Recombinant mouse NICD1 (mNICD1) expressed in HeLa cells (human cervical carcinoma cell line) associates with human RBPJ and, after binding to a recombinant mouse Hes1 promoter, activates transcription of a reporter gene (Jarriault et al. 1995). The deletion of RBP-J results in increased differentiation of Ngn3 cells, most likely because of decreased expression of Hes1 and other Notch targets (Apelqvist et al. 1999, Jensen et al. 2000).