Notch proteins are involved in cell-fate selection throughout development. Signalling through the transmembrane receptor Notch is triggered by ligand binding, which induces the proteolytic cleavage of the Notch protein. This cleavage generates an intracellular fragment of the Notch protein (Notch-ICD), which translocates into the nucleus and modifies transcription of target genes through its association with the CSL familily of DNA binding protein (where CSL stands for CBF1, Su (H), Lag-1). Notch activity affects the implementation of differentiation, proliferation, and apoptotic programs, providing a general developmental tool to influence organ formation and morphogenesis. To obtain recombinant rat NICD, a long template and high fidelity PCR was used to clone NICD (1744V-2530K) DNA fragment from rat brain cDNA library. The cloned NICD fragment was confirmed by sequencing and then subcloned into glutathione -S-transferase (GST) fusion protein expression vector pGEX-KG. The GST-NICD fusion proteins were expressed in E.coli JM109 after inducing by IPTG. The fusion proteins were purified by affinity chromatography on glutathione Sepharose 4B.