Fig. 5. Forced activation of Notch signaling by CNIC^C89 transfection. Stage 28 PV were transfected with indicated expression vectors and cultured for 72 hours. Control explants transfected with EGFP form simple glands and express differentiation markers (A-C). Transfection of CNIC^C89 inhibits gland formation and expression of differentiation-marker genes (D-F). More than 100 explants and more than 40 sections from each explant were investigated. Successfully transfected epithelial cells never expressed differentiation marker genes. Scale bar: 100 µm.