Transduction of NeuroD2 protein induced neural cell differentiation

NeuroD2, one of the neurospecific basic helix–loop–helix transcription factors, has the ability to induce neural differentiation in undifferentiated cells. In this paper, we show that transduction of NeuroD2 protein induced mouse neuroblastoma cell line N1E-115 into neural differentiation. NeuroD2 has two basic-rich domains, one is nuclear localization signal (NLS) and the other is basic region of basic helix–loop–helix (basic). We constructed some mutants of NeuroD2, ND2 Δ100–115 (lack of NLS), ND2 Δ123–134 (lack of basic) and ND2 Δ100–134 (lack of both NLS and basic) for transduction experiments. Using these proteins, we have shown that NLS region of NeuroD2 plays a role of protein transduction. Continuous addition of NeuroD2 protein resulted in N1E-115 cells adopting neural morphology after 4 days and Tau mRNA expression was increased. These results suggest that neural differentiation can be induced by direct addition of NeuroD2 protein.