A Functional Role for REST Co-Repressor 2 (Rcor2) in Callosal Development
Ontology highlight
ABSTRACT: Pallial functional organization is mediated by the dynamic interplay of a broad spectrum of cellular and molecular cues that promote midline patterning, neurogenesis, axon guidance and neural connectivity. The regulators that orchestrate these seminal processes are still poorly understood. By employing a pallial conditional ablation model, we report that the transcriptional and epigenetic modulator, REST corepressor 2 (Rcor2) plays key roles in organizing the developing corticoseptal boundary. ChIP-seq and RNA-seq analyses reveal that Rcor2 modulates a diverse repertoire of classes of genes with essential roles in CC development, including pallial/subpallial patterning, cell fate specification and axon guidance.
Project description:RNA-based regulatory mechanisms play important roles in the development and plasticity of neural circuits and neurologic disease. Developing axons provide a well suited model to study RNA-based regulation, and contain specific subsets of mRNAs that are locally translated and have roles in axon pathfinding. However, the RNA-binding proteins involved in axon pathfinding, and their corresponding mRNA targets, are still largely unknown. Here we find that the RNA-binding protein IMP2 (Igf2bp2) is strikingly enriched in developing axon tracts, including in spinal commissural axons. We used the HITS-CLIP approach to perform a genome-wide identification of RNAs that interact directly with IMP2 in the native context of developing brain. This IMP2 interactome was highly enriched for mRNA targets related to axon guidance. Accordingly, IMP2 knockdown in the developing spinal cord led to strong defects in commissural axon trajectories at the midline intermediate target. These results reveal a highly distinctive axonal enrichment of IMP2, show that it interacts with a network of axon guidance-related mRNAs, and reveal its requirement for normal axon pathfinding during vertebrate development. CLIP-seq
Project description:During the development of the Drosophila central nervous system the process of midline crossing is orchestrated by a number of guidance receptors and ligands. Many key axon guidance molecules have been identified in both invertebrates and vertebrates, but the transcriptional regulation of growth cone guidance remains largely unknown. One open question is whether transcriptional regulation plays a role in midline crossing, or if local translation can account for the necessary fine tuning of protein levels. To investigate this issue, we conducted a genome wide analysis of transcription in Drosophila embryos using wild type and a number of well-characterized Drosophila guidance mutants and transgenics. We also analyzed a publicly available microarray time course of Drosophila embryonic development with an axon guidance focus. Using hopach, a novel clustering method which is well suited to microarray data analysis, we identified groups of genes with similar expression patterns across guidance mutants and transgenics. We then systematically characterized the resulting clusters with respect to their relevance to axon guidance using two complementary controlled vocabularies: the Gene Ontology (GO) and anatomical annotations of the Atlas of Pattern of Gene Expression (APoGE) in situ hybridization database. The analysis indicates that regulation of gene expression does play a role in the process of axon guidance in Drosophila. We also find a strong link between axon guidance and hemocyte migration, a result that agrees with mounting evidence that axon guidance molecules are co-opted in vertebrate vascularization. Cell cyclin activity in the context of axon guidance is also suggested from our array data. RNA and protein patterns of cell cyclin in axon guidance mutants and transgenics support this possible link. This study provides important insights into the regulation of axon guidance in vivo and suggests that transcription does play a role in control of axon guidance. Experiment Overall Design: Several mutants and transgenics were analyzed, totalizing 17 distinct conditions. Individual descriptions are included in each microarray. For each condition there are 3 or 4 replicates. The file's name indicates the replicates, e.g., comm.a reflects the replicate a of mutant commissureless. The experiment design covers a range of mutants and transgenics of key axon guidance mutans, in different dosages. The protocol was the standard Affymetrix protocol.
Project description:During the development of the Drosophila central nervous system the process of midline crossing is orchestrated by a number of guidance receptors and ligands. Many key axon guidance molecules have been identified in both invertebrates and vertebrates, but the transcriptional regulation of growth cone guidance remains largely unknown. One open question is whether transcriptional regulation plays a role in midline crossing, or if local translation can account for the necessary fine tuning of protein levels. To investigate this issue, we conducted a genome wide analysis of transcription in Drosophila embryos using wild type and a number of well-characterized Drosophila guidance mutants and transgenics. We also analyzed a publicly available microarray time course of Drosophila embryonic development with an axon guidance focus. Using hopach, a novel clustering method which is well suited to microarray data analysis, we identified groups of genes with similar expression patterns across guidance mutants and transgenics. We then systematically characterized the resulting clusters with respect to their relevance to axon guidance using two complementary controlled vocabularies: the Gene Ontology (GO) and anatomical annotations of the Atlas of Pattern of Gene Expression (APoGE) in situ hybridization database. The analysis indicates that regulation of gene expression does play a role in the process of axon guidance in Drosophila. We also find a strong link between axon guidance and hemocyte migration, a result that agrees with mounting evidence that axon guidance molecules are co-opted in vertebrate vascularization. Cell cyclin activity in the context of axon guidance is also suggested from our array data. RNA and protein patterns of cell cyclin in axon guidance mutants and transgenics support this possible link. This study provides important insights into the regulation of axon guidance in vivo and suggests that transcription does play a role in control of axon guidance. Keywords: Mutant Analysis
Project description:RNA-based regulatory mechanisms play important roles in the development and plasticity of neural circuits and neurologic disease. Developing axons provide a well suited model to study RNA-based regulation, and contain specific subsets of mRNAs that are locally translated and have roles in axon pathfinding. However, the RNA-binding proteins involved in axon pathfinding, and their corresponding mRNA targets, are still largely unknown. Here we find that the RNA-binding protein IMP2 (Igf2bp2) is strikingly enriched in developing axon tracts, including in spinal commissural axons. We used the HITS-CLIP approach to perform a genome-wide identification of RNAs that interact directly with IMP2 in the native context of developing brain. This IMP2 interactome was highly enriched for mRNA targets related to axon guidance. Accordingly, IMP2 knockdown in the developing spinal cord led to strong defects in commissural axon trajectories at the midline intermediate target. These results reveal a highly distinctive axonal enrichment of IMP2, show that it interacts with a network of axon guidance-related mRNAs, and reveal its requirement for normal axon pathfinding during vertebrate development.
Project description:The connectivity, activity, and plasticity of the telencephalon are shaped by pallial and subpallial GABAergic neurons, two large populations that are produced in the embryonic medial, caudal and lateral ganglionic eminences in a highly complicated manner. Dysregulated development of GABAergic neurons is associated with neuropsychiatric disorders. However, knowledge about the specification of GABAergic neuron subtypes is limited. Here, using single-cell RNA sequencing combined with loss-of-function we delineated developmental trajectories and revealed transcriptional programs that specify GABAergic neuron subtypes in each GE lineage and transcription factors that direct lineage bifurcation decisions. Our study illuminates the control of production between pallial and subpallial populations and offers transcriptomic insights into the pathogenesis of GABAergic neuron-related disorders.
Project description:The connectivity, activity, and plasticity of the telencephalon are shaped by pallial and subpallial GABAergic neurons, two large populations that are produced in the embryonic medial, caudal and lateral ganglionic eminences in a highly complicated manner. Dysregulated development of GABAergic neurons is associated with neuropsychiatric disorders. However, knowledge about the specification of GABAergic neuron subtypes is limited. Here, using single-cell RNA sequencing combined with loss-of-function we delineated developmental trajectories and revealed transcriptional programs that specify GABAergic neuron subtypes in each GE lineage and transcription factors that direct lineage bifurcation decisions. Our study illuminates the control of production between pallial and subpallial populations and offers transcriptomic insights into the pathogenesis of GABAergic neuron-related disorders.
Project description:The connectivity, activity, and plasticity of the telencephalon are shaped by pallial and subpallial GABAergic neurons, two large populations that are produced in the embryonic medial, caudal and lateral ganglionic eminences in a highly complicated manner. Dysregulated development of GABAergic neurons is associated with neuropsychiatric disorders. However, knowledge about the specification of GABAergic neuron subtypes is limited. Here, using single-cell RNA sequencing combined with loss-of-function we delineated developmental trajectories and revealed transcriptional programs that specify GABAergic neuron subtypes in each GE lineage and transcription factors that direct lineage bifurcation decisions. Our study illuminates the control of production between pallial and subpallial populations and offers transcriptomic insights into the pathogenesis of GABAergic neuron-related disorders.
Project description:We have discovered subsets of axon guidance molecules and transcription factors that are enriched in specific subsets of olfactory sensory neurons. We have demonstrated guidance activity for three of the candidate axon guidance genes we identified, suggesting that this approach is an efficient method for characterizing guidance systems relevant to olfactory axon targeting.
Project description:The ventricular-subventricular zone (V-SVZ) is the largest neurogenic region of the postnatal forebrain, containing neural stem cells (NSCs) that emerge from both the embryonic pallium and subpallium. Despite of this dual origin, glutamatergic neurogenesis declines rapidly after birth, while gabaergic neurogenesis persists throughout life. We performed single-cell RNA-sequencing (scRNA-Seq) of the postnatal dorsal V-SVZ for unravelling the mechanisms leading to pallial lineage germinal activity silencing. We show that pallial NSCs enter a state of deep quiescence, characterized by high BMP-signaling, reduced transcriptional activity and Hopx expression, whilst in contrast, subpallial NSCs remain primed for activation. Induction of deep quiescence is paralleled by a rapid blockade of glutamatergic neurons production and differentiation. Finally, manipulation of Bmpr1a demonstrates its key role in mediating these effects. Together, our results highlight a central role of BMP-signaling in synchronizing quiescence induction and blockade of neuronal differentiation to rapidly silence pallial germinal activity after birth.