Explore the vast range of titles available.

Germline–soma segregation is a fundamental event during mammalian embryonic development. Here we establish the epigenetic principles of human primordial germ cell (hPGC) development using in vivo hPGCs and stem cell models recapitulating gastrulation. We show that morphogen-induced remodelling of mesendoderm enhancers transiently confers the competence for hPGC fate, but further activation favours mesoderm and endoderm fates. Consistently, reducing the expression of the mesendodermal transcription factor OTX2 promotes the PGC fate. In hPGCs, SOX17 and TFAP2C initiate activation of enhancers to establish a core germline programme, including the transcriptional repressor PRDM1 and pluripotency factors POU5F1 and NANOG. We demonstrate that SOX17 enhancers are the critical components in the regulatory circuitry of germline competence. Furthermore, activation of upstream cis -regulatory elements by an optimized CRISPR activation system is sufficient for hPGC specification. We reveal an enhancer-linked germline transcription factor network that provides the basis for the evolutionary divergence of mammalian germlines. Tang et al. report that sequential epigenetic remodelling of mesendoderm enhancers is required for the segregation of human primordial germ cell and mesendodermal cell fates.

The X‐chromosomal MECP2/Mecp2 gene encodes methyl‐CpG‐binding protein 2, a transcriptional activator and repressor regulating many other genes. We discovered in male FVB/N mice that mild (~50%) transgenic overexpression of Mecp2 enhances aggression. Surprisingly, when the same transgene was expressed in C57BL/6N mice, transgenics showed reduced aggression and social interaction. This suggests that Mecp2 modulates aggressive social behavior. To test this hypothesis in humans, we performed a phenotype‐based genetic association study (PGAS) in >1000 schizophrenic individuals. We found MECP2 SNPs rs2239464 (G/A) and rs2734647 (C/T; 3′UTR) associated with aggression, with the G and C carriers, respectively, being more aggressive. This finding was replicated in an independent schizophrenia cohort. Allele‐specific MECP2 mRNA expression differs in peripheral blood mononuclear cells by ~50% (rs2734647: C > T). Notably, the brain‐expressed, species‐conserved miR‐511 binds to MECP2 3′UTR only in T carriers, thereby suppressing gene expression. To conclude, subtle MECP2/Mecp2 expression alterations impact aggression. While the mouse data provides evidence of an interaction between genetic background and mild Mecp2 over expression, the human data convey means by which genetic variation affects MECP2 expression and behavior. Synopsis The transcriptional regulator MECP2 is known to affect neurodevelopment. This study associates aggressive social behavior with MECP2 genotype and expression changes in both male schizophrenic patients and mouse models of different genetic background. Mild (50%) overexpression of Mecp2 in mice influences male social aggression. The genetic background (FVB/N versus C57Bl/6N) modulates this overexpression‐associated phenotype. Normal genetic variation of MECP2 (single nucleotide polymorphisms) co‐determines the level of aggression in two independent cohorts of schizophrenic men. miR‐511 downregulates MECP2 expression in T but not C carriers of SNP rs2734647, suggesting miR‐511 targeted therapies in MECP2 gene duplication syndrome. Graphical Abstract The transcriptional regulator MECP2 is known to affect neurodevelopment. This study associates aggressive social behavior with MECP2 genotype and expression changes in both male schizophrenic patients and mouse models of different genetic background.

The X‐chromosomal MECP2/Mecp2 gene encodes methyl‐CpG‐binding protein 2, a transcriptional activator and repressor regulating many other genes. We discovered in male FVB/N mice that mild (~50%) transgenic overexpression of Mecp2 enhances aggression. Surprisingly, when the same transgene was expressed in C57BL/6N mice, transgenics showed reduced aggression and social interaction. This suggests that Mecp2 modulates aggressive social behavior. To test this hypothesis in humans, we performed a phenotype‐based genetic association study (PGAS) in >1000 schizophrenic individuals. We found MECP2 SNPs rs2239464 (G/A) and rs2734647 (C/T; 3′UTR) associated with aggression, with the G and C carriers, respectively, being more aggressive. This finding was replicated in an independent schizophrenia cohort. Allele‐specific MECP2 mRNA expression differs in peripheral blood mononuclear cells by ~50% (rs2734647: C > T). Notably, the brain‐expressed, species‐conserved miR‐511 binds to MECP2 3′UTR only in T carriers, thereby suppressing gene expression. To conclude, subtle MECP2/Mecp2 expression alterations impact aggression. While the mouse data provides evidence of an interaction between genetic background and mild Mecp2 over expression, the human data convey means by which genetic variation affects MECP2 expression and behavior. image The transcriptional regulator MECP 2 is known to affect neurodevelopment. This study associates aggressive social behavior with MECP 2 genotype and expression changes in both male schizophrenic patients and mouse models of different genetic background. Mild (50%) overexpression of Mecp2 in mice influences male social aggression. The genetic background ( FVB /N versus C57Bl/6N) modulates this overexpression‐associated phenotype. Normal genetic variation of MECP 2 (single nucleotide polymorphisms) co‐determines the level of aggression in two independent cohorts of schizophrenic men. miR‐511 downregulates MECP 2 expression in T but not C carriers of SNP rs2734647, suggesting miR‐511 targeted therapies in MECP 2 gene duplication syndrome.

Altered transcription is a cardinal feature of acute myeloid leukemia (AML); however, exactly how mutations synergize to remodel the epigenetic landscape and rewire three-dimensional DNA topology is unknown. Here, we apply an integrated genomic approach to a murine allelic series that models the two most common mutations in AML: Flt3 - ITD and Npm1c . We then deconvolute the contribution of each mutation to alterations of the epigenetic landscape and genome organization, and infer how mutations synergize in the induction of AML. Our studies demonstrate that Flt3-ITD signals to chromatin to alter the epigenetic environment and synergizes with mutations in Npm1c to alter gene expression and drive leukemia induction. These analyses also allow the identification of long-range cis -regulatory circuits, including a previously unknown superenhancer of Hoxa locus, as well as larger and more detailed gene-regulatory networks, driven by transcription factors including PU.1 and IRF8, whose importance we demonstrate through perturbation of network members. Mice bearing mutations in Flt3-ITD and Npm1c , which are commonly found in acute myeloid leukemia, are used to characterize the cooperative effects of these cancer drivers on the cellular epigenome and three-dimensional genome conformation during tumor development.

Altered transcription is a cardinal feature of acute myeloid leukemia (AML), however, exactly how mutations synergize to remodel the epigenetic landscape and rewire 3-Dimensional (3D) DNA topology is unknown. Here we apply an integrated genomic approach to a murine allelic series that models the two most common mutations in AML, Flt3-ITD and Npm1c. We then deconvolute the contribution of each mutation to alterations of the epigenetic landscape and genome organization, and infer how mutations synergize in the induction of AML. Our studies demonstrate that Flt3-ITD signals to chromatin to alter the epigenetic environment and synergizes with Npm1c mutation to alter gene expression and drive leukemia induction. These analyses also allow the identification of long-range cis-regulatory circuits, including a novel super-enhancer of Hoxa locus, as well as larger and more detailed gene-regulatory networks, driven by transcription factors including PU.1 and IRF8, whose importance we demonstrate through perturbation of network members.

Human germline–soma segregation occurs during weeks 2–3 in gastrulating embryos. Although direct studies are hindered, here, we investigate the dynamics of human primordial germ cell (PGCs) specification using in vitro models with temporally resolved single-cell transcriptomics and in-depth characterisation using in vivo datasets from human and nonhuman primates, including a 3D marmoset reference atlas. We elucidate the molecular signature for the transient gain of competence for germ cell fate during peri-implantation epiblast development. Furthermore, we show that both the PGCs and amnion arise from transcriptionally similar TFAP2A-positive progenitors at the posterior end of the embryo. Notably, genetic loss of function experiments shows that TFAP2A is crucial for initiating the PGC fate without detectably affecting the amnion and is subsequently replaced by TFAP2C as an essential component of the genetic network for PGC fate. Accordingly, amniotic cells continue to emerge from the progenitors in the posterior epiblast, but importantly, this is also a source of nascent PGCs.

During embryonic development, cells undertake a series of fate decisions to form a complete organism comprised of various cell types, epitomising a branching process. A striking example of branching occurs in humans around the time of implantation, when primordial germ cells (PGCs), precursors of sperm and eggs, and somatic lineages are specified. Due to inaccessibility of human embryos at this stage of development, understanding the mechanisms of PGC specification remains difficult. The integrative modelling of single cell transcriptomics data from embryos and appropriate in vitro models should prove to be a useful resource for investigating this system, provided that the cells can be suitably ordered over a developmental axis. Unfortunately, most methods for inferring cell ordering were not designed with structured (time series) data in mind. Although some probabilistic approaches address these limitations by incorporating prior information about the developmental stage (capture time) of the cell, they do not allow the ordering of cells over processes with more than one terminal cell fate. To investigate the mechanisms of PGC specification, we develop a probabilistic pseudotime approach, branch-recombinant Gaussian process latent variable models (B-RGPLVMs), that use an explicit model of transcriptional branching in individual marker genes, allowing the ordering of cells over developmental trajectories with arbitrary numbers of branches. We use first demonstrate the advantage of our approach over existing pseudotime algorithms and subsequently use it to investigate early human development, as primordial germ cells (PGCs) and somatic cells diverge. We identify known master regulators of human PGCs, and predict roles for a variety of signalling pathways, transcription factors, and epigenetic modifiers. By concentrating on the earliest branched signalling events, we identified an antagonistic role for FGF receptor (FGFR) signalling pathway in the acquisition of competence for human PGC fate, and identify putative roles for PRC1 and PRC2 in PGC specification. We experimentally validate our predictions using pharmacological blocking of FGFR or its downstream effectors (MEK, PI3K and JAK), and demonstrate enhanced competency for PGC fate in vitro, whilst small molecule inhibition of the enzymatic component of PRC1/PRC2 reveals reduced capacity of cells to form PGCs in vitro. Thus, B-RGPLVMs represent a powerful and flexible data-driven approach for dissecting the temporal dynamics of cell fate decisions, providing unique insights into the mechanisms of early embryogenesis. Footnotes * Updated benchmarking against existing methods and biological experiments

Human germline-soma segregation occurs during weeks 2-3 in gastrulating embryos. While direct studies are hindered, here we investigate the dynamics of human primordial germ cell (PGCs) specification using in vitro models with temporally resolved single-cell transcriptomics and in-depth characterisation to in vivo datasets from human and non-human primates, including a 3D marmoset reference atlas. We elucidate the molecular signature for the transient gain of competence for germ cell fate during peri-implantation epiblast development. Further, we show that both the PGCs and amnion arise from transcriptionally similar TFAP2A positive progenitors at the posterior end of the embryo. Notably, genetic loss of function experiments show that TFAP2A is crucial for initiating the PGC fate without detectably affecting the amnion, and its subsequently replaced by TFAP2C as an essential component of the genetic network for PGC fate. Accordingly, amniotic cells continue to emerge from the progenitors in the posterior epiblast, but importantly, this is also a source of nascent PGCs.

Altered transcription is a cardinal feature of acute myeloid leukemia (AML), however, exactly how mutations synergize to remodel the epigenetic landscape and rewire 3-Dimensional (3-D) DNA topology is unknown. Here we apply an integrated genomic approach to a murine allelic series that models the two most common mutations in AML, Flt3-ITD and Npm1c. We then deconvolute the contribution of each mutation to alterations of the epigenetic landscape and genome organization, and infer how mutations synergize in the induction of AML. These analyses allow the identification of long-range cis-regulatory circuits, including a novel super-enhancer of the Hoxa locus, as well as larger and more detailed gene-regulatory networks, whose importance we demonstrate through perturbation of network members.