Fig. 7. Expression of Numb, Notch1-IC and activated β-catenin in early embryos. Confocal images (maximum projection by z-stacking, XY planes) of whole-mount immunostaining for (A) Numb, (B) cleaved Notch1 intracellular domain (Notch1-IC) and (C) activated β-catenin in different staged mouse embryos and yolk sacs. Yellow arrows show the yolk sac; white arrowheads indicate the posterior primitive streak region in neural plate stage embryos, and white arrows indicate the embryo proper. Broken lines delineate the YS region in somite-stage embryos. Scale bars: 100 µm. Red, Numb, Notch1-IC or activated β-catenin; blue, DAPI