@unpublished{8813, abstract = {In mammals, chromatin marks at imprinted genes are asymmetrically inherited to control parentally-biased gene expression. This control is thought predominantly to involve parent-specific differentially methylated regions (DMR) in genomic DNA. However, neither parent-of-origin-specific transcription nor DMRs have been comprehensively mapped. We here address this by integrating transcriptomic and epigenomic approaches in mouse preimplantation embryos (blastocysts). Transcriptome-analysis identified 71 genes expressed with previously unknown parent-of-origin-specific expression in blastocysts (nBiX: novel blastocyst-imprinted expression). Uniparental expression of nBiX genes disappeared soon after implantation. Micro-whole-genome bisulfite sequencing (μWGBS) of individual uniparental blastocysts detected 859 DMRs. Only 18% of nBiXs were associated with a DMR, whereas 60% were associated with parentally-biased H3K27me3. This suggests a major role for Polycomb-mediated imprinting in blastocysts. Five nBiX-clusters contained at least one known imprinted gene, and five novel clusters contained exclusively nBiX-genes. These data suggest a complex program of stage-specific imprinting involving different tiers of regulation.}, author = {Santini, Laura and Halbritter, Florian and Titz-Teixeira, Fabian and Suzuki, Toru and Asami, Maki and Ramesmayer, Julia and Ma, Xiaoyan and Lackner, Andreas and Warr, Nick and Pauler, Florian and Hippenmeyer, Simon and Laue, Ernest and Farlik, Matthias and Bock, Christoph and Beyer, Andreas and Perry, Anthony C. F. and Leeb, Martin}, booktitle = {bioRxiv}, publisher = {Cold Spring Harbor Laboratory}, title = {{Novel imprints in mouse blastocysts are predominantly DNA methylation independent}}, doi = {10.1101/2020.11.03.366948}, year = {2020}, } @article{8949, abstract = {Development of the nervous system undergoes important transitions, including one from neurogenesis to gliogenesis which occurs late during embryonic gestation. Here we report on clonal analysis of gliogenesis in mice using Mosaic Analysis with Double Markers (MADM) with quantitative and computational methods. Results reveal that developmental gliogenesis in the cerebral cortex occurs in a fraction of earlier neurogenic clones, accelerating around E16.5, and giving rise to both astrocytes and oligodendrocytes. Moreover, MADM-based genetic deletion of the epidermal growth factor receptor (Egfr) in gliogenic clones revealed that Egfr is cell autonomously required for gliogenesis in the mouse dorsolateral cortices. A broad range in the proliferation capacity, symmetry of clones, and competitive advantage of MADM cells was evident in clones that contained one cellular lineage with double dosage of Egfr relative to their environment, while their sibling Egfr-null cells failed to generate glia. Remarkably, the total numbers of glia in MADM clones balance out regardless of significant alterations in clonal symmetries. The variability in glial clones shows stochastic patterns that we define mathematically, which are different from the deterministic patterns in neuronal clones. This study sets a foundation for studying the biological significance of stochastic and deterministic clonal principles underlying tissue development, and identifying mechanisms that differentiate between neurogenesis and gliogenesis.}, author = {Zhang, Xuying and Mennicke, Christine V. and Xiao, Guanxi and Beattie, Robert J and Haider, Mansoor and Hippenmeyer, Simon and Ghashghaei, H. Troy}, issn = {2073-4409}, journal = {Cells}, number = {12}, publisher = {MDPI}, title = {{Clonal analysis of gliogenesis in the cerebral cortex reveals stochastic expansion of glia and cell autonomous responses to Egfr dosage}}, doi = {10.3390/cells9122662}, volume = {9}, year = {2020}, } @article{8978, abstract = {Mosaic analysis with double markers (MADM) technology enables concomitant fluorescent cell labeling and induction of uniparental chromosome disomy (UPD) with single-cell resolution. In UPD, imprinted genes are either overexpressed 2-fold or are not expressed. Here, the MADM platform is utilized to probe imprinting phenotypes at the transcriptional level. This protocol highlights major steps for the generation and isolation of projection neurons and astrocytes with MADM-induced UPD from mouse cerebral cortex for downstream single-cell and low-input sample RNA-sequencing experiments. For complete details on the use and execution of this protocol, please refer to Laukoter et al. (2020b).}, author = {Laukoter, Susanne and Amberg, Nicole and Pauler, Florian and Hippenmeyer, Simon}, issn = {2666-1667}, journal = {STAR Protocols}, number = {3}, publisher = {Elsevier}, title = {{Generation and isolation of single cells from mouse brain with mosaic analysis with double markers-induced uniparental chromosome disomy}}, doi = {10.1016/j.xpro.2020.100215}, volume = {1}, year = {2020}, } @article{7253, abstract = {The cyclin-dependent kinase inhibitor p57KIP2 is encoded by the imprinted Cdkn1c locus, exhibits maternal expression, and is essential for cerebral cortex development. How Cdkn1c regulates corticogenesis is however not clear. To this end we employ Mosaic Analysis with Double Markers (MADM) technology to genetically dissect Cdkn1c gene function in corticogenesis at single cell resolution. We find that the previously described growth-inhibitory Cdkn1c function is a non-cell-autonomous one, acting on the whole organism. In contrast we reveal a growth-promoting cell-autonomous Cdkn1c function which at the mechanistic level mediates radial glial progenitor cell and nascent projection neuron survival. Strikingly, the growth-promoting function of Cdkn1c is highly dosage sensitive but not subject to genomic imprinting. Collectively, our results suggest that the Cdkn1c locus regulates cortical development through distinct cell-autonomous and non-cell-autonomous mechanisms. More generally, our study highlights the importance to probe the relative contributions of cell intrinsic gene function and tissue-wide mechanisms to the overall phenotype.}, author = {Laukoter, Susanne and Beattie, Robert J and Pauler, Florian and Amberg, Nicole and Nakayama, Keiichi I. and Hippenmeyer, Simon}, issn = {2041-1723}, journal = {Nature Communications}, publisher = {Springer Nature}, title = {{Imprinted Cdkn1c genomic locus cell-autonomously promotes cell survival in cerebral cortex development}}, doi = {10.1038/s41467-019-14077-2}, volume = {11}, year = {2020}, } @article{7593, abstract = {Heterozygous loss of human PAFAH1B1 (coding for LIS1) results in the disruption of neurogenesis and neuronal migration via dysregulation of microtubule (MT) stability and dynein motor function/localization that alters mitotic spindle orientation, chromosomal segregation, and nuclear migration. Recently, human induced pluripotent stem cell (iPSC) models revealed an important role for LIS1 in controlling the length of terminal cell divisions of outer radial glial (oRG) progenitors, suggesting cellular functions of LIS1 in regulating neural progenitor cell (NPC) daughter cell separation. Here we examined the late mitotic stages NPCs in vivo and mouse embryonic fibroblasts (MEFs) in vitro from Pafah1b1-deficient mutants. Pafah1b1-deficient neocortical NPCs and MEFs similarly exhibited cleavage plane displacement with mislocalization of furrow-associated markers, associated with actomyosin dysfunction and cell membrane hyper-contractility. Thus, it suggests LIS1 acts as a key molecular link connecting MTs/dynein and actomyosin, ensuring that cell membrane contractility is tightly controlled to execute proper daughter cell separation.}, author = {Moon, Hyang Mi and Hippenmeyer, Simon and Luo, Liqun and Wynshaw-Boris, Anthony}, issn = {2050-084X}, journal = {eLife}, publisher = {eLife Sciences Publications}, title = {{LIS1 determines cleavage plane positioning by regulating actomyosin-mediated cell membrane contractility}}, doi = {10.7554/elife.51512}, volume = {9}, year = {2020}, } @article{27, abstract = {The cerebral cortex is composed of a large variety of distinct cell-types including projection neurons, interneurons and glial cells which emerge from distinct neural stem cell (NSC) lineages. The vast majority of cortical projection neurons and certain classes of glial cells are generated by radial glial progenitor cells (RGPs) in a highly orchestrated manner. Recent studies employing single cell analysis and clonal lineage tracing suggest that NSC and RGP lineage progression are regulated in a profound deterministic manner. In this review we focus on recent advances based mainly on correlative phenotypic data emerging from functional genetic studies in mice. We establish hypotheses to test in future research and outline a conceptual framework how epigenetic cues modulate the generation of cell-type diversity during cortical development. This article is protected by copyright. All rights reserved.}, author = {Amberg, Nicole and Laukoter, Susanne and Hippenmeyer, Simon}, journal = {Journal of Neurochemistry}, number = {1}, pages = {12--26}, publisher = {Wiley}, title = {{Epigenetic cues modulating the generation of cell type diversity in the cerebral cortex}}, doi = {10.1111/jnc.14601}, volume = {149}, year = {2019}, } @article{6830, author = {Contreras, Ximena and Hippenmeyer, Simon}, issn = {10974199}, journal = {Neuron}, number = {5}, pages = {750--752}, publisher = {Elsevier}, title = {{Memo1 tiles the radial glial cell grid}}, doi = {10.1016/j.neuron.2019.08.021}, volume = {103}, year = {2019}, } @article{6844, abstract = {Studying the progression of the proliferative and differentiative patterns of neural stem cells at the individual cell level is crucial to the understanding of cortex development and how the disruption of such patterns can lead to malformations and neurodevelopmental diseases. However, our understanding of the precise lineage progression programme at single-cell resolution is still incomplete due to the technical variations in lineage- tracing approaches. One of the key challenges involves developing a robust theoretical framework in which we can integrate experimental observations and introduce correction factors to obtain a reliable and representative description of the temporal modulation of proliferation and differentiation. In order to obtain more conclusive insights, we carry out virtual clonal analysis using mathematical modelling and compare our results against experimental data. Using a dataset obtained with Mosaic Analysis with Double Markers, we illustrate how the theoretical description can be exploited to interpret and reconcile the disparity between virtual and experimental results.}, author = {Picco, Noemi and Hippenmeyer, Simon and Rodarte, Julio and Streicher, Carmen and Molnár, Zoltán and Maini, Philip K. and Woolley, Thomas E.}, issn = {1469-7580}, journal = {Journal of Anatomy}, number = {3}, pages = {686--696}, publisher = {Wiley}, title = {{A mathematical insight into cell labelling experiments for clonal analysis}}, doi = {10.1111/joa.13001}, volume = {235}, year = {2019}, } @article{7005, abstract = {Activity-dependent bulk endocytosis generates synaptic vesicles (SVs) during intense neuronal activity via a two-step process. First, bulk endosomes are formed direct from the plasma membrane from which SVs are then generated. SV generation from bulk endosomes requires the efflux of previously accumulated calcium and activation of the protein phosphatase calcineurin. However, it is still unknown how calcineurin mediates SV generation. We addressed this question using a series of acute interventions that decoupled the generation of SVs from bulk endosomes in rat primary neuronal culture. This was achieved by either disruption of protein–protein interactions via delivery of competitive peptides, or inhibition of enzyme activity by known inhibitors. SV generation was monitored using either a morphological horseradish peroxidase assay or an optical assay that monitors the replenishment of the reserve SV pool. We found that SV generation was inhibited by, (i) peptides that disrupt calcineurin interactions, (ii) an inhibitor of dynamin I GTPase activity and (iii) peptides that disrupt the phosphorylation-dependent dynamin I–syndapin I interaction. Peptides that disrupted syndapin I interactions with eps15 homology domain-containing proteins had no effect. This revealed that (i) calcineurin must be localized at bulk endosomes to mediate its effect, (ii) dynamin I GTPase activity is essential for SV fission and (iii) the calcineurin-dependent interaction between dynamin I and syndapin I is essential for SV generation. We therefore propose that a calcineurin-dependent dephosphorylation cascade that requires both dynamin I GTPase and syndapin I lipid-deforming activity is essential for SV generation from bulk endosomes.}, author = {Cheung, Giselle T and Cousin, Michael A.}, issn = {1471-4159}, journal = {Journal of Neurochemistry}, number = {5}, pages = {570--583}, publisher = {Wiley}, title = {{Synaptic vesicle generation from activity‐dependent bulk endosomes requires a dephosphorylation‐dependent dynamin–syndapin interaction}}, doi = {10.1111/jnc.14862}, volume = {151}, year = {2019}, } @article{7202, abstract = {The cerebral cortex contains multiple areas with distinctive cytoarchitectonical patterns, but the cellular mechanisms underlying the emergence of this diversity remain unclear. Here, we have investigated the neuronal output of individual progenitor cells in the developing mouse neocortex using a combination of methods that together circumvent the biases and limitations of individual approaches. Our experimental results indicate that progenitor cells generate pyramidal cell lineages with a wide range of sizes and laminar configurations. Mathematical modelling indicates that these outcomes are compatible with a stochastic model of cortical neurogenesis in which progenitor cells undergo a series of probabilistic decisions that lead to the specification of very heterogeneous progenies. Our findings support a mechanism for cortical neurogenesis whose flexibility would make it capable to generate the diverse cytoarchitectures that characterize distinct neocortical areas.}, author = {Llorca, Alfredo and Ciceri, Gabriele and Beattie, Robert J and Wong, Fong Kuan and Diana, Giovanni and Serafeimidou-Pouliou, Eleni and Fernández-Otero, Marian and Streicher, Carmen and Arnold, Sebastian J. and Meyer, Martin and Hippenmeyer, Simon and Maravall, Miguel and Marín, Oscar}, issn = {2050084X}, journal = {eLife}, publisher = {eLife Sciences Publications}, title = {{A stochastic framework of neurogenesis underlies the assembly of neocortical cytoarchitecture}}, doi = {10.7554/eLife.51381}, volume = {8}, year = {2019}, } @article{7399, abstract = {Long non-coding (lnc) RNAs are numerous and found throughout the mammalian genome, and many are thought to be involved in the regulation of gene expression. However, the majority remain relatively uncharacterised and of uncertain function making the use of model systems to uncover their mode of action valuable. Imprinted lncRNAs target and recruit epigenetic silencing factors to a cluster of imprinted genes on the same chromosome, making them one of the best characterized lncRNAs for silencing distant genes in cis. In this study we examined silencing of the distant imprinted gene Slc22a3 by the lncRNA Airn in the Igf2r imprinted cluster in mouse. Previously we proposed that imprinted lncRNAs may silence distant imprinted genes by disrupting promoter-enhancer interactions by being transcribed through the enhancer, which we called the enhancer interference hypothesis. Here we tested this hypothesis by first using allele-specific chromosome conformation capture (3C) to detect interactions between the Slc22a3 promoter and the locus of the Airn lncRNA that silences it on the paternal chromosome. In agreement with the model, we found interactions enriched on the maternal allele across the entire Airn gene consistent with multiple enhancer-promoter interactions. Therefore, to test the enhancer interference hypothesis we devised an approach to delete the entire Airn gene. However, the deletion showed that there are no essential enhancers for Slc22a2, Pde10a and Slc22a3 within the Airn gene, strongly indicating that the Airn RNA rather than its transcription is responsible for silencing distant imprinted genes. Furthermore, we found that silent imprinted genes were covered with large blocks of H3K27me3 on the repressed paternal allele. Therefore we propose an alternative hypothesis whereby the chromosome interactions may initially guide the lncRNA to target imprinted promoters and recruit repressive chromatin, and that these interactions are lost once silencing is established.}, author = {Andergassen, Daniel and Muckenhuber, Markus and Bammer, Philipp C. and Kulinski, Tomasz M. and Theussl, Hans-Christian and Shimizu, Takahiko and Penninger, Josef M. and Pauler, Florian and Hudson, Quanah J.}, issn = {1553-7404}, journal = {PLoS Genetics}, number = {7}, publisher = {Public Library of Science}, title = {{The Airn lncRNA does not require any DNA elements within its locus to silence distant imprinted genes}}, doi = {10.1371/journal.pgen.1008268}, volume = {15}, year = {2019}, } @article{6091, abstract = {Cortical networks are characterized by sparse connectivity, with synapses found at only a subset of axo-dendritic contacts. Yet within these networks, neurons can exhibit high connection probabilities, suggesting that cell-intrinsic factors, not proximity, determine connectivity. Here, we identify ephrin-B3 (eB3) as a factor that determines synapse density by mediating a cell-cell competition that requires ephrin-B-EphB signaling. In a microisland culture system designed to isolate cell-cell competition, we find that eB3 determines winning and losing neurons in a contest for synapses. In a Mosaic Analysis with Double Markers (MADM) genetic mouse model system in vivo the relative levels of eB3 control spine density in layer 5 and 6 neurons. MADM cortical neurons in vitro reveal that eB3 controls synapse density independently of action potential-driven activity. Our findings illustrate a new class of competitive mechanism mediated by trans-synaptic organizing proteins which control the number of synapses neurons receive relative to neighboring neurons.}, author = {Henderson, Nathan T. and Le Marchand, Sylvain J. and Hruska, Martin and Hippenmeyer, Simon and Luo, Liqun and Dalva, Matthew B.}, journal = {eLife}, publisher = {eLife Sciences Publications}, title = {{Ephrin-B3 controls excitatory synapse density through cell-cell competition for EphBs}}, doi = {10.7554/eLife.41563}, volume = {8}, year = {2019}, } @article{6451, abstract = {Epidermal growth factor receptor (EGFR) signaling controls skin development and homeostasis inmice and humans, and its deficiency causes severe skin inflammation, which might affect epidermalstem cell behavior. Here, we describe the inflammation-independent effects of EGFR deficiency dur-ing skin morphogenesis and in adult hair follicle stem cells. Expression and alternative splicing analysisof RNA sequencing data from interfollicular epidermis and outer root sheath indicate that EGFR con-trols genes involved in epidermal differentiation and also in centrosome function, DNA damage, cellcycle, and apoptosis. Genetic experiments employingp53deletion in EGFR-deficient epidermis revealthat EGFR signaling exhibitsp53-dependent functions in proliferative epidermal compartments, aswell asp53-independent functions in differentiated hair shaft keratinocytes. Loss of EGFR leads toabsence of LEF1 protein specifically in the innermost epithelial hair layers, resulting in disorganizationof medulla cells. Thus, our results uncover important spatial and temporal features of cell-autonomousEGFR functions in the epidermis.}, author = {Amberg, Nicole and Sotiropoulou, Panagiota A. and Heller, Gerwin and Lichtenberger, Beate M. and Holcmann, Martin and Camurdanoglu, Bahar and Baykuscheva-Gentscheva, Temenuschka and Blanpain, Cedric and Sibilia, Maria}, issn = {2589-0042}, journal = {iScience}, pages = {243--256}, publisher = {Elsevier}, title = {{EGFR controls hair shaft differentiation in a p53-independent manner}}, doi = {10.1016/j.isci.2019.04.018}, volume = {15}, year = {2019}, } @article{6454, abstract = {Adult neural stem cells and multiciliated ependymalcells are glial cells essential for neurological func-tions. Together, they make up the adult neurogenicniche. Using both high-throughput clonal analysisand single-cell resolution of progenitor division pat-terns and fate, we show that these two componentsof the neurogenic niche are lineally related: adult neu-ral stem cells are sister cells to ependymal cells,whereas most ependymal cells arise from the termi-nal symmetric divisions of the lineage. Unexpectedly,we found that the antagonist regulators of DNA repli-cation, GemC1 and Geminin, can tune the proportionof neural stem cells and ependymal cells. Our find-ings reveal the controlled dynamic of the neurogenicniche ontogeny and identify the Geminin familymembers as key regulators of the initial pool of adultneural stem cells.}, author = {Ortiz-Álvarez, G and Daclin, M and Shihavuddin, A and Lansade, P and Fortoul, A and Faucourt, M and Clavreul, S and Lalioti, ME and Taraviras, S and Hippenmeyer, Simon and Livet, J and Meunier, A and Genovesio, A and Spassky, N}, issn = {1097-4199}, journal = {Neuron}, number = {1}, pages = {159--172.e7}, publisher = {Elsevier}, title = {{Adult neural stem cells and multiciliated ependymal cells share a common lineage regulated by the Geminin family members}}, doi = {10.1016/j.neuron.2019.01.051}, volume = {102}, year = {2019}, } @article{6455, abstract = {During corticogenesis, distinct subtypes of neurons are sequentially born from ventricular zone progenitors. How these cells are molecularly temporally patterned is poorly understood. We used single-cell RNA sequencing at high temporal resolution to trace the lineage of the molecular identities of successive generations of apical progenitors (APs) and their daughter neurons in mouse embryos. We identified a core set of evolutionarily conserved, temporally patterned genes that drive APs from internally driven to more exteroceptive states. We found that the Polycomb repressor complex 2 (PRC2) epigenetically regulates AP temporal progression. Embryonic age–dependent AP molecular states are transmitted to their progeny as successive ground states, onto which essentially conserved early postmitotic differentiation programs are applied, and are complemented by later-occurring environment-dependent signals. Thus, epigenetically regulated temporal molecular birthmarks present in progenitors act in their postmitotic progeny to seed adult neuronal diversity.}, author = {Telley, L and Agirman, G and Prados, J and Amberg, Nicole and Fièvre, S and Oberst, P and Bartolini, G and Vitali, I and Cadilhac, C and Hippenmeyer, Simon and Nguyen, L and Dayer, A and Jabaudon, D}, issn = {1095-9203}, journal = {Science}, number = {6440}, publisher = {AAAS}, title = {{Temporal patterning of apical progenitors and their daughter neurons in the developing neocortex}}, doi = {10.1126/science.aav2522}, volume = {364}, year = {2019}, } @article{28, abstract = {This scientific commentary refers to ‘NEGR1 and FGFR2 cooperatively regulate cortical development and core behaviours related to autism disorders in mice’ by Szczurkowska et al. }, author = {Contreras, Ximena and Hippenmeyer, Simon}, journal = {Brain a journal of neurology}, number = {9}, pages = {2542 -- 2544}, publisher = {Oxford University Press}, title = {{Incorrect trafficking route leads to autism}}, doi = {10.1093/brain/awy218}, volume = {141}, year = {2018}, } @unpublished{8547, abstract = {The cerebral cortex contains multiple hierarchically organized areas with distinctive cytoarchitectonical patterns, but the cellular mechanisms underlying the emergence of this diversity remain unclear. Here, we have quantitatively investigated the neuronal output of individual progenitor cells in the ventricular zone of the developing mouse neocortex using a combination of methods that together circumvent the biases and limitations of individual approaches. We found that individual cortical progenitor cells show a high degree of stochasticity and generate pyramidal cell lineages that adopt a wide range of laminar configurations. Mathematical modelling these lineage data suggests that a small number of progenitor cell populations, each generating pyramidal cells following different stochastic developmental programs, suffice to generate the heterogenous complement of pyramidal cell lineages that collectively build the complex cytoarchitecture of the neocortex.}, author = {Llorca, Alfredo and Ciceri, Gabriele and Beattie, Robert J and Wong, Fong K. and Diana, Giovanni and Serafeimidou, Eleni and Fernández-Otero, Marian and Streicher, Carmen and Arnold, Sebastian J. and Meyer, Martin and Hippenmeyer, Simon and Maravall, Miguel and Marín, Oscar}, booktitle = {bioRxiv}, publisher = {Cold Spring Harbor Laboratory}, title = {{Heterogeneous progenitor cell behaviors underlie the assembly of neocortical cytoarchitecture}}, doi = {10.1101/494088}, year = {2018}, } @article{20, abstract = {Background: Norepinephrine (NE) signaling has a key role in white adipose tissue (WAT) functions, including lipolysis, free fatty acid liberation and, under certain conditions, conversion of white into brite (brown-in-white) adipocytes. However, acute effects of NE stimulation have not been described at the transcriptional network level. Results: We used RNA-seq to uncover a broad transcriptional response. The inference of protein-protein and protein-DNA interaction networks allowed us to identify a set of immediate-early genes (IEGs) with high betweenness, validating our approach and suggesting a hierarchical control of transcriptional regulation. In addition, we identified a transcriptional regulatory network with IEGs as master regulators, including HSF1 and NFIL3 as novel NE-induced IEG candidates. Moreover, a functional enrichment analysis and gene clustering into functional modules suggest a crosstalk between metabolic, signaling, and immune responses. Conclusions: Altogether, our network biology approach explores for the first time the immediate-early systems level response of human adipocytes to acute sympathetic activation, thereby providing a first network basis of early cell fate programs and crosstalks between metabolic and transcriptional networks required for proper WAT function.}, author = {Higareda Almaraz, Juan and Karbiener, Michael and Giroud, Maude and Pauler, Florian and Gerhalter, Teresa and Herzig, Stephan and Scheideler, Marcel}, issn = {1471-2164}, journal = {BMC Genomics}, number = {1}, publisher = {BioMed Central}, title = {{Norepinephrine triggers an immediate-early regulatory network response in primary human white adipocytes}}, doi = {10.1186/s12864-018-5173-0}, volume = {19}, year = {2018}, } @phdthesis{10, abstract = {Genomic imprinting is an epigenetic process that leads to parent of origin-specific gene expression in a subset of genes. Imprinted genes are essential for brain development, and deregulation of imprinting is associated with neurodevelopmental diseases and the pathogenesis of psychiatric disorders. However, the cell-type specificity of imprinting at single cell resolution, and how imprinting and thus gene dosage regulates neuronal circuit assembly is still largely unknown. Here, MADM (Mosaic Analysis with Double Markers) technology was employed to assess genomic imprinting at single cell level. By visualizing MADM-induced uniparental disomies (UPDs) in distinct colors at single cell level in genetic mosaic animals, this experimental paradigm provides a unique quantitative platform to systematically assay the UPD-mediated imbalances in imprinted gene expression at unprecedented resolution. An experimental pipeline based on FACS, RNA-seq and bioinformatics analysis was established and applied to systematically map cell-type-specific ‘imprintomes’ in the mouse brain. The results revealed that parental-specific expression of imprinted genes per se is rarely cell-type-specific even at the individual cell level. Conversely, when we extended the comparison to downstream responses resulting from imbalanced imprinted gene expression, we discovered an unexpectedly high degree of cell-type specificity. Furthermore, we determined a novel function of genomic imprinting in cortical astrocyte production and in olfactory bulb (OB) granule cell generation. These results suggest important functional implication of genomic imprinting for generating cell-type diversity in the brain. In addition, MADM provides a powerful tool to study candidate genes by concomitant genetic manipulation and fluorescent labelling of single cells. MADM-based candidate gene approach was utilized to identify potential imprinted genes involved in the generation of cortical astrocytes and OB granule cells. We investigated p57Kip2, a maternally expressed gene and known cell cycle regulator. Although we found that p57Kip2 does not play a role in these processes, we detected an unexpected function of the paternal allele previously thought to be silent. Finally, we took advantage of a key property of MADM which is to allow unambiguous investigation of environmental impact on single cells. The experimental pipeline based on FACS and RNA-seq analysis of MADM-labeled cells was established to probe the functional differences of single cell loss of gene function compared to global loss of function on a transcriptional level. With this method, both common and distinct responses were isolated due to cell-autonomous and non-autonomous effects acting on genotypically identical cells. As a result, transcriptional changes were identified which result solely from the surrounding environment. Using the MADM technology to study genomic imprinting at single cell resolution, we have identified cell-type-specific gene expression, novel gene function and the impact of environment on single cell transcriptomes. Together, these provide important insights to the understanding of mechanisms regulating cell-type specificity and thus diversity in the brain.}, author = {Laukoter, Susanne}, issn = {2663-337X}, pages = {1 -- 139}, publisher = {Institute of Science and Technology Austria}, title = {{Role of genomic imprinting in cerebral cortex development}}, doi = {10.15479/AT:ISTA:th1057}, year = {2018}, } @misc{9807, abstract = {Table S1. Genes with highest betweenness. Table S2. Local and Master regulators up-regulated. Table S3. Local and Master regulators down-regulated (XLSX 23 kb).}, author = {Higareda Almaraz, Juan and Karbiener, Michael and Giroud, Maude and Pauler, Florian and Gerhalter, Teresa and Herzig, Stephan and Scheideler, Marcel}, publisher = {Springer Nature}, title = {{Additional file 1: Of Norepinephrine triggers an immediate-early regulatory network response in primary human white adipocytes}}, doi = {10.6084/m9.figshare.7295339.v1}, year = {2018}, }