Nanog mediated control of TBX3-GATA6 circuitry in primitive endoderm differentiation of mESCs.

Cell fate decisions in the early embryo rely on reciprocal transcriptional networks that balance pluripotency with lineage commitment. NANOG is essential for directing the epiblast-primitive endoderm (PrE) fate choice, but the molecular mechanisms underlying its repressive activity remain incompletely understood. Here we show that NANOG partners with TBX3 and the PRC2 complex to maintain embryonic stem cell (ESC) identity by silencing PrE genes through newly identified distal enhancers. Loss of Nanog reduces PRC2-mediated repression of Gata6, initiating its expression independently of TBX3. Subsequent TBX3 upregulation enables its association with GATA6, driving a feed-forward programme that activates Gata6, Gata4 and Sox17 and promotes PrE differentiation. Thus, NANOG suppresses PrE fate not only by direct repression but also by preventing TBX3 from switching partners. These findings define a Nanog-Tbx3-Gata6 regulatory axis that integrates enhancer control, chromatin regulation and transcription factor redeployment to couple ESC maintenance with lineage commitment.