Figure 1: Schematic illustration of pluripotency maintenance by transcriptional regulation, epigenetic regulation, and signaling pathways. Oct4, Sox2 and Nanog form the core transcriptional regulatory circuitry for pluripotency (highlighted with a red circle). Pluripotency-associated transcription factors, together with the core transcriptional regulatory circuitry, form the expanded transcriptional regulatory network of pluripotency. Transcriptional co-factors and chromatin regulators collaborate with transcription factors to maintain pluripotency. Different signaling events facilitate the maintenance of the na´ve or primed pluripotency.