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Rice KL, Chan CM, Kelu JJ, Miller AL, Webb SE. A Role for Two-Pore Channel Type 2 (TPC2)-Mediated Regulation of Membrane Contact Sites During Zebrafish Notochord Biogenesis? CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2023; 6:25152564231211409. [PMID: 38028019 PMCID: PMC10658360 DOI: 10.1177/25152564231211409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 10/09/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023]
Abstract
We have previously shown that in the developing trunk of zebrafish embryos, two-pore channel type 2 (TPC2)-mediated Ca2+ release from endolysosomes plays a role in the formation of the skeletal slow muscle. In addition, TPC2-mediated Ca2+ signaling is required for axon extension and the establishment of synchronized activity in the primary motor neurons. Here, we report that TPC2 might also play a role in the development of the notochord of zebrafish embryos. For example, when tpcn2 was knocked down or out, increased numbers of small vacuoles were formed in the inner notochord cells, compared with the single large vacuole in the notochord of control embryos. This abnormal vacuolation was associated with embryos displaying attenuated body axis straightening. We also showed that TPC2 has a distinct pattern of localization in the notochord in embryos at ∼24 hpf. Finally, we conducted RNAseq to identify differentially expressed genes in tpcn2 mutants compared to wild-type controls, and found that those involved in actin filament severing, cellular component morphogenesis, Ca2+ binding, and structural constituent of cytoskeleton were downregulated in the mutants. Together, our data suggest that TPC2 activity plays a key role in notochord biogenesis in zebrafish embryos.
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Affiliation(s)
- Keira L. Rice
- The Division of Life Science and Key State Laboratory for Molecular Neuroscience, HKUST, Hong Kong, People’s Republic of China
| | - Ching Man Chan
- The Division of Life Science and Key State Laboratory for Molecular Neuroscience, HKUST, Hong Kong, People’s Republic of China
| | - Jeffrey J. Kelu
- The Division of Life Science and Key State Laboratory for Molecular Neuroscience, HKUST, Hong Kong, People’s Republic of China
| | - Andrew L. Miller
- The Division of Life Science and Key State Laboratory for Molecular Neuroscience, HKUST, Hong Kong, People’s Republic of China
| | - Sarah E. Webb
- The Division of Life Science and Key State Laboratory for Molecular Neuroscience, HKUST, Hong Kong, People’s Republic of China
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2
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Koyama H, Suzuki M, Yasue N, Sasaki H, Ueno N, Fujimori T. Differential Cellular Stiffness Contributes to Tissue Elongation on an Expanding Surface. Front Cell Dev Biol 2022; 10:864135. [PMID: 35425767 PMCID: PMC9001851 DOI: 10.3389/fcell.2022.864135] [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: 01/28/2022] [Accepted: 03/03/2022] [Indexed: 12/02/2022] Open
Abstract
Pattern formation and morphogenesis of cell populations is essential for successful embryogenesis. Steinberg proposed the differential adhesion hypothesis, and differences in cell–cell adhesion and interfacial tension have proven to be critical for cell sorting. Standard theoretical models such as the vertex model consider not only cell–cell adhesion/tension but also area elasticity of apical cell surfaces and viscous friction forces. However, the potential contributions of the latter two parameters to pattern formation and morphogenesis remain to be determined. In this theoretical study, we analyzed the effect of both area elasticity and the coefficient of friction on pattern formation and morphogenesis. We assumed the presence of two cell populations, one population of which is surrounded by the other. Both populations were placed on the surface of a uniformly expanding environment analogous to growing embryos, in which friction forces are exerted between cell populations and their expanding environment. When the area elasticity or friction coefficient in the cell cluster was increased relative to that of the surrounding cell population, the cell cluster was elongated. In comparison with experimental observations, elongation of the notochord in mice is consistent with the hypothesis based on the difference in area elasticity but not the difference in friction coefficient. Because area elasticity is an index of cellular stiffness, we propose that differential cellular stiffness may contribute to tissue elongation within an expanding environment.
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Affiliation(s)
- Hiroshi Koyama
- Division of Embryology, National Institute for Basic Biology (Div. Embryology, NIBB), Okazaki, Japan.,Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Japan
| | - Makoto Suzuki
- Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Japan.,Division of Morphogenesis, National Institute for Basic Biology (Div. Morphogenesis, NIBB), Okazaki, Japan.,Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University (ARC, Hiroshima Univ.), Higashihiroshima, Japan
| | - Naoko Yasue
- Division of Morphogenesis, National Institute for Basic Biology (Div. Morphogenesis, NIBB), Okazaki, Japan
| | - Hiroshi Sasaki
- Laboratory for Embryogenesis, Graduate School of Frontier Biosciences, Osaka University (FBS, Osaka Univ.), Suita, Japan
| | - Naoto Ueno
- Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Japan.,Division of Morphogenesis, National Institute for Basic Biology (Div. Morphogenesis, NIBB), Okazaki, Japan
| | - Toshihiko Fujimori
- Division of Embryology, National Institute for Basic Biology (Div. Embryology, NIBB), Okazaki, Japan.,Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Japan
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3
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Almazán A, Ferrández-Roldán A, Albalat R, Cañestro C. Developmental atlas of appendicularian Oikopleura dioica actins provides new insights into the evolution of the notochord and the cardio-paraxial muscle in chordates. Dev Biol 2019; 448:260-270. [DOI: 10.1016/j.ydbio.2018.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/13/2018] [Accepted: 09/05/2018] [Indexed: 12/22/2022]
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4
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Yoshimura K, Morino Y, Wada H. Regeneration of the acorn worm pygochord with the implication for its convergent evolution with the notochord. Dev Growth Differ 2018; 61:158-165. [PMID: 30561008 DOI: 10.1111/dgd.12581] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 11/06/2018] [Accepted: 11/08/2018] [Indexed: 01/14/2023]
Abstract
The origin of the notochord is a central issue in chordate evolution. This study examined the development of the acorn worm pygochord, a putative homologue of the notochord. Because the pygochord differentiates only after metamorphosis, the developmental was followed process by inducing regeneration after artificial amputation in Ptychodera flava. It was found that although the regeneration of the posterior part of the body did not proceed via formation of an obvious regeneration bud, pygochord regeneration was observed within a few weeks, possibly via trans-differentiation of endoderm cells. The expression of the fibrillary collagen gene (Fcol) and elav in the pygochord during regeneration was detected. This indicates that pygochord cells are not part of gut epithelial cells, but that they differentiated as a distinct cell type. Our gene expression analyses do not provide supporting evidence for the homology between the pygochord and notochord, but rather favored the convergent evolution between them.
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Affiliation(s)
- Koji Yoshimura
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Yoshiaki Morino
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Hiroshi Wada
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
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5
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Lu Q, Bhattachan P, Dong B. Ascidian notochord elongation. Dev Biol 2018; 448:147-153. [PMID: 30458170 DOI: 10.1016/j.ydbio.2018.11.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 11/15/2018] [Accepted: 11/15/2018] [Indexed: 11/27/2022]
Abstract
The elongation of embryo and tissue is a key morphogenetic event in embryogenesis and organogenesis. Notochord, a typical chordate organ, undergoes elongation to perform its regulatory roles and to form the structural support in the embryo. Notochord elongation is morphologically similar across all chordates, but ascidian has evolved distinct molecular and cellular processes. Here, we summarize the current understanding of ascidian notochord elongation. We divide the process into three phases and discuss the underlying molecular mechanisms in each phase. In the first phase, the notochord converges and extends through invagination and mediolateral intercalation, and partially elongates to form a single diameter cell column along the anterior-posterior axis. In the second phase, a cytokinesis-like actomyosin ring is constructed at the equator of each cell and drives notochord to elongate approximately two-fold. The molecular composition and architecture of the ascidian notochord contractile ring are similar to that of the cytokinetic ring. However, the notochord contractile ring does not impose cell division but only drives cell elongation followed by disassembly. We discuss the self-organizing property of the circumferential actomyosin ring, and why it disassembles when certain notochord length is achieved. The similar ring structures are also present in the elongation process of other organs in evolutionarily divergent animals such as Drosophila and C. elegans. We hereby propose that actomyosin ring-based circumferential contraction is a common mechanism adopted in diverse systems to drive embryo and tissue elongation. In the third phase, the notochord experiences tubulogenesis and the endothelial-like cells crawl bi-directionally on the notochord sheath to further lengthen the notochord. In this review, we also discuss extracellular matrix proteins, notochord sheath, and surrounding tissues that may contribute to notochord integrity and morphogenesis.
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Affiliation(s)
- Qiongxuan Lu
- Ministry of Education Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Punit Bhattachan
- Ministry of Education Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Bo Dong
- Ministry of Education Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China.
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6
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Wang F, Zhang C, Shi R, Xie ZY, Chen L, Wang K, Wang YT, Xie XH, Wu XT. The embryonic and evolutionary boundaries between notochord and cartilage: a new look at nucleus pulposus-specific markers. Osteoarthritis Cartilage 2018; 26:1274-1282. [PMID: 29935307 DOI: 10.1016/j.joca.2018.05.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/16/2018] [Accepted: 05/23/2018] [Indexed: 02/02/2023]
Abstract
The adult nucleus pulposus (NP) and articular cartilage are similar in terms of their histocytological components and biomechanical functionalities, requiring a deep understanding of NP-specific markers to better evaluate stem-cell-based NP regeneration. Here, we seek to distinguish NP cells from articular chondrocytes (ACs), focusing on differences in their embryonic formation and evolutionary origin. Embryonically, NP cells are conservatively derived from the axial notochord, whereas ACs originate in a diversified manner from paraxial mesoderm and neural crest cells. Evolutionarily, although the origins of vertebrate NP and AC cells can be traced to similar structures within protostomia-like bilaterian ancestors, the distant phylogenetic relationship between the two groups of animals and the differences in the bodily origins of the tissues suggest that the tissues may in fact have undergone parallel evolution within the protostomia and deuterostomia. The numbers of supposedly NP-specific markers are increasing gradually as microarray studies proceed, but no final consensus has been attained on the specificity and physiology of "exclusive" NP markers because of innate variations among species; intrinsic expression of genes that destabilize the circadian clock; and cooperation by, and crosstalk among, different genes in terms of physiology-related phenotypes. We highlight the embryonic and evolutionary boundaries between NP and AC cells, to aid in recognition of the challenges associated with evaluation of the role played by nucleopulpogenic differentiation during stem-cell-based intervertebral disc regeneration.
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Affiliation(s)
- F Wang
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China; Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China.
| | - C Zhang
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China; Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China.
| | - R Shi
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China; Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China.
| | - Z-Y Xie
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China; Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China.
| | - L Chen
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China; Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China.
| | - K Wang
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China; Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China.
| | - Y-T Wang
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China; Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China.
| | - X-H Xie
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China; Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China.
| | - X-T Wu
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China; Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, 210009 Nanjing, China.
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Wang F, Gao ZX, Cai F, Sinkemani A, Xie ZY, Shi R, Wei JN, Wu XT. Formation, function, and exhaustion of notochordal cytoplasmic vacuoles within intervertebral disc: current understanding and speculation. Oncotarget 2017; 8:57800-57812. [PMID: 28915712 PMCID: PMC5593684 DOI: 10.18632/oncotarget.18101] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 05/01/2017] [Indexed: 01/08/2023] Open
Abstract
Notochord nucleus pulposus cells are characteristic of containing abundant and giant cytoplasmic vacuoles. This review explores the embryonic formation, biological function, and postnatal exhaustion of notochord vacuoles, aiming to characterize the signal network transforming the vacuolated nucleus pulposus cells into the vacuole-less chondrocytic cells. Embryonically, the cytoplasmic vacuoles within vertebrate notochord originate from an evolutionarily conserved vacuolation process during neurulation, which may continue to provide mechanical and signal support in constructing a mammalian intervertebral disc. For full vacuolation, a vacuolating specification from dorsal organizer cells, synchronized convergent extension, well-structured notochord sheath, and sufficient post-Golgi trafficking in notochord cells are required. Postnatally, age-related and species-specific exhaustion of vacuolated nucleus pulposus cells could be potentiated by Fas- and Fas ligand-induced apoptosis, intolerance to mechanical stress and nutrient deficiency, vacuole-mediated proliferation check, and gradual de-vacuolation within the avascular and compression-loaded intervertebral disc. These results suggest that the notochord vacuoles are active and versatile organelles for both embryonic notochord and postnatal nucleus pulposus, and may provide novel information on intervertebral disc degeneration to guide cell-based regeneration.
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Affiliation(s)
- Feng Wang
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu Province, China
- Surgery Research Center, School of Medicine, Southeast University, Nanjing, Jiangsu Province, China
| | - Zeng-Xin Gao
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu Province, China
- Surgery Research Center, School of Medicine, Southeast University, Nanjing, Jiangsu Province, China
| | - Feng Cai
- Department of Orthopedic Surgery, The First Affiliated Hospital of Soochow University, Soochow, Jiangsu Province, China
| | - Arjun Sinkemani
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu Province, China
- Surgery Research Center, School of Medicine, Southeast University, Nanjing, Jiangsu Province, China
| | - Zhi-Yang Xie
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu Province, China
- Surgery Research Center, School of Medicine, Southeast University, Nanjing, Jiangsu Province, China
| | - Rui Shi
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu Province, China
- Surgery Research Center, School of Medicine, Southeast University, Nanjing, Jiangsu Province, China
| | - Ji-Nan Wei
- Surgery Research Center, School of Medicine, Southeast University, Nanjing, Jiangsu Province, China
- Department of Orthopedics, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu Province, China
| | - Xiao-Tao Wu
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu Province, China
- Surgery Research Center, School of Medicine, Southeast University, Nanjing, Jiangsu Province, China
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8
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Towards a systems-level understanding of development in the marine annelid Platynereis dumerilii. Curr Opin Genet Dev 2016; 39:175-181. [PMID: 27501412 DOI: 10.1016/j.gde.2016.07.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/30/2016] [Accepted: 07/07/2016] [Indexed: 01/12/2023]
Abstract
Platynereis dumerilii is a segmented marine worm from the phylum Annelida, a member of the Lophotrochozoans. Platynereis is easily maintained in the lab and exhibits a highly stereotypic development through spiral cleavage with a small, transparent, free-swimming larva highly suitable for microscopy studies. A protocol for embryo microinjection in Platynereis has enabled several genetic tools to be developed, paving the way for functional studies. Recent Platynereis studies have provided insights into the function of several signaling pathways in development. Platynereis has also proven a useful model system for comparative evolutionary developmental studies, allowing the formation of new hypotheses on the evolution of neuroendocrine signaling, body patterning, and organ development. Combining existing large datasets of spatial gene expression mapping, cell lineage mapping, and neuronal circuits with functional analyses of developmental genes represents a promising approach for future studies aiming at a systems-level understanding of development in Platynereis.
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Holland ND. Nervous systems and scenarios for the invertebrate-to-vertebrate transition. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150047. [PMID: 26598728 PMCID: PMC4685584 DOI: 10.1098/rstb.2015.0047] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2015] [Indexed: 01/09/2023] Open
Abstract
Older evolutionary scenarios for the origin of vertebrates often gave nervous systems top billing in accordance with the notion that a big-brained Homo sapiens crowned a tree of life shaped mainly by progressive evolution. Now, however, tree thinking positions all extant organisms equidistant from the tree's root, and molecular phylogenies indicate that regressive evolution is more common than previously suspected. Even so, contemporary theories of vertebrate origin still focus on the nervous system because of its functional importance, its richness in characters for comparative biology, and its central position in the two currently prominent scenarios for the invertebrate-to-vertebrate transition, which grew out of the markedly neurocentric annelid and enteropneust theories of the nineteenth century. Both these scenarios compare phyla with diverse overall body plans. This diversity, exacerbated by the scarcity of relevant fossil data, makes it challenging to establish plausible homologies between component parts (e.g. nervous system regions). In addition, our current understanding of the relation between genotype and phenotype is too preliminary to permit us to convert gene network data into structural features in any simple way. These issues are discussed here with special reference to the evolution of nervous systems during proposed transitions from invertebrates to vertebrates.
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Affiliation(s)
- Nicholas D Holland
- Marine Biology Research Division, Scripps Institution of Oceanography, La Jolla, CA 92093-0202, USA
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Liebeskind BJ, Hillis DM, Zakon HH, Hofmann HA. Complex Homology and the Evolution of Nervous Systems. Trends Ecol Evol 2015; 31:127-135. [PMID: 26746806 DOI: 10.1016/j.tree.2015.12.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 12/01/2015] [Accepted: 12/02/2015] [Indexed: 02/07/2023]
Abstract
We examine the complex evolution of animal nervous systems and discuss the ramifications of this complexity for inferring the nature of early animals. Although reconstructing the origins of nervous systems remains a central challenge in biology, and the phenotypic complexity of early animals remains controversial, a compelling picture is emerging. We now know that the nervous system and other key animal innovations contain a large degree of homoplasy, at least on the molecular level. Conflicting hypotheses about early nervous system evolution are due primarily to differences in the interpretation of this homoplasy. We highlight the need for explicit discussion of assumptions and discuss the limitations of current approaches for inferring ancient phenotypic states.
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Affiliation(s)
- Benjamin J Liebeskind
- Center for Systems and Synthetic Biology, University of Texas, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, University of Texas, Austin, TX 78712, USA; Center for Computational Biology and Bioinformatics, University of Texas, Austin, TX 78712.
| | - David M Hillis
- Institute for Cellular and Molecular Biology, University of Texas, Austin, TX 78712, USA; Center for Computational Biology and Bioinformatics, University of Texas, Austin, TX 78712; Department of Integrative Biology, University of Texas, Austin, TX 78712, USA
| | - Harold H Zakon
- Institute for Cellular and Molecular Biology, University of Texas, Austin, TX 78712, USA; Center for Computational Biology and Bioinformatics, University of Texas, Austin, TX 78712; Department of Integrative Biology, University of Texas, Austin, TX 78712, USA; Department of Neuroscience, University of Texas, Austin, TX 78712, USA; Institute for Neuroscience, University of Texas, Austin, TX 78712, USA; Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Hans A Hofmann
- Institute for Cellular and Molecular Biology, University of Texas, Austin, TX 78712, USA; Center for Computational Biology and Bioinformatics, University of Texas, Austin, TX 78712; Department of Integrative Biology, University of Texas, Austin, TX 78712, USA; Department of Neuroscience, University of Texas, Austin, TX 78712, USA; Institute for Neuroscience, University of Texas, Austin, TX 78712, USA
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11
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Abstract
A notochord is characteristic of developing chordates (which comprise amphioxus, tunicates and vertebrates), and, more arguably, is also found in some other animals. Although notochords have been well reviewed from a developmental genetic point of view, there has heretofore been no adequate survey of the dozen or so scenarios accounting for their evolutionary origin. Advances in molecular phylogenetics and developmental genetics have, on the one hand, failed to support many of these ideas (although, it is not impossible that some of these rejects may yet, at least in part, return to favor). On the other hand, current molecular approaches have actually stimulated the revival of two of the old proposals: first that the notochord is a novelty that arose in the chordates, and second that it is derived from a homologous structure, the axochord, that was present in annelid-like ancestors. In the long term, choosing whether the notochord is a chordate novelty or a legacy from an ancient annelid (or perhaps an evolutionary derivative from precursors yet to be proposed) will probably require descriptions of gene regulatory networks involved in the development of notochords and notochord-like structures in a wide spectrum of animals. For now, one-way forward will be studies of all aspects of the biology of enteropneust hemichordates, a group widely thought to be the key to understanding the evolutionary origin of the chordates.
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Affiliation(s)
- Giovanni Annona
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy
| | - Nicholas D Holland
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093 USA
| | - Salvatore D'Aniello
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy
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12
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Scherholz M, Redl E, Wollesen T, Todt C, Wanninger A. From complex to simple: myogenesis in an aplacophoran mollusk reveals key traits in aculiferan evolution. BMC Evol Biol 2015; 15:201. [PMID: 26385077 PMCID: PMC4575435 DOI: 10.1186/s12862-015-0467-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 08/26/2015] [Indexed: 11/23/2022] Open
Abstract
Background Recent studies suggest a bifurcation at the base of Mollusca, resulting in the primarily single-shelled Conchifera (Bivalvia, Gastropoda, Scaphopoda, Monoplacophora, Cephalopoda) and the spicule-bearing Aculifera (Polyplacophora, Neomeniomorpha, Chaetodermomorpha). A recent study revealed a complex larval musculature exclusively shared by Neomeniomorpha and Polyplacophora, supporting a close relationship of both taxa. However, the ontogenetic transition from the complex larval to the simple adult neomeniomorph musculature, which mainly consists of a three-layered body-wall musculature and serially iterated dorsoventral muscles, remains unknown. To close this gap in knowledge, we studied remodeling of the larval musculature during metamorphosis in the neomeniomorph Wirenia argentea. A comparative analysis with a novel data set of a polyplacophoran, Leptochiton asellus, allows us to infer the morphology of the last common ancestor of Aculifera and the evolution of its subclades therefrom. Results The complex larval musculature of Wirenia argentea persists through metamorphosis and becomes modified to form two of the three muscle layers of the adult body wall. The innermost longitudinal layer of the three-layered body wall musculature is generated by transformation and expansion of distinct larval longitudinal muscle bundles. The larval ventrolateral muscle strands are remodeled and eventually become the most ventral part of the adult longitudinal layer of the body wall musculature. The paired larval enrolling muscle forms the lateral parts and the former rectus muscle is destined to become the most dorsal part of the longitudinal layer of the body wall musculature. The transient ventromedian muscle is lost during postmetamorphic development. Conclusions Postmetamorphic remodeling in W. argentea supports the hypothesis of a complex myoanatomy rather than a three-layered body wall musculature at the base of Aculifera, and thus argues against homology of the body wall musculature of adult Neomeniomorpha and other potential molluscan sister groups. Our data show that the neomeniomorph body wall musculature is a derived condition and not an aculiferan or molluscan plesiomorphy.
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Affiliation(s)
- Maik Scherholz
- Department of Integrative Zoology, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090, Vienna, Austria.
| | - Emanuel Redl
- Department of Integrative Zoology, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090, Vienna, Austria.
| | - Tim Wollesen
- Department of Integrative Zoology, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090, Vienna, Austria.
| | - Christiane Todt
- University Museum of Bergen, University of Bergen, Allégaten 41, 5007, Bergen, Norway.
| | - Andreas Wanninger
- Department of Integrative Zoology, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090, Vienna, Austria.
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Corallo D, Trapani V, Bonaldo P. The notochord: structure and functions. Cell Mol Life Sci 2015; 72:2989-3008. [PMID: 25833128 PMCID: PMC11114051 DOI: 10.1007/s00018-015-1897-z] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 03/23/2015] [Accepted: 03/26/2015] [Indexed: 01/08/2023]
Abstract
The notochord is an embryonic midline structure common to all members of the phylum Chordata, providing both mechanical and signaling cues to the developing embryo. In vertebrates, the notochord arises from the dorsal organizer and it is critical for proper vertebrate development. This evolutionary conserved structure located at the developing midline defines the primitive axis of embryos and represents the structural element essential for locomotion. Besides its primary structural function, the notochord is also a source of developmental signals that patterns surrounding tissues. Among the signals secreted by the notochord, Hedgehog proteins play key roles during embryogenesis. The Hedgehog signaling pathway is a central regulator of embryonic development, controlling the patterning and proliferation of a wide variety of organs. In this review, we summarize the current knowledge on notochord structure and functions, with a particular emphasis on the key developmental events that take place in vertebrates. Moreover, we discuss some genetic studies highlighting the phenotypic consequences of impaired notochord development, which enabled to understand the molecular basis of different human congenital defects and diseases.
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Affiliation(s)
- Diana Corallo
- Department of Molecular Medicine, University of Padova, Viale G. Colombo 3, 35131 Padua, Italy
| | - Valeria Trapani
- Department of Molecular Medicine, University of Padova, Viale G. Colombo 3, 35131 Padua, Italy
| | - Paolo Bonaldo
- Department of Molecular Medicine, University of Padova, Viale G. Colombo 3, 35131 Padua, Italy
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Brunet T, Lauri A, Arendt D. Did the notochord evolve from an ancient axial muscle? The axochord hypothesis. Bioessays 2015; 37:836-50. [PMID: 26172338 PMCID: PMC5054868 DOI: 10.1002/bies.201500027] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 06/03/2015] [Accepted: 06/05/2015] [Indexed: 12/20/2022]
Abstract
The origin of the notochord is one of the key remaining mysteries of our evolutionary ancestry. Here, we present a multi‐level comparison of the chordate notochord to the axochord, a paired axial muscle spanning the ventral midline of annelid worms and other invertebrates. At the cellular level, comparative molecular profiling in the marine annelids P. dumerilii and C. teleta reveals expression of similar, specific gene sets in presumptive axochordal and notochordal cells. These cells also occupy corresponding positions in a conserved anatomical topology and undergo similar morphogenetic movements. At the organ level, a detailed comparison of bilaterian musculatures reveals that most phyla form axochord‐like muscles, suggesting that such a muscle was already present in urbilaterian ancestors. Integrating comparative evidence at the cell and organ level, we propose that the notochord evolved by modification of a ventromedian muscle followed by the assembly of an axial complex supporting swimming in vertebrate ancestors.
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Affiliation(s)
- Thibaut Brunet
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Antonella Lauri
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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