In the August 21st issue of Cell, J. Silva et al. from the University of Cambridge (U.K.) reported their study results on the Nanog mediating the pluripotent state of both embryonic and reprogrammed somatic cells. In cell fusion experiments, pluripotent cell hybrids required Nanog expression. The investigators also found that induced pluripotent stem cells reprogrammed with transcription factors (Sox2, Oct4, Klf4, and c-Myc) required Nanog expression as the somatic cells transitioned to the pluripotent ground state. During embryogenesis, Nanog is required for the blastocyts in the cell mass to reach the pluripotent state. Embryonic cells lacking Nanog were found to be trapped in the pre-pluripotent and the indeterminate state which eventually become non-viable cells. The authors concluded from their observation that "Nanog choreographs synthesis of the naive epiblast ground state in the embryo and that this function is recapitulated in the culmination of somatic cell reprogramming."