is required for the establishment of appropriate adherens junctions (AJs) and its absence results in the formation of mESC colonies with a “primed” phenotype. (A) Representative images showing characteristic colony morphology of WT and knockout E14 cells seeded under stemness conditions and images of alkaline phosphatase activity for colonies grown in the presence or absence of LIF. Scale bar: 100 μm. (B,C) Analysis of AJs and colony thickness by confocal microscopy orthogonal projections of three-dimensional reconstruction images in the indicated genotypes (B) or after TAp73 ectopic expression in E14-TAp73KO cells (C). Cells were immunostained with anti-β-catenin (red) and anti-E-cadherin (green) antibodies. Scale bar: 20 μm. White arrows indicate continuous and tight AJ (B,C), yellow arrows pleated and broken up AJ (C) and pink and dotted arrows indicate recovered AJ and second layer of cells after TAp73KO re-expression, respectively. The insert represents a magnification of the indicated area (RED square). (D) Quantification of colony thickness using orthogonal projections from Z-stacks of confocal microscopy images. * p-value < 0.05, *** p-value < 0.001.