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Takahashi H, Hisata K, Iguchi R, Kikuchi S, Ogasawara M, Satoh N. scRNA-seq analysis of cells comprising the amphioxus notochord. Dev Biol 2024; 508:24-37. [PMID: 38224933 DOI: 10.1016/j.ydbio.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 01/04/2024] [Accepted: 01/06/2024] [Indexed: 01/17/2024]
Abstract
Cephalochordates occupy a key phylogenetic position for deciphering the origin and evolution of chordates, since they diverged earlier than urochordates and vertebrates. The notochord is the most prominent feature of chordates. The amphioxus notochord features coin-shaped cells bearing myofibrils. Notochord-derived hedgehog signaling contributes to patterning of the dorsal nerve cord, as in vertebrates. However, properties of constituent notochord cells remain unknown at the single-cell level. We examined these properties using Iso-seq analysis, single-cell RNA-seq analysis, and in situ hybridization (ISH). Gene expression profiles broadly categorize notochordal cells into myofibrillar cells and non-myofibrillar cells. Myofibrillar cells occupy most of the central portion of the notochord, and some cells extend the notochordal horn to both sides of the ventral nerve cord. Some notochord myofibrillar genes are not expressed in myotomes, suggesting an occurrence of myofibrillar genes that are preferentially expressed in notochord. On the other hand, non-myofibrillar cells contain dorsal, lateral, and ventral Müller cells, and all three express both hedgehog and Brachyury. This was confirmed by ISH, although expression of hedgehog in ventral Müller cells was minimal. In addition, dorsal Müller cells express neural transmission-related genes, suggesting an interaction with nerve cord. Lateral Müller cells express hedgehog and other signaling-related genes, suggesting an interaction with myotomes positioned lateral to the notochord. Ventral Müller cells also expressed genes for FGF- and EGF-related signaling, which may be associated with development of endoderm, ventral to the notochord. Lateral Müller cells were intermediate between dorsal/ventral Müller cells. Since vertebrate notochord contributes to patterning and differentiation of ectoderm (nerve cord), mesoderm (somite), and endoderm, this investigation provides evidence that an ancestral or original form of vertebrate notochord is present in extant cephalochordates.
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Affiliation(s)
- Hiroki Takahashi
- Interdisciplinary Research Unit, National Institute for Basic Biology, Okazaki, Aichi, 444-8585, Japan.
| | - Kanako Hisata
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, 904-0495, Japan
| | - Rin Iguchi
- Department of Biology, Graduate School of Science, Chiba University, Chiba, 262-8522, Japan
| | - Sakura Kikuchi
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, 904-0495, Japan
| | - Michio Ogasawara
- Department of Biology, Graduate School of Science, Chiba University, Chiba, 262-8522, Japan.
| | - Noriyuki Satoh
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, 904-0495, Japan.
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2
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Fritzsch B, Glover JC. Gene networks and the evolution of olfactory organs, eyes, hair cells and motoneurons: a view encompassing lancelets, tunicates and vertebrates. Front Cell Dev Biol 2024; 12:1340157. [PMID: 38533086 PMCID: PMC10963430 DOI: 10.3389/fcell.2024.1340157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 02/26/2024] [Indexed: 03/28/2024] Open
Abstract
Key developmental pathways and gene networks underlie the formation of sensory cell types and structures involved in chemosensation, vision and mechanosensation, and of the efferents these sensory inputs can activate. We describe similarities and differences in these pathways and gene networks in selected species of the three main chordate groups, lancelets, tunicates, and vertebrates, leading to divergent development of olfactory receptors, eyes, hair cells and motoneurons. The lack of appropriately posited expression of certain transcription factors in lancelets and tunicates prevents them from developing vertebrate-like olfactory receptors and eyes, although they generate alternative structures for chemosensation and vision. Lancelets and tunicates lack mechanosensory cells associated with the sensation of acoustic stimuli, but have gravisensitive organs and ciliated epidermal sensory cells that may (and in some cases clearly do) provide mechanosensation and thus the capacity to respond to movement relative to surrounding water. Although functionally analogous to the vertebrate vestibular apparatus and lateral line, homology is questionable due to differences in the expression of the key transcription factors Neurog and Atoh1/7, on which development of vertebrate hair cells depends. The vertebrate hair cell-bearing inner ear and lateral line thus likely represent major evolutionary advances specific to vertebrates. Motoneurons develop in vertebrates under the control of the ventral signaling molecule hedgehog/sonic hedgehog (Hh,Shh), against an opposing inhibitory effect mediated by dorsal signaling molecules. Many elements of Shh-signaling and downstream genes involved in specifying and differentiating motoneurons are also exhibited by lancelets and tunicates, but the repertoire of MNs in vertebrates is broader, indicating greater diversity in motoneuron differentiation programs.
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Affiliation(s)
- Bernd Fritzsch
- Department of Biological Sciences, University of Nebraska Medical Center, Omaha, NE, United States
| | - Joel C. Glover
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
- Laboratory of Neural Development and Optical Recording (NDEVOR), Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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3
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Papadogiannis V, Hockman D, Mercurio S, Ramsay C, Hintze M, Patthey C, Streit A, Shimeld SM. Evolution of the expression and regulation of the nuclear hormone receptor ERR gene family in the chordate lineage. Dev Biol 2023; 504:12-24. [PMID: 37696353 DOI: 10.1016/j.ydbio.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 09/01/2023] [Accepted: 09/09/2023] [Indexed: 09/13/2023]
Abstract
The Estrogen Related Receptor (ERR) nuclear hormone receptor genes have a wide diversity of roles in vertebrate development. In embryos, ERR genes are expressed in several tissues, including the central and peripheral nervous systems. Here we seek to establish the evolutionary history of chordate ERR genes, their expression and their regulation. We examine ERR expression in mollusc, amphioxus and sea squirt embryos, finding the single ERR orthologue is expressed in the nervous system in all three, with muscle expression also found in the two chordates. We show that most jawed vertebrates and lampreys have four ERR paralogues, and that vertebrate ERR genes were ancestrally linked to Estrogen Receptor genes. One of the lamprey paralogues shares conserved expression domains with jawed vertebrate ERRγ in the embryonic vestibuloacoustic ganglion, eye, brain and spinal cord. Hypothesising that conserved expression derives from conserved regulation, we identify a suite of pan-vertebrate conserved non-coding sequences in ERR introns. We use transgenesis in lamprey and chicken embryos to show that these sequences are regulatory and drive reporter gene expression in the nervous system. Our data suggest an ancient association between ERR and the nervous system, including expression in cells associated with photosensation and mechanosensation. This includes the origin in the vertebrate common ancestor of a suite of regulatory elements in the 3' introns that drove nervous system expression and have been conserved from this point onwards.
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Affiliation(s)
| | - Dorit Hockman
- Division of Cell Biology, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Neuroscience Institute, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Silvia Mercurio
- Department of Environmental Science and Policy, Università Degli Studi di Milano, Via Celoria 2, 20133, Milano, Italy
| | - Claire Ramsay
- Department of Biology, University of Oxford, 11a Mansfield Road, Oxford, OX1 3SZ, UK
| | - Mark Hintze
- Centre for Craniofacial & Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College London, London, UK
| | - Cedric Patthey
- Department of Radiosciences, Umeå University, 901 85, Umeå, Sweden
| | - Andrea Streit
- Centre for Craniofacial & Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College London, London, UK
| | - Sebastian M Shimeld
- Department of Biology, University of Oxford, 11a Mansfield Road, Oxford, OX1 3SZ, UK.
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4
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Huang X, Ren Q, Wang Y, Shimeld SM, Li G. Amphioxus Gli knockout disrupts the development of left-right asymmetry but has limited impact on neural patterning. MARINE LIFE SCIENCE & TECHNOLOGY 2023; 5:492-499. [PMID: 38045549 PMCID: PMC10689630 DOI: 10.1007/s42995-023-00195-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 09/18/2023] [Indexed: 12/05/2023]
Abstract
The Gli transcription factors are the primary mediators of Hedgehog (Hh) signaling. Vertebrate genomes contain multiple Gli paralogues with different functions downstream of Hh signal receipt, in part explaining the complexity of cellular responses to Hh that allow concentration-dependent target gene activation. Amphioxus is a chordate that split from the vertebrate lineage early in the evolution of chordates, before the genome duplications that occurred in early vertebrate evolution. It has a single Gli gene whose transcripts can be alternately spliced to yield two protein isoforms called GliS and GliL. We generated two knockout mutations in amphioxus Gli, one that affects the whole gene and a second that only affects GliL. Both knockouts showed major morphological and molecular defects in the development of left-right asymmetry, a phenotype that is similar but not identical to that previously found in Hh mutants. Hh signaling also patterns the amphioxus neural tube. Here, however, knockout of GliL showed no identifiable phenotype, while knockout of the full gene showed only small changes to the expression of one gene family, Olig. Other genes that were prominently affected by Hh knockout were not altered in expression in either knockout. Reasons for the differences between Hh and Gli knockouts in the pharynx and neural tube are discussed in the context of the likely different functions of amphioxus Gli isoforms. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-023-00195-w.
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Affiliation(s)
- Xin Huang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, 361005 China
| | - Qiongqiong Ren
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, 361005 China
| | - Yiquan Wang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, 361005 China
| | | | - Guang Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, 361005 China
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5
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D'Aniello S, Bertrand S, Escriva H. Amphioxus as a model to study the evolution of development in chordates. eLife 2023; 12:e87028. [PMID: 37721204 PMCID: PMC10506793 DOI: 10.7554/elife.87028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 08/10/2023] [Indexed: 09/19/2023] Open
Abstract
Cephalochordates and tunicates represent the only two groups of invertebrate chordates, and extant cephalochordates - commonly known as amphioxus or lancelets - are considered the best proxy for the chordate ancestor, from which they split around 520 million years ago. Amphioxus has been an important organism in the fields of zoology and embryology since the 18th century, and the morphological and genomic simplicity of cephalochordates (compared to vertebrates) makes amphioxus an attractive model for studying chordate biology at the cellular and molecular levels. Here we describe the life cycle of amphioxus, and discuss the natural histories and habitats of the different species of amphioxus. We also describe their use as laboratory animal models, and discuss the techniques that have been developed to study different aspects of amphioxus.
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Affiliation(s)
- Salvatore D'Aniello
- Biology and Evolution of Marine Organisms (BEOM), Stazione Zoologica Anton DohrnNapoliItaly
| | - Stephanie Bertrand
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins (BIOM), Observatoire OcéanologiqueBanyuls-sur-MerFrance
| | - Hector Escriva
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins (BIOM), Observatoire OcéanologiqueBanyuls-sur-MerFrance
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6
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Ma P, Liu X, Xu Z, Liu H, Ding X, Huang Z, Shi C, Liang L, Xu L, Li X, Li G, He Y, Ding Z, Chai C, Wang H, Qiu J, Zhu J, Wang X, Ding P, Zhou S, Yuan Y, Wu W, Wan C, Yan Y, Zhou Y, Zhou QJ, Wang GD, Zhang Q, Xu X, Li G, Zhang S, Mao B, Chen D. Joint profiling of gene expression and chromatin accessibility during amphioxus development at single-cell resolution. Cell Rep 2022; 39:110979. [PMID: 35732129 DOI: 10.1016/j.celrep.2022.110979] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 03/21/2022] [Accepted: 05/27/2022] [Indexed: 11/03/2022] Open
Abstract
Vertebrate evolution was accompanied by two rounds of whole-genome duplication followed by functional divergence in terms of regulatory circuits and gene expression patterns. As a basal and slow-evolving chordate species, amphioxus is an ideal paradigm for exploring the origin and evolution of vertebrates. Single-cell sequencing has been widely used to construct the developmental cell atlas of several representative species of vertebrates (human, mouse, zebrafish, and frog) and tunicates (sea squirts). Here, we perform single-nucleus RNA sequencing (snRNA-seq) and single-cell assay for transposase accessible chromatin sequencing (scATAC-seq) for different stages of amphioxus (covering embryogenesis and adult tissues). With the datasets generated, we constructed a developmental tree for amphioxus cell fate commitment and lineage specification and characterize the underlying key regulators and genetic regulatory networks. The data are publicly available on the online platform AmphioxusAtlas.
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Affiliation(s)
- Pengcheng Ma
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Xingyan Liu
- Academy of Mathematics and Systems Science, Chinese Academy of Science, Beijing 100190, China; School of Mathematical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zaoxu Xu
- BGI-Shenzhen, Shenzhen 518083, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Huimin Liu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiangan District, Xiamen, Fujian 361102, China
| | - Xiangning Ding
- BGI-Shenzhen, Shenzhen 518083, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhen Huang
- Fujian Key Laboratory of Special Marine Bio-resources Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, 350117 Fujian, China; Fuzhou Institute of Oceanography, Minjiang University, Fuzhou 350108, China; Fujian Key Laboratory on Conservation and Sustainable Utilization of Marine Biodiversity, Minjiang University, Fuzhou 350108, China
| | - Chenggang Shi
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiangan District, Xiamen, Fujian 361102, China
| | - Langchao Liang
- BGI-Shenzhen, Shenzhen 518083, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Luohao Xu
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China
| | - Xiaolu Li
- Genome Center of Biodiversity, Kunming Institute of Zoology, Chinese Academy of Science, Kunming 650223, China
| | - Guimei Li
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Yuqi He
- Genome Center of Biodiversity, Kunming Institute of Zoology, Chinese Academy of Science, Kunming 650223, China
| | - Zhaoli Ding
- Genome Center of Biodiversity, Kunming Institute of Zoology, Chinese Academy of Science, Kunming 650223, China
| | - Chaochao Chai
- BGI-Shenzhen, Shenzhen 518083, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haoyu Wang
- BGI-Shenzhen, Shenzhen 518083, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiaying Qiu
- BGI-Shenzhen, Shenzhen 518083, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiacheng Zhu
- BGI-Shenzhen, Shenzhen 518083, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | | | - Peiwen Ding
- BGI-Shenzhen, Shenzhen 518083, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Si Zhou
- BGI-Shenzhen, Shenzhen 518083, China
| | | | - Wendi Wu
- BGI-Shenzhen, Shenzhen 518083, China
| | - Cen Wan
- Fujian Key Laboratory of Special Marine Bio-resources Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, 350117 Fujian, China
| | - Yanan Yan
- Fujian Key Laboratory of Special Marine Bio-resources Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, 350117 Fujian, China
| | - Yitao Zhou
- Fujian Key Laboratory of Special Marine Bio-resources Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, 350117 Fujian, China
| | - Qi-Jun Zhou
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Guo-Dong Wang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; Genome Center of Biodiversity, Kunming Institute of Zoology, Chinese Academy of Science, Kunming 650223, China; Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
| | - Qiujin Zhang
- Fujian Key Laboratory of Special Marine Bio-resources Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, 350117 Fujian, China.
| | - Xun Xu
- BGI-Shenzhen, Shenzhen 518083, China.
| | - Guang Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiangan District, Xiamen, Fujian 361102, China.
| | - Shihua Zhang
- Academy of Mathematics and Systems Science, Chinese Academy of Science, Beijing 100190, China; Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China; Key Laboratory of Systems Biology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Hangzhou 310024, China.
| | - Bingyu Mao
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China.
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7
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Zhou R, Lu G, Yan Z, Jiang R, Sun Y, Zhang P. Epigenetic mechanisms of DNA methylation in the transgenerational effect of ethylhexyl salicylate on zebrafish. CHEMOSPHERE 2022; 295:133926. [PMID: 35150701 DOI: 10.1016/j.chemosphere.2022.133926] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 01/24/2022] [Accepted: 02/06/2022] [Indexed: 06/14/2023]
Abstract
In this study, a 120-day whole-life cycle exposure and oviposition experiment on zebrafish with maternal and paternal mixed mating strategy was conducted to investigate the epigenetic mechanism of DNA methylation in ethylhexyl salicylate (EHS, 1, 10, 100 μg/L)-induced transgenerational effects. Results showed that EHS could induce the decrease of DNA methyltransferase 1 (DNMT1) activity and average global DNA methylation level in maternal parents and the increase of the above indexes in paternal parents, while the change of glycine N-methyltransferase activity was opposite to DNMT1. The average global DNA methylation levels were significantly increased in the offsprings of both parents exposed and father-only exposed to EHS, suggesting that EHS-induced epigenetic modifications may be stable and heritable. Hierarchical clustering analysis of promoter at different methylation sites showed that the DNA methylation pattern of offsprings were similar to that of the paternal parents, meaning that the offsprings may have inherited paternal DNA methylation pattern with eya2, pcdh2g5 and pcdh2g1 as key genes and lead to high locomotor activity in offsprings. KEGG pathway analysis showed that parental exposure to EHS may interfere with the central nervous system, insulin function system, melanogenesis system and the normal development of somatic axis of offsprings.
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Affiliation(s)
- Ranran Zhou
- Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, PR China; School of Environmental Science & Engineering, Nanjing Tech University, 30 Puzhu Southern Road, Nanjing, 211816, China
| | - Guanghua Lu
- Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, PR China.
| | - Zhenhua Yan
- Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, PR China
| | - Runren Jiang
- Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, PR China
| | - Yu Sun
- Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, PR China
| | - Peng Zhang
- Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, PR China
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8
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Holland LZ, Holland ND. The invertebrate chordate amphioxus gives clues to vertebrate origins. Curr Top Dev Biol 2022; 147:563-594. [PMID: 35337463 DOI: 10.1016/bs.ctdb.2021.12.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Amphioxus (cepholochordates) have long been used to infer how the vertebrates evolved from their invertebrate ancestors. However, some of the body part homologies between amphioxus and vertebrates have been controversial. This is not surprising as the amphioxus and vertebrate lineages separated half a billion years ago-plenty of time for independent loss and independent gain of features. The development of new techniques in the late 20th and early 21st centuries including transmission electron microscopy and serial blockface scanning electron microscopy in combination with in situ hybridization and immunocytochemistry to reveal spatio-temporal patterns of gene expression and gene products have greatly strengthened inference of some homologies (like those between regions of the central nervous system), although others (like nephridia) still need further support. These major advances in establishing homologies between amphioxus and vertebrates, together with strong support from comparative genomics, have firmly established amphioxus as a stand-in or model for the ancestral vertebrate.
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Affiliation(s)
- Linda Z Holland
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States.
| | - Nicholas D Holland
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States
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9
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Hines JH. Evolutionary Origins of the Oligodendrocyte Cell Type and Adaptive Myelination. Front Neurosci 2021; 15:757360. [PMID: 34924932 PMCID: PMC8672417 DOI: 10.3389/fnins.2021.757360] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 10/29/2021] [Indexed: 12/23/2022] Open
Abstract
Oligodendrocytes are multifunctional central nervous system (CNS) glia that are essential for neural function in gnathostomes. The evolutionary origins and specializations of the oligodendrocyte cell type are among the many remaining mysteries in glial biology and neuroscience. The role of oligodendrocytes as CNS myelinating glia is well established, but recent studies demonstrate that oligodendrocytes also participate in several myelin-independent aspects of CNS development, function, and maintenance. Furthermore, many recent studies have collectively advanced our understanding of myelin plasticity, and it is now clear that experience-dependent adaptations to myelination are an additional form of neural plasticity. These observations beg the questions of when and for which functions the ancestral oligodendrocyte cell type emerged, when primitive oligodendrocytes evolved new functionalities, and the genetic changes responsible for these evolutionary innovations. Here, I review recent findings and propose working models addressing the origins and evolution of the oligodendrocyte cell type and adaptive myelination. The core gene regulatory network (GRN) specifying the oligodendrocyte cell type is also reviewed as a means to probe the existence of oligodendrocytes in basal vertebrates and chordate invertebrates.
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Affiliation(s)
- Jacob H. Hines
- Biology Department, Winona State University, Winona, MN, United States
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10
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Mukaigasa K, Sakuma C, Yaginuma H. The developmental hourglass model is applicable to the spinal cord based on single-cell transcriptomes and non-conserved cis-regulatory elements. Dev Growth Differ 2021; 63:372-391. [PMID: 34473348 PMCID: PMC9293469 DOI: 10.1111/dgd.12750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/24/2021] [Accepted: 08/26/2021] [Indexed: 11/27/2022]
Abstract
The developmental hourglass model predicts that embryonic morphology is most conserved at the mid‐embryonic stage and diverges at the early and late stages. To date, this model has been verified by examining the anatomical features or gene expression profiles at the whole embryonic level. Here, by data mining approach utilizing multiple genomic and transcriptomic datasets from different species in combination, and by experimental validation, we demonstrate that the hourglass model is also applicable to a reduced element, the spinal cord. In the middle of spinal cord development, dorsoventrally arrayed neuronal progenitor domains are established, which are conserved among vertebrates. By comparing the publicly available single‐cell transcriptome datasets of mice and zebrafish, we found that ventral subpopulations of post‐mitotic spinal neurons display divergent molecular profiles. We also detected the non‐conservation of cis‐regulatory elements located around the progenitor fate determinants, indicating that the cis‐regulatory elements contributing to the progenitor specification are evolvable. These results demonstrate that, despite the conservation of the progenitor domains, the processes before and after the progenitor domain specification diverged. This study will be helpful to understand the molecular basis of the developmental hourglass model.
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Affiliation(s)
- Katsuki Mukaigasa
- Department of Neuroanatomy and Embryology, School of Medicine, Fukushima Medical University, Fukushima, Japan
| | - Chie Sakuma
- Department of Neuroanatomy and Embryology, School of Medicine, Fukushima Medical University, Fukushima, Japan
| | - Hiroyuki Yaginuma
- Department of Neuroanatomy and Embryology, School of Medicine, Fukushima Medical University, Fukushima, Japan
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11
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Zou J, Wu X, Shi C, Zhong Y, Zhang L, Yan Q, Su L, Li G. A Potential Method for Rapid Screening of Amphioxus Founder Harboring Germline Mutation and Transgene. Front Cell Dev Biol 2021; 9:702290. [PMID: 34458263 PMCID: PMC8387717 DOI: 10.3389/fcell.2021.702290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022] Open
Abstract
Amphioxus is a promising model organism for understanding the origin and evolution of vertebrates due to its basal phylogenetic position among chordates. We here compared the mutation efficacy and mutation type of tail tips and gametes of amphioxus founders injected with Cas9 protein and six different sgRNAs targeting five distinct genes, and revealed a strong correlation for mutation efficacy and a mild correlation for mutation type among the two tissues. In addition, we also observed a positive relationship between gene insertions observed in tail tips and gametes of amphioxus founders injected with Tol2 transposase and two different transgenic constructs. Finally, we showed that amphioxus larvae which had their tail tips cut at the 3-4 gill-slit stage were able to recover within 6 days and developed a normal number of gonads at the adult stage, and that F0 larvae carry similar mutation efficacy and type in the posterior end to that in the tail tips after their metamorphosis. Together, these findings suggest a great potential for obtaining valid amphioxus founders with desired mutations and transgenes at as early as the early larval stage, which will certainly speed up the generation of amphioxus mutants and transgenes and make it more cost- and labor-effective.
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Affiliation(s)
- Jiaqi Zou
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Xiaotong Wu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Chenggang Shi
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Yanhong Zhong
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Lei Zhang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Qiuning Yan
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Liuru Su
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Guang Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
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12
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Xing C, Pan R, Hu G, Liu X, Wang Y, Li G. Pitx controls amphioxus asymmetric morphogenesis by promoting left-side development and repressing right-side formation. BMC Biol 2021; 19:166. [PMID: 34416880 PMCID: PMC8377849 DOI: 10.1186/s12915-021-01095-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 07/13/2021] [Indexed: 11/21/2022] Open
Abstract
Background Left-right (LR) asymmetry is an essential feature of bilateral animals. Studies in vertebrates show that LR asymmetry formation comprises three major steps: symmetry breaking, asymmetric gene expression, and LR morphogenesis. Although much progress has been made in the first two events, mechanisms underlying asymmetric morphogenesis remain largely unknown due to the complex developmental processes deployed by vertebrate organs. Results We here addressed this question by studying Pitx gene function in the basal chordate amphioxus whose asymmetric organogenesis, unlike that in vertebrates, occurs essentially in situ and does not rely on cell migration. Pitx null mutation in amphioxus causes loss of all left-sided organs and incomplete ectopic formation of all right-sided organs on the left side, whereas Pitx partial loss-of-function leads to milder phenotypes with only some LR organs lost or ectopically formed. At the N1 to N3 stages, Pitx expression is gradually expanded from the dorsal anterior domain to surrounding regions. This leads to activation of genes like Lhx3 and/or Prop1 and Pit, which are essential for left-side organs, and downregulation of genes like Hex and/or Nkx2.1 and FoxE4, which are required for right-side organs to form ectopically on the left side. In Pitx mutants, the left-side expressed genes are not activated, while the right-side genes fail to decrease expression on the left side. In contrast, in embryos overexpressing Pitx genes, the left-side genes are induced ectopically on the right side, and the right-side genes are inhibited. Several Pitx binding sites are identified in the upstream sequences of the left-side and right-side genes which are essential for activation of the former and repression of the latter by Pitx. Conclusions Our results demonstrate that (1) Pitx is a major (although not the only) determinant of asymmetric morphogenesis in amphioxus, (2) the development of different LR organs have distinct requirements for Pitx activity, and (3) Pitx controls amphioxus LR morphogenesis probably through inducing left-side organs and inhibiting right-side organs directly. These findings show much more dependence of LR organogenesis on Pitx in amphioxus than in vertebrates. They also provide insight into the molecular developmental mechanism of some vertebrate LR organs like the lungs and atria, since they show a right-isomerism phenotype in Pitx2 knockout mice like right-sided organs in Pitx mutant amphioxus. Our results also explain why some organs like the adenohypophysis are asymmetrically located in amphioxus but symmetrically positioned in vertebrates. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01095-0.
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Affiliation(s)
- Chaofan Xing
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiangan District, Xiamen, 361102, Fujian, China
| | - Rongrong Pan
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiangan District, Xiamen, 361102, Fujian, China
| | - Guangwei Hu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiangan District, Xiamen, 361102, Fujian, China.,Jiangsu Key Laboratory of Marine Biotechnology, School of Marine Science and Fisheries, Jiangsu Ocean University, Lianyungang, 222005, China
| | - Xian Liu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiangan District, Xiamen, 361102, Fujian, China
| | - Yiquan Wang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiangan District, Xiamen, 361102, Fujian, China
| | - Guang Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiangan District, Xiamen, 361102, Fujian, China.
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13
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Ho EK, Stearns T. Hedgehog signaling and the primary cilium: implications for spatial and temporal constraints on signaling. Development 2021; 148:dev195552. [PMID: 33914866 PMCID: PMC8126410 DOI: 10.1242/dev.195552] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The mechanisms of vertebrate Hedgehog signaling are linked to the biology of the primary cilium, an antenna-like organelle that projects from the surface of most vertebrate cell types. Although the advantages of restricting signal transduction to cilia are often noted, the constraints imposed are less frequently considered, and yet they are central to how Hedgehog signaling operates in developing tissues. In this Review, we synthesize current understanding of Hedgehog signal transduction, ligand secretion and transport, and cilia dynamics to explore the temporal and spatial constraints imposed by the primary cilium on Hedgehog signaling in vivo.
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Affiliation(s)
- Emily K. Ho
- Department of Developmental Biology, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Tim Stearns
- Department of Biology, Stanford University, Stanford, CA 94305, USA
- Department of Genetics, Stanford School of Medicine, Stanford, CA 94305, USA
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14
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Bozzo M, Lacalli TC, Obino V, Caicci F, Marcenaro E, Bachetti T, Manni L, Pestarino M, Schubert M, Candiani S. Amphioxus neuroglia: Molecular characterization and evidence for early compartmentalization of the developing nerve cord. Glia 2021; 69:1654-1678. [PMID: 33624886 DOI: 10.1002/glia.23982] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 02/02/2021] [Accepted: 02/09/2021] [Indexed: 12/19/2022]
Abstract
Glial cells play important roles in the development and homeostasis of metazoan nervous systems. However, while their involvement in the development and function in the central nervous system (CNS) of vertebrates is increasingly well understood, much less is known about invertebrate glia and the evolutionary history of glial cells more generally. An investigation into amphioxus glia is therefore timely, as this organism is the best living proxy for the last common ancestor of all chordates, and hence provides a window into the role of glial cell development and function at the transition of invertebrates and vertebrates. We report here our findings on amphioxus glia as characterized by molecular probes correlated with anatomical data at the transmission electron microscopy (TEM) level. The results show that amphioxus glial lineages express genes typical of vertebrate astroglia and radial glia, and that they segregate early in development, forming what appears to be a spatially separate cell proliferation zone positioned laterally, between the dorsal and ventral zones of neural cell proliferation. Our study provides strong evidence for the presence of vertebrate-type glial cells in amphioxus, while highlighting the role played by segregated progenitor cell pools in CNS development. There are implications also for our understanding of glial cells in a broader evolutionary context, and insights into patterns of precursor cell deployment in the chordate nerve cord.
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Affiliation(s)
- Matteo Bozzo
- Department of Earth, Environment and Life Sciences, University of Genoa, Genoa, Italy
| | - Thurston C Lacalli
- Biology Department, University of Victoria, Victoria, British Columbia, Canada
| | - Valentina Obino
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | | | - Emanuela Marcenaro
- Department of Experimental Medicine, University of Genoa, Genoa, Italy.,Centre of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
| | - Tiziana Bachetti
- Department of Earth, Environment and Life Sciences, University of Genoa, Genoa, Italy
| | - Lucia Manni
- Centre of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
| | - Mario Pestarino
- Department of Earth, Environment and Life Sciences, University of Genoa, Genoa, Italy
| | - Michael Schubert
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-Mer, Villefranche-sur-Mer, France
| | - Simona Candiani
- Department of Earth, Environment and Life Sciences, University of Genoa, Genoa, Italy
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