Project description:DNA methylation, in concert with other epigenetic regulators, controls the accessibility of transcription factors to DNA. While comprehensively described in the development of neuronal progenitors, the role of DNA methylation/demethylation in neuronal lineage/subtype specification is not known. By profiling two distinct neuronal lineages, and five neuron subtypes in the hippocampus and striatum, we uncovered a set of five principles that govern DNA methylation dynamics in neurodevelopment. By dividing neurodevelopment to three alternating methylation and demethylation periods and applying the principles to each of these stages, we created a matrix that comprehensively describes the targets, genomic contexts, functional consequences and putative mechanisms of methylation/demethylation events. The overarching theme is that the developmental methylation program is remarkably similar in the hippocampal and striatal lineages, with significant divergence only occurring during subtype specification. Our matrix can be cross-referenced with disease-associated epigenetic changes to specify the possible events and underlying principles compromised in disease. Compared tissue from C57BL6 male animals at differenent developmental timepoints and regions for differences in DNA methylation and RNA expression. Additionally Dnmt3a conditional knockdown mice were used to determine role of Dnmt3a during development.
Project description:DNA methylation, in concert with other epigenetic regulators, controls the accessibility of transcription factors to DNA. While comprehensively described in the development of neuronal progenitors, the role of DNA methylation/demethylation in neuronal lineage/subtype specification is not known. By profiling two distinct neuronal lineages, and five neuron subtypes in the hippocampus and striatum, we uncovered a set of five principles that govern DNA methylation dynamics in neurodevelopment. By dividing neurodevelopment to three alternating methylation and demethylation periods and applying the principles to each of these stages, we created a matrix that comprehensively describes the targets, genomic contexts, functional consequences and putative mechanisms of methylation/demethylation events. The overarching theme is that the developmental methylation program is remarkably similar in the hippocampal and striatal lineages, with significant divergence only occurring during subtype specification. Our matrix can be cross-referenced with disease-associated epigenetic changes to specify the possible events and underlying principles compromised in disease.
Project description:Neural crest cells are migratory progenitor cells that contribute to nearly all tissues and organs throughout the body. Their formation, migration and differentiation are regulated by a multitude of signaling pathways, that when disrupted can lead to disorders termed neurocristopathies. While work in avian and amphibian species has revealed essential factors governing the specification and induction of neural crest cells during gastrulation and neurulation in non-mammalian species, their functions do not appear to be conserved in mice, leaving major gaps in our understanding of neural crest cell formation in mammals. Here we describe Germ Cell Nuclear Factor (GCNF/Nr6a1), an orphan nuclear receptor, as a critical regulator of neural crest cell formation in mice. Gcnf null mutant mice, exhibit a major disruption of neural crest cell formation. The purpose of this experiment is to examine gene expression changes in response to Gcnf mutation in E9.0 mouse embryos.
Project description:Comparative principles of DNA methylation reprogramming during human and mouse in vitro primordial germ cell specification [Mouse smallRNA-Seq]
Project description:Heterogeneous pools of adult neural stem cells (NSCs) contribute to brain maintenance and regeneration after injury. The balance of NSC activation and quiescence, as well as the induction of lineage-specific transcription factors, may contribute to diversity of neuronal and glial fates. To identify molecular hallmarks governing these characteristics, we performed single-cell sequencing of an unbiased pool of adult subventricular zone NSCs. This analysis identified a discrete, dormant NSC subpopulation that already expresses distinct combinations of lineage-specific transcription factors during homeostasis. Dormant NSCs enter a primed-quiescent state before activation, which is accompanied by downregulation of glycolytic metabolism, Notch, and BMP signaling and a concomitant upregulation of lineage-specific transcription factors and protein synthesis. In response to brain ischemia, interferon gamma signaling induces dormant NSC subpopulations to enter the primed-quiescent state. This study unveils general principles underlying NSC activation and lineage priming and opens potential avenues for regenerative medicine in the brain. Single cell RNAseq of cells isolated from their in vivo niche in the subventricular zone, Striatum and Cortex during homeostasis as well as following ischemic injury. In total 272 single cells. (<WT>: homeostasis samples; <Ischemic_injured> and <Ischemic_injured_and_Interferon_gamma_knockout>: samples following ischemic injuried).
Project description:Neural crest cells are migratory progenitor cells that contribute to nearly all tissues and organs throughout the body. Their formation, migration and differentiation are regulated by a multitude of signaling pathways, that when disrupted can lead to disorders termed neurocristopathies. While work in avian and amphibian species has revealed essential factors governing the specification and induction of neural crest cells during gastrulation and neurulation in non-mammalian species, their functions do not appear to be conserved in mice, leaving major gaps in our understanding of neural crest cell formation in mammals. Here we describe Germ Cell Nuclear Factor (GCNF/Nr6a1), an orphan nuclear receptor, as a critical regulator of neural crest cell formation in mice. Gcnf null mutant mice, exhibit a major disruption of neural crest cell formation. The purpose of this experiment is to examine gene expression changes in response to Gcnf mutation in anterior and posterior cranial regions of E9.25 mouse embryos.
Project description:Methylation is a repressive modification of DNA prevalent throughout mammalian genomes yet mostly absent at CG rich stretches referred to as CGI. Here we identify their building principles by parallel genomic targeting of sequence libraries. Iterative insertions generated over 3,000 variants of genome-derived and artificial sequences at the same genomic site. Single molecule profiling of the methylation status of this collection allowed modeling the contribution of CG content and DNA binding factors towards the unmethylated state. It made the surprising prediction that the majority of CGs within endogenous islands are susceptible to methylation changes modulated by the presence of transcription factors, which is indeed confirmed by genome-wide methylation dynamics during multiple cellular differentiations. Our model further predicts blocks of constitutively unmethylated CGs independent from TF binding, which have a median size of ~300bp but are only present in half of all islands. Their constitutively unmethylated state is a hallmark of untransformed cells but their increased methylation is a specific and predictive feature of cancer. This study quantifies the two principal mechanisms governing methylation patterns in mammalian genomes. It provides a framework to interpret methylation data across normal and cancer samples and refines the concept of CpG islands. Methylation is a repressive modification of DNA prevalent throughout mammalian genomes yet mostly absent at CG rich stretches referred to as CGI. Here we identify their building principles by parallel genomic targeting of sequence libraries. Iterative insertions generated over 3,000 variants of genome-derived and artificial sequences at the same genomic site. Single molecule profiling of the methylation status of this collection allowed modeling the contribution of CG content and DNA binding factors towards the unmethylated state. It made the surprising prediction that the majority of CGs within endogenous islands are susceptible to methylation changes modulated by the presence of transcription factors, which is indeed confirmed by genome-wide methylation dynamics during multiple cellular differentiations. Our model further predicts blocks of constitutively unmethylated CGs independent from TF binding, which have a median size of ~300bp but are only present in half of all islands. Their constitutively unmethylated state is a hallmark of untransformed cells but their increased methylation is a specific and predictive feature of cancer. This study quantifies the two principal mechanisms governing methylation patterns in mammalian genomes. It provides a framework to interpret methylation data across normal and cancer samples and refines the concept of CpG islands. Libraries of DNA sequences were constructed either by mouse genome (129S6) or E.coli genome (NC_010473.1) subrepresentation or custom synthesis. DNA fragments were inserted into the genome of mouse embryonic stem cells by recombination mediated casette exchange (RMCE) at the B-globin locus. Methylation status of the inserted DNA sequences was profiled by bisulfite sequencing using a pair of universal primers flanking the fragments.