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Zhang X, Sun D, Wong K, Salkini A, Najafi H, Kim WJ. The astrocyte-enriched gene deathstar plays a crucial role in the development, locomotion, and lifespan of D. melanogaster. Fly (Austin) 2024; 18:2368336. [PMID: 38884422 PMCID: PMC11185185 DOI: 10.1080/19336934.2024.2368336] [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: 10/22/2023] [Accepted: 06/11/2024] [Indexed: 06/18/2024] Open
Abstract
The Drosophila melanogaster brain is a complex organ with various cell types, orchestrating the development, physiology, and behaviors of the fly. While each cell type in Drosophila brain is known to express a unique gene set, their complete genetic profile is still unknown. Advances in the RNA sequencing techniques at single-cell resolution facilitate identifying novel cell type markers and/or re-examining the specificity of the available ones. In this study, exploiting a single-cell RNA sequencing data of Drosophila optic lobe, we categorized the cells based on their expression pattern for known markers, then the genes with enriched expression in astrocytes were identified. CG11000 was identified as a gene with a comparable expression profile to the Eaat1 gene, an astrocyte marker, in every individual cell inside the Drosophila optic lobe and midbrain, as well as in the entire Drosophila brain throughout its development. Consistent with our bioinformatics data, immunostaining of the brains dissected from transgenic adult flies showed co-expression of CG11000 with Eaat1 in a set of single cells corresponding to the astrocytes in the Drosophila brain. Physiologically, inhibiting CG11000 through RNA interference disrupted the normal development of male D. melanogaster, while having no impact on females. Expression suppression of CG11000 in adult flies led to decreased locomotion activity and also shortened lifespan specifically in astrocytes, indicating the gene's significance in astrocytes. We designated this gene as 'deathstar' due to its crucial role in maintaining the star-like shape of glial cells, astrocytes, throughout their development into adult stage.
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Affiliation(s)
- Xiaoli Zhang
- The HIT Center for Life Sciences, Harbin Institute of Technology, Harbin, China
| | - Dongyu Sun
- The HIT Center for Life Sciences, Harbin Institute of Technology, Harbin, China
| | - Kyle Wong
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Ammar Salkini
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Hadi Najafi
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Woo Jae Kim
- The HIT Center for Life Sciences, Harbin Institute of Technology, Harbin, China
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
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2
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Nguyen TH, Vicidomini R, Choudhury SD, Han TH, Maric D, Brody T, Serpe M. scRNA-seq data from the larval Drosophila ventral cord provides a resource for studying motor systems function and development. Dev Cell 2024; 59:1210-1230.e9. [PMID: 38569548 PMCID: PMC11078614 DOI: 10.1016/j.devcel.2024.03.016] [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: 06/27/2023] [Revised: 12/05/2023] [Accepted: 03/06/2024] [Indexed: 04/05/2024]
Abstract
The Drosophila larval ventral nerve cord (VNC) shares many similarities with the spinal cord of vertebrates and has emerged as a major model for understanding the development and function of motor systems. Here, we use high-quality scRNA-seq, validated by anatomical identification, to create a comprehensive census of larval VNC cell types. We show that the neural lineages that comprise the adult VNC are already defined, but quiescent, at the larval stage. Using fluorescence-activated cell sorting (FACS)-enriched populations, we separate all motor neuron bundles and link individual neuron clusters to morphologically characterized known subtypes. We discovered a glutamate receptor subunit required for basal neurotransmission and homeostasis at the larval neuromuscular junction. We describe larval glia and endorse the general view that glia perform consistent activities throughout development. This census represents an extensive resource and a powerful platform for future discoveries of cellular and molecular mechanisms in repair, regeneration, plasticity, homeostasis, and behavioral coordination.
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Affiliation(s)
| | | | | | | | - Dragan Maric
- Flow and Imaging Cytometry Core, NINDS, NIH, Bethesda, MD 20892, USA
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3
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Gilbert G, Renaud Y, Teste C, Anglaret N, Bertrand R, Hoehn S, Jurkowski TP, Schuettengruber B, Cavalli G, Waltzer L, Vandel L. Drosophila TET acts with PRC1 to activate gene expression independently of its catalytic activity. SCIENCE ADVANCES 2024; 10:eadn5861. [PMID: 38701218 PMCID: PMC11068012 DOI: 10.1126/sciadv.adn5861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 04/03/2024] [Indexed: 05/05/2024]
Abstract
Enzymes of the ten-eleven translocation (TET) family play a key role in the regulation of gene expression by oxidizing 5-methylcytosine (5mC), a prominent epigenetic mark in many species. Yet, TET proteins also have less characterized noncanonical modes of action, notably in Drosophila, whose genome is devoid of 5mC. Here, we show that Drosophila TET activates the expression of genes required for larval central nervous system (CNS) development mainly in a catalytic-independent manner. Genome-wide profiling shows that TET is recruited to enhancer and promoter regions bound by Polycomb group complex (PcG) proteins. We found that TET interacts and colocalizes on chromatin preferentially with Polycomb repressor complex 1 (PRC1) rather than PRC2. Furthermore, PRC1 but not PRC2 is required for the activation of TET target genes. Last, our results suggest that TET and PRC1 binding to activated genes is interdependent. These data highlight the importance of TET noncatalytic function and the role of PRC1 for gene activation in the Drosophila larval CNS.
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Affiliation(s)
- Guerric Gilbert
- Université Clermont Auvergne, CNRS, INSERM, iGReD, F-63000 Clermont-Ferrand, France
| | - Yoan Renaud
- Université Clermont Auvergne, CNRS, INSERM, iGReD, F-63000 Clermont-Ferrand, France
| | - Camille Teste
- Université Clermont Auvergne, CNRS, INSERM, iGReD, F-63000 Clermont-Ferrand, France
| | - Nadège Anglaret
- Université Clermont Auvergne, CNRS, INSERM, iGReD, F-63000 Clermont-Ferrand, France
| | - Romane Bertrand
- Université Clermont Auvergne, CNRS, INSERM, iGReD, F-63000 Clermont-Ferrand, France
| | - Sven Hoehn
- Cardiff University, School of Biosciences, Museum Avenue, CF10 3AX Cardiff, Wales, UK
| | - Tomasz P. Jurkowski
- Cardiff University, School of Biosciences, Museum Avenue, CF10 3AX Cardiff, Wales, UK
| | - Bernd Schuettengruber
- Institute of Human Genetics, UMR9002, CNRS and University of Montpellier, Montpellier, France
| | - Giacomo Cavalli
- Institute of Human Genetics, UMR9002, CNRS and University of Montpellier, Montpellier, France
| | - Lucas Waltzer
- Université Clermont Auvergne, CNRS, INSERM, iGReD, F-63000 Clermont-Ferrand, France
| | - Laurence Vandel
- Université Clermont Auvergne, CNRS, INSERM, iGReD, F-63000 Clermont-Ferrand, France
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4
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Ko BS, Han MH, Kwon MJ, Cha DG, Ji Y, Park ES, Jeon MJ, Kim S, Lee K, Choi YH, Lee J, Torras-Llort M, Yoon KJ, Lee H, Kim JK, Lee SB. Baf-mediated transcriptional regulation of teashirt is essential for the development of neural progenitor cell lineages. Exp Mol Med 2024; 56:422-440. [PMID: 38374207 PMCID: PMC10907700 DOI: 10.1038/s12276-024-01169-3] [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: 03/10/2023] [Revised: 09/20/2023] [Accepted: 12/10/2023] [Indexed: 02/21/2024] Open
Abstract
Accumulating evidence hints heterochromatin anchoring to the inner nuclear membrane as an upstream regulatory process of gene expression. Given that the formation of neural progenitor cell lineages and the subsequent maintenance of postmitotic neuronal cell identity critically rely on transcriptional regulation, it seems possible that the development of neuronal cells is influenced by cell type-specific and/or context-dependent programmed regulation of heterochromatin anchoring. Here, we explored this possibility by genetically disrupting the evolutionarily conserved barrier-to-autointegration factor (Baf) in the Drosophila nervous system. Through single-cell RNA sequencing, we demonstrated that Baf knockdown induces prominent transcriptomic changes, particularly in type I neuroblasts. Among the differentially expressed genes, our genetic analyses identified teashirt (tsh), a transcription factor that interacts with beta-catenin, to be closely associated with Baf knockdown-induced phenotypes that were suppressed by the overexpression of tsh or beta-catenin. We also found that Baf and tsh colocalized in a region adjacent to heterochromatin in type I NBs. Notably, the subnuclear localization pattern remained unchanged when one of these two proteins was knocked down, indicating that both proteins contribute to the anchoring of heterochromatin to the inner nuclear membrane. Overall, this study reveals that the Baf-mediated transcriptional regulation of teashirt is a novel molecular mechanism that regulates the development of neural progenitor cell lineages.
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Affiliation(s)
- Byung Su Ko
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
| | - Myeong Hoon Han
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
| | - Min Jee Kwon
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
| | - Dong Gon Cha
- Department of New Biology, DGIST, Daegu, 42988, Republic of Korea
| | - Yuri Ji
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
| | - Eun Seo Park
- Department of New Biology, DGIST, Daegu, 42988, Republic of Korea
| | - Min Jae Jeon
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
| | - Somi Kim
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Kyeongho Lee
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
- Convergence Research Advanced Centre for Olfaction, DGIST, Daegu, 42988, Republic of Korea
| | - Yoon Ha Choi
- Department of New Biology, DGIST, Daegu, 42988, Republic of Korea
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Jusung Lee
- Department of New Biology, DGIST, Daegu, 42988, Republic of Korea
| | | | - Ki-Jun Yoon
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Hyosang Lee
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
- Convergence Research Advanced Centre for Olfaction, DGIST, Daegu, 42988, Republic of Korea
| | - Jong Kyoung Kim
- Department of New Biology, DGIST, Daegu, 42988, Republic of Korea.
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
| | - Sung Bae Lee
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea.
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5
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Yin C, Morita T, Parrish JZ. A cell atlas of the larval Aedes aegypti ventral nerve cord. Neural Dev 2024; 19:2. [PMID: 38297398 PMCID: PMC10829479 DOI: 10.1186/s13064-023-00178-8] [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: 09/23/2023] [Accepted: 11/28/2023] [Indexed: 02/02/2024] Open
Abstract
Mosquito-borne diseases account for nearly 1 million human deaths annually, yet we have a limited understanding of developmental events that influence host-seeking behavior and pathogen transmission in mosquitoes. Mosquito-borne pathogens are transmitted during blood meals, hence adult mosquito behavior and physiology have been intensely studied. However, events during larval development shape adult traits, larvae respond to many of the same sensory cues as adults, and larvae are susceptible to infection by many of the same disease-causing agents as adults. Hence, a better understanding of larval physiology will directly inform our understanding of physiological processes in adults. Here, we use single cell RNA sequencing (scRNA-seq) to provide a comprehensive view of cellular composition in the Aedes aegypti larval ventral nerve cord (VNC), a central hub of sensory inputs and motor outputs which additionally controls multiple aspects of larval physiology. We identify more than 35 VNC cell types defined in part by neurotransmitter and neuropeptide expression. We also explore diversity among monoaminergic and peptidergic neurons that likely control key elements of larval physiology and developmental timing, and identify neuroblasts and immature neurons, providing a view of neuronal differentiation in the VNC. Finally, we find that larval cell composition, number, and position are preserved in the adult abdominal VNC, suggesting studies of larval VNC form and function will likely directly inform our understanding adult mosquito physiology. Altogether, these studies provide a framework for targeted analysis of VNC development and neuronal function in Aedes aegypti larvae.
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Affiliation(s)
- Chang Yin
- Department of Biology, University of Washington, Seattle, WA, 98195, USA
- Division of Education, Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA, 02543, USA
| | - Takeshi Morita
- Division of Education, Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA, 02543, USA
- Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, NY, 10065, USA
- Howard Hughes Medical Institute, New York, NY, 10065, USA
| | - Jay Z Parrish
- Department of Biology, University of Washington, Seattle, WA, 98195, USA.
- Division of Education, Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA, 02543, USA.
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6
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Sun C, Shao Y, Iqbal J. Insect Insights at the Single-Cell Level: Technologies and Applications. Cells 2023; 13:91. [PMID: 38201295 PMCID: PMC10777908 DOI: 10.3390/cells13010091] [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: 11/22/2023] [Revised: 12/23/2023] [Accepted: 12/28/2023] [Indexed: 01/12/2024] Open
Abstract
Single-cell techniques are a promising way to unravel the complexity and heterogeneity of transcripts at the cellular level and to reveal the composition of different cell types and functions in a tissue or organ. In recent years, advances in single-cell RNA sequencing (scRNA-seq) have further changed our view of biological systems. The application of scRNA-seq in insects enables the comprehensive characterization of both common and rare cell types and cell states, the discovery of new cell types, and revealing how cell types relate to each other. The recent application of scRNA-seq techniques to insect tissues has led to a number of exciting discoveries. Here we provide an overview of scRNA-seq and its application in insect research, focusing on biological applications, current challenges, and future opportunities to make new discoveries with scRNA-seq in insects.
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Affiliation(s)
- Chao Sun
- Analysis Center of Agrobiology and Environmental Sciences, Zhejiang University, Hangzhou 310058, China;
| | - Yongqi Shao
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
| | - Junaid Iqbal
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
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7
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Thompson MK, Ceccarelli A, Ish-Horowicz D, Davis I. Dynamically regulated transcription factors are encoded by highly unstable mRNAs in the Drosophila larval brain. RNA (NEW YORK, N.Y.) 2023; 29:1020-1032. [PMID: 37041032 DOI: 10.1261/rna.079552.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 03/14/2023] [Indexed: 06/18/2023]
Abstract
The level of each RNA species depends on the balance between its rates of production and decay. Although previous studies have measured RNA decay across the genome in tissue culture and single-celled organisms, few experiments have been performed in intact complex tissues and organs. It is therefore unclear whether the determinants of RNA decay found in cultured cells are preserved in an intact tissue, and whether they differ between neighboring cell types and are regulated during development. To address these questions, we measured RNA synthesis and decay rates genome wide via metabolic labeling of whole cultured Drosophila larval brains using 4-thiouridine. Our analysis revealed that decay rates span a range of more than 100-fold, and that RNA stability is linked to gene function, with mRNAs encoding transcription factors being much less stable than mRNAs involved in core metabolic functions. Surprisingly, among transcription factor mRNAs there was a clear demarcation between more widely used transcription factors and those that are expressed only transiently during development. mRNAs encoding transient transcription factors are among the least stable in the brain. These mRNAs are characterized by epigenetic silencing in most cell types, as shown by their enrichment with the histone modification H3K27me3. Our data suggest the presence of an mRNA destabilizing mechanism targeted to these transiently expressed transcription factors to allow their levels to be regulated rapidly with high precision. Our study also demonstrates a general method for measuring mRNA transcription and decay rates in intact organs or tissues, offering insights into the role of mRNA stability in the regulation of complex developmental programs.
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Affiliation(s)
- Mary Kay Thompson
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Arianna Ceccarelli
- Mathematical Institute, University of Oxford, Oxford OX1 3LB, United Kingdom
| | - David Ish-Horowicz
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Ilan Davis
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
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8
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Rajan A, Anhezini L, Rives-Quinto N, Chhabra JY, Neville MC, Larson ED, Goodwin SF, Harrison MM, Lee CY. Low-level repressive histone marks fine-tune gene transcription in neural stem cells. eLife 2023; 12:e86127. [PMID: 37314324 PMCID: PMC10344426 DOI: 10.7554/elife.86127] [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: 01/11/2023] [Accepted: 06/11/2023] [Indexed: 06/15/2023] Open
Abstract
Coordinated regulation of gene activity by transcriptional and translational mechanisms poise stem cells for a timely cell-state transition during differentiation. Although important for all stemness-to-differentiation transitions, mechanistic understanding of the fine-tuning of gene transcription is lacking due to the compensatory effect of translational control. We used intermediate neural progenitor (INP) identity commitment to define the mechanisms that fine-tune stemness gene transcription in fly neural stem cells (neuroblasts). We demonstrate that the transcription factor FruitlessC (FruC) binds cis-regulatory elements of most genes uniquely transcribed in neuroblasts. Loss of fruC function alone has no effect on INP commitment but drives INP dedifferentiation when translational control is reduced. FruC negatively regulates gene expression by promoting low-level enrichment of the repressive histone mark H3K27me3 in gene cis-regulatory regions. Identical to fruC loss-of-function, reducing Polycomb Repressive Complex 2 activity increases stemness gene activity. We propose low-level H3K27me3 enrichment fine-tunes gene transcription in stem cells, a mechanism likely conserved from flies to humans.
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Affiliation(s)
- Arjun Rajan
- Life Sciences Institute, University of Michigan-Ann ArborAnn ArborUnited States
| | - Lucas Anhezini
- Life Sciences Institute, University of Michigan-Ann ArborAnn ArborUnited States
| | - Noemi Rives-Quinto
- Life Sciences Institute, University of Michigan-Ann ArborAnn ArborUnited States
| | - Jay Y Chhabra
- Life Sciences Institute, University of Michigan-Ann ArborAnn ArborUnited States
| | - Megan C Neville
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Elizabeth D Larson
- Department of Biomolecular Chemistry, University of Wisconsin-MadisonMadisonUnited States
| | - Stephen F Goodwin
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Melissa M Harrison
- Department of Biomolecular Chemistry, University of Wisconsin-MadisonMadisonUnited States
| | - Cheng-Yu Lee
- Life Sciences Institute, University of Michigan-Ann ArborAnn ArborUnited States
- Department of Cell and Developmental Biology, University of Michigan Medical SchoolAnn ArborUnited States
- Division of Genetic Medicine, Department of Internal Medicine, University of Michigan Medical SchoolAnn ArborUnited States
- Rogel Cancer Center, University of Michigan Medical SchoolAnn ArborUnited States
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9
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Rusin LY. Evolution of homology: From archetype towards a holistic concept of cell type. J Morphol 2023; 284:e21569. [PMID: 36789784 DOI: 10.1002/jmor.21569] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 01/10/2023] [Accepted: 02/13/2023] [Indexed: 02/16/2023]
Abstract
The concept of homology lies in the heart of comparative biological science. The distinction between homology as structure and analogy as function has shaped the evolutionary paradigm for a century and formed the axis of comparative anatomy and embryology, which accept the identity of structure as a ground measure of relatedness. The advent of single-cell genomics overturned the classical view of cell homology by establishing a backbone regulatory identity of cell types, the basic biological units bridging the molecular and phenotypic dimensions, to reveal that the cell is the most flexible unit of living matter and that many approaches of classical biology need to be revised to understand evolution and diversity at the cellular level. The emerging theory of cell types explicitly decouples cell identity from phenotype, essentially allowing for the divergence of evolutionarily related morphotypes beyond recognition, as well as it decouples ontogenetic cell lineage from cell-type phylogeny, whereby explicating that cell types can share common descent regardless of their structure, function or developmental origin. The article succinctly summarizes current progress and opinion in this field and formulates a more generalistic view of biological cell types as avatars, transient or terminal cell states deployed in a continuum of states by the developmental programme of one and the same omnipotent cell, capable of changing or combining identities with distinct evolutionary histories or inventing ad hoc identities that never existed in evolution or development. It highlights how the new logic grounded in the regulatory nature of cell identity transforms the concepts of cell homology and phenotypic stability, suggesting that cellular evolution is inherently and massively network-like, with one-to-one homologies being rather uncommon and restricted to shallower levels of the animal tree of life.
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Affiliation(s)
- Leonid Y Rusin
- Laboratory for Mathematic Methods and Models in Bioinformatics, Institute for Information Transmission Problems (Kharkevich Institute), Russian Academy of Sciences, Moscow, Russia
- EvoGenome Analytics LLC, Odintsovo, Moscow Region, Russia
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10
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Moroz LL, Romanova DY. Alternative neural systems: What is a neuron? (Ctenophores, sponges and placozoans). Front Cell Dev Biol 2022; 10:1071961. [PMID: 36619868 PMCID: PMC9816575 DOI: 10.3389/fcell.2022.1071961] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022] Open
Abstract
How to make a neuron, a synapse, and a neural circuit? Is there only one 'design' for a neural architecture with a universally shared genomic blueprint across species? The brief answer is "No." Four early divergent lineages from the nerveless common ancestor of all animals independently evolved distinct neuroid-type integrative systems. One of these is a subset of neural nets in comb jellies with unique synapses; the second lineage is the well-known Cnidaria + Bilateria; the two others are non-synaptic neuroid systems in sponges and placozoans. By integrating scRNA-seq and microscopy data, we revise the definition of neurons as synaptically-coupled polarized and highly heterogenous secretory cells at the top of behavioral hierarchies with learning capabilities. This physiological (not phylogenetic) definition separates 'true' neurons from non-synaptically and gap junction-coupled integrative systems executing more stereotyped behaviors. Growing evidence supports the hypothesis of multiple origins of neurons and synapses. Thus, many non-bilaterian and bilaterian neuronal classes, circuits or systems are considered functional rather than genetic categories, composed of non-homologous cell types. In summary, little-explored examples of convergent neuronal evolution in representatives of early branching metazoans provide conceptually novel microanatomical and physiological architectures of behavioral controls in animals with prospects of neuro-engineering and synthetic biology.
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Affiliation(s)
- Leonid L. Moroz
- Departments 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,*Correspondence: Leonid L. Moroz, ; Daria Y. Romanova,
| | - Daria Y. Romanova
- Institute of Higher Nervous Activity and Neurophysiology of RAS, 5A Butlerova, Moscow, Russia,*Correspondence: Leonid L. Moroz, ; Daria Y. Romanova,
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