Spatial enhancer activation influences inhibitory neuron identity during mouse embryonic development
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE231774 | GEO | 2024/02/19
REPOSITORIES: GEO
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Project description:The mammalian telencephalon contains a tremendous diversity of GABAergic projection neuron and interneuron types, that originate in a germinal zone of the embryonic basal ganglia. How genetic information in this transient structure is transformed into different cell types is not yet fully understood. Using a combination of in vivo lineage tracing, CRISPR perturbation and ChIP-seq in mice, we found that the transcription factor MEIS2 favors the development of projection neurons through genomic binding sites in regulatory enhancers of projection neuron specific genes. MEIS2 requires the presence of the homeodomain transcription factor DLX5 to direct its functional activity towards these sites. In interneurons, the activation of projection neuron specific enhancers by MEIS2 and DLX5 is repressed by the transcription factor LHX6. When MEIS2 carries a mutation associated with intellectual disability in humans, it is less effective at activating enhancers involved in projection neuron development. This suggests that GABAergic differentiation may be impaired in patients carrying this mutation. Our research has uncovered a mechanism by which the selective activation of enhancers plays a crucial role in the establishment of neuronal identity, as well as in potential pathological mechanisms
2024-02-19 | GSE231777 | GEO
Project description:The Dlx homeodomain transcription factors are implicated in regulating the function of inhibitory GABAergic interneurons; therefore understanding their functions will provide insights into disorders such as epilepsy, mental retardation and autism. Identifying genes that are downstream of Dlx1/2 function and are relevant for the differentiation and survival of GABAergic interneurons. During embryonic development, cortical GABAergic interneurons are generated in the proliferative zone of the medial ganglionic eminence (MGE), from where they migrate to reach their final positions in the cortex. The differentiation of these interneuron precursors is dependent on Dlx genes, as shown by Dlx1/Dlx2 double mutants, which have a block in GABAergic cell differentiation and in cell migration. When interneuron progenitors are isolated from the mutant MGE and growth in culture, they are able to proceed along their differentiation program. However, mutant cells growth in vitro show defects in cell morphogenesis and increased cell apoptosis. We hypothesize that Dlx transcription factors regulate important aspects of GABAergic neuron differentiation such as the formation and growth of axon and dendrites, and the formation of inhibitory synapses. We generated E15.5 mouse embryos that are Dlx1/2 -/- or Dlx1/2 +/?. Genotype was confirmed by PCR. A total of 8 litters were used. For each experiment, we pooled tissue from at least 6 different embryos of the same genotype. We dissected the ventricular and subventricular zones of the MGE (rostral part). This area contains ~1 million of progenitor cells per embryo. We isolated total RNA using the Stratagene RNA Miniprep kit (these samples are called MGE+/ and MGE-/- in our proposal). In addition, we used the same area (ventricular and subventricular zones of the rostral MGE) to perform primary neuronal cultures. Cells were maintained 3 days in vitro. After that, we isolated total RNA using the Stratagene RNA Miniprep kit (samples called primary cells+/ and primary cells-/- in our proposal). We would like to perform gene expression comparison between: 1) MGE+/ and MGE-/-, and 2) primary cells+/ and primary cells-/-.
2008-06-16 | E-GEOD-8311 | biostudies-arrayexpress
Project description:The olfactory sensory system is formed by the coordinated morphogenesis and differentiation of the peripheral olfactory epithelium (OE) and the anterior forebrain. At early stages, immature olfactory receptor neurons (ORN) elongate their axons to penetrate the brain basement membrane, contact and form synapses with projection neurons of the olfactory bulb primordium. Axonal elongation is accompanied by migration of the GnRH+ neurons, followed by their ingression in the septo-hypothalamic area of the forebrain. This process is specifically impaired in the KallmannM-bM-^@M-^Ys syndrome (KS), a disorder characterized by anosmia and central hypogonadism. A set of transcription factors are master regulators of olfactory connectivity and GnRH neuron migration. We explored the transcriptional network underlying this process, by profiling the OE and adjacent mesenchyme at distinct embryonic ages. We also profiled the OE from embryos null for Dlx5, a homeogene essential for olfactory development, that causes a KS-like phenotype when deleted. We also applied analysis of conserved co-expression to integrate the obtained data with information on KS disease genes. The prevalent categories of genes differentially expressed during development are neuronal differentiation, extracellular remodelling and cell adhesion. From the analysis of Dlx5 mutant tissues we identify about 120 genes with a prevalence of intermediate filaments, cell signalling, epithelial and neuronal differentiation. Filtering for true OE expression and for the presence of Dlx5 binding sites, yielded twenty genes, of the following categories: 1) transmembrane adhesion/receptor molecules, 2) axon-glia interaction molecules, 3) synaptic proteins, 4) scaffold/adapter for signalling molecules. To functionally analyze these genes in vivo, we used three zebrafish fluorescent reporter zebrafish strains, in which we monitored early phases of olfactory/GnRH development upon gene downmodulation. The depletion of three (of five) Dlx5 targets affected axonal extension and targeting, while two (of two) altered GnRH neuron position and neurite organization. In one experiment we compare the olfactrory sensory epithelium from wild-type embryos, at three times of development, i.e. E11.5, E12.5 and E14.5. In a second experiment we compare the olfactory sensory epithelium from wild-type embryo with that from Dlx5 knock-out embryos, at the age E12.5
2014-01-31 | E-GEOD-52800 | biostudies-arrayexpress
Project description:The embryonic basal ganglia generates multiple projection neurons and interneuron subtypes from distinct progenitor domains. Combinatorial interactions of transcription factors (TFs), regulatory elements (REs), and chromatin are thought to precisely regulate gene expression. In the medial ganglionic eminence (MGE), the NKX2-1 TF controls regional identity and, with LHX6, is necessary to specify pallidal projection neurons and forebrain interneurons. We dissected the molecular functions of NKX2-1 by defining its chromosomal binding regions, regulation of gene expression and epigenetic state. NKX2-1 binding at distal REs led to a repressed epigenetic state and transcriptional repression in the ventricular zone. Conversely, Nkx2-1 is required to establish a permissive chromatin state and transcriptional activation in the sub- ventricular and mantle zones. Moreover, combinatorial binding of NKX2-1 and LHX6 promotes transcriptionally permissive chromatin and activates genes expressed in cortical migrating interneurons. Our integrated approach provides a foundation for elucidating transcriptional networks guiding the development of the MGE and its descendants.
2016-09-21 | GSE85704 | GEO
Project description:The embryonic basal ganglia generates multiple projection neurons and interneuron subtypes from distinct progenitor domains. Combinatorial interactions of transcription factors (TFs), regulatory elements (REs), and chromatin are thought to precisely regulate gene expression. In the medial ganglionic eminence (MGE), the NKX2-1 TF controls regional identity and, with LHX6, is necessary to specify pallidal projection neurons and forebrain interneurons. We dissected the molecular functions of NKX2-1 by defining its chromosomal binding regions, regulation of gene expression and epigenetic state. NKX2-1 binding at distal REs led to a repressed epigenetic state and transcriptional repression in the ventricular zone. Conversely, Nkx2-1 is required to establish a permissive chromatin state and transcriptional activation in the sub- ventricular and mantle zones. Moreover, combinatorial binding of NKX2-1 and LHX6 promotes transcriptionally permissive chromatin and activates genes expressed in cortical migrating interneurons. Our integrated approach provides a foundation for elucidating transcriptional networks guiding the development of the MGE and its descendants.
2016-09-21 | GSE85703 | GEO
Project description:A crucial step in understanding the sleep-control mechanism is to identify sleep neurons. In principle, a neuron could promote sleep by inhibiting wake-promoting neurons. Using rabies virus (RV)-mediated transsynaptic tracing, we identified several brain regions with GABAergic neurons that broadly inhibit multiple wake-promoting neuronal populations, and the most prominent source of GABAergic inputs was found in a posterior part of the CeA. The CeA is known to contain multiple subtypes of GABAergic neurons with distinct molecular markers, projection targets, and functional properties. Using translating ribosome affinity purification (TRAP) RNA-Seq, we identified molecular markers for the canditate sleep-promoting neurons in CeA.
2020-04-06 | GSE121888 | GEO
Project description:How neurons are wired to form precise circuits is crucial to understand the development of cortical functions. Glutamatergic pyramidal cell and GABAergic interneuron wire up the cortex through differentiated cellular events. However, little is known about the molecular mechanisms that underlie the unique features of interneuron wiring. We performed a high-throughput genomic screen for genes upregulated specifically during GABAergic wiring.
2018-07-31 | GSE115948 | GEO
Project description:The Dlx homeodomain transcription factors are implicated in regulating the function of inhibitory GABAergic interneurons; therefore understanding their functions will provide insights into disorders such as epilepsy, mental retardation and autism. Identifying genes that are downstream of Dlx1/2 function and are relevant for the differentiation and survival of GABAergic interneurons. During embryonic development, cortical GABAergic interneurons are generated in the proliferative zone of the medial ganglionic eminence (MGE), from where they migrate to reach their final positions in the cortex. The differentiation of these interneuron precursors is dependent on Dlx genes, as shown by Dlx1/Dlx2 double mutants, which have a block in GABAergic cell differentiation and in cell migration. When interneuron progenitors are isolated from the mutant MGE and growth in culture, they are able to proceed along their differentiation program. However, mutant cells growth in vitro show defects in cell morphogenesis and increased cell apoptosis. We hypothesize that Dlx transcription factors regulate important aspects of GABAergic neuron differentiation such as the formation and growth of axon and dendrites, and the formation of inhibitory synapses. We generated E15.5 mouse embryos that are Dlx1/2 -/- or Dlx1/2 +/?. Genotype was confirmed by PCR. A total of 8 litters were used. For each experiment, we pooled tissue from at least 6 different embryos of the same genotype. We dissected the ventricular and subventricular zones of the MGE (rostral part). This area contains ~1 million of progenitor cells per embryo. We isolated total RNA using the Stratagene RNA Miniprep kit (these samples are called MGE+/ and MGE-/- in our proposal). In addition, we used the same area (ventricular and subventricular zones of the rostral MGE) to perform primary neuronal cultures. Cells were maintained 3 days in vitro. After that, we isolated total RNA using the Stratagene RNA Miniprep kit (samples called primary cells+/ and primary cells-/- in our proposal). We would like to perform gene expression comparison between: 1) MGE+/ and MGE-/-, and 2) primary cells+/ and primary cells-/-. Keywords: Dlx mutants, medial ganglionic eminence, neuronal cultures
2007-06-27 | GSE8311 | GEO
Project description:How neuronal connections are established and organized in functional networks determines brain function. In the mouse cerebral cortex, different classes of GABAergic interneurons exhibit specific connectivity patterns that underlie their ability to shape temporal dynamics and information processing. Much progress has been made parsing interneuron diversity, yet the molecular mechanisms by which interneuron subtype-specific connectivity motifs emerge remain unclear. Here we investigate transcriptional dynamics in different classes of interneurons during the formation of cortical inhibitory circuits. We found that whether the interneurons synapse with pyramidal neurons on their dendrites, soma, or axon initial segment is determined by synaptic molecules that are expressed in a subtype-specific manner. Thus cell-specific molecular programs that unfold during early postnatal development underlie the connectivity patterns of cortical interneurons.
2019-01-25 | GSE120161 | GEO
Project description:The olfactory sensory system is formed by the coordinated morphogenesis and differentiation of the peripheral olfactory epithelium (OE) and the anterior forebrain. At early stages, immature olfactory receptor neurons (ORN) elongate their axons to penetrate the brain basement membrane, contact and form synapses with projection neurons of the olfactory bulb primordium. Axonal elongation is accompanied by migration of the GnRH+ neurons, followed by their ingression in the septo-hypothalamic area of the forebrain. This process is specifically impaired in the Kallmann’s syndrome (KS), a disorder characterized by anosmia and central hypogonadism. A set of transcription factors are master regulators of olfactory connectivity and GnRH neuron migration. We explored the transcriptional network underlying this process, by profiling the OE and adjacent mesenchyme at distinct embryonic ages. We also profiled the OE from embryos null for Dlx5, a homeogene essential for olfactory development, that causes a KS-like phenotype when deleted. We also applied analysis of conserved co-expression to integrate the obtained data with information on KS disease genes. The prevalent categories of genes differentially expressed during development are neuronal differentiation, extracellular remodelling and cell adhesion. From the analysis of Dlx5 mutant tissues we identify about 120 genes with a prevalence of intermediate filaments, cell signalling, epithelial and neuronal differentiation. Filtering for true OE expression and for the presence of Dlx5 binding sites, yielded twenty genes, of the following categories: 1) transmembrane adhesion/receptor molecules, 2) axon-glia interaction molecules, 3) synaptic proteins, 4) scaffold/adapter for signalling molecules. To functionally analyze these genes in vivo, we used three zebrafish fluorescent reporter zebrafish strains, in which we monitored early phases of olfactory/GnRH development upon gene downmodulation. The depletion of three (of five) Dlx5 targets affected axonal extension and targeting, while two (of two) altered GnRH neuron position and neurite organization.
2014-01-31 | GSE52800 | GEO