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Smith JJ, Taylor SR, Blum JA, Feng W, Collings R, Gitler AD, Miller DM, Kratsios P. A molecular atlas of adult C. elegans motor neurons reveals ancient diversity delineated by conserved transcription factor codes. Cell Rep 2024; 43:113857. [PMID: 38421866 PMCID: PMC11091551 DOI: 10.1016/j.celrep.2024.113857] [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: 08/18/2023] [Revised: 01/17/2024] [Accepted: 02/08/2024] [Indexed: 03/02/2024] Open
Abstract
Motor neurons (MNs) constitute an ancient cell type targeted by multiple adult-onset diseases. It is therefore important to define the molecular makeup of adult MNs in animal models and extract organizing principles. Here, we generate a comprehensive molecular atlas of adult Caenorhabditis elegans MNs and a searchable database. Single-cell RNA sequencing of 13,200 cells reveals that ventral nerve cord MNs cluster into 29 molecularly distinct subclasses. Extending C. elegans Neuronal Gene Expression Map and Network (CeNGEN) findings, all MN subclasses are delineated by distinct expression codes of either neuropeptide or transcription factor gene families. Strikingly, combinatorial codes of homeodomain transcription factor genes succinctly delineate adult MN diversity in both C. elegans and mice. Further, molecularly defined MN subclasses in C. elegans display distinct patterns of connectivity. Hence, our study couples the connectivity map of the C. elegans motor circuit with a molecular atlas of its constituent MNs and uncovers organizing principles and conserved molecular codes of adult MN diversity.
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Affiliation(s)
- Jayson J Smith
- Department of Neurobiology, University of Chicago, Chicago, IL 60637, USA; University of Chicago Neuroscience Institute, Chicago, IL 60637, USA
| | - Seth R Taylor
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA; Department of Cell Biology and Physiology, Brigham Young University, Provo, UT 84602, USA
| | - Jacob A Blum
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - Weidong Feng
- Department of Neurobiology, University of Chicago, Chicago, IL 60637, USA; University of Chicago Neuroscience Institute, Chicago, IL 60637, USA
| | - Rebecca Collings
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Aaron D Gitler
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - David M Miller
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA; Program in Neuroscience, Vanderbilt University, Nashville, TN 37240, USA.
| | - Paschalis Kratsios
- Department of Neurobiology, University of Chicago, Chicago, IL 60637, USA; University of Chicago Neuroscience Institute, Chicago, IL 60637, USA.
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2
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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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3
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Smith JJ, Taylor SR, Blum JA, Gitler AD, Miller DM, Kratsios P. A molecular atlas of adult C. elegans motor neurons reveals ancient diversity delineated by conserved transcription factor codes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.04.552048. [PMID: 37577463 PMCID: PMC10418256 DOI: 10.1101/2023.08.04.552048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Motor neurons (MNs) constitute an ancient cell type targeted by multiple adult-onset diseases. It is therefore important to define the molecular makeup of adult MNs in animal models and extract organizing principles. Here, we generated a comprehensive molecular atlas of adult Caenorhabditis elegans MNs and a searchable database (http://celegans.spinalcordatlas.org). Single-cell RNA-sequencing of 13,200 cells revealed that ventral nerve cord MNs cluster into 29 molecularly distinct subclasses. All subclasses are delineated by unique expression codes of either neuropeptide or transcription factor gene families. Strikingly, we found that combinatorial codes of homeodomain transcription factor genes define adult MN diversity both in C. elegans and mice. Further, molecularly defined MN subclasses in C. elegans display distinct patterns of connectivity. Hence, our study couples the connectivity map of the C. elegans motor circuit with a molecular atlas of its constituent MNs, and uncovers organizing principles and conserved molecular codes of adult MN diversity.
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Affiliation(s)
- Jayson J. Smith
- Department of Neurobiology, University of Chicago, Chicago, IL, 60637, USA
- University of Chicago Neuroscience Institute, Chicago, IL, 60637, USA
| | - Seth R. Taylor
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37240, USA
- Department of Cell Biology and Physiology, Brigham Young University, Provo, UT, 84602, USA
| | - Jacob A. Blum
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - Aaron D. Gitler
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - David M. Miller
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37240, USA
- Program in Neuroscience, Vanderbilt University, Nashville, TN, 37240, USA
| | - Paschalis Kratsios
- Department of Neurobiology, University of Chicago, Chicago, IL, 60637, USA
- University of Chicago Neuroscience Institute, Chicago, IL, 60637, USA
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Wang Y, Lobb-Rabe M, Ashley J, Chatterjee P, Anand V, Bellen HJ, Kanca O, Carrillo RA. Systematic expression profiling of Dpr and DIP genes reveals cell surface codes in Drosophila larval motor and sensory neurons. Development 2022; 149:dev200355. [PMID: 35502740 PMCID: PMC9188756 DOI: 10.1242/dev.200355] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 04/20/2022] [Indexed: 07/26/2023]
Abstract
In complex nervous systems, neurons must identify their correct partners to form synaptic connections. The prevailing model to ensure correct recognition posits that cell-surface proteins (CSPs) in individual neurons act as identification tags. Thus, knowing what cells express which CSPs would provide insights into neural development, synaptic connectivity, and nervous system evolution. Here, we investigated expression of Dpr and DIP genes, two CSP subfamilies belonging to the immunoglobulin superfamily, in Drosophila larval motor neurons (MNs), muscles, glia and sensory neurons (SNs) using a collection of GAL4 driver lines. We found that Dpr genes are more broadly expressed than DIP genes in MNs and SNs, and each examined neuron expresses a unique combination of Dpr and DIP genes. Interestingly, many Dpr and DIP genes are not robustly expressed, but are found instead in gradient and temporal expression patterns. In addition, the unique expression patterns of Dpr and DIP genes revealed three uncharacterized MNs. This study sets the stage for exploring the functions of Dpr and DIP genes in Drosophila MNs and SNs and provides genetic access to subsets of neurons.
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Affiliation(s)
- Yupu Wang
- Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL 60637, USA
- Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Meike Lobb-Rabe
- Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL 60637, USA
- Program in Cell and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - James Ashley
- Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL 60637, USA
| | - Purujit Chatterjee
- Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL 60637, USA
| | - Veera Anand
- Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL 60637, USA
| | - Hugo J. Bellen
- Department of Molecular and Human Genetics and Jan and Dan Duncan Neurobiological Research Institute, Baylor College of Medicine (BCM), Houston, TX 77030, USA
- Department of Neuroscience and Howard Hughes Medical Institute, Baylor College of Medicine (BCM), Houston, TX 77030, USA
| | - Oguz Kanca
- Department of Molecular and Human Genetics and Jan and Dan Duncan Neurobiological Research Institute, Baylor College of Medicine (BCM), Houston, TX 77030, USA
| | - Robert A. Carrillo
- Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL 60637, USA
- Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL 60637, USA
- Program in Cell and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
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5
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Kalis AK, Sterrett MC, Armstrong C, Ballmer A, Burkstrand K, Chilson E, Emlen E, Ferrer E, Loeb S, Olin T, Tran K, Wheeler A, Ross Wolff J. Hox proteins interact to pattern neuronal subtypes in Caenorhabditis elegans males. Genetics 2022; 220:iyac010. [PMID: 35137058 PMCID: PMC8982040 DOI: 10.1093/genetics/iyac010] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 01/10/2022] [Indexed: 11/14/2022] Open
Abstract
Hox transcription factors are conserved regulators of neuronal subtype specification on the anteroposterior axis in animals, with disruption of Hox gene expression leading to homeotic transformations of neuronal identities. We have taken advantage of an unusual mutation in the Caenorhabditis elegans Hox gene lin-39, lin-39(ccc16), which transforms neuronal fates in the C. elegans male ventral nerve cord in a manner that depends on a second Hox gene, mab-5. We have performed a genetic analysis centered around this homeotic allele of lin-39 in conjunction with reporters for neuronal target genes and protein interaction assays to explore how LIN-39 and MAB-5 exert both flexibility and specificity in target regulation. We identify cis-regulatory modules in neuronal reporters that are both region-specific and Hox-responsive. Using these reporters of neuronal subtype, we also find that the lin-39(ccc16) mutation disrupts neuronal fates specifically in the region where lin-39 and mab-5 are coexpressed, and that the protein encoded by lin-39(ccc16) is active only in the absence of mab-5. Moreover, the fates of neurons typical to the region of lin-39-mab-5 coexpression depend on both Hox genes. Our genetic analysis, along with evidence from Bimolecular Fluorescence Complementation protein interaction assays, supports a model in which LIN-39 and MAB-5 act at an array of cis-regulatory modules to cooperatively activate and to individually activate or repress neuronal gene expression, resulting in regionally specific neuronal fates.
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Affiliation(s)
- Andrea K Kalis
- Department of Biology, St. Catherine University, St. Paul, MN 55105, USA
| | - Maria C Sterrett
- Department of Biology, Carleton College, Northfield, MN 55057, USA
| | - Cecily Armstrong
- Department of Biology, St. Catherine University, St. Paul, MN 55105, USA
| | | | - Kylie Burkstrand
- Department of Biology, St. Catherine University, St. Paul, MN 55105, USA
| | - Elizabeth Chilson
- Department of Biology, St. Catherine University, St. Paul, MN 55105, USA
| | - Estee Emlen
- Department of Biology, Carleton College, Northfield, MN 55057, USA
| | - Emma Ferrer
- Department of Biology, Carleton College, Northfield, MN 55057, USA
| | - Seanna Loeb
- Department of Biology, St. Catherine University, St. Paul, MN 55105, USA
| | - Taylor Olin
- Department of Biology, St. Catherine University, St. Paul, MN 55105, USA
| | - Kevin Tran
- Department of Biology, Carleton College, Northfield, MN 55057, USA
| | - Andrew Wheeler
- Department of Biology, Carleton College, Northfield, MN 55057, USA
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6
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Chen YC, Konstantinides N. Integration of Spatial and Temporal Patterning in the Invertebrate and Vertebrate Nervous System. Front Neurosci 2022; 16:854422. [PMID: 35392413 PMCID: PMC8981590 DOI: 10.3389/fnins.2022.854422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 02/15/2022] [Indexed: 11/25/2022] Open
Abstract
The nervous system is one of the most sophisticated animal tissues, consisting of thousands of interconnected cell types. How the nervous system develops its diversity from a few neural stem cells remains a challenging question. Spatial and temporal patterning mechanisms provide an efficient model through which diversity can be generated. The molecular mechanism of spatiotemporal patterning has been studied extensively in Drosophila melanogaster, where distinct sets of transcription factors define the spatial domains and temporal windows that give rise to different cell types. Similarly, in vertebrates, spatial domains defined by transcription factors produce different types of neurons in the brain and neural tube. At the same time, different cortical neuronal types are generated within the same cell lineage with a specific birth order. However, we still do not understand how the orthogonal information of spatial and temporal patterning is integrated into the progenitor and post-mitotic cells to combinatorially give rise to different neurons. In this review, after introducing spatial and temporal patterning in Drosophila and mice, we discuss possible mechanisms that neural progenitors may use to integrate spatial and temporal information. We finally review the functional implications of spatial and temporal patterning and conclude envisaging how small alterations of these mechanisms can lead to the evolution of new neuronal cell types.
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Affiliation(s)
- Yen-Chung Chen
- Department of Biology, New York University, New York, NY, United States
- *Correspondence: Yen-Chung Chen,
| | - Nikolaos Konstantinides
- Université de Paris, Centre National de la Recherche Scientifique, Institut Jacques Monod, Paris, France
- Nikolaos Konstantinides,
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7
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Catela C, Chen Y, Weng Y, Wen K, Kratsios P. Control of spinal motor neuron terminal differentiation through sustained Hoxc8 gene activity. eLife 2022; 11:70766. [PMID: 35315772 PMCID: PMC8940177 DOI: 10.7554/elife.70766] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 03/12/2022] [Indexed: 12/30/2022] Open
Abstract
Spinal motor neurons (MNs) constitute cellular substrates for several movement disorders. Although their early development has received much attention, how spinal MNs become and remain terminally differentiated is poorly understood. Here, we determined the transcriptome of mouse MNs located at the brachial domain of the spinal cord at embryonic and postnatal stages. We identified novel transcription factors (TFs) and terminal differentiation genes (e.g. ion channels, neurotransmitter receptors, adhesion molecules) with continuous expression in MNs. Interestingly, genes encoding homeodomain TFs (e.g. HOX, LIM), previously implicated in early MN development, continue to be expressed postnatally, suggesting later functions. To test this idea, we inactivated Hoxc8 at successive stages of mouse MN development and observed motor deficits. Our in vivo findings suggest that Hoxc8 is not only required to establish, but also maintain expression of several MN terminal differentiation markers. Data from in vitro generated MNs indicate Hoxc8 acts directly and is sufficient to induce expression of terminal differentiation genes. Our findings dovetail recent observations in Caenorhabditis elegans MNs, pointing toward an evolutionarily conserved role for Hox in neuronal terminal differentiation.
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Affiliation(s)
- Catarina Catela
- Department of Neurobiology, University of Chicago, Chicago, United States.,University of Chicago Neuroscience Institute, Chicago, United States
| | - Yihan Chen
- Department of Neurobiology, University of Chicago, Chicago, United States.,University of Chicago Neuroscience Institute, Chicago, United States
| | - Yifei Weng
- Department of Neurobiology, University of Chicago, Chicago, United States.,University of Chicago Neuroscience Institute, Chicago, United States
| | - Kailong Wen
- Department of Neurobiology, University of Chicago, Chicago, United States.,University of Chicago Neuroscience Institute, Chicago, United States
| | - Paschalis Kratsios
- Department of Neurobiology, University of Chicago, Chicago, United States.,University of Chicago Neuroscience Institute, Chicago, United States
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8
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Feng W, Li Y, Kratsios P. Emerging Roles for Hox Proteins in the Last Steps of Neuronal Development in Worms, Flies, and Mice. Front Neurosci 2022; 15:801791. [PMID: 35185450 PMCID: PMC8855150 DOI: 10.3389/fnins.2021.801791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 12/31/2021] [Indexed: 12/28/2022] Open
Abstract
A remarkable diversity of cell types characterizes every animal nervous system. Previous studies provided important insights into how neurons commit to a particular fate, migrate to the right place and form precise axodendritic patterns. However, the mechanisms controlling later steps of neuronal development remain poorly understood. Hox proteins represent a conserved family of homeodomain transcription factors with well-established roles in anterior-posterior (A-P) patterning and the early steps of nervous system development, including progenitor cell specification, neuronal migration, cell survival, axon guidance and dendrite morphogenesis. This review highlights recent studies in Caenorhabditis elegans, Drosophila melanogaster and mice that suggest new roles for Hox proteins in processes occurring during later steps of neuronal development, such as synapse formation and acquisition of neuronal terminal identity features (e.g., expression of ion channels, neurotransmitter receptors, and neuropeptides). Moreover, we focus on exciting findings suggesting Hox proteins are required to maintain synaptic structures and neuronal terminal identity during post-embryonic life. Altogether, these studies, in three model systems, support the hypothesis that certain Hox proteins are continuously required, from early development throughout post-embryonic life, to build and maintain a functional nervous system, significantly expanding their functional repertoire beyond the control of early A-P patterning.
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Affiliation(s)
- Weidong Feng
- Department of Neurobiology, University of Chicago, Chicago, IL, United States
- University of Chicago Neuroscience Institute, Chicago, IL, United States
- Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL, United States
| | - Yinan Li
- Department of Neurobiology, University of Chicago, Chicago, IL, United States
- University of Chicago Neuroscience Institute, Chicago, IL, United States
- Committee on Neurobiology, University of Chicago, Chicago, IL, United States
| | - Paschalis Kratsios
- Department of Neurobiology, University of Chicago, Chicago, IL, United States
- University of Chicago Neuroscience Institute, Chicago, IL, United States
- *Correspondence: Paschalis Kratsios,
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Poliacikova G, Maurel-Zaffran C, Graba Y, Saurin AJ. Hox Proteins in the Regulation of Muscle Development. Front Cell Dev Biol 2021; 9:731996. [PMID: 34733846 PMCID: PMC8558437 DOI: 10.3389/fcell.2021.731996] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 09/28/2021] [Indexed: 11/13/2022] Open
Abstract
Hox genes encode evolutionary conserved transcription factors that specify the anterior-posterior axis in all bilaterians. Being well known for their role in patterning ectoderm-derivatives, such as CNS and spinal cord, Hox protein function is also crucial in mesodermal patterning. While well described in the case of the vertebrate skeleton, much less is known about Hox functions in the development of different muscle types. In contrast to vertebrates however, studies in the fruit fly, Drosophila melanogaster, have provided precious insights into the requirement of Hox at multiple stages of the myogenic process. Here, we provide a comprehensive overview of Hox protein function in Drosophila and vertebrate muscle development, with a focus on the molecular mechanisms underlying target gene regulation in this process. Emphasizing a tight ectoderm/mesoderm cross talk for proper locomotion, we discuss shared principles between CNS and muscle lineage specification and the emerging role of Hox in neuromuscular circuit establishment.
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Affiliation(s)
| | | | - Yacine Graba
- Aix-Marseille University, CNRS, IBDM, UMR 7288, Marseille, France
| | - Andrew J Saurin
- Aix-Marseille University, CNRS, IBDM, UMR 7288, Marseille, France
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10
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Hajirnis N, Mishra RK. Homeotic Genes: Clustering, Modularity, and Diversity. Front Cell Dev Biol 2021; 9:718308. [PMID: 34458272 PMCID: PMC8386295 DOI: 10.3389/fcell.2021.718308] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022] Open
Abstract
Hox genes code for transcription factors and are evolutionarily conserved. They regulate a plethora of downstream targets to define the anterior-posterior (AP) body axis of a developing bilaterian embryo. Early work suggested a possible role of clustering and ordering of Hox to regulate their expression in a spatially restricted manner along the AP axis. However, the recent availability of many genome assemblies for different organisms uncovered several examples that defy this constraint. With recent advancements in genomics, the current review discusses the arrangement of Hox in various organisms. Further, we revisit their discovery and regulation in Drosophila melanogaster. We also review their regulation in different arthropods and vertebrates, with a significant focus on Hox expression in the crustacean Parahyale hawaiensis. It is noteworthy that subtle changes in the levels of Hox gene expression can contribute to the development of novel features in an organism. We, therefore, delve into the distinct regulation of these genes during primary axis formation, segment identity, and extra-embryonic roles such as in the formation of hair follicles or misregulation leading to cancer. Toward the end of each section, we emphasize the possibilities of several experiments involving various organisms, owing to the advancements in the field of genomics and CRISPR-based genome engineering. Overall, we present a holistic view of the functioning of Hox in the animal world.
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Affiliation(s)
- Nikhil Hajirnis
- CSIR – Centre for Cellular and Molecular Biology (CCMB), Hyderabad, India
| | - Rakesh K. Mishra
- CSIR – Centre for Cellular and Molecular Biology (CCMB), Hyderabad, India
- AcSIR – Academy of Scientific and Innovative Research, Ghaziabad, India
- Tata Institute for Genetics and Society (TIGS), Bangalore, India
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11
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Kolb D, Kaspar P, Klöppel C, Walldorf U. The Drosophila homeodomain transcription factor Homeobrain is involved in the formation of the embryonic protocerebrum and the supraesophageal brain commissure. Cells Dev 2021; 165:203657. [PMID: 33993980 DOI: 10.1016/j.cdev.2021.203657] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 12/06/2020] [Accepted: 12/09/2020] [Indexed: 11/28/2022]
Abstract
During the embryonic development of Drosophila melanogaster many transcriptional activators are involved in the formation of the embryonic brain. In our study we show that the transcription factor Homeobrain (Hbn), a member of the 57B homeobox gene cluster, is an additional factor involved in the formation of the embryonic Drosophila brain. Using a Hbn antibody and specific cell type markers a detailed expression analysis during embryonic brain development was conducted. We show that Hbn is expressed in several regions in the protocerebrum, including fibre tract founder cells closely associated with the supraesophageal brain commissure and also in the mushroom bodies. During the formation of the supraesophageal commissure, Hbn and FasII-positive founder cells build an interhemispheric bridge priming the commissure and thereby linking both brain hemispheres. The Hbn expression is restricted to neural but not glial cells in the embryonic brain. In a mutagenesis screen we generated two mutant hbn alleles that both show embryonic lethality. The phenotype of the hbn mutant alleles is characterized by a reduction of the protocerebrum, a loss of the supraesophageal commissure and mushroom body progenitors and also by a dislocation of the optic lobes. Extensive apoptosis correlates with the impaired formation of the embryonic protocerebrum and the supraesophageal commissure. Our results show that Hbn is another important factor for embryonic brain development in Drosophila melanogaster.
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Affiliation(s)
- Dieter Kolb
- Developmental Biology, Saarland University, Building 61, 66421 Homburg/Saar, Germany
| | - Petra Kaspar
- Developmental Biology, Saarland University, Building 61, 66421 Homburg/Saar, Germany
| | - Christine Klöppel
- Developmental Biology, Saarland University, Building 61, 66421 Homburg/Saar, Germany
| | - Uwe Walldorf
- Developmental Biology, Saarland University, Building 61, 66421 Homburg/Saar, Germany.
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12
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Development of motor circuits: From neuronal stem cells and neuronal diversity to motor circuit assembly. Curr Top Dev Biol 2020; 142:409-442. [PMID: 33706923 DOI: 10.1016/bs.ctdb.2020.11.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In this review, we discuss motor circuit assembly starting from neuronal stem cells. Until recently, studies of neuronal stem cells focused on how a relatively small pool of stem cells could give rise to a large diversity of different neuronal identities. Historically, neuronal identity has been assayed in embryos by gene expression, gross anatomical features, neurotransmitter expression, and physiological properties. However, these definitions of identity are largely unlinked to mature functional neuronal features relevant to motor circuits. Such mature neuronal features include presynaptic and postsynaptic partnerships, dendrite morphologies, as well as neuronal firing patterns and roles in behavior. This review focuses on recent work that links the specification of neuronal molecular identity in neuronal stem cells to mature, circuit-relevant identity specification. Specifically, these studies begin to address the question: to what extent are the decisions that occur during motor circuit assembly controlled by the same genetic information that generates diverse embryonic neuronal diversity? Much of the research addressing this question has been conducted using the Drosophila larval motor system. Here, we focus largely on Drosophila motor circuits and we point out parallels to other systems. And we highlight outstanding questions in the field. The main concepts addressed in this review are: (1) the description of temporal cohorts-novel units of developmental organization that link neuronal stem cell lineages to motor circuit configuration and (2) the discovery that temporal transcription factors expressed in neuronal stem cells control aspects of circuit assembly by controlling the size of temporal cohorts and influencing synaptic partner choice.
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13
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Li Y, Osuma A, Correa E, Okebalama MA, Dao P, Gaylord O, Aburas J, Islam P, Brown AE, Kratsios P. Establishment and maintenance of motor neuron identity via temporal modularity in terminal selector function. eLife 2020; 9:59464. [PMID: 33001031 PMCID: PMC7529460 DOI: 10.7554/elife.59464] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 09/20/2020] [Indexed: 02/06/2023] Open
Abstract
Terminal selectors are transcription factors (TFs) that establish during development and maintain throughout life post-mitotic neuronal identity. We previously showed that UNC-3/Ebf, the terminal selector of C. elegans cholinergic motor neurons (MNs), acts indirectly to prevent alternative neuronal identities (Feng et al., 2020). Here, we globally identify the direct targets of UNC-3. Unexpectedly, we find that the suite of UNC-3 targets in MNs is modified across different life stages, revealing ‘temporal modularity’ in terminal selector function. In all larval and adult stages examined, UNC-3 is required for continuous expression of various protein classes (e.g. receptors, transporters) critical for MN function. However, only in late larvae and adults, UNC-3 is required to maintain expression of MN-specific TFs. Minimal disruption of UNC-3’s temporal modularity via genome engineering affects locomotion. Another C. elegans terminal selector (UNC-30/Pitx) also exhibits temporal modularity, supporting the potential generality of this mechanism for the control of neuronal identity.
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Affiliation(s)
- Yinan Li
- Department of Neurobiology, University of Chicago, Chicago, United States.,Committee on Neurobiology, University of Chicago, Chicago, United States
| | - Anthony Osuma
- Department of Neurobiology, University of Chicago, Chicago, United States.,Committee on Neurobiology, University of Chicago, Chicago, United States
| | - Edgar Correa
- Department of Neurobiology, University of Chicago, Chicago, United States.,Cell and Molecular Biology Program, University of Chicago, Chicago, United States
| | | | - Pauline Dao
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Olivia Gaylord
- Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, Chicago, United States
| | - Jihad Aburas
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Priota Islam
- MRC London Institute of Medical Sciences, London, United Kingdom.,Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - André Ex Brown
- MRC London Institute of Medical Sciences, London, United Kingdom.,Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - Paschalis Kratsios
- Department of Neurobiology, University of Chicago, Chicago, United States.,Committee on Neurobiology, University of Chicago, Chicago, United States.,Cell and Molecular Biology Program, University of Chicago, Chicago, United States.,Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, Chicago, United States.,The Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, United States
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14
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Kumar S, Tumu SC, Helm C, Hausen H. The development of early pioneer neurons in the annelid Malacoceros fuliginosus. BMC Evol Biol 2020; 20:117. [PMID: 32928118 PMCID: PMC7489019 DOI: 10.1186/s12862-020-01680-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 08/27/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Nervous system development is an interplay of many processes: the formation of individual neurons, which depends on whole-body and local patterning processes, and the coordinated growth of neurites and synapse formation. While knowledge of neural patterning in several animal groups is increasing, data on pioneer neurons that create the early axonal scaffold are scarce. Here we studied the first steps of nervous system development in the annelid Malacoceros fuliginosus. RESULTS We performed a dense expression profiling of a broad set of neural genes. We found that SoxB expression begins at 4 h postfertilization, and shortly later, the neuronal progenitors can be identified at the anterior and the posterior pole by the transient and dynamic expression of proneural genes. At 9 hpf, the first neuronal cells start differentiating, and we provide a detailed description of axonal outgrowth of the pioneer neurons that create the primary neuronal scaffold. Tracing back the clonal origin of the ventral nerve cord pioneer neuron revealed that it is a descendant of the blastomere 2d (2d221), which after 7 cleavages starts expressing Neurogenin, Acheate-Scute and NeuroD. CONCLUSIONS We propose that an anterior and posterior origin of the nervous system is ancestral in annelids. We suggest that closer examination of the first pioneer neurons will be valuable in better understanding of nervous system development in spirally cleaving animals, to determine the potential role of cell-intrinsic properties in neuronal specification and to resolve the evolution of nervous systems.
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Affiliation(s)
- Suman Kumar
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Sharat Chandra Tumu
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Conrad Helm
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway.,Present Address: Johann-Friedrich-Blumenbach Institute for Zoology and Anthropology, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Harald Hausen
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway.
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15
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Yalgin C, Rovenko B, Andjelković A, Neefjes M, Oymak B, Dufour E, Hietakangas V, Jacobs HT. Effects on Dopaminergic Neurons Are Secondary in COX-Deficient Locomotor Dysfunction in Drosophila. iScience 2020; 23:101362. [PMID: 32738610 PMCID: PMC7394922 DOI: 10.1016/j.isci.2020.101362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/15/2020] [Accepted: 07/08/2020] [Indexed: 12/31/2022] Open
Abstract
Dopaminergic (DA) neurons have been implicated as key targets in neurological disorders, notably those involving locomotor impairment, and are considered to be highly vulnerable to mitochondrial dysfunction, a common feature of such diseases. Here we investigated a Drosophila model of locomotor disorders in which functional impairment is brought about by pan-neuronal RNAi knockdown of subunit COX7A of cytochrome oxidase (COX). Despite minimal neuronal loss by apoptosis, the expression and activity of tyrosine hydroxylase was decreased by half. Surprisingly, COX7A knockdown specifically targeted to DA neurons did not produce locomotor defect. Instead, using various drivers, we found that COX7A knockdown in specific groups of cholinergic and glutamatergic neurons underlay the phenotype. Based on our main finding, the vulnerability of DA neurons to mitochondrial dysfunction as a cause of impaired locomotion in other organisms, including mammals, warrants detailed investigation.
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Affiliation(s)
- Cagri Yalgin
- Faculty of Medicine and Health Technology, FI-33014 Tampere University, Finland; Institute of Biotechnology, FI-00014 University of Helsinki, Finland
| | - Bohdana Rovenko
- Institute of Biotechnology, FI-00014 University of Helsinki, Finland; Faculty of Biological and Environmental Sciences, FI-00014 University of Helsinki, Finland
| | - Ana Andjelković
- Faculty of Medicine and Health Technology, FI-33014 Tampere University, Finland
| | - Margot Neefjes
- Faculty of Medicine and Health Technology, FI-33014 Tampere University, Finland; Institute of Biotechnology, FI-00014 University of Helsinki, Finland
| | - Burak Oymak
- Institute of Biotechnology, FI-00014 University of Helsinki, Finland
| | - Eric Dufour
- Faculty of Medicine and Health Technology, FI-33014 Tampere University, Finland
| | - Ville Hietakangas
- Institute of Biotechnology, FI-00014 University of Helsinki, Finland; Faculty of Biological and Environmental Sciences, FI-00014 University of Helsinki, Finland
| | - Howard T Jacobs
- Faculty of Medicine and Health Technology, FI-33014 Tampere University, Finland.
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16
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Mira H, Morante J. Neurogenesis From Embryo to Adult - Lessons From Flies and Mice. Front Cell Dev Biol 2020; 8:533. [PMID: 32695783 PMCID: PMC7339912 DOI: 10.3389/fcell.2020.00533] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 06/08/2020] [Indexed: 12/30/2022] Open
Abstract
The human brain is composed of billions of cells, including neurons and glia, with an undetermined number of subtypes. During the embryonic and early postnatal stages, the vast majority of these cells are generated from neural progenitors and stem cells located in all regions of the neural tube. A smaller number of neurons will continue to be generated throughout our lives, in localized neurogenic zones, mainly confined at least in rodents to the subependymal zone of the lateral ventricles and the subgranular zone of the hippocampal dentate gyrus. During neurogenesis, a combination of extrinsic cues interacting with temporal and regional intrinsic programs are thought to be critical for increasing neuronal diversity, but their underlying mechanisms need further elucidation. In this review, we discuss the recent findings in Drosophila and mammals on the types of cell division and cell interactions used by neural progenitors and stem cells to sustain neurogenesis, and how they are influenced by glia.
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Affiliation(s)
- Helena Mira
- Instituto de Biomedicina de Valencia, Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Javier Morante
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas y Universidad Miguel Hernandez, Alicante, Spain
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17
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Feng W, Li Y, Dao P, Aburas J, Islam P, Elbaz B, Kolarzyk A, Brown AE, Kratsios P. A terminal selector prevents a Hox transcriptional switch to safeguard motor neuron identity throughout life. eLife 2020; 9:50065. [PMID: 31902393 PMCID: PMC6944445 DOI: 10.7554/elife.50065] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 12/08/2019] [Indexed: 01/01/2023] Open
Abstract
To become and remain functional, individual neuron types must select during development and maintain throughout life their distinct terminal identity features, such as expression of specific neurotransmitter receptors, ion channels and neuropeptides. Here, we report a molecular mechanism that enables cholinergic motor neurons (MNs) in the C. elegans ventral nerve cord to select and maintain their unique terminal identity. This mechanism relies on the dual function of the conserved terminal selector UNC-3 (Collier/Ebf). UNC-3 synergizes with LIN-39 (Scr/Dfd/Hox4-5) to directly co-activate multiple terminal identity traits specific to cholinergic MNs, but also antagonizes LIN-39’s ability to activate terminal features of alternative neuronal identities. Loss of unc-3 causes a switch in the transcriptional targets of LIN-39, thereby alternative, not cholinergic MN-specific, terminal features become activated and locomotion defects occur. The strategy of a terminal selector preventing a transcriptional switch may constitute a general principle for safeguarding neuronal identity throughout life.
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Affiliation(s)
- Weidong Feng
- Department of Neurobiology, University of Chicago, Chicago, United States.,Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, Chicago, United States
| | - Yinan Li
- Department of Neurobiology, University of Chicago, Chicago, United States.,Committee on Neurobiology, University of Chicago, Chicago, United States
| | - Pauline Dao
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Jihad Aburas
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Priota Islam
- MRC London Institute of Medical Sciences, London, United Kingdom.,Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - Benayahu Elbaz
- Department of Neurology, Center for Peripheral Neuropathy, University of Chicago, Chicago, United States
| | - Anna Kolarzyk
- Department of Neurology, Center for Peripheral Neuropathy, University of Chicago, Chicago, United States
| | - André Ex Brown
- MRC London Institute of Medical Sciences, London, United Kingdom.,Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - Paschalis Kratsios
- Department of Neurobiology, University of Chicago, Chicago, United States.,Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, Chicago, United States.,Committee on Neurobiology, University of Chicago, Chicago, United States.,The Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, United States
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18
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Altuna M, Urdánoz-Casado A, Sánchez-Ruiz de Gordoa J, Zelaya MV, Labarga A, Lepesant JMJ, Roldán M, Blanco-Luquin I, Perdones Á, Larumbe R, Jericó I, Echavarri C, Méndez-López I, Di Stefano L, Mendioroz M. DNA methylation signature of human hippocampus in Alzheimer's disease is linked to neurogenesis. Clin Epigenetics 2019; 11:91. [PMID: 31217032 PMCID: PMC6585076 DOI: 10.1186/s13148-019-0672-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 04/25/2019] [Indexed: 12/22/2022] Open
Abstract
Background Drawing the epigenome landscape of Alzheimer’s disease (AD) still remains a challenge. To characterize the epigenetic molecular basis of the human hippocampus in AD, we profiled genome-wide DNA methylation levels in hippocampal samples from a cohort of pure AD patients and controls by using the Illumina 450K methylation arrays. Results Up to 118 AD-related differentially methylated positions (DMPs) were identified in the AD hippocampus, and extended mapping of specific regions was obtained by bisulfite cloning sequencing. AD-related DMPs were significantly correlated with phosphorylated tau burden. Functional analysis highlighted that AD-related DMPs were enriched in poised promoters that were not generally maintained in committed neural progenitor cells, as shown by ChiP-qPCR experiments. Interestingly, AD-related DMPs preferentially involved neurodevelopmental and neurogenesis-related genes. Finally, InterPro ontology analysis revealed enrichment in homeobox-containing transcription factors in the set of AD-related DMPs. Conclusions These results suggest that altered DNA methylation in the AD hippocampus occurs at specific regulatory regions crucial for neural differentiation supporting the notion that adult hippocampal neurogenesis may play a role in AD through epigenetic mechanisms. Graphical abstract ![]()
Electronic supplementary material The online version of this article (10.1186/s13148-019-0672-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Miren Altuna
- Neuroepigenetics Laboratory, Navarrabiomed, Public University of Navarre (UPNA), IdiSNA (Navarra Institute for Health Research), c/ Irunlarrea, 3, 31008, Pamplona, Spain.,Department of Neurology, Complejo Hospitalario de Navarra, IdiSNA (Navarra Institute for Health Research), Pamplona, Spain
| | - Amaya Urdánoz-Casado
- Neuroepigenetics Laboratory, Navarrabiomed, Public University of Navarre (UPNA), IdiSNA (Navarra Institute for Health Research), c/ Irunlarrea, 3, 31008, Pamplona, Spain
| | - Javier Sánchez-Ruiz de Gordoa
- Neuroepigenetics Laboratory, Navarrabiomed, Public University of Navarre (UPNA), IdiSNA (Navarra Institute for Health Research), c/ Irunlarrea, 3, 31008, Pamplona, Spain.,Department of Neurology, Complejo Hospitalario de Navarra, IdiSNA (Navarra Institute for Health Research), Pamplona, Spain
| | - María V Zelaya
- Department of Pathology, Complejo Hospitalario de Navarra- IdiSNA (Navarra Institute for Health Research), Pamplona, Spain
| | - Alberto Labarga
- Bioinformatics Unit, Navarrabiomed, Public University of Navarre (UPNA), IdiSNA (Navarra Institute for Health Research), Pamplona, Spain
| | - Julie M J Lepesant
- Laboratoire de biologie cellulaire et moléculaire du contrôle de la prolifération (LBCMCP), Université Paul Sabatier, CNRS, Toulouse, France
| | - Miren Roldán
- Neuroepigenetics Laboratory, Navarrabiomed, Public University of Navarre (UPNA), IdiSNA (Navarra Institute for Health Research), c/ Irunlarrea, 3, 31008, Pamplona, Spain
| | - Idoia Blanco-Luquin
- Neuroepigenetics Laboratory, Navarrabiomed, Public University of Navarre (UPNA), IdiSNA (Navarra Institute for Health Research), c/ Irunlarrea, 3, 31008, Pamplona, Spain
| | - Álvaro Perdones
- Bioinformatics Unit, Navarrabiomed, Public University of Navarre (UPNA), IdiSNA (Navarra Institute for Health Research), Pamplona, Spain
| | - Rosa Larumbe
- Neuroepigenetics Laboratory, Navarrabiomed, Public University of Navarre (UPNA), IdiSNA (Navarra Institute for Health Research), c/ Irunlarrea, 3, 31008, Pamplona, Spain.,Department of Neurology, Complejo Hospitalario de Navarra, IdiSNA (Navarra Institute for Health Research), Pamplona, Spain
| | - Ivonne Jericó
- Department of Neurology, Complejo Hospitalario de Navarra, IdiSNA (Navarra Institute for Health Research), Pamplona, Spain
| | - Carmen Echavarri
- Neuroepigenetics Laboratory, Navarrabiomed, Public University of Navarre (UPNA), IdiSNA (Navarra Institute for Health Research), c/ Irunlarrea, 3, 31008, Pamplona, Spain.,Department of Neurology, Complejo Hospitalario de Navarra, IdiSNA (Navarra Institute for Health Research), Pamplona, Spain
| | - Iván Méndez-López
- Neuroepigenetics Laboratory, Navarrabiomed, Public University of Navarre (UPNA), IdiSNA (Navarra Institute for Health Research), c/ Irunlarrea, 3, 31008, Pamplona, Spain.,Department of Internal Medicine, Hospital García-Orcoyen, Estella, Spain
| | - Luisa Di Stefano
- Laboratoire de biologie cellulaire et moléculaire du contrôle de la prolifération (LBCMCP), Université Paul Sabatier, CNRS, Toulouse, France
| | - Maite Mendioroz
- Neuroepigenetics Laboratory, Navarrabiomed, Public University of Navarre (UPNA), IdiSNA (Navarra Institute for Health Research), c/ Irunlarrea, 3, 31008, Pamplona, Spain. .,Department of Neurology, Complejo Hospitalario de Navarra, IdiSNA (Navarra Institute for Health Research), Pamplona, Spain.
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19
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Wang H, Hu H, Xiang Z, Lu C, Dai F, Tong X. Identification and characterization of a new long noncoding RNA iab-1 in the Hox cluster of silkworm, Bombyx mori identification of iab-1. J Cell Biochem 2019; 120:17283-17292. [PMID: 31106470 DOI: 10.1002/jcb.28990] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 04/06/2019] [Accepted: 04/11/2019] [Indexed: 02/04/2023]
Abstract
Long noncoding RNAs (lncRNAs) areinvolvedin a variety of biological processes. In silkworm, numerous lncRNAs have been predicted through deep transcriptome sequencing, but no functional role has been experimentally validated yet. Here, we characterized a new lncRNA iab-1 that was mainly encoded by the intergenic region between Bmabd-A and Bmabd-B in the Homeobox (Hox) cluster of the silkworm, Bombyx mori. More than seven alternative splicing isoforms of lncRNA iab-1 were cloned, which were subgrouped into types 1 and 2 based on the location of the 3'-ends. The iab-1 was expressed at a low level, but the expression of iab-1 peaked at several specific development stages, including 3 to 4 days during the embryonic stage, stages before fourth molting, and the sixth hour after the fourth molting, and early stages during metamorphosis. It was highly expressed in the nervus and epidermis, especially the epidermis of the posterior abdomen at the fourth instar premolting stage. The relationship between iab-1 and nearby Hox genes was analyzed at different developmental stages. Iab-1 expression was highly associated with Bmabd-A as well as Bmabd-B in the embryonic and larval stages, while this association was decreased at the metamorphic stage; iab-1 expression was highly associated with BmUbx only in the embryonic stage. Downregulation of iab-1 expression by small interfering RNA led to the death of most of the treated individuals at the larval stage, suggesting that iab-1 transcript expression might be involved in certain relevant physiological processes. The expression of Bmabd-A and Bmabd-B did not change in iab-1 downregulated individuals, indicating that the relevance between the two genes and iab-1 was not induced by iab-1 transcript. Collectively, the results showed that the newly identified iab-1 may be involved in some physiological processes, and the interaction between iab-1 and Hox genes was also preliminarily analyzed.
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Affiliation(s)
- Honglei Wang
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing, China
| | - Hai Hu
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing, China
| | - Zhonghuai Xiang
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing, China
| | - Cheng Lu
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing, China
| | - Fangyin Dai
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing, China
| | - Xiaoling Tong
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing, China
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20
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Walsh KT, Doe CQ. Drosophila embryonic type II neuroblasts: origin, temporal patterning, and contribution to the adult central complex. Development 2017; 144:4552-4562. [PMID: 29158446 DOI: 10.1242/dev.157826] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 11/03/2017] [Indexed: 12/27/2022]
Abstract
Drosophila neuroblasts are an excellent model for investigating how neuronal diversity is generated. Most brain neuroblasts generate a series of ganglion mother cells (GMCs) that each make two neurons (type I lineage), but 16 brain neuroblasts generate a series of intermediate neural progenitors (INPs) that each produce 4-6 GMCs and 8-12 neurons (type II lineage). Thus, type II lineages are similar to primate cortical lineages, and may serve as models for understanding cortical expansion. Yet the origin of type II neuroblasts remains mysterious: do they form in the embryo or larva? If they form in the embryo, do their progeny populate the adult central complex, as do the larval type II neuroblast progeny? Here, we present molecular and clonal data showing that all type II neuroblasts form in the embryo, produce INPs and express known temporal transcription factors. Embryonic type II neuroblasts and INPs undergo quiescence, and produce embryonic-born progeny that contribute to the adult central complex. Our results provide a foundation for investigating the development of the central complex, and tools for characterizing early-born neurons in central complex function.
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Affiliation(s)
- Kathleen T Walsh
- Howard Hughes Medical Institute, Institute of Molecular Biology, and Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Chris Q Doe
- Howard Hughes Medical Institute, Institute of Molecular Biology, and Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
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21
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Kratsios P, Kerk SY, Catela C, Liang J, Vidal B, Bayer EA, Feng W, De La Cruz ED, Croci L, Consalez GG, Mizumoto K, Hobert O. An intersectional gene regulatory strategy defines subclass diversity of C. elegans motor neurons. eLife 2017; 6. [PMID: 28677525 PMCID: PMC5498135 DOI: 10.7554/elife.25751] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 06/13/2017] [Indexed: 01/09/2023] Open
Abstract
A core principle of nervous system organization is the diversification of neuron classes into subclasses that share large sets of features but differ in select traits. We describe here a molecular mechanism necessary for motor neurons to acquire subclass-specific traits in the nematode Caenorhabditis elegans. Cholinergic motor neuron classes of the ventral nerve cord can be subdivided into subclasses along the anterior-posterior (A-P) axis based on synaptic connectivity patterns and molecular features. The conserved COE-type terminal selector UNC-3 not only controls the expression of traits shared by all members of a neuron class, but is also required for subclass-specific traits expressed along the A-P axis. UNC-3, which is not regionally restricted, requires region-specific cofactors in the form of Hox proteins to co-activate subclass-specific effector genes in post-mitotic motor neurons. This intersectional gene regulatory principle for neuronal subclass diversification may be conserved from nematodes to mice.
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Affiliation(s)
- Paschalis Kratsios
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Sze Yen Kerk
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, United States
| | - Catarina Catela
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Joseph Liang
- Department of Zoology, The University of British Columbia, Vancouver, Canada
| | - Berta Vidal
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, United States
| | - Emily A Bayer
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, United States
| | - Weidong Feng
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Estanisla Daniel De La Cruz
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, United States
| | - Laura Croci
- Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - G Giacomo Consalez
- Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy.,Università Vita-Salute San Raffaele, Milan, Italy
| | - Kota Mizumoto
- Department of Zoology, The University of British Columbia, Vancouver, Canada
| | - Oliver Hobert
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, United States
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22
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Alvarez-Rivero J, Moris-Sanz M, Estacio-Gómez A, Montoliu-Nerin M, Díaz-Benjumea FJ, Herrero P. Variability in the number of abdominal leucokinergic neurons in adult Drosophila melanogaster. J Comp Neurol 2016; 525:639-660. [PMID: 27506156 DOI: 10.1002/cne.24093] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 07/25/2016] [Accepted: 07/25/2016] [Indexed: 12/15/2022]
Abstract
Developmental plasticity allows individuals with the same genotype to show different phenotypes in response to environmental changes. An example of this is how neuronal diversity is protected at the expense of neuronal number under sustained undernourishment during the development of the Drosophila optic lobe. In the development of the Drosophila central nervous system, neuroblasts go through two phases of neurogenesis separated by a period of mitotic quiescence. Although during embryonic development much evidence indicates that both cell number and the cell fates generated by each neuroblast are very precisely controlled in a cell autonomous manner, after quiescence extrinsic factors control the reactivation of neuroblast proliferation in a fashion that has not yet been elucidated. Moreover, there is very little information about whether environmental changes affect lineage progression during postembryonic neurogenesis. Using as a model system the pattern of abdominal leucokinergic neurons (ABLKs), we have analyzed how changes in a set of environmental factors affect the number of ABLKs generated during postembryonic neurogenesis. We describe the variability in ABLK number between individuals and between hemiganglia of the same individual and, by genetic analysis, we identify the bithorax-complex genes and the ecdysone hormone as critical factors in these differences. We also explore the possible adaptive roles involved in this process. J. Comp. Neurol. 525:639-660, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
| | - Marta Moris-Sanz
- Severo Ochoa Center for Molecular Biology (CBMSO), 28049, Madrid, Spain
| | | | | | | | - Pilar Herrero
- Severo Ochoa Center for Molecular Biology (CBMSO), 28049, Madrid, Spain.,Department of Biology, Faculty of Sciences, Autonoma University of Madrid, 28049, Madrid, Spain
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23
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Moris-Sanz M, Estacio-Gómez A, Sánchez-Herrero E, Díaz-Benjumea FJ. The study of the Bithorax-complex genes in patterning CCAP neurons reveals a temporal control of neuronal differentiation by Abd-B. Biol Open 2015; 4:1132-42. [PMID: 26276099 PMCID: PMC4582124 DOI: 10.1242/bio.012872] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
During development, HOX genes play critical roles in the establishment of segmental differences. In the Drosophila central nervous system, these differences are manifested in the number and type of neurons generated by each neuroblast in each segment. HOX genes can act either in neuroblasts or in postmitotic cells, and either early or late in a lineage. Additionally, they can be continuously required during development or just at a specific stage. Moreover, these features are generally segment-specific. Lately, it has been shown that contrary to what happens in other tissues, where HOX genes define domains of expression, these genes are expressed in individual cells as part of the combinatorial codes involved in cell type specification. In this report we analyse the role of the Bithorax-complex genes - Ultrabithorax, abdominal-A and Abdominal-B - in sculpting the pattern of crustacean cardioactive peptide (CCAP)-expressing neurons. These neurons are widespread in invertebrates, express CCAP, Bursicon and MIP neuropeptides and play major roles in controlling ecdysis. There are two types of CCAP neuron: interneurons and efferent neurons. Our results indicate that Ultrabithorax and Abdominal-A are not necessary for specification of the CCAP-interneurons, but are absolutely required to prevent the death by apoptosis of the CCAP-efferent neurons. Furthermore, Abdominal-B controls by repression the temporal onset of neuropeptide expression in a subset of CCAP-efferent neurons, and a peak of ecdysone hormone at the end of larval life counteracts this repression. Thus, Bithorax complex genes control the developmental appearance of these neuropeptides both temporally and spatially.
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Affiliation(s)
- M Moris-Sanz
- Centro de Biología Molecular-Severo Ochoa (CSIC-UAM), c./Nicolás Cabrera 1, Universidad Autónoma, Madrid 28049, Spain
| | - A Estacio-Gómez
- Centro de Biología Molecular-Severo Ochoa (CSIC-UAM), c./Nicolás Cabrera 1, Universidad Autónoma, Madrid 28049, Spain
| | - E Sánchez-Herrero
- Centro de Biología Molecular-Severo Ochoa (CSIC-UAM), c./Nicolás Cabrera 1, Universidad Autónoma, Madrid 28049, Spain
| | - F J Díaz-Benjumea
- Centro de Biología Molecular-Severo Ochoa (CSIC-UAM), c./Nicolás Cabrera 1, Universidad Autónoma, Madrid 28049, Spain
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