<i>Nanog</i> regulates <i>Pou3f1</i> expression at the exit from pluripotency during gastrulation

Abstract

Pluripotency is regulated by a network of transcription factors that maintain early embryonic cells in an undifferentiated state while allowing them to proliferate. NANOG is a critical factor for maintaining pluripotency and its role in primordial germ cell differentiation has been well described. However, <i>Nanog</i> is expressed during gastrulation across all the posterior epiblast, and only later in development is its expression restricted to primordial germ cells. In this work, we unveiled a previously unknown mechanism by which <i>Nanog</i> specifically represses genes involved in anterior epiblast lineage. Analysis of transcriptional data from both embryonic stem cells and gastrulating mouse embryos revealed <i>Pou3f1</i> expression to be negatively correlated with that of <i>Nanog</i> during the early stages of differentiation. We have functionally demonstrated <i>Pou3f1</i> to be a direct target of NANOG by using a dual transgene system for the controlled expression of <i>Nanog</i> Use of <i>Nanog</i> null ES cells further demonstrated a role for <i>Nanog</i> in repressing a subset of anterior neural genes. Deletion of a NANOG binding site (BS) located nine kilobases downstream of the transcription start site of <i>Pou3f1</i> revealed this BS to have a specific role in the regionalization of the expression of this gene in the embryo. Our results indicate an active role of <i>Nanog</i> inhibiting neural regulatory networks by repressing <i>Pou3f1</i> at the onset of gastrulation.This article has an associated First Person interview with the joint first authors of the paper.