We study embryonic stem cells (ESCs). These cells are pluripotent, meaning they can change into all the cell types of our bodies (differentiation). ESCs can also divide to produce cells identical to themselves, a process termed self-renewal. The simultaneous possession of these properties is what makes ESCs useful.
Pluripotent cell identity is controlled by the action of transcription factors (TFs) that together form cell-specific gene regulatory networks. In ESCs the gene regulatory network is centred on the TFs OCT4, SOX2 and NANOG. We identified NANOG in a genetic screen, searching for molecules that could allow ESCs to self-renew in the absence of the otherwise obligatory cytokine, LIF. Because of this phenotype, we named it Nanog, after Tir nan Og, the mythological Celtic land of the ever-young, where visitors remain unaged. We use Nanog as a tool to investigate how pluripotent cells are regulated.