Transcriptional profiling of E14.5 control and Tbr2 fl/fl;Foxg1::Cre cortices
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ABSTRACT: The abscence of TBR2 gene in human leads to microcephaly. This condition is mimicked by the specific ablation of the murine gene in developing cerebral cortex. Herein we compared gene expression in control and Tbr2 cKO in E14.5 cerebral cortices. This approach represents a useful tool to identify the molecular mechanisms at the basis of the phenotype.
Project description:The abscence of TBR2 gene in human leads to microcephaly. This condition is mimicked by the specific ablation of the murine gene in developing cerebral cortex. Herein we compared gene expression in control and Tbr2 cKO in E14.5 cerebral cortices. This approach represents a useful tool to identify the molecular mechanisms at the basis of the phenotype. 6 samples, 3x Tbr2 +/+;Foxg1::Cre (control) and 3x Tbr2 fl/fl;Foxg1::Cre
Project description:To date, speculations on the molecular roles of Tbr2 transcription factor during specification, maintenance and differentiation of cortical specific Intermediate Neural Progenitors are coming from the analysis of loss- and gain-of-function experiments. However since its capacity to bind the DNA to extert its function we did Chromatin Immuno-Precipitation followed by deep sequencing to profile its target on the genome. We performed this approach directly in vivo to respect the physiological and peculiar enviroment of its action during cortical development. Moreover we did the same approach for Neurogenin 2 proneural gene. Interestingly the vast majority of the Neurog2 peaks are in common with Tbr2 dataset suggesting a co-operation between the two factors confirmed by biochemical and functional assays. Finally we compared Tbr2 dataset with the DNA regions bound by the H3K27me3 histone demethylase Jmjd3 (NCBI:Kdm6b) obtained by others. Interestingly we were able to find regions in common linked to important genes for neuronal differentiation. 3 samples, one input chromatin, one ChIP for Tbr2 and one ChIP for Neurog2
Project description:To date, speculations on the molecular roles of Tbr2 transcription factor during specification, maintenance and differentiation of cortical specific Intermediate Neural Progenitors are coming from the analysis of loss- and gain-of-function experiments. However since its capacity to bind the DNA to extert its function we did Chromatin Immuno-Precipitation followed by deep sequencing to profile its target on the genome. We performed this approach directly in vivo to respect the physiological and peculiar enviroment of its action during cortical development. Moreover we did the same approach for Neurogenin 2 proneural gene. Interestingly the vast majority of the Neurog2 peaks are in common with Tbr2 dataset suggesting a co-operation between the two factors confirmed by biochemical and functional assays. Finally we compared Tbr2 dataset with the DNA regions bound by the H3K27me3 histone demethylase Jmjd3 (NCBI:Kdm6b) obtained by others. Interestingly we were able to find regions in common linked to important genes for neuronal differentiation.
Project description:Epigenetic factors (EFs) regulate multiple aspects of cerebral cortex development, including proliferation, neuronal differentiation, laminar fate, and regional identity. The same neurodevelopmental processes are also regulated by transcription factors (TFs), notably the Pax6→Tbr2→Tbr1 cascade expressed sequentially in radial glial progenitors, intermediate progenitors, and postmitotic projection neurons, respectively. Here, we studied the EF landscape and its regulation in embryonic mouse neocortex. Microarray and in situ hybridization assays revealed that many EF genes are expressed in specific cortical cell types, such as intermediate progenitors, or in rostrocaudal gradients. Furthermore, many EF genes are directly bound and transcriptionally regulated by Pax6, Tbr2, or Tbr1, as determined by chromatin immunoprecipitation-sequencing and gene expression analysis of TF mutant cortices. The results demonstrated that Pax6, Tbr2, and Tbr1 form a direct feedforward genetic cascade, with direct feedback repression. Results also revealed that each TF regulates multiple EF genes that control DNA methylation, histone marks, chromatin remodeling, and noncoding RNA.
Project description:Human brain structure and size requires regulated division of neural stem cells (NSCs). NSCs undergo precise divisions to self-renew and to produce intermediate neural progenitors (INPs) and neurons. The factors that regulate NSC divisions remain poorly understood, as do mechanistic explanations of how aberrant NSC division causes reduced brain size, as seen in microcephaly. Here we demonstrate that Magoh, a component of the core exon junction complex (EJC) that binds spliced RNA, controls cerebral cortical size by regulating NSC division. Magoh haploinsufficiency causes microcephaly due to INP depletion, neuronal apoptosis, and improper mitotic spindle orientation. Defective mitosis underlies these phenotypes as depletion of EJC components disrupts mitotic spindle integrity, chromosome number and genomic stability. We show that an essential function of Magoh is to regulate expression of the human microcephaly protein, LIS1, and that Lis1 addition rescues neurogenesis defects caused by Magoh knockdown, thus providing a genetic explanation for the microcephaly. This study uncovers new requirements for the EJC in brain development, NSC maintenance, mitosis and chromosome stability, thus implicating this complex in the pathogenesis of microcephaly. Mouse embryonic cortices were used for expression analysis 5 biological replicates each of control (C57BL/6) and Magoh mutant brains were analyzed
Project description:Human brain structure and size requires regulated division of neural stem cells (NSCs). NSCs undergo precise divisions to self-renew and to produce intermediate neural progenitors (INPs) and neurons. The factors that regulate NSC divisions remain poorly understood, as do mechanistic explanations of how aberrant NSC division causes reduced brain size, as seen in microcephaly. Here we demonstrate that Magoh, a component of the core exon junction complex (EJC) that binds spliced RNA, controls cerebral cortical size by regulating NSC division. Magoh haploinsufficiency causes microcephaly due to INP depletion, neuronal apoptosis, and improper mitotic spindle orientation. Defective mitosis underlies these phenotypes as depletion of EJC components disrupts mitotic spindle integrity, chromosome number and genomic stability. We show that an essential function of Magoh is to regulate expression of the human microcephaly protein, LIS1, and that Lis1 addition rescues neurogenesis defects caused by Magoh knockdown, thus providing a genetic explanation for the microcephaly. This study uncovers new requirements for the EJC in brain development, NSC maintenance, mitosis and chromosome stability, thus implicating this complex in the pathogenesis of microcephaly. Mouse embryonic cortices were used for expression analysis
Project description:We performed RNA-Seq and H3K9ac ChIP-Seq from Tbr2+ and Tbr2- nuclei sorted by FACS from E16.5 embryonic cortex treated with either vehicle or HDAC inhibitor (TSA).