Project description:In early mammalian development, cleavage stage blastomeres and cells of the inner cell mass (ICM) of the blastocyst co-express embryonic and extra-embryonic transcriptional determinants. Using a double protein-based reporter we identify embryonic stem cells (ESC) that co-express the extra-embryonic factor GATA6 alongside the embryonic factor SOX2 in specific conditions. Based on single cell transcriptomics we find these population resemble unsegregated ICM, exhibiting enhanced differentiation potential for endoderm while maintaining epiblast competence and suggesting they represent an ideal model to determine how GATA6 and SOX2 influence each other's DNA binding. To relate this binding to future fate, we describe a complete enhancer set in both ESCs and naïve extraembryonic endoderm stem cells and ask whether SOX2 and GATA6 recognize these elements in ICM-like ESC sub-population. Both factors support cooperative recognition in these lineages, with GATA6 bound alongside SOX2 on a fraction of pluripotency enhancers and SOX2 alongside GATA6 more extensively on endoderm enhancers. Our findings suggest that cooperative binding between these antagonistic factors both supports self-renewal and prepares progenitor cells for later differentiation
Project description:Epiblast cells in the early post-implantation stage mammalian embryo undergo a transition described as lineage priming before cell fate allocation, but signaling pathways acting upstream remain ill defined. Genetic studies demonstrate that Smad2/3 double-mutant mouse embryos die shortly after implantation. To learn more about the molecular disturbances underlying this abrupt failure, here we characterised Smad2/3-deificient embryonic stem cells (ESCs). We found that Smad2/3 double-knockout ESCs induced to form epiblast-like cells (EpiLCs) display changes in naïve and primed pluripotency marker gene expression, associated with the disruption of Oct4-bound distal regulatory element. In the absence of Smad2/3, we observed enhanced Bmp target gene expression and de-repression of extra-embryonic gene expression. Cell fate allocation into all three embryonic germ lakers is disrupted. Collectively, these experiments demonstrate that combinatorial Smad2/3 functional activities are required to maintain distinct embryonic and/or extra-embryonic cell identity during lineage priming in the epiblast before gastrulation.
Project description:Epiblast cells in the early post-implantation stage mammalian embryo undergo a transition described as lineage priming before cell fate allocation, but signaling pathways acting upstream remain ill defined. Genetic studies demonstrate that Smad2/3 double-mutant mouse embryos die shortly after implantation. To learn more about the molecular disturbances underlying this abrupt failure, here we characterised Smad2/3-deificient embryonic stem cells (ESCs). We found that Smad2/3 double-knockout ESCs induced to form epiblast-like cells (EpiLCs) display changes in naïve and primed pluripotency marker gene expression, associated with the disruption of Oct4-bound distal regulatory element. In the absence of Smad2/3, we observed enhanced Bmp target gene expression and de-repression of extra-embryonic gene expression. Cell fate allocation into all three embryonic germ lakers is disrupted. Collectively, these experiments demonstrate that combinatorial Smad2/3 functional activities are required to maintain distinct embryonic and/or extra-embryonic cell identity during lineage priming in the epiblast before gastrulation.
Project description:Epiblast cells in the early post-implantation stage mammalian embryo undergo a transition described as lineage priming before cell fate allocation, but signaling pathways acting upstream remain ill defined. Genetic studies demonstrate that Smad2/3 double-mutant mouse embryos die shortly after implantation. To learn more about the molecular disturbances underlying this abrupt failure, here we characterised Smad2/3-deificient embryonic stem cells (ESCs). We found that Smad2/3 double-knockout ESCs induced to form epiblast-like cells (EpiLCs) display changes in naïve and primed pluripotency marker gene expression, associated with the disruption of Oct4-bound distal regulatory element. In the absence of Smad2/3, we observed enhanced Bmp target gene expression and de-repression of extra-embryonic gene expression. Cell fate allocation into all three embryonic germ lakers is disrupted. Collectively, these experiments demonstrate that combinatorial Smad2/3 functional activities are required to maintain distinct embryonic and/or extra-embryonic cell identity during lineage priming in the epiblast before gastrulation.