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Aguilar GR, Vidal B, Ji H, Evenblij J, Ji H, Valperga G, Liao CP, Fang-Yen C, Hobert O. Functional analysis of conserved C. elegans bHLH family members uncovers lifespan control by a peptidergic hub neuron. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.12.603289. [PMID: 39071424 PMCID: PMC11275782 DOI: 10.1101/2024.07.12.603289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Throughout the animal kingdom, several members of the basic helix-loop-helix (bHLH) family act as proneural genes during early steps of nervous system development. Roles of bHLH genes in specifying terminal differentiation of postmitotic neurons have been less extensively studied. We analyze here the function of five C. elegans bHLH genes, falling into three phylogenetically conserved subfamilies, which are continuously expressed in a very small number of postmitotic neurons in the central nervous system. We show (a) that two orthologs of the vertebrate bHLHb4/b5 genes, called hlh-17 and hlh-32, function redundantly to specify the identity of a single head interneuron (AUA), as well as an individual motor neuron (VB2), (b) that the PTF1a ortholog hlh-13 acts as a terminal selector to control terminal differentiation and function of the sole octopaminergic neuron class in C. elegans , RIC, and (c) that the NHLH1/2 ortholog hlh-15 controls terminal differentiation and function of the peptidergic AVK head interneuron class, a known neuropeptidergic signaling hub in the animal. Strikingly, through null mutant analysis and cell-specific rescue experiments, we find that loss of hlh-15/NHLH in the peptidergic AVK neurons and the resulting abrogation of neuropeptide secretion causes a substantially expanded lifespan of the animal, revealing an unanticipated impact of a central, peptidergic hub neuron in regulating lifespan, which we propose to be akin to hypothalamic control of lifespan in vertebrates. Taken together, our functional analysis reveals themes of bHLH gene function during terminal differentiation that are complementary to the earlier lineage specification roles of other bHLH family members. However, such late functions are much more sparsely employed by members of the bHLH transcription factor family, compared to the function of the much more broadly employed homeodomain transcription factor family.
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2
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Ow MC, Nishiguchi MA, Dar AR, Butcher RA, Hall SE. RNAi-dependent expression of sperm genes in ADL chemosensory neurons is required for olfactory responses in Caenorhabditis elegans. Front Mol Biosci 2024; 11:1396587. [PMID: 39055986 PMCID: PMC11269235 DOI: 10.3389/fmolb.2024.1396587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 06/11/2024] [Indexed: 07/28/2024] Open
Abstract
Environmental conditions experienced early in the life of an animal can result in gene expression changes later in its life history. We have previously shown that C. elegans animals that experienced the developmentally arrested and stress resistant dauer stage (postdauers) retain a cellular memory of early-life stress that manifests during adulthood as genome-wide changes in gene expression, chromatin states, and altered life history traits. One consequence of developmental reprogramming in C. elegans postdauer adults is the downregulation of osm-9 TRPV channel gene expression in the ADL chemosensory neurons resulting in reduced avoidance to a pheromone component, ascr#3. This altered response to ascr#3 requires the principal effector of the somatic nuclear RNAi pathway, the Argonaute (AGO) NRDE-3. To investigate the role of the somatic nuclear RNAi pathway in regulating the developmental reprogramming of ADL due to early-life stress, we profiled the mRNA transcriptome of control and postdauer ADL in wild-type and nrde-3 mutant adults. We found 711 differentially expressed (DE) genes between control and postdauer ADL neurons, 90% of which are dependent upon NRDE-3. Additionally, we identified a conserved sequence that is enriched in the upstream regulatory sequences of the NRDE-3-dependent differentially expressed genes. Surprisingly, 214 of the ADL DE genes are considered "germline-expressed", including 21 genes encoding the Major Sperm Proteins and two genes encoding the sperm-specific PP1 phosphatases, GSP-3 and GSP-4. Loss of function mutations in gsp-3 resulted in both aberrant avoidance and attraction behaviors. We also show that an AGO pseudogene, Y49F6A.1 (wago-11), is expressed in ADL and is required for ascr#3 avoidance. Overall, our results suggest that small RNAs and reproductive genes program the ADL mRNA transcriptome during their developmental history and highlight a nexus between neuronal and reproductive networks in calibrating animal neuroplasticity.
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Affiliation(s)
- Maria C. Ow
- Biology Department, Syracuse University, Syracuse, NY, United States
| | | | - Abdul Rouf Dar
- Department of Chemistry, University of Florida, Gainesville, FL, United States
| | - Rebecca A. Butcher
- Department of Chemistry, University of Florida, Gainesville, FL, United States
| | - Sarah E. Hall
- Biology Department, Syracuse University, Syracuse, NY, United States
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3
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Babonis LS. On the evolutionary developmental biology of the cell. Trends Genet 2024:S0168-9525(24)00150-1. [PMID: 38971670 DOI: 10.1016/j.tig.2024.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 06/11/2024] [Accepted: 06/12/2024] [Indexed: 07/08/2024]
Abstract
Organisms are complex assemblages of cells, cells that produce light, shoot harpoons, and secrete glue. Therefore, identifying the mechanisms that generate novelty at the level of the individual cell is essential for understanding how multicellular life evolves. For decades, the field of evolutionary developmental biology (Evo-Devo) has been developing a framework for connecting genetic variation that arises during embryonic development to the emergence of diverse adult forms. With increasing access to new single cell 'omics technologies and an array of techniques for manipulating gene expression, we can now extend these inquiries inward to the level of the individual cell. In this opinion, I argue that applying an Evo-Devo framework to single cells makes it possible to explore the natural history of cells, where this was once only possible at the organismal level.
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Affiliation(s)
- Leslie S Babonis
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA.
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4
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Brown RE. Evo-devo applied to sleep research: an approach whose time has come. SLEEP ADVANCES : A JOURNAL OF THE SLEEP RESEARCH SOCIETY 2024; 5:zpae040. [PMID: 39022590 PMCID: PMC11253433 DOI: 10.1093/sleepadvances/zpae040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 06/10/2024] [Indexed: 07/20/2024]
Abstract
Sleep occurs in all animals but its amount, form, and timing vary considerably between species and between individuals. Currently, little is known about the basis for these differences, in part, because we lack a complete understanding of the brain circuitry controlling sleep-wake states and markers for the cell types which can identify similar circuits across phylogeny. Here, I explain the utility of an "Evo-devo" approach for comparative studies of sleep regulation and function as well as for sleep medicine. This approach focuses on the regulation of evolutionary ancient transcription factors which act as master controllers of cell-type specification. Studying these developmental transcription factor cascades can identify novel cell clusters which control sleep and wakefulness, reveal the mechanisms which control differences in sleep timing, amount, and expression, and identify the timepoint in evolution when different sleep-wake control neurons appeared. Spatial transcriptomic studies, which identify cell clusters based on transcription factor expression, will greatly aid this approach. Conserved developmental pathways regulate sleep in mice, Drosophila, and C. elegans. Members of the LIM Homeobox (Lhx) gene family control the specification of sleep and circadian neurons in the forebrain and hypothalamus. Increased Lhx9 activity may account for increased orexin/hypocretin neurons and reduced sleep in Mexican cavefish. Other transcription factor families specify sleep-wake circuits in the brainstem, hypothalamus, and basal forebrain. The expression of transcription factors allows the generation of specific cell types for transplantation approaches. Furthermore, mutations in developmental transcription factors are linked to variation in sleep duration in humans, risk for restless legs syndrome, and sleep-disordered breathing. This paper is part of the "Genetic and other molecular underpinnings of sleep, sleep disorders, and circadian rhythms including translational approaches" collection.
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Affiliation(s)
- Ritchie E Brown
- Department of Psychiatry, VA Boston Healthcare System and Harvard Medical School, West Roxbury, MA, USA
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5
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Smolin N, Dombrovski M, Hina BW, Moreno-Sanchez A, Gossart R, Carmona CR, Rehan A, Hussein RH, Mirshahidi P, Ausborn J, Kurmangaliyev YZ, von Reyn CR. Neuronal identity control at the resolution of a single transcription factor isoform. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.14.598883. [PMID: 38915533 PMCID: PMC11195191 DOI: 10.1101/2024.06.14.598883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
The brain exhibits remarkable neuronal diversity which is critical for its functional integrity. From the sheer number of cell types emerging from extensive transcriptional, morphological, and connectome datasets, the question arises of how the brain is capable of generating so many unique identities. 'Terminal selectors' are transcription factors hypothesized to determine the final identity characteristics in post-mitotic cells. Which transcription factors function as terminal selectors and the level of control they exert over different terminal characteristics are not well defined. Here, we establish a novel role for the transcription factor broad as a terminal selector in Drosophila melanogaster. We capitalize on existing large sequencing and connectomics datasets and employ a comprehensive characterization of terminal characteristics including Perturb-seq and whole-cell electrophysiology. We find a single isoform broad-z4 serves as the switch between the identity of two visual projection neurons LPLC1 and LPLC2. Broad-z4 is natively expressed in LPLC1, and is capable of transforming the transcriptome, morphology, and functional connectivity of LPLC2 cells into LPLC1 cells when perturbed. Our comprehensive work establishes a single isoform as the smallest unit underlying an identity switch, which may serve as a conserved strategy replicated across developmental programs.
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Affiliation(s)
- Natalie Smolin
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA
| | - Mark Dombrovski
- Howard Hughes Medical Institute, Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA
| | - Bryce W. Hina
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA
| | - Anthony Moreno-Sanchez
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA
| | - Ryan Gossart
- Brandeis University, Department of Biology, Waltham, MA
| | | | - Aadil Rehan
- Howard Hughes Medical Institute, Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA
| | - Roni H. Hussein
- Howard Hughes Medical Institute, Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA
| | - Parmis Mirshahidi
- Howard Hughes Medical Institute, Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA
| | - Jessica Ausborn
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA
| | | | - Catherine R. von Reyn
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA
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6
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Kulakova MA, Maslakov GP, Poliushkevich LO. Irreducible Complexity of Hox Gene: Path to the Canonical Function of the Hox Cluster. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:987-1001. [PMID: 38981695 DOI: 10.1134/s0006297924060014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 03/22/2024] [Accepted: 03/27/2024] [Indexed: 07/11/2024]
Abstract
The evolution of major taxa is often associated with the emergence of new gene families. In all multicellular animals except sponges and comb jellies, the genomes contain Hox genes, which are crucial regulators of development. The canonical function of Hox genes involves colinear patterning of body parts in bilateral animals. This general function is implemented through complex, precisely coordinated mechanisms, not all of which are evolutionarily conserved and fully understood. We suggest that the emergence of this regulatory complexity was preceded by a stage of cooperation between more ancient morphogenetic programs or their individual elements. Footprints of these programs may be present in modern animals to execute non-canonical Hox functions. Non-canonical functions of Hox genes are involved in maintaining terminal nerve cell specificity, autophagy, oogenesis, pre-gastrulation embryogenesis, vertical signaling, and a number of general biological processes. These functions are realized by the basic properties of homeodomain protein and could have triggered the evolution of ParaHoxozoa and Nephrozoa subsequently. Some of these non-canonical Hox functions are discussed in our review.
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Affiliation(s)
- Milana A Kulakova
- Department of Embryology, Faculty of Biology, St. Petersburg State University, St. Petersburg, 199034, Russia.
| | - Georgy P Maslakov
- Department of Embryology, Faculty of Biology, St. Petersburg State University, St. Petersburg, 199034, Russia
| | - Liudmila O Poliushkevich
- Department of Embryology, Faculty of Biology, St. Petersburg State University, St. Petersburg, 199034, Russia
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7
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Haque R, Kurien SP, Setty H, Salzberg Y, Stelzer G, Litvak E, Gingold H, Rechavi O, Oren-Suissa M. Sex-specific developmental gene expression atlas unveils dimorphic gene networks in C. elegans. Nat Commun 2024; 15:4273. [PMID: 38769103 PMCID: PMC11106331 DOI: 10.1038/s41467-024-48369-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 04/24/2024] [Indexed: 05/22/2024] Open
Abstract
Sex-specific traits and behaviors emerge during development by the acquisition of unique properties in the nervous system of each sex. However, the genetic events responsible for introducing these sex-specific features remain poorly understood. In this study, we create a comprehensive gene expression atlas of pure populations of hermaphrodites and males of the nematode Caenorhabditis elegans across development. We discover numerous differentially expressed genes, including neuronal gene families like transcription factors, neuropeptides, and G protein-coupled receptors. We identify INS-39, an insulin-like peptide, as a prominent male-biased gene expressed specifically in ciliated sensory neurons. We show that INS-39 serves as an early-stage male marker, facilitating the effective isolation of males in high-throughput experiments. Through complex and sex-specific regulation, ins-39 plays pleiotropic sexually dimorphic roles in various behaviors, while also playing a shared, dimorphic role in early life stress. This study offers a comparative sexual and developmental gene expression database for C. elegans. Furthermore, it highlights conserved genes that may underlie the sexually dimorphic manifestation of different human diseases.
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Affiliation(s)
- Rizwanul Haque
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel
- Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot, Israel
| | - Sonu Peedikayil Kurien
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel
- Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot, Israel
| | - Hagar Setty
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel
- Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot, Israel
| | - Yehuda Salzberg
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel
- Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot, Israel
| | - Gil Stelzer
- Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Einav Litvak
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Hila Gingold
- Department of Neurobiology, Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Oded Rechavi
- Department of Neurobiology, Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Meital Oren-Suissa
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel.
- Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot, Israel.
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8
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Fisher J, Verhagen M, Long Z, Moissidis M, Yan Y, He C, Wang J, Micoli E, Alastruey CM, Moors R, Marín O, Mi D, Lim L. Cortical somatostatin long-range projection neurons and interneurons exhibit divergent developmental trajectories. Neuron 2024; 112:558-573.e8. [PMID: 38086373 DOI: 10.1016/j.neuron.2023.11.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 08/22/2023] [Accepted: 11/10/2023] [Indexed: 02/24/2024]
Abstract
The mammalian cerebral cortex contains an extraordinary diversity of cell types that emerge by implementing different developmental programs. Delineating when and how cellular diversification occurs is particularly challenging for cortical inhibitory neurons because they represent a small proportion of all cortical cells and have a protracted development. Here, we combine single-cell RNA sequencing and spatial transcriptomics to characterize the emergence of neuronal diversity among somatostatin-expressing (SST+) cells in mice. We found that SST+ inhibitory neurons segregate during embryonic stages into long-range projection (LRP) neurons and two types of interneurons, Martinotti cells and non-Martinotti cells, following distinct developmental trajectories. Two main subtypes of LRP neurons and several subtypes of interneurons are readily distinguishable in the embryo, although interneuron diversity is likely refined during early postnatal life. Our results suggest that the timing for cellular diversification is unique for different subtypes of SST+ neurons and particularly divergent for LRP neurons and interneurons.
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Affiliation(s)
- Josephine Fisher
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, SE1 1UL London, UK; MRC Centre for Neurodevelopmental Disorders, King's College London, SE1 1UL, London, UK
| | - Marieke Verhagen
- VIB Center for Brain and Disease, 3000 Leuven, Belgium; Department of Neurosciences, Katholieke Universiteit (KU) Leuven, 3000 Leuven, Belgium
| | - Zhen Long
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Monika Moissidis
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, SE1 1UL London, UK; MRC Centre for Neurodevelopmental Disorders, King's College London, SE1 1UL, London, UK
| | - Yiming Yan
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Chenyi He
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jingyu Wang
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Elia Micoli
- VIB Center for Brain and Disease, 3000 Leuven, Belgium; Department of Neurosciences, Katholieke Universiteit (KU) Leuven, 3000 Leuven, Belgium
| | - Clara Milían Alastruey
- VIB Center for Brain and Disease, 3000 Leuven, Belgium; Department of Neurosciences, Katholieke Universiteit (KU) Leuven, 3000 Leuven, Belgium
| | - Rani Moors
- VIB Center for Brain and Disease, 3000 Leuven, Belgium; Department of Neurosciences, Katholieke Universiteit (KU) Leuven, 3000 Leuven, Belgium
| | - Oscar Marín
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, SE1 1UL London, UK; MRC Centre for Neurodevelopmental Disorders, King's College London, SE1 1UL, London, UK.
| | - Da Mi
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing 100084, China.
| | - Lynette Lim
- VIB Center for Brain and Disease, 3000 Leuven, Belgium; Department of Neurosciences, Katholieke Universiteit (KU) Leuven, 3000 Leuven, Belgium.
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9
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Xu C, Ramos TB, Marshall OJ, Doe CQ. Notch signaling and Bsh homeodomain activity are integrated to diversify Drosophila lamina neuron types. eLife 2024; 12:RP90136. [PMID: 38193901 PMCID: PMC10945509 DOI: 10.7554/elife.90136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024] Open
Abstract
Notch signaling is an evolutionarily conserved pathway for specifying binary neuronal fates, yet how it specifies different fates in different contexts remains elusive. In our accompanying paper, using the Drosophila lamina neuron types (L1-L5) as a model, we show that the primary homeodomain transcription factor (HDTF) Bsh activates secondary HDTFs Ap (L4) and Pdm3 (L5) and specifies L4/L5 neuronal fates. Here we test the hypothesis that Notch signaling enables Bsh to differentially specify L4 and L5 fates. We show asymmetric Notch signaling between newborn L4 and L5 neurons, but they are not siblings; rather, Notch signaling in L4 is due to Delta expression in adjacent L1 neurons. While Notch signaling and Bsh expression are mutually independent, Notch is necessary and sufficient for Bsh to specify L4 fate over L5. The NotchON L4, compared to NotchOFF L5, has a distinct open chromatin landscape which allows Bsh to bind distinct genomic loci, leading to L4-specific identity gene transcription. We propose a novel model in which Notch signaling is integrated with the primary HDTF activity to diversify neuron types by directly or indirectly generating a distinct open chromatin landscape that constrains the pool of genes that a primary HDTF can activate.
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Affiliation(s)
- Chundi Xu
- Institute of Neuroscience, Howard Hughes Medical Institute, University of OregonEugeneUnited States
| | - Tyler B Ramos
- Institute of Neuroscience, Howard Hughes Medical Institute, University of OregonEugeneUnited States
| | - Owen J Marshall
- Menzies Institute for Medical Research, University of TasmaniaHobartAustralia
| | - Chris Q Doe
- Institute of Neuroscience, Howard Hughes Medical Institute, University of OregonEugeneUnited States
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10
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Li Y, Chen S, Liu W, Zhao D, Gao Y, Hu S, Liu H, Li Y, Qu L, Liu X. A full-body transcription factor expression atlas with completely resolved cell identities in C. elegans. Nat Commun 2024; 15:358. [PMID: 38195740 PMCID: PMC10776613 DOI: 10.1038/s41467-023-42677-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 10/18/2023] [Indexed: 01/11/2024] Open
Abstract
Invariant cell lineage in C. elegans enables spatiotemporal resolution of transcriptional regulatory mechanisms controlling the fate of each cell. Here, we develop RAPCAT (Robust-point-matching- And Piecewise-affine-based Cell Annotation Tool) to automate cell identity assignment in three-dimensional image stacks of L1 larvae and profile reporter expression of 620 transcription factors in every cell. Transcription factor profile-based clustering analysis defines 80 cell types distinct from conventional phenotypic cell types and identifies three general phenotypic modalities related to these classifications. First, transcription factors are broadly downregulated in quiescent stage Hermaphrodite Specific Neurons, suggesting stage- and cell type-specific variation in transcriptome size. Second, transcription factor expression is more closely associated with morphology than other phenotypic modalities in different pre- and post-differentiation developmental stages. Finally, embryonic cell lineages can be associated with specific transcription factor expression patterns and functions that persist throughout postembryonic life. This study presents a comprehensive transcription factor atlas for investigation of intra-cell type heterogeneity.
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Affiliation(s)
- Yongbin Li
- College of Life Sciences, Capital Normal University, Beijing, 100048, China
| | - Siyu Chen
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Weihong Liu
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Intelligent Perception Lab, Hanwang Technology Co., Ltd, Beijing, 100193, China
| | - Di Zhao
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Institute of Sport, Exercise & Health, Tianjin University of Sport, Tianjin, 300381, China
| | - Yimeng Gao
- College of Life Sciences, Capital Normal University, Beijing, 100048, China
| | - Shipeng Hu
- College of Life Sciences, Capital Normal University, Beijing, 100048, China
| | - Hanyu Liu
- College of Life Sciences, Capital Normal University, Beijing, 100048, China
| | - Yuanyuan Li
- Ministry of Education Key Laboratory of Intelligent Computation & Signal Processing, Information Materials and Intelligent Sensing Laboratory of Anhui Province, School of Electronics and Information Engineering, Anhui University, Hefei, 230039, China
| | - Lei Qu
- Ministry of Education Key Laboratory of Intelligent Computation & Signal Processing, Information Materials and Intelligent Sensing Laboratory of Anhui Province, School of Electronics and Information Engineering, Anhui University, Hefei, 230039, China
| | - Xiao Liu
- College of Life Sciences, Capital Normal University, Beijing, 100048, China.
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11
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Xu C, Ramos TB, Rogers EM, Reiser MB, Doe CQ. Homeodomain proteins hierarchically specify neuronal diversity and synaptic connectivity. eLife 2024; 12:RP90133. [PMID: 38180023 PMCID: PMC10942767 DOI: 10.7554/elife.90133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2024] Open
Abstract
How our brain generates diverse neuron types that assemble into precise neural circuits remains unclear. Using Drosophila lamina neuron types (L1-L5), we show that the primary homeodomain transcription factor (HDTF) brain-specific homeobox (Bsh) is initiated in progenitors and maintained in L4/L5 neurons to adulthood. Bsh activates secondary HDTFs Ap (L4) and Pdm3 (L5) and specifies L4/L5 neuronal fates while repressing the HDTF Zfh1 to prevent ectopic L1/L3 fates (control: L1-L5; Bsh-knockdown: L1-L3), thereby generating lamina neuronal diversity for normal visual sensitivity. Subsequently, in L4 neurons, Bsh and Ap function in a feed-forward loop to activate the synapse recognition molecule DIP-β, thereby bridging neuronal fate decision to synaptic connectivity. Expression of a Bsh:Dam, specifically in L4, reveals Bsh binding to the DIP-β locus and additional candidate L4 functional identity genes. We propose that HDTFs function hierarchically to coordinate neuronal molecular identity, circuit formation, and function. Hierarchical HDTFs may represent a conserved mechanism for linking neuronal diversity to circuit assembly and function.
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Affiliation(s)
- Chundi Xu
- Institute of Neuroscience, Howard Hughes Medical Institute, University of OregonEugeneUnited States
| | - Tyler B Ramos
- Institute of Neuroscience, Howard Hughes Medical Institute, University of OregonEugeneUnited States
| | - Edward M Rogers
- Janelia Research Campus, Howard Hughes Medical Institute, Helix DriveAshburnUnited States
| | - Michael B Reiser
- Janelia Research Campus, Howard Hughes Medical Institute, Helix DriveAshburnUnited States
| | - Chris Q Doe
- Institute of Neuroscience, Howard Hughes Medical Institute, University of OregonEugeneUnited States
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12
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Miller A, Dasen JS. Establishing and maintaining Hox profiles during spinal cord development. Semin Cell Dev Biol 2024; 152-153:44-57. [PMID: 37029058 PMCID: PMC10524138 DOI: 10.1016/j.semcdb.2023.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/18/2023] [Accepted: 03/30/2023] [Indexed: 04/09/2023]
Abstract
The chromosomally-arrayed Hox gene family plays central roles in embryonic patterning and the specification of cell identities throughout the animal kingdom. In vertebrates, the relatively large number of Hox genes and pervasive expression throughout the body has hindered understanding of their biological roles during differentiation. Studies on the subtype diversification of spinal motor neurons (MNs) have provided a tractable system to explore the function of Hox genes during differentiation, and have provided an entry point to explore how neuronal fate determinants contribute to motor circuit assembly. Recent work, using both in vitro and in vivo models of MN subtype differentiation, have revealed how patterning morphogens and regulation of chromatin structure determine cell-type specific programs of gene expression. These studies have not only shed light on basic mechanisms of rostrocaudal patterning in vertebrates, but also have illuminated mechanistic principles of gene regulation that likely operate in the development and maintenance of terminal fates in other systems.
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Affiliation(s)
- Alexander Miller
- NYU Neuroscience Institute and Developmental Genetics Programs, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA.
| | - Jeremy S Dasen
- NYU Neuroscience Institute and Developmental Genetics Programs, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA.
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13
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Smith JJ, Kratsios P. Hox gene functions in the C. elegans nervous system: From early patterning to maintenance of neuronal identity. Semin Cell Dev Biol 2024; 152-153:58-69. [PMID: 36496326 PMCID: PMC10244487 DOI: 10.1016/j.semcdb.2022.11.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/14/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022]
Abstract
The nervous system emerges from a series of genetic programs that generate a remarkable array of neuronal cell types. Each cell type must acquire a distinct anatomical position, morphology, and function, enabling the generation of specialized circuits that drive animal behavior. How are these diverse cell types and circuits patterned along the anterior-posterior (A-P) axis of the animal body? Hox genes encode transcription factors that regulate cell fate and patterning events along the A-P axis of the nervous system. While most of our understanding of Hox-mediated control of neuronal development stems from studies in segmented animals like flies, mice, and zebrafish, important new themes are emerging from work in a non-segmented animal: the nematode Caenorhabditis elegans. Studies in C. elegans support the idea that Hox genes are needed continuously and across different life stages in the nervous system; they are not only required in dividing progenitor cells, but also in post-mitotic neurons during development and adult life. In C. elegans embryos and young larvae, Hox genes control progenitor cell specification, cell survival, and neuronal migration, consistent with their neural patterning roles in other animals. In late larvae and adults, C. elegans Hox genes control neuron type-specific identity features critical for neuronal function, thereby extending the Hox functional repertoire beyond early patterning. Here, we provide a comprehensive review of Hox studies in the C. elegans nervous system. To relate to readers outside the C. elegans community, we highlight conserved roles of Hox genes in patterning the nervous system of invertebrate and vertebrate animals. We end by calling attention to new functions in adult post-mitotic neurons for these paradigmatic regulators of cell fate.
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Affiliation(s)
- Jayson J Smith
- Department of Neurobiology, University of Chicago, 947 East 58th Street, Chicago, IL 60637, USA; University of Chicago Neuroscience Institute, 947 East 58th Street, Chicago, IL 60637, USA.
| | - Paschalis Kratsios
- Department of Neurobiology, University of Chicago, 947 East 58th Street, Chicago, IL 60637, USA; University of Chicago Neuroscience Institute, 947 East 58th Street, Chicago, IL 60637, USA.
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14
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Moroz LL, Romanova DY. Homologous vs. homocratic neurons: revisiting complex evolutionary trajectories. Front Cell Dev Biol 2023; 11:1336093. [PMID: 38178869 PMCID: PMC10764524 DOI: 10.3389/fcell.2023.1336093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 12/08/2023] [Indexed: 01/06/2024] Open
Affiliation(s)
- Leonid L. Moroz
- Department of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, FL, United States
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States
| | - Daria Y. Romanova
- Institute of Higher Nervous Activity and Neurophysiology of RAS, Moscow, Russia
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15
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Liu J, Murray JI. Mechanisms of lineage specification in Caenorhabditis elegans. Genetics 2023; 225:iyad174. [PMID: 37847877 DOI: 10.1093/genetics/iyad174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Accepted: 09/18/2023] [Indexed: 10/19/2023] Open
Abstract
The studies of cell fate and lineage specification are fundamental to our understanding of the development of multicellular organisms. Caenorhabditis elegans has been one of the premiere systems for studying cell fate specification mechanisms at single cell resolution, due to its transparent nature, the invariant cell lineage, and fixed number of somatic cells. We discuss the general themes and regulatory mechanisms that have emerged from these studies, with a focus on somatic lineages and cell fates. We next review the key factors and pathways that regulate the specification of discrete cells and lineages during embryogenesis and postembryonic development; we focus on transcription factors and include numerous lineage diagrams that depict the expression of key factors that specify embryonic founder cells and postembryonic blast cells, and the diverse somatic cell fates they generate. We end by discussing some future perspectives in cell and lineage specification.
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Affiliation(s)
- Jun Liu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - John Isaac Murray
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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16
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Wani AR, Chowdhury B, Luong J, Chaya GM, Patel K, Isaacman-Beck J, Shafer O, Kayser MS, Syed MH. Stem cell-specific ecdysone signaling regulates the development and function of a Drosophila sleep homeostat. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.29.560022. [PMID: 37873323 PMCID: PMC10592846 DOI: 10.1101/2023.09.29.560022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Complex behaviors arise from neural circuits that are assembled from diverse cell types. Sleep is a conserved and essential behavior, yet little is known regarding how the nervous system generates neuron types of the sleep-wake circuit. Here, we focus on the specification of Drosophila sleep-promoting neurons-long-field tangential input neurons that project to the dorsal layers of the fan-shaped body neuropil in the central complex (CX). We use lineage analysis and genetic birth dating to identify two bilateral Type II neural stem cells that generate these dorsal fan-shaped body (dFB) neurons. We show that adult dFB neurons express Ecdysone-induced protein E93, and loss of Ecdysone signaling or E93 in Type II NSCs results in the misspecification of the adult dFB neurons. Finally, we show that E93 knockdown in Type II NSCs affects adult sleep behavior. Our results provide insight into how extrinsic hormonal signaling acts on NSCs to generate neuronal diversity required for adult sleep behavior. These findings suggest that some adult sleep disorders might derive from defects in stem cell-specific temporal neurodevelopmental programs.
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Affiliation(s)
- Adil R Wani
- Neural Diversity Lab, Department of Biology, University of New Mexico, 219 Yale Blvd Ne, 87131 Albuquerque, NM, USA
| | - Budhaditya Chowdhury
- The Advanced Science Research Center, City University of New York, New York, NY 10031, USA
| | - Jenny Luong
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gonzalo Morales Chaya
- Neural Diversity Lab, Department of Biology, University of New Mexico, 219 Yale Blvd Ne, 87131 Albuquerque, NM, USA
| | - Krishna Patel
- Neural Diversity Lab, Department of Biology, University of New Mexico, 219 Yale Blvd Ne, 87131 Albuquerque, NM, USA
| | | | - Orie Shafer
- The Advanced Science Research Center, City University of New York, New York, NY 10031, USA
| | - Matthew S. Kayser
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- Chronobiology Sleep Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mubarak Hussain Syed
- Neural Diversity Lab, Department of Biology, University of New Mexico, 219 Yale Blvd Ne, 87131 Albuquerque, NM, USA
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17
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Zhao J, Xu Y. PITX1 plays essential functions in cancer. Front Oncol 2023; 13:1253238. [PMID: 37841446 PMCID: PMC10570508 DOI: 10.3389/fonc.2023.1253238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 09/15/2023] [Indexed: 10/17/2023] Open
Abstract
PITX1, also known as the pituitary homeobox 1 gene, has emerged as a key regulator in animal growth and development, attracting significant research attention. Recent investigations have revealed the implication of dysregulated PITX1 expression in tumorigenesis, highlighting its involvement in cancer development. Notably, PITX1 interacts with p53 and exerts control over crucial cellular processes including cell cycle progression, apoptosis, and chemotherapy resistance. Its influence extends to various tumors, such as esophageal, colorectal, gastric, and liver cancer, contributing to tumor progression and metastasis. Despite its significance, a comprehensive review examining PITX1's role in oncology remains lacking. This review aims to address this gap by providing a comprehensive overview of PITX1 in different cancer types, with a particular focus on its clinicopathological significance.
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Affiliation(s)
- Jingpu Zhao
- Affiliated Hospital of Weifang Medical University, School of Clinical Medicine, Weifang Medical University, Weifang, Shandong, China
| | - Yongfeng Xu
- Abdominal Oncology Ward, Cancer Center, West China Hospital of Sichuan University, Chengdu, Sichuan, China
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18
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Jourdon A, Wu F, Mariani J, Capauto D, Norton S, Tomasini L, Amiri A, Suvakov M, Schreiner JD, Jang Y, Panda A, Nguyen CK, Cummings EM, Han G, Powell K, Szekely A, McPartland JC, Pelphrey K, Chawarska K, Ventola P, Abyzov A, Vaccarino FM. Modeling idiopathic autism in forebrain organoids reveals an imbalance of excitatory cortical neuron subtypes during early neurogenesis. Nat Neurosci 2023; 26:1505-1515. [PMID: 37563294 PMCID: PMC10573709 DOI: 10.1038/s41593-023-01399-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/30/2023] [Indexed: 08/12/2023]
Abstract
Idiopathic autism spectrum disorder (ASD) is highly heterogeneous, and it remains unclear how convergent biological processes in affected individuals may give rise to symptoms. Here, using cortical organoids and single-cell transcriptomics, we modeled alterations in the forebrain development between boys with idiopathic ASD and their unaffected fathers in 13 families. Transcriptomic changes suggest that ASD pathogenesis in macrocephalic and normocephalic probands involves an opposite disruption of the balance between excitatory neurons of the dorsal cortical plate and other lineages such as early-generated neurons from the putative preplate. The imbalance stemmed from divergent expression of transcription factors driving cell fate during early cortical development. While we did not find genomic variants in probands that explained the observed transcriptomic alterations, a significant overlap between altered transcripts and reported ASD risk genes affected by rare variants suggests a degree of gene convergence between rare forms of ASD and the developmental transcriptome in idiopathic ASD.
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Affiliation(s)
- Alexandre Jourdon
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
| | - Feinan Wu
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
| | - Jessica Mariani
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
| | - Davide Capauto
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
| | - Scott Norton
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
| | - Livia Tomasini
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
| | - Anahita Amiri
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
| | - Milovan Suvakov
- Department of Quantitative Health Sciences, Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
| | - Jeremy D Schreiner
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
| | - Yeongjun Jang
- Department of Quantitative Health Sciences, Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
| | - Arijit Panda
- Department of Quantitative Health Sciences, Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
| | - Cindy Khanh Nguyen
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
| | - Elise M Cummings
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
| | - Gloria Han
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
| | - Kelly Powell
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
| | - Anna Szekely
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
| | - James C McPartland
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
| | - Kevin Pelphrey
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
- Brain Institute, Department of Neurology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | | | - Pamela Ventola
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
| | - Alexej Abyzov
- Department of Quantitative Health Sciences, Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA.
| | - Flora M Vaccarino
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA.
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA.
- Kavli Institute for Neuroscience, Yale University, New Haven, CT, USA.
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19
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Klingler E. Temporal controls over cortical projection neuron fate diversity. Curr Opin Neurobiol 2023; 79:102677. [PMID: 36736108 DOI: 10.1016/j.conb.2023.102677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 12/19/2022] [Accepted: 01/04/2023] [Indexed: 02/04/2023]
Abstract
During neocortex development, cortical projection neurons (PN) are sequentially produced and assemble into circuits underlying our interactions with the environment. Cortical PN are heterogeneous in terms of birthdate, layer position, molecular identity, connectivity, and function. This diversity increases in evolutionarily most recent species, but when and how it emerges during corticogenesis is still debated. While time-locked expression of determinant genes and early stochasticity allow the production of different types of PN, temporal differences in unfolding similar transcriptional programs, rather than fundamental differences in these programs, further account for anatomical variability between PN subtypes and across species. Altogether, these mechanisms, which will be discussed here, participate in increasing cortical PN diversity.
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Affiliation(s)
- Esther Klingler
- Department of Basic Neurosciences, University of Geneva, 1 Rue Michel Servet, 1211, Geneva, Switzerland.
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20
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Hippenmeyer S. Principles of neural stem cell lineage progression: Insights from developing cerebral cortex. Curr Opin Neurobiol 2023; 79:102695. [PMID: 36842274 DOI: 10.1016/j.conb.2023.102695] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/18/2023] [Accepted: 01/29/2023] [Indexed: 02/28/2023]
Abstract
How to generate a brain of correct size and with appropriate cell-type diversity during development is a major question in Neuroscience. In the developing neocortex, radial glial progenitor (RGP) cells are the main neural stem cells that produce cortical excitatory projection neurons, glial cells, and establish the prospective postnatal stem cell niche in the lateral ventricles. RGPs follow a tightly orchestrated developmental program that when disrupted can result in severe cortical malformations such as microcephaly and megalencephaly. The precise cellular and molecular mechanisms instructing faithful RGP lineage progression are however not well understood. This review will summarize recent conceptual advances that contribute to our understanding of the general principles of RGP lineage progression.
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Affiliation(s)
- Simon Hippenmeyer
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria.
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21
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Heo W, Hwang H, Kim J, Oh SH, Yu Y, Lee JH, Kim K. The CCAAT-box transcription factor, NF-Y complex, mediates the specification of the IL1 neurons in C. elegans. BMB Rep 2023; 56:153-159. [PMID: 36330709 PMCID: PMC10068339 DOI: 10.5483/bmbrep.2022-0146] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 10/07/2022] [Accepted: 10/27/2022] [Indexed: 09/16/2023] Open
Abstract
Neuronal differentiation is highly coordinated through a cascade of gene expression, mediated via interactions between transacting transcription factors and cis-regulatory elements of their target genes. However, the mechanisms of transcriptional regulation that determine neuronal cell-fate are not fully understood. Here, we show that the nuclear transcription factor Y (NF-Y) subunit, NFYA-1, is necessary and sufficient to express the flp-3 neuropeptide gene in the IL1 neurons of C. elegans. flp-3 expression is decreased in dorsal and lateral, but not ventral IL1s of nfya-1 mutants. The expression of another terminally differentiated gene, eat-4 vesicular glutamate transporter, is abolished, whereas the unc-8 DEG/ENaC gene and pan-neuronal genes are expressed normally in IL1s of nfya-1 mutants. nfya-1 is expressed in and acts in IL1s to regulate flp-3 and eat-4 expression. Ectopic expression of NFYA-1 drives the expression of flp-3 gene in other cell-types. Promoter analysis of IL1-expressed genes results in the identification of several cisregulatory motifs which are necessary for IL1 expression, including a putative CCAAT-box located in the flp-3 promoter that NFYA-1 directly interacts with. NFYA-1 and NFYA-2, together with NFYB-1 and NFYC-1, exhibit partly or fully redundant roles in the regulation of flp-3 or unc-8 expression, respectively. Taken together, our data indicate that the NF-Y complex regulates neuronal subtype-specification via regulating a set of terminal-differentiation genes. [BMB Reports 2023; 56(3): 153-159].
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Affiliation(s)
- Woojung Heo
- Department of Brain Sciences, DGIST, Daegu 42988, Korea
| | | | - Jimin Kim
- Department of Brain Sciences, DGIST, Daegu 42988, Korea
| | - Seung Hee Oh
- Department of Brain Sciences, DGIST, Daegu 42988, Korea
| | - Youngseok Yu
- Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul 02447, Korea
| | - Jae-Hyung Lee
- Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul 02447, Korea
- Department of Oral Microbiology, College of Dentistry, Kyung Hee University, Seoul 02447, Korea
| | - Kyuhyung Kim
- Department of Brain Sciences, DGIST, Daegu 42988, Korea
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22
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Heo W, Hwang H, Kim J, Oh SH, Yu Y, Lee JH, Kim K. The CCAAT-box transcription factor, NF-Y complex, mediates the specification of the IL1 neurons in C. elegans. BMB Rep 2023; 56:153-159. [PMID: 36330709 PMCID: PMC10068339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 10/07/2022] [Accepted: 10/27/2022] [Indexed: 03/29/2023] Open
Abstract
Neuronal differentiation is highly coordinated through a cascade of gene expression, mediated via interactions between transacting transcription factors and cis-regulatory elements of their target genes. However, the mechanisms of transcriptional regulation that determine neuronal cell-fate are not fully understood. Here, we show that the nuclear transcription factor Y (NF-Y) subunit, NFYA-1, is necessary and sufficient to express the flp-3 neuropeptide gene in the IL1 neurons of C. elegans. flp-3 expression is decreased in dorsal and lateral, but not ventral IL1s of nfya-1 mutants. The expression of another terminally differentiated gene, eat-4 vesicular glutamate transporter, is abolished, whereas the unc-8 DEG/ENaC gene and pan-neuronal genes are expressed normally in IL1s of nfya-1 mutants. nfya-1 is expressed in and acts in IL1s to regulate flp-3 and eat-4 expression. Ectopic expression of NFYA-1 drives the expression of flp-3 gene in other cell-types. Promoter analysis of IL1-expressed genes results in the identification of several cisregulatory motifs which are necessary for IL1 expression, including a putative CCAAT-box located in the flp-3 promoter that NFYA-1 directly interacts with. NFYA-1 and NFYA-2, together with NFYB-1 and NFYC-1, exhibit partly or fully redundant roles in the regulation of flp-3 or unc-8 expression, respectively. Taken together, our data indicate that the NF-Y complex regulates neuronal subtype-specification via regulating a set of terminal-differentiation genes. [BMB Reports 2023; 56(3): 153-159].
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Affiliation(s)
- Woojung Heo
- Department of Brain Sciences, DGIST, Daegu 42988, Korea
| | | | - Jimin Kim
- Department of Brain Sciences, DGIST, Daegu 42988, Korea
| | - Seung Hee Oh
- Department of Brain Sciences, DGIST, Daegu 42988, Korea
| | - Youngseok Yu
- Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul 02447, Korea
| | - Jae-Hyung Lee
- Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul 02447, Korea
- Department of Oral Microbiology, College of Dentistry, Kyung Hee University, Seoul 02447, Korea
| | - Kyuhyung Kim
- Department of Brain Sciences, DGIST, Daegu 42988, Korea
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23
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Nagel S. The Role of IRX Homeobox Genes in Hematopoietic Progenitors and Leukemia. Genes (Basel) 2023; 14:genes14020297. [PMID: 36833225 PMCID: PMC9957183 DOI: 10.3390/genes14020297] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 01/24/2023] Open
Abstract
IRX genes are members of the TALE homeobox gene class and encode six related transcription factors (IRX1-IRX6) controlling development and cell differentiation of several tissues in humans. Classification of TALE homeobox gene expression patterns for the hematopoietic compartment, termed TALE-code, has revealed exclusive IRX1 activity in pro-B-cells and megakaryocyte erythroid progenitors (MEPs), highlighting its specific contribution to developmental processes at these early stages of hematopoietic lineage differentiation. Moreover, aberrant expression of IRX homeobox genes IRX1, IRX2, IRX3 and IRX5 has been detected in hematopoietic malignancies, including B-cell precursor acute lymphoblastic leukemia (BCP-ALL), T-cell ALL, and some subtypes of acute myeloid leukemia (AML). Expression analyses of patient samples and experimental studies using cell lines and mouse models have revealed oncogenic functions in cell differentiation arrest and upstream and downstream genes, thus, revealing normal and aberrant regulatory networks. These studies have shown how IRX genes play key roles in the development of both normal blood and immune cells, and hematopoietic malignancies. Understanding their biology serves to illuminate developmental gene regulation in the hematopoietic compartment, and may improve diagnostic classification of leukemias in the clinic and reveal new therapeutic targets and strategies.
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Affiliation(s)
- Stefan Nagel
- Department of Human and Animal Cell Cultures, Leibniz-Institute DSMZ, 38124 Braunschweig, Germany
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24
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RING Finger Protein 10 Regulates AP-1/Meox2 to Mediate Pirarubicin-Induced Cardiomyocyte Apoptosis. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2023; 2023:7872193. [PMID: 36713029 PMCID: PMC9883094 DOI: 10.1155/2023/7872193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 10/12/2022] [Accepted: 11/25/2022] [Indexed: 01/21/2023]
Abstract
Pirarubicin (THP) is one of the classic chemotherapy drugs for cancer treatment. It is often clinically limited because of its cardiotoxicity. The occurrence and development of THP-mediated chemotherapy-related cardiotoxicity (CRC) may be reversed by RING finger protein 10 (RNF10). This study was performed with the aim of evaluating the inhibitory effect of RNF10 on THP-mediated CRC and its molecular mechanism. In vivo, we found that the expression of RNF10 decreased in THP-induced CRC rats, accompanied by Meox2 inhibition and AP-1 activation, resulting in increased cardiomyocyte apoptosis. After small interfering RNA (siRNA) and lentivirus transfection (Lv) of RNF10 in vitro, the expression of RNF10, Meox2, and AP-1 proteins and the degree of cardiomyocyte apoptosis were detected. We found that overexpression of RNF10 in H9C2 cardiomyocytes significantly promoted Meox2 and inhibited AP-1, alleviated apoptosis, and showed further inhibitory activity on THP-induced cardiomyocyte toxicity. Silencing RNF10 showed the opposite result. Our study showed that RNF10 inhibited THP-induced CRC through the activity of Meox2 and AP-1 proteins. RNF10 may be the next drug target for the treatment of CRC and other related cardiovascular diseases.
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25
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Wang Q, Wang Y, Chang C, Ma F, Peng D, Yang S, An Y, Deng Q, Wang Q, Gao F, Wang F, Tang H, Qi X, Jiang X, Cai D, Zhou G. Comparative analysis of mesenchymal stem/stromal cells derived from human induced pluripotent stem cells and the cognate umbilical cord mesenchymal stem/stromal cells. Heliyon 2023; 9:e12683. [PMID: 36647346 PMCID: PMC9840238 DOI: 10.1016/j.heliyon.2022.e12683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 12/05/2022] [Accepted: 12/22/2022] [Indexed: 01/06/2023] Open
Abstract
Mesenchymal stem/stromal cells (MSCs) show tremendous potential for regenerative medicine due to their self-renewal, multi-differentiation and immunomodulatory capabilities. Largely studies had indicated conventional tissue-derived MSCs have considerable limited expandability and donor variability which hinders further application. Induced pluripotent stem cell (iPSCs)-derived MSCs (iMSCs) have created exciting source for standardized cellular therapy. However, the cellular and molecular differences between iMSCs and the cognate tissue-derived MSCs remains poorly explored. In this study, we first successfully reprogrammed human umbilical cords-derived mesenchymal stem/stromal cells (UMSCs) into iPSCs by using the cocktails of mRNA. Subsequently, iPSCs were further differentiated into iMSCs in xeno-free induction medium. Then, iMSCs were compared with the donor matched UMSCs by assessing proliferative state, differentiation capability, immunomodulatory potential through immunohistochemical analysis, flow cytometric analysis, transcriptome sequencing analysis, and combine with coculture with immune cell population. The results showed that iMSCs exhibited high expression of MSCs positive-makers CD73, CD90, CD105 and lack expression of negative-maker cocktails CD34, CD45, CD11b, CD19, HLA-DR; also successfully differentiated into osteocytes, chondrocytes and adipocytes. Further, the iMSCs were similar with their parental UMSCs in cell proliferative state detected by the CCK-8 assay, and in cell rejuvenation state assessed by β-Galactosidase staining and telomerase activity related mRNA and protein analysis. However, iMSCs exhibited similarity to resident MSCs in Homeobox (Hox) genes expression profile and presented better neural differentiation potential by activation of NESTIN related pathway. Moreover, iMSCs owned enhanced immunosuppression capacity through downregulation pools of pro-inflammatory factors, including IL6, IL1B etc. and upregulation anti-inflammatory factors NOS1, TGFB etc. signals. In summary, our study provides an attractive cell source for basic research and offers fundamental biological insight of iMSCs-based therapy.
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Affiliation(s)
- Quanlei Wang
- Key Laboratory of Regenerative Medicine of Ministry of Education, Biology Postdoctoral Research Station, Jinan University, Guangzhou, China,Cheerland Danlun Biopharma Co. Ltd., Dapeng New District, Shenzhen, China,Department of Medical Cell Biology and Genetics, Guangdong Key Laboratory of Genomic Stability and Disease Prevention, Shenzhen Key Laboratory of Anti-Aging and Regenerative Medicine, and Shenzhen Engineering Laboratory of Regenerative Technologies for Orthopaedic Diseases, Health Science Center, Shenzhen University, Shenzhen, China
| | - Yuwei Wang
- Cheerland Danlun Biopharma Co. Ltd., Dapeng New District, Shenzhen, China,The SZU-Cheerland Institute for Advanced and Innovative Medicine, Shenzhen, China
| | - Chongfei Chang
- Cheerland Danlun Biopharma Co. Ltd., Dapeng New District, Shenzhen, China
| | - Feilong Ma
- Cheerland Danlun Biopharma Co. Ltd., Dapeng New District, Shenzhen, China
| | - Dongxiu Peng
- Cheerland Danlun Biopharma Co. Ltd., Dapeng New District, Shenzhen, China
| | - Shun Yang
- Cheerland Danlun Biopharma Co. Ltd., Dapeng New District, Shenzhen, China
| | | | - Qiuting Deng
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Qixiao Wang
- Department of Oral and Maxillofacial Surgery, The First People's Hospital of Huaihua, University of South China, Huaihua, Hunan, China
| | - Fei Gao
- China Food and Drug Administration, Beijing, China
| | - Fei Wang
- The SZU-Cheerland Institute for Advanced and Innovative Medicine, Shenzhen, China
| | - Huiru Tang
- Cheerland Danlun Biopharma Co. Ltd., Dapeng New District, Shenzhen, China
| | - Xufeng Qi
- Key Laboratory of Regenerative Medicine of Ministry of Education, Biology Postdoctoral Research Station, Jinan University, Guangzhou, China
| | - Xiaoming Jiang
- The SZU-Cheerland Institute for Advanced and Innovative Medicine, Shenzhen, China,Corresponding author. The SZU-Cheerland Institute for Advanced and Innovative Medicine, Shenzhen, China.
| | - Dongqing Cai
- Key Laboratory of Regenerative Medicine of Ministry of Education, Biology Postdoctoral Research Station, Jinan University, Guangzhou, China,Corresponding author. Key Laboratory of Regenerative Medicine of Ministry of Education, Biology Postdoctoral Research Station, Jinan University, Guangzhou, China.
| | - Guangqian Zhou
- Cheerland Danlun Biopharma Co. Ltd., Dapeng New District, Shenzhen, China,Department of Medical Cell Biology and Genetics, Guangdong Key Laboratory of Genomic Stability and Disease Prevention, Shenzhen Key Laboratory of Anti-Aging and Regenerative Medicine, and Shenzhen Engineering Laboratory of Regenerative Technologies for Orthopaedic Diseases, Health Science Center, Shenzhen University, Shenzhen, China,The SZU-Cheerland Institute for Advanced and Innovative Medicine, Shenzhen, China,Corresponding author. The SZU-Cheerland Institute for Advanced and Innovative Medicine, Shenzhen, China.
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26
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Masoudi N, Schnabel R, Yemini E, Leyva-Díaz E, Hobert O. Cell-specific effects of the sole C. elegans Daughterless/E protein homolog, HLH-2, on nervous system development. Development 2023; 150:286219. [PMID: 36595352 PMCID: PMC10108603 DOI: 10.1242/dev.201366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 11/30/2022] [Indexed: 01/04/2023]
Abstract
Are there common mechanisms of neurogenesis used throughout an entire nervous system? We explored to what extent canonical proneural class I/II bHLH complexes are responsible for neurogenesis throughout the entire Caenorhabditis elegans nervous system. Distinct, lineage-specific proneural class II bHLH factors are generally thought to operate via interaction with a common, class I bHLH subunit, encoded by Daughterless in flies, the E proteins in vertebrates and HLH-2 in C. elegans. To eliminate function of all proneuronal class I/II bHLH complexes, we therefore genetically removed maternal and zygotic hlh-2 gene activity. We observed broad effects on neurogenesis, but still detected normal neurogenesis in many distinct neuron-producing lineages of the central and peripheral nervous system. Moreover, we found that hlh-2 selectively affects some aspects of neuron differentiation while leaving others unaffected. Although our studies confirm the function of proneuronal class I/II bHLH complexes in many different lineages throughout a nervous system, we conclude that their function is not universal, but rather restricted by lineage, cell type and components of differentiation programs affected.
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Affiliation(s)
- Neda Masoudi
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, NY 10027, USA
| | - Ralf Schnabel
- Institute of Genetics, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - Eviatar Yemini
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, NY 10027, USA.,University of Massachusetts, Department of Neurobiology, Worcester, MA 1605-2324, USA
| | - Eduardo Leyva-Díaz
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, NY 10027, USA
| | - Oliver Hobert
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, NY 10027, USA
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27
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Pinto PB, Domsch K, Lohmann I. Hox function and specificity – A tissue centric view. Semin Cell Dev Biol 2022:S1084-9521(22)00353-6. [PMID: 36517344 DOI: 10.1016/j.semcdb.2022.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 11/11/2022] [Accepted: 11/30/2022] [Indexed: 12/15/2022]
Abstract
Since their discovery, the Hox genes, with their incredible power to reprogram the identity of complete body regions, a phenomenon called homeosis, have captured the fascination of many biologists. Recent research has provided new insights into the function of Hox proteins in different germ layers and the mechanisms they employ to control tissue morphogenesis. We focus in this review on the ectoderm and mesoderm to highlight new findings and discuss them with regards to established concepts of Hox target gene regulation. Furthermore, we highlight the molecular mechanisms involved the transcriptional repression of specific groups of Hox target genes, and summarize the role of Hox mediated gene silencing in tissue development. Finally, we reflect on recent findings identifying a large number of tissue-specific Hox interactor partners, which open up new avenues and directions towards a better understanding of Hox function and specificity in different tissues.
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28
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Tomas-Roca L, Qiu Z, Fransén E, Gokhale R, Bulovaite E, Price DJ, Komiyama NH, Grant SGN. Developmental disruption and restoration of brain synaptome architecture in the murine Pax6 neurodevelopmental disease model. Nat Commun 2022; 13:6836. [PMID: 36369219 PMCID: PMC9652404 DOI: 10.1038/s41467-022-34131-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 10/14/2022] [Indexed: 11/13/2022] Open
Abstract
Neurodevelopmental disorders of genetic origin delay the acquisition of normal abilities and cause disabling phenotypes. Nevertheless, spontaneous attenuation and even complete amelioration of symptoms in early childhood and adolescence can occur in many disorders, suggesting that brain circuits possess an intrinsic capacity to overcome the deficits arising from some germline mutations. We examined the molecular composition of almost a trillion excitatory synapses on a brain-wide scale between birth and adulthood in mice carrying a mutation in the homeobox transcription factor Pax6, a neurodevelopmental disorder model. Pax6 haploinsufficiency had no impact on total synapse number at any age. By contrast, the molecular composition of excitatory synapses, the postnatal expansion of synapse diversity and the acquisition of normal synaptome architecture were delayed in all brain regions, interfering with networks and electrophysiological simulations of cognitive functions. Specific excitatory synapse types and subtypes were affected in two key developmental age-windows. These phenotypes were reversed within 2-3 weeks of onset, restoring synapse diversity and synaptome architecture to the normal developmental trajectory. Synapse subtypes with rapid protein turnover mediated the synaptome remodeling. This brain-wide capacity for remodeling of synapse molecular composition to recover and maintain the developmental trajectory of synaptome architecture may help confer resilience to neurodevelopmental genetic disorders.
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Affiliation(s)
- Laura Tomas-Roca
- grid.4305.20000 0004 1936 7988Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK
| | - Zhen Qiu
- grid.4305.20000 0004 1936 7988Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK
| | - Erik Fransén
- grid.5037.10000000121581746Science for Life Laboratory, KTH Royal Institute of Technology, SE-171 65 Solna, Sweden
| | - Ragini Gokhale
- grid.4305.20000 0004 1936 7988Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK
| | - Edita Bulovaite
- grid.4305.20000 0004 1936 7988Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK
| | - David J. Price
- grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain (SIDB), Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Noboru H. Komiyama
- grid.4305.20000 0004 1936 7988Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain (SIDB), Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Seth G. N. Grant
- grid.4305.20000 0004 1936 7988Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain (SIDB), Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK
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29
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Feng W, Destain H, Smith JJ, Kratsios P. Maintenance of neurotransmitter identity by Hox proteins through a homeostatic mechanism. Nat Commun 2022; 13:6097. [PMID: 36243871 PMCID: PMC9569373 DOI: 10.1038/s41467-022-33781-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 09/30/2022] [Indexed: 12/24/2022] Open
Abstract
Hox transcription factors play fundamental roles during early patterning, but they are also expressed continuously, from embryonic stages through adulthood, in the nervous system. However, the functional significance of their sustained expression remains unclear. In C. elegans motor neurons (MNs), we find that LIN-39 (Scr/Dfd/Hox4-5) is continuously required during post-embryonic life to maintain neurotransmitter identity, a core element of neuronal function. LIN-39 acts directly to co-regulate genes that define cholinergic identity (e.g., unc-17/VAChT, cho-1/ChT). We further show that LIN-39, MAB-5 (Antp/Hox6-8) and the transcription factor UNC-3 (Collier/Ebf) operate in a positive feedforward loop to ensure continuous and robust expression of cholinergic identity genes. Finally, we identify a two-component design principle for homeostatic control of Hox gene expression in adult MNs: Hox transcriptional autoregulation is counterbalanced by negative UNC-3 feedback. These findings uncover a noncanonical role for Hox proteins during post-embryonic life, critically broadening their functional repertoire from early patterning to the control of neurotransmitter identity.
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Affiliation(s)
- Weidong Feng
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
- University of Chicago Neuroscience Institute, Chicago, IL, USA
- Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL, USA
| | - Honorine Destain
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
- University of Chicago Neuroscience Institute, Chicago, IL, USA
- Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL, USA
| | - Jayson J Smith
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
- University of Chicago Neuroscience Institute, Chicago, IL, USA
| | - Paschalis Kratsios
- Department of Neurobiology, University of Chicago, Chicago, IL, USA.
- University of Chicago Neuroscience Institute, Chicago, IL, USA.
- Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL, USA.
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30
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Widespread employment of conserved C. elegans homeobox genes in neuronal identity specification. PLoS Genet 2022; 18:e1010372. [PMID: 36178933 PMCID: PMC9524666 DOI: 10.1371/journal.pgen.1010372] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 08/03/2022] [Indexed: 11/20/2022] Open
Abstract
Homeobox genes are prominent regulators of neuronal identity, but the extent to which their function has been probed in animal nervous systems remains limited. In the nematode Caenorhabditis elegans, each individual neuron class is defined by the expression of unique combinations of homeobox genes, prompting the question of whether each neuron class indeed requires a homeobox gene for its proper identity specification. We present here progress in addressing this question by extending previous mutant analysis of homeobox gene family members and describing multiple examples of homeobox gene function in different parts of the C. elegans nervous system. To probe homeobox function, we make use of a number of reporter gene tools, including a novel multicolor reporter transgene, NeuroPAL, which permits simultaneous monitoring of the execution of multiple differentiation programs throughout the entire nervous system. Using these tools, we add to the previous characterization of homeobox gene function by identifying neuronal differentiation defects for 14 homeobox genes in 24 distinct neuron classes that are mostly unrelated by location, function and lineage history. 12 of these 24 neuron classes had no homeobox gene function ascribed to them before, while in the other 12 neuron classes, we extend the combinatorial code of transcription factors required for specifying terminal differentiation programs. Furthermore, we demonstrate that in a particular lineage, homeotic identity transformations occur upon loss of a homeobox gene and we show that these transformations are the result of changes in homeobox codes. Combining the present with past analyses, 113 of the 118 neuron classes of C. elegans are now known to require a homeobox gene for proper execution of terminal differentiation programs. Such broad deployment indicates that homeobox function in neuronal identity specification may be an ancestral feature of animal nervous systems.
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31
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Doyle JJ. Cell types as species: Exploring a metaphor. FRONTIERS IN PLANT SCIENCE 2022; 13:868565. [PMID: 36072310 PMCID: PMC9444152 DOI: 10.3389/fpls.2022.868565] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 07/29/2022] [Indexed: 06/05/2023]
Abstract
The concept of "cell type," though fundamental to cell biology, is controversial. Cells have historically been classified into types based on morphology, physiology, or location. More recently, single cell transcriptomic studies have revealed fine-scale differences among cells with similar gross phenotypes. Transcriptomic snapshots of cells at various stages of differentiation, and of cells under different physiological conditions, have shown that in many cases variation is more continuous than discrete, raising questions about the relationship between cell type and cell state. Some researchers have rejected the notion of fixed types altogether. Throughout the history of discussions on cell type, cell biologists have compared the problem of defining cell type with the interminable and often contentious debate over the definition of arguably the most important concept in systematics and evolutionary biology, "species." In the last decades, systematics, like cell biology, has been transformed by the increasing availability of molecular data, and the fine-grained resolution of genetic relationships have generated new ideas about how that variation should be classified. There are numerous parallels between the two fields that make exploration of the "cell types as species" metaphor timely. These parallels begin with philosophy, with discussion of both cell types and species as being either individuals, groups, or something in between (e.g., homeostatic property clusters). In each field there are various different types of lineages that form trees or networks that can (and in some cases do) provide criteria for grouping. Developing and refining models for evolutionary divergence of species and for cell type differentiation are parallel goals of the two fields. The goal of this essay is to highlight such parallels with the hope of inspiring biologists in both fields to look for new solutions to similar problems outside of their own field.
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Abstract
Bicoid is famous for its role in early embryo patterning of Drosophila by activating Hunchback expression to establish the anterior-posterior axis. A new study found that in a type of post-mitotic neuron Hunchback conversely activates Bicoid expression to regulate synapse targeting and locomotor behavior.
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33
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Danchin A, Fenton AA. From Analog to Digital Computing: Is Homo sapiens’ Brain on Its Way to Become a Turing Machine? Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.796413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The abstract basis of modern computation is the formal description of a finite state machine, the Universal Turing Machine, based on manipulation of integers and logic symbols. In this contribution to the discourse on the computer-brain analogy, we discuss the extent to which analog computing, as performed by the mammalian brain, is like and unlike the digital computing of Universal Turing Machines. We begin with ordinary reality being a permanent dialog between continuous and discontinuous worlds. So it is with computing, which can be analog or digital, and is often mixed. The theory behind computers is essentially digital, but efficient simulations of phenomena can be performed by analog devices; indeed, any physical calculation requires implementation in the physical world and is therefore analog to some extent, despite being based on abstract logic and arithmetic. The mammalian brain, comprised of neuronal networks, functions as an analog device and has given rise to artificial neural networks that are implemented as digital algorithms but function as analog models would. Analog constructs compute with the implementation of a variety of feedback and feedforward loops. In contrast, digital algorithms allow the implementation of recursive processes that enable them to generate unparalleled emergent properties. We briefly illustrate how the cortical organization of neurons can integrate signals and make predictions analogically. While we conclude that brains are not digital computers, we speculate on the recent implementation of human writing in the brain as a possible digital path that slowly evolves the brain into a genuine (slow) Turing machine.
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34
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Vidal B, Gulez B, Cao WX, Leyva-Diaz E, Reilly MB, Tekieli T, Hobert O. The enteric nervous system of the C. elegans pharynx is specified by the Sine oculis-like homeobox gene ceh-34. eLife 2022; 11:76003. [PMID: 35324425 PMCID: PMC8989417 DOI: 10.7554/elife.76003] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 03/23/2022] [Indexed: 11/29/2022] Open
Abstract
Overarching themes in the terminal differentiation of the enteric nervous system, an autonomously acting unit of animal nervous systems, have so far eluded discovery. We describe here the overall regulatory logic of enteric nervous system differentiation of the nematode Caenorhabditis elegans that resides within the foregut (pharynx) of the worm. A C. elegans homolog of the Drosophila Sine oculis homeobox gene, ceh-34, is expressed in all 14 classes of interconnected pharyngeal neurons from their birth throughout their life time, but in no other neuron type of the entire animal. Constitutive and temporally controlled ceh-34 removal shows that ceh-34 is required to initiate and maintain the neuron type-specific terminal differentiation program of all pharyngeal neuron classes, including their circuit assembly. Through additional genetic loss of function analysis, we show that within each pharyngeal neuron class, ceh-34 cooperates with different homeodomain transcription factors to individuate distinct pharyngeal neuron classes. Our analysis underscores the critical role of homeobox genes in neuronal identity specification and links them to the control of neuronal circuit assembly of the enteric nervous system. Together with the pharyngeal nervous system simplicity as well as its specification by a Sine oculis homolog, our findings invite speculations about the early evolution of nervous systems.
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Affiliation(s)
- Berta Vidal
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, United States
| | - Burcu Gulez
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, United States
| | - Wen Xi Cao
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, United States
| | - Eduardo Leyva-Diaz
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, United States
| | - Molly B Reilly
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, United States
| | - Tessa Tekieli
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, United States
| | - Oliver Hobert
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, United States
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35
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Leyva-Díaz E, Hobert O. Robust regulatory architecture of pan-neuronal gene expression. Curr Biol 2022; 32:1715-1727.e8. [PMID: 35259341 PMCID: PMC9050922 DOI: 10.1016/j.cub.2022.02.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/04/2022] [Accepted: 02/10/2022] [Indexed: 12/17/2022]
Abstract
Pan-neuronally expressed genes, such as genes involved in the synaptic vesicle cycle or in neuropeptide maturation, are critical for proper function of all neurons, but the transcriptional control mechanisms that direct such genes to all neurons of a nervous system remain poorly understood. We show here that six members of the CUT family of homeobox genes control pan-neuronal identity specification in Caenorhabditis elegans. Single CUT mutants show barely any effects on pan-neuronal gene expression or global nervous system function, but such effects become apparent and progressively worsen upon removal of additional CUT family members, indicating a critical role of gene dosage. Overexpression of each individual CUT gene rescued the phenotype of compound mutants, corroborating that gene dosage, rather than the activity of specific members of the gene family, is critical for CUT gene family function. Genome-wide binding profiles, as well as mutation of CUT homeodomain binding sites by CRISPR/Cas9 genome engineering show that CUT genes directly control the expression of pan-neuronal features. Moreover, CUT genes act in conjunction with neuron-type-specific transcription factors to control pan-neuronal gene expression. Our study, therefore, provides a previously missing key insight into how neuronal gene expression programs are specified and reveals a highly buffered and robust mechanism that controls the most critical functional features of all neuronal cell types.
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36
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Velten J, Gao X, Van Nierop y Sanchez P, Domsch K, Agarwal R, Bognar L, Paulsen M, Velten L, Lohmann I. Single‐cell RNA sequencing of motoneurons identifies regulators of synaptic wiring in
Drosophila
embryos. Mol Syst Biol 2022; 18:e10255. [PMID: 35225419 PMCID: PMC8883443 DOI: 10.15252/msb.202110255] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 01/28/2022] [Accepted: 02/07/2022] [Indexed: 12/14/2022] Open
Abstract
The correct wiring of neuronal circuits is one of the most complex processes in development, since axons form highly specific connections out of a vast number of possibilities. Circuit structure is genetically determined in vertebrates and invertebrates, but the mechanisms guiding each axon to precisely innervate a unique pre‐specified target cell are poorly understood. We investigated Drosophila embryonic motoneurons using single‐cell genomics, imaging, and genetics. We show that a cell‐specific combination of homeodomain transcription factors and downstream immunoglobulin domain proteins is expressed in individual cells and plays an important role in determining cell‐specific connections between differentiated motoneurons and target muscles. We provide genetic evidence for a functional role of five homeodomain transcription factors and four immunoglobulins in the neuromuscular wiring. Knockdown and ectopic expression of these homeodomain transcription factors induces cell‐specific synaptic wiring defects that are partly phenocopied by genetic modulations of their immunoglobulin targets. Taken together, our data suggest that homeodomain transcription factor and immunoglobulin molecule expression could be directly linked and function as a crucial determinant of neuronal circuit structure.
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Affiliation(s)
- Jessica Velten
- Department of Developmental Biology Centre for Organismal Studies (COS) Heidelberg Heidelberg Germany
- The Barcelona Institute of Science and Technology Centre for Genomic Regulation (CRG) Barcelona Spain
- Flow Cytometry Core Facility European Molecular Biology Laboratory (EMBL) Heidelberg Germany
| | - Xuefan Gao
- Department of Developmental Biology Centre for Organismal Studies (COS) Heidelberg Heidelberg Germany
| | | | - Katrin Domsch
- Department of Developmental Biology Centre for Organismal Studies (COS) Heidelberg Heidelberg Germany
- Developmental Biology Erlangen‐Nürnberg University Erlangen Germany
| | - Rashi Agarwal
- Department of Developmental Biology Centre for Organismal Studies (COS) Heidelberg Heidelberg Germany
| | - Lena Bognar
- Department of Developmental Biology Centre for Organismal Studies (COS) Heidelberg Heidelberg Germany
| | - Malte Paulsen
- Flow Cytometry Core Facility European Molecular Biology Laboratory (EMBL) Heidelberg Germany
| | - Lars Velten
- The Barcelona Institute of Science and Technology Centre for Genomic Regulation (CRG) Barcelona Spain
- Universitat Pompeu Fabra (UPF) Barcelona Spain
| | - Ingrid Lohmann
- Department of Developmental Biology Centre for Organismal Studies (COS) Heidelberg Heidelberg Germany
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37
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Sousa E, Flames N. Transcriptional regulation of neuronal identity. Eur J Neurosci 2021; 55:645-660. [PMID: 34862697 PMCID: PMC9306894 DOI: 10.1111/ejn.15551] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 11/29/2022]
Abstract
Neuronal diversity is an intrinsic feature of the nervous system. Transcription factors (TFs) are key regulators in the establishment of different neuronal identities; how are the actions of different TFs coordinated to orchestrate this diversity? Are there common features shared among the different neuron types of an organism or even among different animal groups? In this review, we provide a brief overview on common traits emerging on the transcriptional regulation of neuron type diversification with a special focus on the comparison between mouse and Caenorhabditis elegans model systems. In the first part, we describe general concepts on neuronal identity and transcriptional regulation of gene expression. In the second part of the review, TFs are classified in different categories according to their key roles at specific steps along the protracted process of neuronal specification and differentiation. The same TF categories can be identified both in mammals and nematodes. Importantly, TFs are very pleiotropic: Depending on the neuron type or the time in development, the same TF can fulfil functions belonging to different categories. Finally, we describe the key role of transcriptional repression at all steps controlling neuronal diversity and propose that acquisition of neuronal identities could be considered a metastable process.
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Affiliation(s)
- Erick Sousa
- Developmental Neurobiology Unit, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
| | - Nuria Flames
- Developmental Neurobiology Unit, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
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38
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Abstract
Asymmetries in the functional and structural organization of the nervous system are widespread in the animal kingdom and especially characterize the human brain. Although there is little doubt that asymmetries arise through genetic and nongenetic factors, an overarching model to explain the development of functional lateralization patterns is still lacking. Current genetic psychology collects data on genes relevant to brain lateralizations, while animal research provides information on the cellular mechanisms mediating the effects of not only genetic but also environmental factors. This review combines data from human and animal research (especially on birds) and outlines a multi-level model for asymmetry formation. The relative impact of genetic and nongenetic factors varies between different developmental phases and neuronal structures. The basic lateralized organization of a brain is already established through genetically controlled embryonic events. During ongoing development, hemispheric specialization increases for specific functions and subsystems interact to shape the final functional organization of a brain. In particular, these developmental steps are influenced by environmental experiences, which regulate the fine-tuning of neural networks via processes that are referred to as ontogenetic plasticity. The plastic potential of the nervous system could be decisive for the evolutionary success of lateralized brains.
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