Facilitators and Impediments of the Pluripotency Reprogramming Factors’ Initial Engagement with the Genome The ectopic expression of transcription factors can reprogram cell fate, yet it is unknown how the initial binding of factors to the genome relates functionally to the binding seen in the minority of cells that become reprogrammed. The authors report a map of Oct4, Sox2, Klf4, and c-Myc on the human genome during the first 48 hours of reprogramming fibroblasts to pluripotency. [Cell] Abstract | Press Release | Graphical Abstract Distinct Metabolic Flow Enables Large-Scale Purification of Mouse and Human Pluripotent Stem Cell-Derived Cardiomyocytes Investigators report a nongenetic method for mass-producing cardiomyocytes from mouse and human pluripotent stem cell derivatives that is based on the marked biochemical differences in glucose and lactate metabolism between cardiomyocytes and noncardiomyocytes, including undifferentiated cells. [Cell Stem Cell] Abstract | Graphical Abstract Polycomb PHF19 Binds H3K36me3 and Recruits PRC2 and Demethylase NO66 to Embryonic Stem Cell Genes during Differentiation The authors proposed a model whereby PHF19 functions during mouse embryonic stem cell differentiation to transiently bind the trimethylated histone H3 Lys36 (H3K36me3) mark via its Tudor domain, forming essential contact points that allow recruitment of Polycomb repressive complex 2 (PRC2) and H3K36me3 demethylase activity to active gene loci during their transition to a Polycomb-repressed state. [Nat Struct Mol Biol] Abstract In Vivo Directed Differentiation of Pluripotent Stem Cells for Skeletal Regeneration Researchers evaluated the ability of an osteogenic microniche consisting of a hydroxyapatite-coated, bone morphogenetic protein-2-releasing poly-l-lactic acid scaffold placed within the context of a macroenvironmental skeletal defect to guide in vivo differentiation of both embryonic and induced pluripotent stem cells. [Proc Natl Acad Sci USA] Abstract | Press Release Regulation of Endodermal Differentiation of Human Embryonic Stem Cells through Integrin-ECM Interactions Data provide evidence that fibronectin (FN) and vitronectin (VTN) promote endoderm differentiation of human embryonic stem cells (hESCs) through interaction with FN-binding integrin α5 and VTN-binding integrin αV, and that extracellular matrix (ECM) protein-integrin interactions are required for hESC differentiation into functionally mature cells. [Cell Death Differ] Full Article Transcription Elongation Factor Tcea3 Regulates the Pluripotent Differentiation Potential of Mouse Embryonic Stem Cells, via the Lefty1-Nodal-Smad2 Pathway Researchers report that the transcription elongation factor Tcea3 is highly enriched in mouse embryonic stem cells and plays important roles in regulating the differentiation. [Stem Cells] Abstract Co-Motif Discovery Identifies an Esrrb-Sox2-Dna Ternary Complex as a Mediator of Transcriptional Differences between Mouse Embryonic and Epiblast Stem Cells Through the use of knockdown experiments researchers argued that the Esrrb-Sox2 complex is an arbiter of gene expression differences between embryonic stem cells and epiblast stem cells. [Stem Cells] Abstract High-Frequency Hippocampal Oscillations Activated by Optogenetic Stimulation of Transplanted Human ESC-Derived Neurons Using multielectrode array recordings, researchers reported activation of high-frequency oscillations in the ß and γ ranges (10-100 Hz) in the host hippocampal network via targeted optogenetic stimulation of transplanted human embryonic stem cell (ESC)-derived neurons. [J Neurosci] Abstract | Press Release Chromatin Decondensation and Nuclear Softening Accompany Nanog Downregulation in Embryonic Stem Cells Researchers showed that naïve embryonic stem cells decondense their chromatin in the course of downregulating the pluripotency marker Nanog before they initiate lineage commitment. [Biophys J] Abstract Mediator and SAGA Have Distinct Roles in Pol II Preinitiation Complex Assembly and Function A key feature of RNA polymerase II (Pol II) preinitiation complexes (PICs) is their ability to coordinate transcription initiation with chromatin modification and remodeling. To understand how this coordination is achieved, researchers employed extensive proteomic and mechanistic analyses to study the composition and assembly of PICs in HeLa cell and mouse embryonic stem cell nuclear extracts. [Cell Rep] Abstract | Full Article |