Project description:<p>Non-coding regions comprise most of the human genome and harbor a significant fraction of risk alleles for neuropsychiatric diseases, yet their functions remain poorly defined. We created a high-resolution map of non-coding elements involved in human cortical neurogenesis by contrasting chromatin accessibility and gene expression in the germinal zone and cortical plate of the developing cerebral cortex. To obtain a high resolution depiction of chromatin structure and gene expression in developing human fetal cortex, we dissected the post-conception week (PCW) 15-17 human neocortex into two major anatomical divisions to distinguish between proliferating neural progenitors and post mitotic neurons: (1) GZ: the neural progenitor-enriched region encompassing the ventricular zone (VZ), subventricular zone (SVZ), and intermediate zone (IZ) and (2) CP: the neuron-enriched region containing the subplate (SP), cortical plate (CP), and marginal zone (MZ). Tissues were obtained from three independent donors and three to four technical replicates from each tissue were processed for ATAC-seq to define the landscape of accessible chromatin and RNA-seq for genome-wide gene expression profiling.</p>
Project description:The cortical area map is initially patterned by transcription factor (TF) gradients in the neocortical primordium, which define a protomap in the embryonic ventricular zone (VZ). However, mechanisms that propagate regional identity from VZ progenitors to cortical plate (CP) neurons are unknown. Here we show that the VZ, subventricular zone (SVZ), and CP contain distinct molecular maps of regional identity, reflecting different gene expression gradients in radial glia progenitors, intermediate progenitors, and projection neurons, respectively. The intermediate map in SVZ is modulated by Eomes (also known as Tbr2), a T-box TF. Eomes inactivation caused rostrocaudal shifts in SVZ and CP gene expression, with loss of corticospinal axons and gain of corticotectal projections. These findings suggest that cortical areas and connections are shaped by sequential maps of regional identity, propagated by the Pax6 ? Eomes ? Tbr1 TF cascade. In humans, PAX6, EOMES, and TBR1 have been linked to intellectual disability and autism. To determine the role of Eomes in the propagation of the protomap to cortical plate neurons, used microarray analysis of E14.5 cortex from five wild type and three Eomes knockout mice.
Project description:The cortical area map is initially patterned by transcription factor (TF) gradients in the neocortical primordium, which define a protomap in the embryonic ventricular zone (VZ). However, mechanisms that propagate regional identity from VZ progenitors to cortical plate (CP) neurons are unknown. Here we show that the VZ, subventricular zone (SVZ), and CP contain distinct molecular maps of regional identity, reflecting different gene expression gradients in radial glia progenitors, intermediate progenitors, and projection neurons, respectively. The intermediate map in SVZ is modulated by Eomes (also known as Tbr2), a T-box TF. Eomes inactivation caused rostrocaudal shifts in SVZ and CP gene expression, with loss of corticospinal axons and gain of corticotectal projections. These findings suggest that cortical areas and connections are shaped by sequential maps of regional identity, propagated by the Pax6 → Eomes → Tbr1 TF cascade. In humans, PAX6, EOMES, and TBR1 have been linked to intellectual disability and autism.
Project description:The expansion of the neocortex during mammalian brain evolution results primarily from an increase in neural progenitor cell divisions in its two principal germinal zones during development, the ventricular zone (VZ) and the subventricular zone (SVZ). Using mRNA sequencing, we analyzed the transcriptomes of fetal human and embryonic mouse VZ, SVZ and cortical plate (CP). We describe sets of genes that are up- or down-regulated in each germinal zone. These data suggest that cell adhesion and cell-extracellular matrix (ECM) interactions promote the proliferation and self-renewal of neural progenitors in the developing human neocortex. Notably, relevant ECM-associated genes include distinct sets of collagens, laminins, proteoglycans and integrins, along with specific sets of growth factors and morphogens. Our data establish a basis for identifying novel cell-type markers and open up avenues to unravel the molecular basis of neocortex expansion during evolution. Total RNA was isolated from the VZ, inner SVZ (ISVZ), outer SVZ (OSVZ) and CP of six 13-16 weeks post-conception (w.p.c.) human fetuses and from the VZ, SVZ and CP of five E14.5 mouse embryos using laser capture microdissection of Nissl-stained cryosections of dorsolateral telencephalon. Poly A+ RNA was used as template for the preparation of cDNA which were then subjected to single-end 76-bp RNA-Seq.
Project description:Cell differentiation and proliferation are mutually exclusive. Although differentiating neurons are recognized as post-mitotic non-dividing cells, some Rb- and Rb family (Rb, p107, and p130)-deficient differentiating neurons proliferate and form tumor. Here, we found that the acute inactivation of all Rb family in differentiating cortical excitatory neurons caused radial migration defect and S-phase progression but not cell division, whereas that in cortical progenitors caused the cell division of the differentiating neurons generated from Rb â??/â??; p107 â??/â??; p130 â??/â?? (Rb-TKO) progenitors. Genome-wide DNA methylation analysis revealed that proximal promoters tended to become methylated during differentiation in vivo. DNA demethylation by DNA methyltransferase inhibitor allowed the acutely inactivated Rb-TKO differentiating neurons to undergo G2/M-phase progression. Our finding illustrate that cortical excitatory neurons epigenetically lose their proliferative potency after neurogenesis. 4 samples of the V/SVZ (ventricular/subventricular zone) tissue and 4 samples of the CP (cortical plate) tissue
Project description:The expansion of the neocortex during mammalian brain evolution results primarily from an increase in neural progenitor cell divisions in its two principal germinal zones during development, the ventricular zone (VZ) and the subventricular zone (SVZ). Using mRNA sequencing, we analyzed the transcriptomes of fetal human and embryonic mouse VZ, SVZ and cortical plate (CP). We describe sets of genes that are up- or down-regulated in each germinal zone. These data suggest that cell adhesion and cell-extracellular matrix (ECM) interactions promote the proliferation and self-renewal of neural progenitors in the developing human neocortex. Notably, relevant ECM-associated genes include distinct sets of collagens, laminins, proteoglycans and integrins, along with specific sets of growth factors and morphogens. Our data establish a basis for identifying novel cell-type markers and open up avenues to unravel the molecular basis of neocortex expansion during evolution.
Project description:Gene expression profiles among avascular region (around ventricular zone), highly vascularized region with honeycomb-patterned vascular plexus (around subventricular zone and intermediate zone), and cortical plate with vertically oriented vessels from laser-captured microdissected E14.5 neocortex were compared by microarray
Project description:Major non primate-primate differences in corticogenesis include the dimensions, precursor lineages and developmental timing of the germinal zones (GZ). microRNAs (miRNAs) of laser dissected GZ compartments and cortical plate (CP) from embryonic E80 macaque visual cortex were deep sequenced. The CP and the GZ including Ventricular Zone (VZ), outer and inner subcompartments of the Outer SubVentricular Zone (OSVZ) in area 17 displayed unique miRNA profiles. miRNAs present in primate, but absent in rodent, contributed disproportionately to the differential expression between GZ sub-regions. Prominent among the validated targets of these miRNAs were cell-cycle and neurogenesis regulators. Co-evolution between the emergent miRNAs and their targets suggested that novel miRNAs became integrated into ancient gene circuitry to exert additional control over proliferation. We conclude that multiple cell-cycle regulatory events contribute to the emergence of primate-specific cortical features, including the OSVZ, generated enlarged supragranular layers, largely responsible for the increased primate cortex computational abilities. target mRNAs for selected miRNAs were detected with RISC trap immunoprecipitation
Project description:Major non primate-primate differences in corticogenesis include the dimensions, precursor lineages and developmental timing of the germinal zones (GZ). microRNAs (miRNAs) of laser dissected GZ compartments and cortical plate (CP) from embryonic E80 macaque visual cortex were deep sequenced. The CP and the GZ including Ventricular Zone (VZ), outer and inner subcompartments of the Outer SubVentricular Zone (OSVZ) in area 17 displayed unique miRNA profiles. miRNAs present in primate, but absent in rodent, contributed disproportionately to the differential expression between GZ sub-regions. Prominent among the validated targets of these miRNAs were cell-cycle and neurogenesis regulators. Co-evolution between the emergent miRNAs and their targets suggested that novel miRNAs became integrated into ancient gene circuitry to exert additional control over proliferation. We conclude that multiple cell-cycle regulatory events contribute to the emergence of primate-specific cortical features, including the OSVZ, generated enlarged supragranular layers, largely responsible for the increased primate cortex computational abilities.
Project description:Quiescent neural stem cells (NSCs) in the adult ventricular-subventricular zone (V-SVZ) undergo activation and divide to generate neurons and glia. Here we show that Platelet-derived Growth Factor Receptor beta (PDGFRβ) is expressed by quiescent and early activated adult V-SVZ NSCs, and maintains their quiescence. We further showed that selective deletion of PDGFRβ in adult V-SVZ NSCs leads to activation of quiescent NSCs. We performed RNA-seq on FACS-sorted V-SVZ quiescent, early activated and late activated NSCs, as well as cortical cells from adult 2-4 month old mice.