NANOG is a transcription factor involved with self-renewal of inner cell mass and embryonic stem (ES) cells by functioning in concert with other factors such as POU5F1 (Oct-4) and SOX2. Nanog imposes pluripotency on ES cells and prevents their differentiation towards extraembryonic endoderm and trophectoderm lineages, and blocks bone morphogenetic protein-induced mesoderm differentiation of ES cells by physically interacting with SMAD1 and interfering with the recruitment of coactivators to the active SMAD transcriptional complexes.Recombinant human NANOG-TAT (rhNANOG-TAT) produced in E.coli is a single chain, 318 amino acids non-glycosylated polypeptide. A fully biologically active molecule, rhNANOG-TAT has a molecular mass of 36.2kDa analyzed by reducing SDS-PAGE and is obtained by proprietary chromatographic techniques at GenScript.