Ligand-induced Notch signaling is not affected by exogenous fringe, which is expressed in stimulator CHO cells. Shimizu K et al. J. Biol. Chem. 2001;276:25753-25758 ©2001 by American Society for Biochemistry and Molecular Biology Ligand-induced Notch signaling is not affected by exogenous fringe, which is expressed in stimulator CHO cells. We addressed the question of whether fringe proteins could exhibit modulating activity for ligand-induced Notch signaling when they are introduced into the stimulator CHO cells with exogenous Notch ligands, as was observed on their introduction into the fN2-CHO cells used as a target (Fig. 4 A). To clarify this, we generated respective fringe protein-expressing fD1-CHO and fJ1-CHO cell lines (fD1-mFng-CHO, fD1-lFng-CHO,fJ1-mFng-CHO, and fJ1-lFng-CHO) and performed a transient transcriptional activation assay using the generated cells for stimulation and pGa986–1-transfected fN2-CHO as the target.