Cis-Acting DNA Sequence at a Replication Origin Promotes Repeat Expansion to Fragile X Full Mutation Investigators examined the relationship between a single-nucleotide polymorphism (SNP) variant that is linked to repeat expansion in haplogroup D and a replication origin located ~53 kb upstream of the repeats. This origin is absent in fragile X syndrome human embryonic stem cells (hESCs), which have the SNP variant C, but present in the nonaffected hESCs, which have a T variant. [J Cell Biol] Abstract | Press Release Conversion of Human Fibroblasts into Monocyte-Like Progenitor Cells Researchers report on the establishment of a novel methodology allowing for the conversion of human fibroblasts into hematopoietic progenitor-like cells with macrophage differentiation potential. [Stem Cells] Abstract Stress-Induced Enzyme Activation Primes Murine Embryonic Stem Cells to Differentiate toward the First Extraembryonic Lineage To understand the effects of stress signaling during a critical period of pregnancy, investigators exposed cultured murine embryonic stem cells to hyperosmotic stress. [Stem Cells Dev] Abstract Effect of Arsenic Compounds on the Mouse Embryonic Stem Cells Differentiation into Cardiomyocytes In Vitro Investigators evaluated effects of arsenic compounds on embryonic stem cells differentiation into cardiomyocytes in vitro and predict the associated toxic effects. [Chem Res Toxicol] Abstract Long Non-Coding RNAs as Surrogate Indicators for Chemical Stress Responses in Human Induced Pluripotent Stem Cells The authors identified six novel long non-coding RNAs (lncRNAs) that respond to model chemical stresses in human induced pluripotent stem cells. Their results indicated that the lncRNAs responded to general and specific chemical stresses. [PLoS One] Full Article Synergistic Transcriptional and Post-Transcriptional Regulation of ESC Characteristics by Core Pluripotency Transcription Factors in Protein-Protein Interaction Networks The authors analyzed the topological properties of the “core” pluripotency transcription factors OCT4, SOX2 and NANOG in protein-protein interaction networks (PPINs). They identified synergistic interactions between these transcription factors and microRNAs in PPINs during embryonic stem cell (ESC) development [PLoS One] Full Article Trisomy 21 Mid-Trimester Amniotic Fluid Induced Pluripotent Stem Cells Maintain Genetic Signatures during Reprogramming: Implications for Disease Modeling and Cryobanking Researchers aimed to derive induced pluripotent stem cells from trisomy 21 human mid-trimester amniotic fluid stem cells and describe their hematopoietic and neurological characteristics. [Cell Reprogram] Abstract Induced Expression of Fndc5 Significantly Increased Cardiomyocyte Differentiation Rate of Mouse Embryonic Stem Cells To help identify the involvement of Fndc5 in the process of cardiomyocyte differentiation, scientists generated a stably inducible transduced mouse embryonic stem cell line that overexpressed Fndc5 following Doxycycline induction. [Gene] Abstract Transient p53 Suppression Increases Reprogramming of Human Fibroblasts without Affecting Apoptosis and DNA Damage Researchers report that transient suppression of tumor protein 53 (p53) during nonintegrative reprogramming of human fibroblasts leads to a significant increase in expression of pluripotency markers and overall number of induced pluripotent stem cell colonies, due to downstream suppression of p21, without affecting apoptosis and DNA damage. [Stem Cell Reports] Full Article | Graphical Abstract Zinc-Finger Nuclease Enhanced Gene Targeting in Human Embryonic Stem Cells Researchers describe targeting of the Pituitary homeobox 3 (PITX3) locus in human embryonic stem cells using custom designed zinc-finger nucleases, which introduce site-specific double-strand DNA breaks, together with a PITX3-EGFP-specific DNA donor vector. [J Vis Exp] Abstract |