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Krueger Q, Phippen B, Reitzel A. Antibiotics alter development and gene expression in the model cnidarian Nematostella vectensis. PeerJ 2024; 12:e17349. [PMID: 38784394 PMCID: PMC11114123 DOI: 10.7717/peerj.17349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 04/17/2024] [Indexed: 05/25/2024] Open
Abstract
Background Antibiotics are commonly used for controlling microbial growth in diseased organisms. However, antibiotic treatments during early developmental stages can have negative impacts on development and physiology that could offset the positive effects of reducing or eliminating pathogens. Similarly, antibiotics can shift the microbial community due to differential effectiveness on resistant and susceptible bacteria. Though antibiotic application does not typically result in mortality of marine invertebrates, little is known about the developmental and transcriptional effects. These sublethal effects could reduce the fitness of the host organism and lead to negative changes after removal of the antibiotics. Here, we quantify the impact of antibiotic treatment on development, gene expression, and the culturable bacterial community of a model cnidarian, Nematostella vectensis. Methods Ampicillin, streptomycin, rifampicin, and neomycin were compared individually at two concentrations, 50 and 200 µg mL-1, and in combination at 50 µg mL-1 each, to assess their impact on N. vectensis. First, we determined the impact antibiotics have on larval development. Next Amplicon 16S rDNA gene sequencing was used to compare the culturable bacteria that persist after antibiotic treatment to determine how these treatments may differentially select against the native microbiome. Lastly, we determined how acute (3-day) and chronic (8-day) antibiotic treatments impact gene expression of adult anemones. Results Under most exposures, the time of larval settlement extended as the concentration of antibiotics increased and had the longest delay of 3 days in the combination treatment. Culturable bacteria persisted through a majority of exposures where we identified 359 amplicon sequence variants (ASVs). The largest proportion of bacteria belonged to Gammaproteobacteria, and the most common ASVs were identified as Microbacterium and Vibrio. The acute antibiotic exposure resulted in differential expression of genes related to epigenetic mechanisms and neural processes, while constant application resulted in upregulation of chaperones and downregulation of mitochondrial genes when compared to controls. Gene Ontology analyses identified overall depletion of terms related to development and metabolism in both antibiotic treatments. Discussion Antibiotics resulted in a significant increase to settlement time of N. vectensis larvae. Culturable bacterial species after antibiotic treatments were taxonomically diverse. Additionally, the transcriptional effects of antibiotics, and after their removal result in significant differences in gene expression that may impact the physiology of the anemone, which may include removal of bacterial signaling on anemone gene expression. Our research suggests that impacts of antibiotics beyond the reduction of bacteria may be important to consider when they are applied to aquatic invertebrates including reef building corals.
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Affiliation(s)
- Quinton Krueger
- Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, United States of America
- Computational Intelligence to Predict Health and Environmental Risks (CIPHER) Center, University of North Carolina at Charlotte, Charlotte, NC, United States of America
| | - Britney Phippen
- Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, United States of America
| | - Adam Reitzel
- Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, United States of America
- Computational Intelligence to Predict Health and Environmental Risks (CIPHER) Center, University of North Carolina at Charlotte, Charlotte, NC, United States of America
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2
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Gilbert E, Craggs J, Modepalli V. Gene Regulatory Network that Shaped the Evolution of Larval Apical Organ in Cnidaria. Mol Biol Evol 2024; 41:msad285. [PMID: 38152864 PMCID: PMC10781443 DOI: 10.1093/molbev/msad285] [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: 09/25/2023] [Revised: 11/24/2023] [Accepted: 12/21/2023] [Indexed: 12/29/2023] Open
Abstract
Among non-bilaterian animals, a larval apical sensory organ with integrated neurons is only found in cnidarians. Within cnidarians, an apical organ with a ciliary tuft is mainly found in Actiniaria. Whether this apical tuft has evolved independently in Actiniaria or alternatively originated in the common ancestor of Cnidaria and Bilateria and was lost in specific groups is uncertain. To test this hypothesis, we generated transcriptomes of the apical domain during the planula stage of four species representing three key groups of cnidarians: Aurelia aurita (Scyphozoa), Nematostella vectensis (Actiniaria), and Acropora millepora and Acropora tenuis (Scleractinia). We showed that the canonical genes implicated in patterning the apical domain of N. vectensis are largely absent in A. aurita. In contrast, the apical domain of the scleractinian planula shares gene expression pattern with N. vectensis. By comparing the larval single-cell transcriptomes, we revealed the apical organ cell type of Scleractinia and confirmed its homology to Actiniaria. However, Fgfa2, a vital regulator of the regionalization of the N. vectensis apical organ, is absent in the scleractinian genome. Likewise, we found that FoxJ1 and 245 genes associated with cilia are exclusively expressed in the N. vectensis apical domain, which is in line with the presence of ciliary apical tuft in Actiniaria and its absence in Scleractinia and Scyphozoa. Our findings suggest that the common ancestor of cnidarians lacked a ciliary apical tuft, and it could have evolved independently in the Actiniaria.
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Affiliation(s)
- Eleanor Gilbert
- Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
- School of Biological and Marine Sciences, University of Plymouth, Plymouth PL4 8AA, UK
| | - Jamie Craggs
- Horniman Museum and Gardens, London SE23 3PQ, UK
| | - Vengamanaidu Modepalli
- Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
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3
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Zimmermann B, Montenegro JD, Robb SMC, Fropf WJ, Weilguny L, He S, Chen S, Lovegrove-Walsh J, Hill EM, Chen CY, Ragkousi K, Praher D, Fredman D, Schultz D, Moran Y, Simakov O, Genikhovich G, Gibson MC, Technau U. Topological structures and syntenic conservation in sea anemone genomes. Nat Commun 2023; 14:8270. [PMID: 38092765 PMCID: PMC10719294 DOI: 10.1038/s41467-023-44080-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 11/29/2023] [Indexed: 12/17/2023] Open
Abstract
There is currently little information about the evolution of gene clusters, genome architectures and karyotypes in early branching animals. Slowly evolving anthozoan cnidarians can be particularly informative about the evolution of these genome features. Here we report chromosome-level genome assemblies of two related anthozoans, the sea anemones Nematostella vectensis and Scolanthus callimorphus. We find a robust set of 15 chromosomes with a clear one-to-one correspondence between the two species. Both genomes show chromosomal conservation, allowing us to reconstruct ancestral cnidarian and metazoan chromosomal blocks, consisting of at least 19 and 16 ancestral linkage groups, respectively. We show that, in contrast to Bilateria, the Hox and NK clusters of investigated cnidarians are largely disintegrated, despite the presence of staggered hox/gbx expression in Nematostella. This loss of microsynteny conservation may be facilitated by shorter distances between cis-regulatory sequences and their cognate transcriptional start sites. We find no clear evidence for topologically associated domains, suggesting fundamental differences in long-range gene regulation compared to vertebrates. These data suggest that large sets of ancestral metazoan genes have been retained in ancestral linkage groups of some extant lineages; yet, higher order gene regulation with associated 3D architecture may have evolved only after the cnidarian-bilaterian split.
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Affiliation(s)
- Bob Zimmermann
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
- Research platform SinCeReSt, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Juan D Montenegro
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
- Research platform SinCeReSt, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Sofia M C Robb
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA
| | - Whitney J Fropf
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA
| | - Lukas Weilguny
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Shuonan He
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA
| | - Shiyuan Chen
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA
| | - Jessica Lovegrove-Walsh
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Eric M Hill
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA
| | - Cheng-Yi Chen
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA
| | - Katerina Ragkousi
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA
- Department of Biology, Amherst College, Amherst, MA, 01002, USA
| | - Daniela Praher
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - David Fredman
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Darrin Schultz
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Yehu Moran
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
- The Alexander Silberman Institute of Life Sciences, Faculty of Science, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Oleg Simakov
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
- Research platform SinCeReSt, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Grigory Genikhovich
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Matthew C Gibson
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA.
| | - Ulrich Technau
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria.
- Research platform SinCeReSt, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria.
- Max Perutz laboratories, University of Vienna, Dr. Bohrgasse 5, 1030, Vienna, Austria.
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Miyokawa R, Kanaya HJ, Itoh TQ, Kobayakawa Y, Kusumi J. Immature symbiotic system between horizontally transmitted green algae and brown hydra. Sci Rep 2021; 11:2921. [PMID: 33536483 PMCID: PMC7859245 DOI: 10.1038/s41598-021-82489-6] [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: 08/24/2020] [Accepted: 01/18/2021] [Indexed: 01/30/2023] Open
Abstract
Some strains of brown hydra (Hydra vulgaris) are able to harbor the green algae Chlorococcum in their endodermal epithelial cells as symbionts. However, the relationship between brown hydra and chlorococcum is considered to be incipient symbiosis because most artificially introduced symbionts are not stable and because symbiotic H. vulgaris strains are rare in the wild. In this study, we compared the gene expression levels of the newly established symbiotic hydra (strain 105G), the native symbiotic strain (J7), and their non-symbiotic polyps to determine what changes would occur at the early stage of the evolution of symbiosis. We found that both the 105G and J7 strains showed comparable expression patterns, exhibiting upregulation of lysosomal enzymes and downregulation of genes related to nematocyte development and function. Meanwhile, genes involved in translation and the respiratory chain were upregulated only in strain 105G. Furthermore, treatment with rapamycin, which inhibits translation activity, induced the degeneration of the symbiotic strains (105G and J7). This effect was severe in strain 105G. Our results suggested that evolving the ability to balance the cellular metabolism between the host and the symbiont is a key requirement for adapting to endosymbiosis with chlorococcum.
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Affiliation(s)
- Ryo Miyokawa
- grid.177174.30000 0001 2242 4849Graduate School of Integrated Science for Global Society, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395 Japan
| | - Hiroyuki J. Kanaya
- grid.177174.30000 0001 2242 4849School of Science, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395 Japan
| | - Taichi Q. Itoh
- grid.177174.30000 0001 2242 4849Faculty of Arts and Science, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395 Japan
| | - Yoshitaka Kobayakawa
- grid.177174.30000 0001 2242 4849Faculty of Arts and Science, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395 Japan
| | - Junko Kusumi
- grid.177174.30000 0001 2242 4849Department of Environmental Changes, Faculty of Social and Cultural Studies, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395 Japan
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5
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Ectopic activation of GABA B receptors inhibits neurogenesis and metamorphosis in the cnidarian Nematostella vectensis. Nat Ecol Evol 2020; 5:111-121. [PMID: 33168995 DOI: 10.1038/s41559-020-01338-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 09/29/2020] [Indexed: 01/22/2023]
Abstract
The metabotropic gamma-aminobutyric acid B receptor (GABABR) is a G protein-coupled receptor that mediates neuronal inhibition by the neurotransmitter GABA. While GABABR-mediated signalling has been suggested to play central roles in neuronal differentiation and proliferation across evolution, it has mostly been studied in the mammalian brain. Here, we demonstrate that ectopic activation of GABABR signalling affects neurogenic functions in the sea anemone Nematostella vectensis. We identified four putative Nematostella GABABR homologues presenting conserved three-dimensional extracellular domains and residues needed for binding GABA and the GABABR agonist baclofen. Moreover, sustained activation of GABABR signalling reversibly arrests the critical metamorphosis transition from planktonic larva to sessile polyp life stage. To understand the processes that underlie the developmental arrest, we combined transcriptomic and spatial analyses of control and baclofen-treated larvae. Our findings reveal that the cnidarian neurogenic programme is arrested following the addition of baclofen to developing larvae. Specifically, neuron development and neurite extension were inhibited, resulting in an underdeveloped and less organized nervous system and downregulation of proneural factors including NvSoxB(2), NvNeuroD1 and NvElav1. Our results thus point to an evolutionarily conserved function of GABABR in neurogenesis regulation and shed light on early cnidarian development.
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6
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Omori A, Shibata TF, Akasaka K. Gene expression analysis of three homeobox genes throughout early and late development of a feather star Anneissia japonica. Dev Genes Evol 2020; 230:305-314. [PMID: 32671457 DOI: 10.1007/s00427-020-00665-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 07/08/2020] [Indexed: 11/26/2022]
Abstract
Crinoids are considered as the most basal extant echinoderms. They retain aboral nervous system with a nerve center, which has been degraded in the eleutherozoan echinoderms. To investigate the evolution of patterning of the nervous systems in crinoids, we examined temporal and spatial expression patterns of three neural patterning-related homeobox genes, six3, pax6, and otx, throughout the development of a feather star Anneissia japonica. These genes were involved in the patterning of endomesodermal tissues instead of the ectodermal neural tissues in the early planktonic stages. In the stages after larval attachment, the expression of these genes was mainly observed in the podia and the oral nervous systems instead of the aboral nerve center. Our results indicate the involvement of these three genes in the formation of oral nervous system in the common ancestor of the echinoderms and suggest that the aboral nerve center is not evolutionally related to the brain of other bilaterians.
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Affiliation(s)
- Akihito Omori
- Marine Biological Station, Sado Island Center for Ecological Sustainability, Niigata University, 87 Tassha, Sado, Niigata, 952-2135, Japan.
- Misaki Marine Biological Station, School of Science, The University of Tokyo, 1024 Koajiro, Misaki, Miura, Kanagawa, 238-0225, Japan.
| | - Tomoko F Shibata
- Misaki Marine Biological Station, School of Science, The University of Tokyo, 1024 Koajiro, Misaki, Miura, Kanagawa, 238-0225, Japan
| | - Koji Akasaka
- Misaki Marine Biological Station, School of Science, The University of Tokyo, 1024 Koajiro, Misaki, Miura, Kanagawa, 238-0225, Japan
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7
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Reddy PC, Gungi A, Ubhe S, Pradhan SJ, Kolte A, Galande S. Molecular signature of an ancient organizer regulated by Wnt/β-catenin signalling during primary body axis patterning in Hydra. Commun Biol 2019; 2:434. [PMID: 31799436 PMCID: PMC6879750 DOI: 10.1038/s42003-019-0680-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 11/06/2019] [Indexed: 11/20/2022] Open
Abstract
Wnt/β-catenin signalling has been shown to play a critical role during head organizer formation in Hydra. Here, we characterized the Wnt signalling regulatory network involved in formation of the head organizer. We found that Wnt signalling regulates genes that are important in tissue morphogenesis. We identified that majority of transcription factors (TFs) regulated by Wnt/β-catenin signalling belong to the homeodomain and forkhead families. Silencing of Margin, one of the Wnt regulated homeodomain TFs, results in loss of the ectopic tentacle phenotype typically seen upon activation of Wnt signalling. Furthermore, we show that the Margin promoter is directly bound and regulated by β-catenin. Ectopic expression of Margin in zebrafish embryos results in body axis abnormalities suggesting that Margin plays a role in axis patterning. Our findings suggest that homeobox TFs came under the regulatory umbrella of Wnt/β-catenin signalling presumably resulting in the evolution of primary body axis in animal phyla.
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Affiliation(s)
- Puli Chandramouli Reddy
- Centre of Excellence in Epigenetics, Department of Biology, Indian Institute of Science Education and Research, Pune, 411008 India
| | - Akhila Gungi
- Centre of Excellence in Epigenetics, Department of Biology, Indian Institute of Science Education and Research, Pune, 411008 India
| | - Suyog Ubhe
- Centre of Excellence in Epigenetics, Department of Biology, Indian Institute of Science Education and Research, Pune, 411008 India
| | - Saurabh J. Pradhan
- Centre of Excellence in Epigenetics, Department of Biology, Indian Institute of Science Education and Research, Pune, 411008 India
| | - Amol Kolte
- Centre of Excellence in Epigenetics, Department of Biology, Indian Institute of Science Education and Research, Pune, 411008 India
| | - Sanjeev Galande
- Centre of Excellence in Epigenetics, Department of Biology, Indian Institute of Science Education and Research, Pune, 411008 India
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Kim HM, Weber JA, Lee N, Park SG, Cho YS, Bhak Y, Lee N, Jeon Y, Jeon S, Luria V, Karger A, Kirschner MW, Jo YJ, Woo S, Shin K, Chung O, Ryu JC, Yim HS, Lee JH, Edwards JS, Manica A, Bhak J, Yum S. The genome of the giant Nomura's jellyfish sheds light on the early evolution of active predation. BMC Biol 2019; 17:28. [PMID: 30925871 PMCID: PMC6441219 DOI: 10.1186/s12915-019-0643-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 02/28/2019] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Unique among cnidarians, jellyfish have remarkable morphological and biochemical innovations that allow them to actively hunt in the water column and were some of the first animals to become free-swimming. The class Scyphozoa, or true jellyfish, are characterized by a predominant medusa life-stage consisting of a bell and venomous tentacles used for hunting and defense, as well as using pulsed jet propulsion for mobility. Here, we present the genome of the giant Nomura's jellyfish (Nemopilema nomurai) to understand the genetic basis of these key innovations. RESULTS We sequenced the genome and transcriptomes of the bell and tentacles of the giant Nomura's jellyfish as well as transcriptomes across tissues and developmental stages of the Sanderia malayensis jellyfish. Analyses of the Nemopilema and other cnidarian genomes revealed adaptations associated with swimming, marked by codon bias in muscle contraction and expansion of neurotransmitter genes, along with expanded Myosin type II family and venom domains, possibly contributing to jellyfish mobility and active predation. We also identified gene family expansions of Wnt and posterior Hox genes and discovered the important role of retinoic acid signaling in this ancient lineage of metazoans, which together may be related to the unique jellyfish body plan (medusa formation). CONCLUSIONS Taken together, the Nemopilema jellyfish genome and transcriptomes genetically confirm their unique morphological and physiological traits, which may have contributed to the success of jellyfish as early multi-cellular predators.
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Affiliation(s)
- Hak-Min Kim
- Korean Genomics Industrialization Center (KOGIC), Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
- Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Jessica A Weber
- Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Nayoung Lee
- Ecological Risk Research Division, Korea Institute of Ocean Science and Technology (KIOST), Geoje, 53201, Republic of Korea
| | - Seung Gu Park
- Korean Genomics Industrialization Center (KOGIC), Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Yun Sung Cho
- Korean Genomics Industrialization Center (KOGIC), Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
- Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
- Clinomics Inc., Ulsan, 44919, Republic of Korea
| | - Youngjune Bhak
- Korean Genomics Industrialization Center (KOGIC), Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
- Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Nayun Lee
- Ecological Risk Research Division, Korea Institute of Ocean Science and Technology (KIOST), Geoje, 53201, Republic of Korea
| | - Yeonsu Jeon
- Korean Genomics Industrialization Center (KOGIC), Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
- Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Sungwon Jeon
- Korean Genomics Industrialization Center (KOGIC), Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
- Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Victor Luria
- Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Amir Karger
- IT - Research Computing, Harvard Medical School, Boston, MA, 02115, USA
| | - Marc W Kirschner
- Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Ye Jin Jo
- Ecological Risk Research Division, Korea Institute of Ocean Science and Technology (KIOST), Geoje, 53201, Republic of Korea
| | - Seonock Woo
- Faculty of Marine Environmental Science, University of Science and Technology (UST), Geoje, 53201, Republic of Korea
- Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology (KIOST), Busan, 49111, Republic of Korea
| | - Kyoungsoon Shin
- Ballast Water Center, Korea Institute of Ocean Science and Technology (KIOST), Geoje, 53201, Republic of Korea
| | - Oksung Chung
- Clinomics Inc., Ulsan, 44919, Republic of Korea
- Personal Genomics Institute, Genome Research Foundation, Cheongju, 28160, Republic of Korea
| | - Jae-Chun Ryu
- Cellular and Molecular Toxicology Laboratory, Center for Environment, Health and Welfare Research, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Hyung-Soon Yim
- Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology (KIOST), Busan, 49111, Republic of Korea
| | - Jung-Hyun Lee
- Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology (KIOST), Busan, 49111, Republic of Korea
| | - Jeremy S Edwards
- Chemistry and Chemical Biology, UNM Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Andrea Manica
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK
| | - Jong Bhak
- Korean Genomics Industrialization Center (KOGIC), Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
- Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
- Clinomics Inc., Ulsan, 44919, Republic of Korea.
- Personal Genomics Institute, Genome Research Foundation, Cheongju, 28160, Republic of Korea.
| | - Seungshic Yum
- Ecological Risk Research Division, Korea Institute of Ocean Science and Technology (KIOST), Geoje, 53201, Republic of Korea.
- Faculty of Marine Environmental Science, University of Science and Technology (UST), Geoje, 53201, Republic of Korea.
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Yasuoka Y, Tando Y, Kubokawa K, Taira M. Evolution of cis-regulatory modules for the head organizer gene goosecoid in chordates: comparisons between Branchiostoma and Xenopus. ZOOLOGICAL LETTERS 2019; 5:27. [PMID: 31388442 PMCID: PMC6679436 DOI: 10.1186/s40851-019-0143-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Accepted: 07/12/2019] [Indexed: 05/03/2023]
Abstract
BACKGROUND In cephalochordates (amphioxus), the notochord runs along the dorsal to the anterior tip of the body. In contrast, the vertebrate head is formed anterior to the notochord, as a result of head organizer formation in anterior mesoderm during early development. A key gene for the vertebrate head organizer, goosecoid (gsc), is broadly expressed in the dorsal mesoderm of amphioxus gastrula. Amphioxus gsc expression subsequently becomes restricted to the posterior notochord from the early neurula. This has prompted the hypothesis that a change in expression patterns of gsc led to development of the vertebrate head during chordate evolution. However, molecular mechanisms of head organizer evolution involving gsc have never been elucidated. RESULTS To address this question, we compared cis-regulatory modules of vertebrate organizer genes between amphioxus, Branchiostoma japonicum, and frogs, Xenopus laevis and Xenopus tropicalis. Here we show conservation and diversification of gene regulatory mechanisms through cis-regulatory modules for gsc, lim1/lhx1, and chordin in Branchiostoma and Xenopus. Reporter analysis using Xenopus embryos demonstrates that activation of gsc by Nodal/FoxH1 signal through the 5' upstream region, that of lim1 by Nodal/FoxH1 signal through the first intron, and that of chordin by Lim1 through the second intron, are conserved between amphioxus and Xenopus. However, activation of gsc by Lim1 and Otx through the 5' upstream region in Xenopus are not conserved in amphioxus. Furthermore, the 5' region of amphioxus gsc recapitulated the amphioxus-like posterior mesoderm expression of the reporter gene in transgenic Xenopus embryos. CONCLUSIONS On the basis of this study, we propose a model, in which the gsc gene acquired the cis-regulatory module bound with Lim1 and Otx at its 5' upstream region to be activated persistently in anterior mesoderm, in the vertebrate lineage. Because Gsc globally represses trunk (notochord) genes in the vertebrate head organizer, this cooption of gsc in vertebrates appears to have resulted in inhibition of trunk genes and acquisition of the head organizer and its derivative prechordal plate.
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Affiliation(s)
- Yuuri Yasuoka
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa, 904-0495 Japan
- Laboratory for Comprehensive Genomic Analysis, RIKEN Center for Integrative Medical Sciences, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045 Japan
| | - Yukiko Tando
- Center for Advance Marine Research, Ocean Research Institute, The University of Tokyo, 1-15-1, Minamidai, Nakano-ku, Tokyo, 164-8639 Japan
- Present address: Cell Resource Center for Biomedical Research, Institute of Development, Aging and Cancer (IDAC), Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575 Japan
| | - Kaoru Kubokawa
- Center for Advance Marine Research, Ocean Research Institute, The University of Tokyo, 1-15-1, Minamidai, Nakano-ku, Tokyo, 164-8639 Japan
- Present address: SIRC, Teikyo University, 2-11-1, Itabashi-ku, Tokyo, 173-8605 Japan
| | - Masanori Taira
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
- Present address: Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551 Japan
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10
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Žídek R, Machoň O, Kozmik Z. Wnt/β-catenin signalling is necessary for gut differentiation in a marine annelid, Platynereis dumerilii. EvoDevo 2018; 9:14. [PMID: 29942461 PMCID: PMC5996498 DOI: 10.1186/s13227-018-0100-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 04/20/2018] [Indexed: 11/10/2022] Open
Abstract
Background Wnt/β-catenin (or canonical) signalling pathway activity is necessary and used independently several times for specification of vegetal fate and endoderm, gut differentiation, maintenance of epithelium in adult intestine and the development of gut-derived organs in various vertebrate and non-vertebrate organisms. However, its conservation in later stages of digestive tract development still remains questionable due to the lack of detailed data, mainly from Spiralia. Results Here we characterize the Pdu-Tcf gene, a Tcf/LEF orthologue and a component of Wnt/β-catenin pathway from Platynereis dumerilii, a spiralian, marine annelid worm. Pdu-Tcf undergoes extensive alternative splicing in the C-terminal region of the gene generating as many as eight mRNA isoforms some of which differ in the presence or absence of a C-clamp domain which suggests a distinct DNA binding activity of individual protein variants. Pdu-Tcf is broadly expressed throughout development which is indicative of many functions. One of the most prominent domains that exhibits rather strong Pdu-Tcf expression is in the putative precursors of endodermal gut cells which are detected after 72 h post-fertilization (hpf). At day 5 post-fertilization (dpf), Pdu-Tcf is expressed in the hindgut and pharynx (foregut), whereas at 7 dpf stage, it is strongly transcribed in the now-cellularized midgut for the first time. In order to gain insight into the role of Wnt/β-catenin signalling, we disrupted its activity using pharmacological inhibitors between day 5 and 7 of development. The inhibition of Wnt/β-catenin signalling led to the loss of midgut marker genes Subtilisin-1, Subtilisin-2, α-Amylase and Otx along with a drop in β-catenin protein levels, Axin expression in the gut and nearly the complete loss of proliferative activity throughout the body of larva. At the same time, a hindgut marker gene Legumain was expanded to the midgut compartment under the same conditions. Conclusions Our findings suggest that high Wnt/β-catenin signalling in the midgut might be necessary for proper differentiation of the endoderm to an epithelium capable of secreting digestive enzymes. Together, our data provide evidence for the role of Wnt/β-catenin signalling in gut differentiation in Platynereis.
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Affiliation(s)
- Radim Žídek
- 1Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - Ondřej Machoň
- 1Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague 4, Czech Republic.,2Present Address: Institute of Experimental Medicine, Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - Zbyněk Kozmik
- 1Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague 4, Czech Republic
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11
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Redl E, Scherholz M, Wollesen T, Todt C, Wanninger A. Expression of six3 and otx in Solenogastres (Mollusca) supports an ancestral role in bilaterian anterior-posterior axis patterning. Evol Dev 2018; 20:17-28. [PMID: 29243871 PMCID: PMC5814893 DOI: 10.1111/ede.12245] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The homeodomain transcription factors six3 and otx are involved in patterning the anterior body and parts of the central nervous system (CNS) in bilaterians. Their similar expression patterns have been used as an argument for homology of heads, brains, segmentation, and ciliated larvae. We investigated the developmental expression of six3 and otx in the aplacophoran mollusk Wirenia argentea. Six3 is expressed in subepithelial cells delimiting the apical organ of the solenogaster pericalymma larva. Otx is expressed in cells of the prototroch and adjacent regions as well as in posterior extensions of the prototrochal expression domain. Advanced larvae also show pretrochal otx expression in the developing CNS. Comparative analysis of six3 and otx expression in bilaterians argues for an ancestral function in anterior-posterior body axis patterning but, due to its presence in animals lacking a head and/or a brain, not necessarily for the presence of these morphological structures in the last common ancestor (LCA) of bilaterians. Likewise, the hypothesis that the posterior border of otx expression corresponds to the border between the unsegmented head and the segmented trunk of the LCA of protostomes is not supported, since otx is extensively expressed in the trunk in W. argentea and numerous other protostomes.
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Affiliation(s)
- Emanuel Redl
- Faculty of Life Sciences, Department of Integrative ZoologyUniversity of ViennaViennaAustria
| | - Maik Scherholz
- Faculty of Life Sciences, Department of Integrative ZoologyUniversity of ViennaViennaAustria
| | - Tim Wollesen
- Faculty of Life Sciences, Department of Integrative ZoologyUniversity of ViennaViennaAustria
| | - Christiane Todt
- The Natural History CollectionsUniversity of BergenUniversity MuseumBergenNorway
| | - Andreas Wanninger
- Faculty of Life Sciences, Department of Integrative ZoologyUniversity of ViennaViennaAustria
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12
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A bipolar role of the transcription factor ERG for cnidarian germ layer formation and apical domain patterning. Dev Biol 2017; 430:346-361. [PMID: 28818668 DOI: 10.1016/j.ydbio.2017.08.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 07/29/2017] [Accepted: 08/09/2017] [Indexed: 02/06/2023]
Abstract
Germ layer formation and axial patterning are biological processes that are tightly linked during embryonic development of most metazoans. In addition to canonical WNT, it has been proposed that ERK-MAPK signaling is involved in specifying oral as well as aboral territories in cnidarians. However, the effector and the molecular mechanism underlying latter phenomenon is unknown. By screening for potential effectors of ERK-MAPK signaling in both domains, we identified a member of the ETS family of transcription factors, Nverg that is bi-polarily expressed prior to gastrulation. We further describe the crucial role of NvERG for gastrulation, endomesoderm as well as apical domain formation. The molecular characterization of the obtained NvERG knock-down phenotype using previously described as well as novel potential downstream targets, provides evidence that a single transcription factor, NvERG, simultaneously controls expression of two different sets of downstream targets, leading to two different embryonic gene regulatory networks (GRNs) in opposite poles of the developing embryo. We also highlight the molecular interaction of cWNT and MEK/ERK/ERG signaling that provides novel insight into the embryonic axial organization of Nematostella, and show a cWNT repressive role of MEK/ERK/ERG signaling in segregating the endomesoderm in two sub-domains, while a common input of both pathways is required for proper apical domain formation. Taking together, we build the first blueprint for a global cnidarian embryonic GRN that is the foundation for additional gene specific studies addressing the evolution of embryonic and larval development.
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13
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Layden MJ, Johnston H, Amiel AR, Havrilak J, Steinworth B, Chock T, Röttinger E, Martindale MQ. MAPK signaling is necessary for neurogenesis in Nematostella vectensis. BMC Biol 2016; 14:61. [PMID: 27480076 PMCID: PMC4968017 DOI: 10.1186/s12915-016-0282-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 07/04/2016] [Indexed: 11/16/2022] Open
Abstract
Background The nerve net of Nematostella is generated using a conserved cascade of neurogenic transcription factors. For example, NvashA, a homolog of the achaete-scute family of basic helix-loop-helix transcription factors, is necessary and sufficient to specify a subset of embryonic neurons. However, positive regulators required for the expression of neurogenic transcription factors remain poorly understood. Results We show that treatment with the MEK/MAPK inhibitor U0126 severely reduces the expression of known neurogenic genes, Nvath-like, NvsoxB(2), and NvashA, and known markers of differentiated neurons, suggesting that MAPK signaling is necessary for neural development. Interestingly, ectopic NvashA fails to rescue the expression of neural markers in U0126-treated animals. Double fluorescence in situ hybridization and transgenic analysis confirmed that NvashA targets represent both unique and overlapping populations of neurons. Finally, we used a genome-wide microarray to identify additional patterning genes downstream of MAPK that might contribute to neurogenesis. We identified 18 likely neural transcription factors, and surprisingly identified ~40 signaling genes and transcription factors that are expressed in either the aboral domain or animal pole that gives rise to the endomesoderm at late blastula stages. Conclusions Together, our data suggest that MAPK is a key early regulator of neurogenesis, and that it is likely required at multiple steps. Initially, MAPK promotes neurogenesis by positively regulating expression of NvsoxB(2), Nvath-like, and NvashA. However, we also found that MAPK is necessary for the activity of the neurogenic transcription factor NvashA. Our forward molecular approach provided insight about the mechanisms of embryonic neurogenesis. For instance, NvashA suppression of Nvath-like suggests that inhibition of progenitor identity is an active process in newly born neurons, and we show that downstream targets of NvashA reflect multiple neural subtypes rather than a uniform neural fate. Lastly, analysis of the MAPK targets in the early embryo suggests that MAPK signaling is critical not only to neurogenesis, but also endomesoderm formation and aboral patterning. Electronic supplementary material The online version of this article (doi:10.1186/s12915-016-0282-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Michael J Layden
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA.
| | - Hereroa Johnston
- Université Nice Sophia Antipolis UMR 7284, CNRS UMR 7284, INSERM U1081, Institute for Research on Cancer and Aging, Nice, France
| | - Aldine R Amiel
- Université Nice Sophia Antipolis UMR 7284, CNRS UMR 7284, INSERM U1081, Institute for Research on Cancer and Aging, Nice, France
| | - Jamie Havrilak
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA
| | - Bailey Steinworth
- The Whitney Marine Laboratory for Marine Science, University of Florida, St. Augustine, Florida, USA
| | - Taylor Chock
- The Whitney Marine Laboratory for Marine Science, University of Florida, St. Augustine, Florida, USA
| | - Eric Röttinger
- Université Nice Sophia Antipolis UMR 7284, CNRS UMR 7284, INSERM U1081, Institute for Research on Cancer and Aging, Nice, France
| | - Mark Q Martindale
- The Whitney Marine Laboratory for Marine Science, University of Florida, St. Augustine, Florida, USA.
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14
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Arendt D, Tosches MA, Marlow H. From nerve net to nerve ring, nerve cord and brain--evolution of the nervous system. Nat Rev Neurosci 2016; 17:61-72. [PMID: 26675821 DOI: 10.1038/nrn.2015.15] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The puzzle of how complex nervous systems emerged remains unsolved. Comparative studies of neurodevelopment in cnidarians and bilaterians suggest that this process began with distinct integration centres that evolved on opposite ends of an initial nerve net. The 'apical nervous system' controlled general body physiology, and the 'blastoporal nervous system' coordinated feeding movements and locomotion. We propose that expansion, integration and fusion of these centres gave rise to the bilaterian nerve cord and brain.
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Affiliation(s)
- Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 699117 Heidelberg, Germany
| | - Maria Antonietta Tosches
- Max Planck Institute for Brain Research, Max-von-Laue-Strasse 4, 60438 Frankfurt am Main, Germany
| | - Heather Marlow
- Pasteur Institute, 25-28 Rue du Dr Roux, 75015 Paris, France
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15
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Layden MJ, Rentzsch F, Röttinger E. The rise of the starlet sea anemone Nematostella vectensis as a model system to investigate development and regeneration. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2016; 5:408-28. [PMID: 26894563 PMCID: PMC5067631 DOI: 10.1002/wdev.222] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 11/20/2015] [Accepted: 11/28/2015] [Indexed: 02/01/2023]
Abstract
Reverse genetics and next‐generation sequencing unlocked a new era in biology. It is now possible to identify an animal(s) with the unique biology most relevant to a particular question and rapidly generate tools to functionally dissect that biology. This review highlights the rise of one such novel model system, the starlet sea anemone Nematostella vectensis. Nematostella is a cnidarian (corals, jellyfish, hydras, sea anemones, etc.) animal that was originally targeted by EvoDevo researchers looking to identify a cnidarian animal to which the development of bilaterians (insects, worms, echinoderms, vertebrates, mollusks, etc.) could be compared. Studies in Nematostella have accomplished this goal and informed our understanding of the evolution of key bilaterian features. However, Nematostella is now going beyond its intended utility with potential as a model to better understand other areas such as regenerative biology, EcoDevo, or stress response. This review intends to highlight key EvoDevo insights from Nematostella that guide our understanding about the evolution of axial patterning mechanisms, mesoderm, and nervous systems in bilaterians, as well as to discuss briefly the potential of Nematostella as a model to better understand the relationship between development and regeneration. Lastly, the sum of research to date in Nematostella has generated a variety of tools that aided the rise of Nematostella to a viable model system. We provide a catalogue of current resources and techniques available to facilitate investigators interested in incorporating Nematostella into their research. WIREs Dev Biol 2016, 5:408–428. doi: 10.1002/wdev.222 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Michael J Layden
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA
| | - Fabian Rentzsch
- Sars Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Eric Röttinger
- Institute for Research on Cancer and Aging (IRCAN), CNRS UMR 7284, INSERM U1081, Université de Nice-Sophia-Antipolis, Nice, France
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16
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Development and Symbiosis Establishment in the Cnidarian Endosymbiosis Model Aiptasia sp. Sci Rep 2016; 6:19867. [PMID: 26804034 PMCID: PMC4726165 DOI: 10.1038/srep19867] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 12/16/2015] [Indexed: 12/19/2022] Open
Abstract
Symbiosis between photosynthetic algae and heterotrophic organisms is widespread. One prominent example of high ecological relevance is the endosymbiosis between dinoflagellate algae of the genus Symbiodinium and reef-building corals, which typically acquire symbionts anew each generation during larval stages. The tropical sea anemone Aiptasia sp. is a laboratory model system for this endosymbiosis and, similar to corals, produces non-symbiotic larvae that establish symbiosis by phagocytosing Symbiodinium from the environment into the endoderm. Here we generate the first overview of Aiptasia embryogenesis and larval development and establish in situ hybridization to analyze expression patterns of key early developmental regulators. Next, we quantify morphological changes in developing larvae and find a substantial enlargement of the gastric cavity over time. Symbiont acquisition starts soon after mouth formation and symbionts occupy a major portion of the host cell in which they reside. During the first 14 days of development, infection efficiency remains constant while in contrast, localization of phagocytosed symbionts changes, indicating that the occurrence of functional phagocytosing cells may be developmentally regulated. Taken together, here we provide the essential framework to further develop Aiptasia as a model system for the analysis of symbiosis establishment in cnidarian larvae at the molecular level.
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17
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Kraus JEM, Fredman D, Wang W, Khalturin K, Technau U. Adoption of conserved developmental genes in development and origin of the medusa body plan. EvoDevo 2015; 6:23. [PMID: 26075050 PMCID: PMC4464714 DOI: 10.1186/s13227-015-0017-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 05/08/2015] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The metagenesis of sessile polyps into pelagic medusae in cnidarians represents one of the most ancient complex life cycles in animals. Interestingly, scyphozoans and hydrozoans generate medusae by apparently fundamentally different processes. It is therefore unclear whether medusa formation has evolved independently in different medusozoans. To this end, a thorough understanding of the correspondence of polyp and medusa is required. RESULTS We monitored the expression patterns of conserved developmental genes in developing medusae of Clytia hemisphaerica (Hydrozoa) and Aurelia aurita (Scyphozoa) and found that developing medusae and polyps share similarities in their morphology and developmental gene expression. Unexpectedly, however, polyp tentacle marker genes were consistently expressed in the developing medusa bell, suggesting that the bell of medusae corresponds to modified and fused polyp tentacle anlagen. CONCLUSIONS Our data represent the first comparative gene expression analysis of developing medusae in two representatives of Scyphozoa and Hydrozoa. The results challenge prevailing views about polyp medusa body plan homology. We propose that the evolution of a new life stage may be facilitated by the adoption of existing developmental genes.
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Affiliation(s)
- Johanna E. M. Kraus
- />Department for Molecular Evolution and Development, Centre for Organismal Systems Biology, University of Vienna, Althanstraße 14, Wien, Vienna 1090 Austria
| | - David Fredman
- />Department for Molecular Evolution and Development, Centre for Organismal Systems Biology, University of Vienna, Althanstraße 14, Wien, Vienna 1090 Austria
- />Present address: Computational Biology Unit, University of Bergen, Thormohlensgate 55, 5008 Bergen, Norway
| | - Wei Wang
- />Zoologisches Institut, Christian-Albrechts Universität zu Kiel, Am Botanischen Garten 1-9, Kiel, 24118 Germany
| | - Konstantin Khalturin
- />Marine Genomics Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495 Japan
| | - Ulrich Technau
- />Department for Molecular Evolution and Development, Centre for Organismal Systems Biology, University of Vienna, Althanstraße 14, Wien, Vienna 1090 Austria
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18
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Schlosser G. Vertebrate cranial placodes as evolutionary innovations--the ancestor's tale. Curr Top Dev Biol 2015; 111:235-300. [PMID: 25662263 DOI: 10.1016/bs.ctdb.2014.11.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Evolutionary innovations often arise by tinkering with preexisting components building new regulatory networks by the rewiring of old parts. The cranial placodes of vertebrates, ectodermal thickenings that give rise to many of the cranial sense organs (ear, nose, lateral line) and ganglia, originated as such novel structures, when vertebrate ancestors elaborated their head in support of a more active and exploratory life style. This review addresses the question of how cranial placodes evolved by tinkering with ectodermal patterning mechanisms and sensory and neurosecretory cell types that have their own evolutionary history. With phylogenetic relationships among the major branches of metazoans now relatively well established, a comparative approach is used to infer, which structures evolved in which lineages and allows us to trace the origin of placodes and their components back from ancestor to ancestor. Some of the core networks of ectodermal patterning and sensory and neurosecretory differentiation were already established in the common ancestor of cnidarians and bilaterians and were greatly elaborated in the bilaterian ancestor (with BMP- and Wnt-dependent patterning of dorsoventral and anteroposterior ectoderm and multiple neurosecretory and sensory cell types). Rostral and caudal protoplacodal domains, giving rise to some neurosecretory and sensory cells, were then established in the ectoderm of the chordate and tunicate-vertebrate ancestor, respectively. However, proper cranial placodes as clusters of proliferating progenitors producing high-density arrays of neurosecretory and sensory cells only evolved and diversified in the ancestors of vertebrates.
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Affiliation(s)
- Gerhard Schlosser
- School of Natural Sciences & Regenerative Medicine Institute (REMEDI), National University of Ireland, Galway, Ireland.
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19
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Fritzsch B, Jahan I, Pan N, Elliott KL. Evolving gene regulatory networks into cellular networks guiding adaptive behavior: an outline how single cells could have evolved into a centralized neurosensory system. Cell Tissue Res 2014; 359:295-313. [PMID: 25416504 DOI: 10.1007/s00441-014-2043-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 10/20/2014] [Indexed: 12/18/2022]
Abstract
Understanding the evolution of the neurosensory system of man, able to reflect on its own origin, is one of the major goals of comparative neurobiology. Details of the origin of neurosensory cells, their aggregation into central nervous systems and associated sensory organs and their localized patterning leading to remarkably different cell types aggregated into variably sized parts of the central nervous system have begun to emerge. Insights at the cellular and molecular level have begun to shed some light on the evolution of neurosensory cells, partially covered in this review. Molecular evidence suggests that high mobility group (HMG) proteins of pre-metazoans evolved into the definitive Sox [SRY (sex determining region Y)-box] genes used for neurosensory precursor specification in metazoans. Likewise, pre-metazoan basic helix-loop-helix (bHLH) genes evolved in metazoans into the group A bHLH genes dedicated to neurosensory differentiation in bilaterians. Available evidence suggests that the Sox and bHLH genes evolved a cross-regulatory network able to synchronize expansion of precursor populations and their subsequent differentiation into novel parts of the brain or sensory organs. Molecular evidence suggests metazoans evolved patterning gene networks early, which were not dedicated to neuronal development. Only later in evolution were these patterning gene networks tied into the increasing complexity of diffusible factors, many of which were already present in pre-metazoans, to drive local patterning events. It appears that the evolving molecular basis of neurosensory cell development may have led, in interaction with differentially expressed patterning genes, to local network modifications guiding unique specializations of neurosensory cells into sensory organs and various areas of the central nervous system.
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Affiliation(s)
- Bernd Fritzsch
- Department of Biology, University of Iowa, CLAS, 143 BB, Iowa City, IA, 52242, USA,
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20
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Molecular conservation of metazoan gut formation: evidence from expression of endomesoderm genes in Capitella teleta (Annelida). EvoDevo 2014; 5:39. [PMID: 25908956 PMCID: PMC4407770 DOI: 10.1186/2041-9139-5-39] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Accepted: 09/17/2014] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Metazoan digestive systems develop from derivatives of ectoderm, endoderm and mesoderm, and vary in the relative contribution of each germ layer across taxa and between gut regions. In a small number of well-studied model systems, gene regulatory networks specify endoderm and mesoderm of the gut within a bipotential germ layer precursor, the endomesoderm. Few studies have examined expression of endomesoderm genes outside of those models, and thus, it is unknown whether molecular specification of gut formation is broadly conserved. In this study, we utilize a sequenced genome and comprehensive fate map to correlate the expression patterns of six transcription factors with embryonic germ layers and gut subregions during early development in Capitella teleta. RESULTS The genome of C. teleta contains the five core genes of the sea urchin endomesoderm specification network. Here, we extend a previous study and characterize expression patterns of three network orthologs and three additional genes by in situ hybridization during cleavage and gastrulation stages and during formation of distinct gut subregions. In cleavage stage embryos, Ct-otx, Ct-blimp1, Ct-bra and Ct-nkx2.1a are expressed in all four macromeres, the endoderm precursors. Ct-otx, Ct-blimp1, and Ct-nkx2.1a are also expressed in presumptive endoderm of gastrulae and later during midgut development. Additional gut-specific expression patterns include Ct-otx, Ct-bra, Ct-foxAB and Ct-gsc in oral ectoderm; Ct-otx, Ct-blimp1, Ct-bra and Ct-nkx2.1a in the foregut; and both Ct-bra and Ct-nkx2.1a in the hindgut. CONCLUSIONS Identification of core sea urchin endomesoderm genes in C. teleta indicates they are present in all three bilaterian superclades. Expression of Ct-otx, Ct-blimp1 and Ct-bra, combined with previously published Ct-foxA and Ct-gataB1 patterns, provide the most comprehensive comparison of these five orthologs from a single species within Spiralia. Each ortholog is likely involved in endoderm specification and midgut development, and several may be essential for establishment of the oral ectoderm, foregut and hindgut, including specification of ectodermal and mesodermal contributions. When the five core genes are compared across the Metazoa, their conserved expression patterns suggest that 'gut gene' networks evolved to specify distinct digestive system subregions, regardless of species-specific differences in gut architecture or germ layer contributions within each subregion.
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Schlosser G, Patthey C, Shimeld SM. The evolutionary history of vertebrate cranial placodes II. Evolution of ectodermal patterning. Dev Biol 2014; 389:98-119. [PMID: 24491817 DOI: 10.1016/j.ydbio.2014.01.019] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 01/21/2014] [Accepted: 01/24/2014] [Indexed: 12/12/2022]
Abstract
Cranial placodes are evolutionary innovations of vertebrates. However, they most likely evolved by redeployment, rewiring and diversification of preexisting cell types and patterning mechanisms. In the second part of this review we compare vertebrates with other animal groups to elucidate the evolutionary history of ectodermal patterning. We show that several transcription factors have ancient bilaterian roles in dorsoventral and anteroposterior regionalisation of the ectoderm. Evidence from amphioxus suggests that ancestral chordates then concentrated neurosecretory cells in the anteriormost non-neural ectoderm. This anterior proto-placodal domain subsequently gave rise to the oral siphon primordia in tunicates (with neurosecretory cells being lost) and anterior (adenohypophyseal, olfactory, and lens) placodes of vertebrates. Likewise, tunicate atrial siphon primordia and posterior (otic, lateral line, and epibranchial) placodes of vertebrates probably evolved from a posterior proto-placodal region in the tunicate-vertebrate ancestor. Since both siphon primordia in tunicates give rise to sparse populations of sensory cells, both proto-placodal domains probably also gave rise to some sensory receptors in the tunicate-vertebrate ancestor. However, proper cranial placodes, which give rise to high density arrays of specialised sensory receptors and neurons, evolved from these domains only in the vertebrate lineage. We propose that this may have involved rewiring of the regulatory network upstream and downstream of Six1/2 and Six4/5 transcription factors and their Eya family cofactors. These proteins, which play ancient roles in neuronal differentiation were first recruited to the dorsal non-neural ectoderm in the tunicate-vertebrate ancestor but subsequently probably acquired new target genes in the vertebrate lineage, allowing them to adopt new functions in regulating proliferation and patterning of neuronal progenitors.
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Affiliation(s)
- Gerhard Schlosser
- Department of Zoology, School of Natural Sciences & Regenerative Medicine Institute (REMEDI), National University of Ireland, University Road, Galway, Ireland.
| | - Cedric Patthey
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - Sebastian M Shimeld
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
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Marlow H, Tosches MA, Tomer R, Steinmetz PR, Lauri A, Larsson T, Arendt D. Larval body patterning and apical organs are conserved in animal evolution. BMC Biol 2014; 12:7. [PMID: 24476105 PMCID: PMC3939940 DOI: 10.1186/1741-7007-12-7] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 01/24/2014] [Indexed: 12/31/2022] Open
Abstract
Background Planktonic ciliated larvae are characteristic for the life cycle of marine invertebrates. Their most prominent feature is the apical organ harboring sensory cells and neurons of largely undetermined function. An elucidation of the relationships between various forms of primary larvae and apical organs is key to understanding the evolution of animal life cycles. These relationships have remained enigmatic due to the scarcity of comparative molecular data. Results To compare apical organs and larval body patterning, we have studied regionalization of the episphere, the upper hemisphere of the trochophore larva of the marine annelid Platynereis dumerilii. We examined the spatial distribution of transcription factors and of Wnt signaling components previously implicated in anterior neural development. Pharmacological activation of Wnt signaling with Gsk3β antagonists abolishes expression of apical markers, consistent with a repressive role of Wnt signaling in the specification of apical tissue. We refer to this Wnt-sensitive, six3- and foxq2-expressing part of the episphere as the ‘apical plate’. We also unraveled a molecular signature of the apical organ - devoid of six3 but expressing foxj, irx, nkx3 and hox - that is shared with other marine phyla including cnidarians. Finally, we characterized the cell types that form part of the apical organ by profiling by image registration, which allows parallel expression profiling of multiple cells. Besides the hox-expressing apical tuft cells, this revealed the presence of putative light- and mechanosensory as well as multiple peptidergic cell types that we compared to apical organ cell types of other animal phyla. Conclusions The similar formation of a six3+, foxq2+ apical plate, sensitive to Wnt activity and with an apical tuft in its six3-free center, is most parsimoniously explained by evolutionary conservation. We propose that a simple apical organ - comprising an apical tuft and a basal plexus innervated by sensory-neurosecretory apical plate cells - was present in the last common ancestors of cnidarians and bilaterians. One of its ancient functions would have been the control of metamorphosis. Various types of apical plate cells would then have subsequently been added to the apical organ in the divergent bilaterian lineages. Our findings support an ancient and common origin of primary ciliated larvae.
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Affiliation(s)
- Heather Marlow
- European Molecular Biology Laboratory, Development Biology Unit, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany.
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Dondua AK, Kostyuchenko RP. Concerning one obsolete tradition: Does gastrulation in sponges exist? Russ J Dev Biol 2013. [DOI: 10.1134/s1062360413050020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Fritz AE, Ikmi A, Seidel C, Paulson A, Gibson MC. Mechanisms of tentacle morphogenesis in the sea anemone Nematostella vectensis. Development 2013; 140:2212-23. [DOI: 10.1242/dev.088260] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Evolution of the capacity to form secondary outgrowths from the principal embryonic axes was a crucial innovation that potentiated the diversification of animal body plans. Precisely how such outgrowths develop in early-branching metazoan species remains poorly understood. Here we demonstrate that three fundamental processes contribute to embryonic tentacle development in the cnidarian Nematostella vectensis. First, a pseudostratified ectodermal placode forms at the oral pole of developing larvae and is transcriptionally patterned into four tentacle buds. Subsequently, Notch signaling-dependent changes in apicobasal epithelial thickness drive elongation of these primordia. In parallel, oriented cell rearrangements revealed by clonal analysis correlate with shaping of the elongating tentacles. Taken together, our results define the mechanism of embryonic appendage development in an early-branching metazoan, and thereby provide a novel foundation for understanding the diversification of body plans during animal evolution.
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Affiliation(s)
- Ashleigh E. Fritz
- Stowers Institute for Medical Research, 1000 E 50th Street, Kansas City, MO 64110, USA
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
| | - Aissam Ikmi
- Stowers Institute for Medical Research, 1000 E 50th Street, Kansas City, MO 64110, USA
| | - Christopher Seidel
- Stowers Institute for Medical Research, 1000 E 50th Street, Kansas City, MO 64110, USA
| | - Ariel Paulson
- Stowers Institute for Medical Research, 1000 E 50th Street, Kansas City, MO 64110, USA
| | - Matthew C. Gibson
- Stowers Institute for Medical Research, 1000 E 50th Street, Kansas City, MO 64110, USA
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
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The bilaterian head patterning gene six3/6 controls aboral domain development in a cnidarian. PLoS Biol 2013; 11:e1001488. [PMID: 23483856 PMCID: PMC3586664 DOI: 10.1371/journal.pbio.1001488] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 01/09/2013] [Indexed: 12/14/2022] Open
Abstract
The origin of the bilaterian head is a fundamental question for the evolution of animal body plans. The head of bilaterians develops at the anterior end of their primary body axis and is the site where the brain is located. Cnidarians, the sister group to bilaterians, lack brain-like structures and it is not clear whether the oral, the aboral, or none of the ends of the cnidarian primary body axis corresponds to the anterior domain of bilaterians. In order to understand the evolutionary origin of head development, we analysed the function of conserved genetic regulators of bilaterian anterior development in the sea anemone Nematostella vectensis. We show that orthologs of the bilaterian anterior developmental genes six3/6, foxQ2, and irx have dynamic expression patterns in the aboral region of Nematostella. Functional analyses reveal that NvSix3/6 acts upstream of NvFoxQ2a as a key regulator of the development of a broad aboral territory in Nematostella. NvSix3/6 initiates an autoregulatory feedback loop involving positive and negative regulators of FGF signalling, which subsequently results in the downregulation of NvSix3/6 and NvFoxQ2a in a small domain at the aboral pole, from which the apical organ develops. We show that signalling by NvFGFa1 is specifically required for the development of the apical organ, whereas NvSix3/6 has an earlier and broader function in the specification of the aboral territory. Our functional and gene expression data suggest that the head-forming region of bilaterians is derived from the aboral domain of the cnidarian-bilaterian ancestor.
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Röttinger E, Dahlin P, Martindale MQ. A framework for the establishment of a cnidarian gene regulatory network for "endomesoderm" specification: the inputs of ß-catenin/TCF signaling. PLoS Genet 2012; 8:e1003164. [PMID: 23300467 PMCID: PMC3531958 DOI: 10.1371/journal.pgen.1003164] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 10/27/2012] [Indexed: 12/03/2022] Open
Abstract
Understanding the functional relationship between intracellular factors and
extracellular signals is required for reconstructing gene regulatory networks
(GRN) involved in complex biological processes. One of the best-studied
bilaterian GRNs describes endomesoderm specification and predicts that both
mesoderm and endoderm arose from a common GRN early in animal evolution.
Compelling molecular, genomic, developmental, and evolutionary evidence supports
the hypothesis that the bifunctional gastrodermis of the cnidarian-bilaterian
ancestor is derived from the same evolutionary precursor of both endodermal and
mesodermal germ layers in all other triploblastic bilaterian animals. We have
begun to establish the framework of a provisional cnidarian
“endomesodermal” gene regulatory network in the sea anemone,
Nematostella vectensis, by using a genome-wide microarray
analysis on embryos in which the canonical Wnt/ß-catenin pathway was
ectopically targeted for activation by two distinct pharmaceutical agents
(lithium chloride and 1-azakenpaullone) to identify potential targets of
endomesoderm specification. We characterized 51 endomesodermally expressed
transcription factors and signaling molecule genes (including 18 newly
identified) with fine-scale temporal (qPCR) and spatial (in
situ) analysis to define distinct co-expression domains within the
animal plate of the embryo and clustered genes based on their earliest zygotic
expression. Finally, we determined the input of the canonical
Wnt/ß-catenin pathway into the cnidarian endomesodermal GRN using
morpholino and mRNA overexpression experiments to show that NvTcf/canonical Wnt
signaling is required to pattern both the future endomesodermal and ectodermal
domains prior to gastrulation, and that both BMP and FGF (but not Notch)
pathways play important roles in germ layer specification in this animal. We
show both evolutionary conserved as well as profound differences in
endomesodermal GRN structure compared to bilaterians that may provide
fundamental insight into how GRN subcircuits have been adopted, rewired, or
co-opted in various animal lineages that give rise to specialized endomesodermal
cell types. Cnidarians (anemones, corals, and “jellyfish”) are an animal group
whose adults possess derivatives of only two germ layers: ectoderm and a
bifunctional (absorptive and contractile) gastrodermal (gut) layer. Cnidarians
are the closest living relatives to bilaterally symmetrical animals that possess
all three germ layers (ecto, meso, and endoderm); and compelling molecular,
genomic, developmental, and evolutionary evidence exists to demonstrate that the
cnidarian gastrodermis is evolutionarily related to both endodermal and
mesodermal germ layers in all other triploblastic bilaterian animals. Little is
known about endomesoderm specification in cnidarians. In this study, we
constructed the framework of a cnidarian endomesodermal gene regulatory network
in the sea anemone, Nematostella vectensis, using a combination
of experimental approaches. We identified and characterized by both qPCR and
in situ hybridization 51 genes expressed in defined domains
within the presumptive endomesoderm. In addition, we functionally demonstrate
that Wnt/Tcf signaling is crucial for regionalized expression of a defined
subset of these genes prior to gut formation and endomesoderm maintenance. Our
results support the idea of an ancient gene regulatory network underlying
endomesoderm specification that involves inputs from multiple signaling pathways
(Wnt, FGF, BMP, but not Notch) early in development, that are temporarily
uncoupled in bilaterian animals.
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Affiliation(s)
- Eric Röttinger
- Kewalo Marine Laboratory, Pacific Biosciences Research Center,
University of Hawai'i, Honolulu, Hawai'i, United States of
America
| | - Paul Dahlin
- Kewalo Marine Laboratory, Pacific Biosciences Research Center,
University of Hawai'i, Honolulu, Hawai'i, United States of
America
| | - Mark Q. Martindale
- Kewalo Marine Laboratory, Pacific Biosciences Research Center,
University of Hawai'i, Honolulu, Hawai'i, United States of
America
- * E-mail:
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Ormestad M, Martindale MQ, Röttinger E. A comparative gene expression database for invertebrates. EvoDevo 2011; 2:17. [PMID: 21861937 PMCID: PMC3180427 DOI: 10.1186/2041-9139-2-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Accepted: 08/24/2011] [Indexed: 12/02/2022] Open
Abstract
Background As whole genome and transcriptome sequencing gets cheaper and faster, a great number of 'exotic' animal models are emerging, rapidly adding valuable data to the ever-expanding Evo-Devo field. All these new organisms serve as a fantastic resource for the research community, but the sheer amount of data, some published, some not, makes detailed comparison of gene expression patterns very difficult to summarize - a problem sometimes even noticeable within a single lab. The need to merge existing data with new information in an organized manner that is publicly available to the research community is now more necessary than ever. Description In order to offer a homogenous way of storing and handling gene expression patterns from a variety of organisms, we have developed the first web-based comparative gene expression database for invertebrates that allows species-specific as well as cross-species gene expression comparisons. The database can be queried by gene name, developmental stage and/or expression domains. Conclusions This database provides a unique tool for the Evo-Devo research community that allows the retrieval, analysis and comparison of gene expression patterns within or among species. In addition, this database enables a quick identification of putative syn-expression groups that can be used to initiate, among other things, gene regulatory network (GRN) projects.
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Affiliation(s)
- Mattias Ormestad
- Kewalo Marine Laboratory, PBRC, University of Hawaii at Manoa, 41, Ahui Street, Honolulu, 96734, HI, USA.
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28
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Mazza ME, Pang K, Reitzel AM, Martindale MQ, Finnerty JR. A conserved cluster of three PRD-class homeobox genes (homeobrain, rx and orthopedia) in the Cnidaria and Protostomia. EvoDevo 2010; 1:3. [PMID: 20849646 PMCID: PMC2938728 DOI: 10.1186/2041-9139-1-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Accepted: 07/05/2010] [Indexed: 01/25/2023] Open
Abstract
Background Homeobox genes are a superclass of transcription factors with diverse developmental regulatory functions, which are found in plants, fungi and animals. In animals, several Antennapedia (ANTP)-class homeobox genes reside in extremely ancient gene clusters (for example, the Hox, ParaHox, and NKL clusters) and the evolution of these clusters has been implicated in the morphological diversification of animal bodyplans. By contrast, similarly ancient gene clusters have not been reported among the other classes of homeobox genes (that is, the LIM, POU, PRD and SIX classes). Results Using a combination of in silico queries and phylogenetic analyses, we found that a cluster of three PRD-class homeobox genes (Homeobrain (hbn), Rax (rx) and Orthopedia (otp)) is present in cnidarians, insects and mollusks (a partial cluster comprising hbn and rx is present in the placozoan Trichoplax adhaerens). We failed to identify this 'HRO' cluster in deuterostomes; in fact, the Homeobrain gene appears to be missing from the chordate genomes we examined, although it is present in hemichordates and echinoderms. To illuminate the ancestral organization and function of this ancient cluster, we mapped the constituent genes against the assembled genome of a model cnidarian, the sea anemone Nematostella vectensis, and characterized their spatiotemporal expression using in situ hybridization. In N. vectensis, these genes reside in a span of 33 kb with the same gene order as previously reported in insects. Comparisons of genomic sequences and expressed sequence tags revealed the presence of alternative transcripts of Nv-otp and two highly unusual protein-coding polymorphisms in the terminal helix of the Nv-rx homeodomain. A population genetic survey revealed the Rx polymorphisms to be widespread in natural populations. During larval development, all three genes are expressed in the ectoderm, in non-overlapping territories along the oral-aboral axis, with distinct temporal expression. Conclusion We report the first evidence for a PRD-class homeobox cluster that appears to have been conserved since the time of the cnidarian-bilaterian ancestor, and possibly even earlier, given the presence of a partial cluster in the placozoan Trichoplax. Very similar clusters comprising these three genes exist in Nematostella and diverse protostomes. Interestingly, in chordates, one member of the ancestral cluster (homeobrain) has apparently been lost, and there is no linkage between rx and orthopedia in any of the vertebrates. In Nematostella, the spatial expression of these three genes along the body column is not colinear with their physical order in the cluster but the temporal expression is, therefore, using the terminology that has been applied to the Hox cluster genes, the HRO cluster would appear to exhibit temporal but not spatial colinearity. It remains to be seen whether the mechanisms responsible for the evolutionary conservation of the HRO cluster are the same mechanisms responsible for cohesion of the Hox cluster and other ANTP-class homeobox clusters that have been widely conserved throughout animal evolution.
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Affiliation(s)
- Maureen E Mazza
- Department of Biology, Boston University, 5 Cummington Street, Boston, MA 02215, USA
| | - Kevin Pang
- Kewalo Marine Lab, Pacific Biosciences Research Center, University of Hawaii, 41 Ahui St., Honolulu, HI 96813, USA
| | - Adam M Reitzel
- Department of Biology, Boston University, 5 Cummington Street, Boston, MA 02215, USA.,Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Mark Q Martindale
- Kewalo Marine Lab, Pacific Biosciences Research Center, University of Hawaii, 41 Ahui St., Honolulu, HI 96813, USA
| | - John R Finnerty
- Department of Biology, Boston University, 5 Cummington Street, Boston, MA 02215, USA
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29
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Nakanishi N, Yuan D, Hartenstein V, Jacobs DK. Evolutionary origin of rhopalia: insights from cellular-level analyses of Otx and POU expression patterns in the developing rhopalial nervous system. Evol Dev 2010; 12:404-15. [DOI: 10.1111/j.1525-142x.2010.00427.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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30
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Degnan SM, Degnan BM. The initiation of metamorphosis as an ancient polyphenic trait and its role in metazoan life-cycle evolution. Philos Trans R Soc Lond B Biol Sci 2010; 365:641-51. [PMID: 20083639 DOI: 10.1098/rstb.2009.0248] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Comparative genomics of representative basal metazoans leaves little doubt that the most recent common ancestor to all modern metazoans was morphogenetically complex. Here, we support this interpretation by demonstrating that the demosponge Amphimedon queenslandica has a biphasic pelagobenthic life cycle resembling that present in a wide range of bilaterians and anthozoan cnidarians. The A. queenslandica life cycle includes a compulsory planktonic larval phase that can end only once the larva develops competence to respond to benthic signals that induce settlement and metamorphosis. The temporal onset of competence varies between individuals as revealed by idiosyncratic responses to inductive cues. Thus, the biphasic life cycle with a dispersing larval phase of variable length appears to be a metazoan synapomorphy and may be viewed as an ancestral polyphenic trait. Larvae of a particular age that are subjected to an inductive cue either maintain the larval form or metamorphose into the post-larval/juvenile form. Variance in the development of competence dictates that only a subset of a larval cohort will settle and undergo metamorphosis at a given time, which in turn leads to variation in dispersal distance and in location of settlement. Population divergence and allopatric speciation are likely outcomes of this conserved developmental polyphenic trait.
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Affiliation(s)
- Sandie M Degnan
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia.
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31
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Degnan BM, Vervoort M, Larroux C, Richards GS. Early evolution of metazoan transcription factors. Curr Opin Genet Dev 2009; 19:591-9. [PMID: 19880309 DOI: 10.1016/j.gde.2009.09.008] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2009] [Revised: 09/16/2009] [Accepted: 09/27/2009] [Indexed: 11/29/2022]
Abstract
Analyses of recently sequenced sponge, cnidarian, placozoan, and choanoflagellate genomes have revealed that most transcription factor (TF) classes and families expressed during bilaterian development originated at the dawn of the animal kingdom, before the divergence of contemporary animal lineages. The ancestral metazoan genome included members of the bHLH, Mef2, Fox, Sox, T-box, ETS, nuclear receptor, Rel/NF-kappaB, bZIP, and Smad families, and a diversity of homeobox-containing classes, including ANTP, Prd-like, Pax, POU, LIM-HD, Six, and TALE. As many of these TF classes and families appear to be metazoan specific and not present in choanoflagellates, fungi and more distant eukaryotes, their genesis and expansion may have contributed to the evolution of animal multicellularity.
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Affiliation(s)
- Bernard M Degnan
- School of Biological Sciences, University of Queensland, Brisbane, QLD 4072, Australia.
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32
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Martindale MQ, Hejnol A. A developmental perspective: changes in the position of the blastopore during bilaterian evolution. Dev Cell 2009; 17:162-74. [PMID: 19686678 DOI: 10.1016/j.devcel.2009.07.024] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Progress in resolving the phylogenetic relationships among animals and the expansion of molecular developmental studies to a broader variety of organisms has provided important insights into the evolution of developmental programs. These new studies make it possible to reevaluate old hypotheses about the evolution of animal body plans and to elaborate new ones. Here, we review recent studies that shed light on the transition from a radially organized ancestor to the last common ancestor of the Bilateria ("Urbilaterian") and present an integrative hypothesis about plausible developmental scenarios for the evolution of complex multicellular animals.
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Affiliation(s)
- Mark Q Martindale
- Kewalo Marine Laboratory, PBRC, University of Hawaii, 41 Ahui Street, Honolulu, HI, 96813, USA.
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BMPs and chordin regulate patterning of the directive axis in a sea anemone. Proc Natl Acad Sci U S A 2009; 106:18592-7. [PMID: 19833871 DOI: 10.1073/pnas.0900151106] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The TGF-beta molecules Dpp/BMP2/4/7 and their antagonist Sog/Chd play a conserved role in establishing the dorso-ventral (DV) axis in bilaterians. Homologues of BMPs and the antagonist, Chordin, have been isolated from Cnidaria and show a striking asymmetric expression pattern with respect to the primary oral-aboral (OA) axis. We used Morpholino knockdowns of Nematostella dpp (bmp2/4), bmp5-8, chordin, and tolloid to investigate their function during early development of the sea anemone Nematostella vectensis. Molecular analysis of the BMP Morpholino phenotypes revealed an upregulated and radialized expression of bmps and chordin in ectoderm and endoderm indicating a negative feedback loop. Our data further suggest that BMP signaling is required for symmetry breaking of bmp and chordin expression during gastrulation. While bmps and chordin marker genes of the ectodermal OA axis extended aborally, other ectodermal markers of the OA axis were not significantly affected. By contrast, expression of other endodermal marker genes marking both the OA and the directive axis were abolished. Our data suggest that the logic of BMP2/4 signaling and the BMP antagonist, Chordin, differs significantly between Cnidaria and Bilateria, yet the double negative feedback loop detected in Nematostella bears systemic similarities with part of the regulatory network of the DV axis patterning system in amphibians.
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Reitzel AM, Tarrant AM. Nuclear receptor complement of the cnidarian Nematostella vectensis: phylogenetic relationships and developmental expression patterns. BMC Evol Biol 2009; 9:230. [PMID: 19744329 PMCID: PMC2749838 DOI: 10.1186/1471-2148-9-230] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Accepted: 09/10/2009] [Indexed: 11/15/2022] Open
Abstract
Background Nuclear receptors are a superfamily of metazoan transcription factors that regulate diverse developmental and physiological processes. Sequenced genomes from an increasing number of bilaterians have provided a more complete picture of duplication and loss of nuclear receptors in protostomes and deuterostomes but have left open the question of which nuclear receptors were present in the cnidarian-bilaterian ancestor. In addition, nuclear receptor expression and function are largely uncharacterized within cnidarians, preventing determination of conserved and novel nuclear receptor functions in the context of animal evolution. Results Here we report the first complete set of nuclear receptors from a cnidarian, the starlet sea anemone Nematostella vectensis. Genomic searches using conserved DNA- and ligand-binding domains revealed seventeen nuclear receptors in N. vectensis. Phylogenetic analyses support N. vectensis orthologs of bilaterian nuclear receptors in four nuclear receptor subfamilies within nuclear receptor family 2 (COUP-TF, TLL, HNF4, TR2/4) and one putative ortholog of GCNF (nuclear receptor family 6). Other N. vectensis genes grouped well with nuclear receptor family 2 but represented lineage-specific duplications somewhere within the cnidarian lineage and were not clear orthologs of bilaterian genes. Three nuclear receptors were not well-supported within any particular nuclear receptor family. The seventeen nuclear receptors exhibited distinct developmental expression patterns, with expression of several nuclear receptors limited to a subset of developmental stages. Conclusion N. vectensis contains a diverse complement of nuclear receptors including orthologs of several bilaterian nuclear receptors. Novel nuclear receptors in N. vectensis may be ancient genes lost from triploblastic lineages or may represent cnidarian-specific radiations. Nuclear receptors exhibited distinct developmental expression patterns, which are consistent with diverse regulatory roles for these genes. Understanding the evolutionary relationships and developmental expression of the N. vectensis nuclear receptor complement provides insight into the evolution of the nuclear receptor superfamily and a foundation for mechanistic characterization of cnidarian nuclear receptor function.
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Affiliation(s)
- Adam M Reitzel
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
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35
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Watanabe H, Fujisawa T, Holstein TW. Cnidarians and the evolutionary origin of the nervous system. Dev Growth Differ 2009; 51:167-83. [PMID: 19379274 DOI: 10.1111/j.1440-169x.2009.01103.x] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cnidarians are widely regarded as one of the first organisms in animal evolution possessing a nervous system. Conventional histological and electrophysiological studies have revealed a considerable degree of complexity of the cnidarian nervous system. Thanks to expressed sequence tags and genome projects and the availability of functional assay systems in cnidarians, this simple nervous system is now genetically accessible and becomes particularly valuable for understanding the origin and evolution of the genetic control mechanisms underlying its development. In the present review, the anatomical and physiological features of the cnidarian nervous system and the interesting parallels in neurodevelopmental mechanisms between Cnidaria and Bilateria are discussed.
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Affiliation(s)
- Hiroshi Watanabe
- University of Heidelberg, Department of Molecular Evolution and Genomics, Im Neuenheimer Feld 230, D-69120 Heidelberg, Germany.
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36
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Yasuoka Y, Kobayashi M, Kurokawa D, Akasaka K, Saiga H, Taira M. Evolutionary origins of blastoporal expression and organizer activity of the vertebrate gastrula organizer gene lhx1 and its ancient metazoan paralog lhx3. Development 2009; 136:2005-14. [DOI: 10.1242/dev.028530] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Expression of the LIM homeobox gene lhx1 (lim1) is specific to the vertebrate gastrula organizer. Lhx1 functions as a transcriptional regulatory core protein to exert `organizer' activity in Xenopus embryos. Its ancient paralog, lhx3 (lim3),is expressed around the blastopore in amphioxus and ascidian, but not vertebrate, gastrulae. These two genes are thus implicated in organizer evolution, and we addressed the evolutionary origins of their blastoporal expression and organizer activity. Gene expression analysis of organisms ranging from cnidarians to chordates suggests that blastoporal expression has its evolutionary root in or before the ancestral eumetazoan for lhx1,but possibly in the ancestral chordate for lhx3, and that in the ascidian lineage, blastoporal expression of lhx1 ceased, whereas endodermal expression of lhx3 has persisted. Analysis of organizer activity using Xenopus embryos suggests that a co-factor of LIM homeodomain proteins, Ldb, has a conserved function in eumetazoans to activate Lhx1, but that Lhx1 acquired organizer activity in the bilaterian lineage,Lhx3 acquired organizer activity in the deuterostome lineage and ascidian Lhx3 acquired a specific transactivation domain to confer organizer activity on this molecule. Knockdown analysis using cnidarian embryos suggests that Lhx1 is required for chordin expression in the blastoporal region. These data suggest that Lhx1 has been playing fundamental roles in the blastoporal region since the ancestral eumetazoan arose, that it contributed as an`original organizer gene' to the evolution of the vertebrate gastrula organizer, and that Lhx3 could be involved in the establishment of organizer gene networks.
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Affiliation(s)
- Yuuri Yasuoka
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masaaki Kobayashi
- Department of Biological Sciences, Graduate School of Science and Engineering,Tokyo Metropolitan University, 1-1 Minamiohsawa, Hachiohji, Tokyo 192-0397,Japan
| | - Daisuke Kurokawa
- Misaki Marine Biological Station, Graduate School of Science, University of Tokyo, 1024 Koajiro, Misaki, Miura Kanagawa, 238-0225, Japan
| | - Koji Akasaka
- Misaki Marine Biological Station, Graduate School of Science, University of Tokyo, 1024 Koajiro, Misaki, Miura Kanagawa, 238-0225, Japan
| | - Hidetoshi Saiga
- Department of Biological Sciences, Graduate School of Science and Engineering,Tokyo Metropolitan University, 1-1 Minamiohsawa, Hachiohji, Tokyo 192-0397,Japan
| | - Masanori Taira
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Marlow HQ, Srivastava M, Matus DQ, Rokhsar D, Martindale MQ. Anatomy and development of the nervous system of Nematostella vectensis, an anthozoan cnidarian. Dev Neurobiol 2009; 69:235-54. [PMID: 19170043 DOI: 10.1002/dneu.20698] [Citation(s) in RCA: 158] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Nematostella vectensis, an anthozoan cnidarian, whose genome has been sequenced and is suitable for developmental and ecological studies, has a complex neural morphology that is modified during development from the larval to adult form. N. vectensis' nervous system is a diffuse nerve net with both ectodermal sensory and effector cells and endodermal multipolar ganglion cells. This nerve net consists of several distinct neural territories along the oral-aboral axis including the pharyngeal and oral nerve rings, and the larval apical tuft. These neuralized regions correspond to expression of conserved bilaterian neural developmental regulatory genes including homeodomain transcription factors and NCAMs. Early neurons and stem cell populations identified with NvMsi, NvELAV, and NvGCM, indicate that neural differentiation occurs throughout the animal and initiates prior to the conclusion of gastrulation. Neural specification in N. vectensis appears to occur through an independent mechanism from that in the classical cnidarian model Hydra.
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Affiliation(s)
- Heather Q Marlow
- Kewalo Marine Laboratory, Pacific Biomedical Research Center, University of Hawaii, Honolulu, Hawaii 96813, USA
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38
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Origins of neurogenesis, a cnidarian view. Dev Biol 2009; 332:2-24. [PMID: 19465018 DOI: 10.1016/j.ydbio.2009.05.563] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 05/14/2009] [Accepted: 05/16/2009] [Indexed: 11/22/2022]
Abstract
New perspectives on the origin of neurogenesis emerged with the identification of genes encoding post-synaptic proteins as well as many "neurogenic" regulators as the NK, Six, Pax, bHLH proteins in the Demosponge genome, a species that might differentiate sensory cells but no neurons. However, poriferans seem to miss some key regulators of the neurogenic circuitry as the Hox/paraHox and Otx-like gene families. Moreover as a general feature, many gene families encoding evolutionarily-conserved signaling proteins and transcription factors were submitted to a wave of gene duplication in the last common eumetazoan ancestor, after Porifera divergence. In contrast gene duplications in the last common bilaterian ancestor, Urbilateria, are limited, except for the bHLH Atonal-class. Hence Cnidaria share with Bilateria a large number of genetic tools. The expression and functional analyses currently available suggest a neurogenic function for numerous orthologs in developing or adult cnidarians where neurogenesis takes place continuously. As an example, in the Hydra polyp, the Clytia medusa and the Acropora coral, the Gsx/cnox2/Anthox-2 ParaHox gene likely supports neurogenesis. Also neurons and nematocytes (mechanosensory cells) share in hydrozoans a common stem cell and several regulatory genes indicating that they can be considered as sister cells. Performed in anthozoan and medusozoan species, these studies should tell us more about the way(s) evolution hazards achieved the transition from epithelial to neuronal cell fate, and about the robustness of the genetic circuitry that allowed neuromuscular transmission to arise and be maintained across evolution.
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39
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Manuel M. Early evolution of symmetry and polarity in metazoan body plans. C R Biol 2009; 332:184-209. [DOI: 10.1016/j.crvi.2008.07.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Accepted: 07/21/2008] [Indexed: 10/21/2022]
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40
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Burton PM, Finnerty JR. Conserved and novel gene expression between regeneration and asexual fission in Nematostella vectensis. Dev Genes Evol 2009; 219:79-87. [PMID: 19184098 DOI: 10.1007/s00427-009-0271-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Accepted: 01/02/2009] [Indexed: 11/28/2022]
Abstract
Due to work in model systems (e.g., flies and mice), the molecular mechanisms of embryogenesis are known in exquisite detail. However, these organisms are incapable of asexual reproduction and possess limited regenerative abilities. Thus, the mechanisms of alternate developmental trajectories and their relation to embryonic mechanisms remain understudied. Because these developmental trajectories are present in a diverse group of animal phyla spanning the metazoan phylogeny, including cnidarians, annelids, and echinoderms, they are likely to have played a major role in animal evolution. The starlet sea anemone Nematostella vectensis, an emerging model system, undergoes larval development, asexual fission, and complete bi-directional regeneration in the field and laboratory. In order to investigate to what extent embryonic patterning mechanisms are utilized during alternate developmental trajectories, we examined expression of developmental regulatory genes during regeneration and fission. When compared to previously reported embryonic expression patterns, we found that all genes displayed some level of expression consistent with embryogenesis. However, five of seven genes investigated also displayed striking differences in gene expression between one or more developmental trajectory. These results demonstrate that alternate developmental trajectories utilize distinct molecular mechanisms upstream of major developmental regulatory genes such as fox, otx, and Hox-like.
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Affiliation(s)
- Patrick M Burton
- Biology Department, Wabash College, Crawfordsville, IN 47933, USA.
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41
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Chiori R, Jager M, Denker E, Wincker P, Da Silva C, Le Guyader H, Manuel M, Quéinnec E. Are Hox genes ancestrally involved in axial patterning? Evidence from the hydrozoan Clytia hemisphaerica (Cnidaria). PLoS One 2009; 4:e4231. [PMID: 19156208 PMCID: PMC2626245 DOI: 10.1371/journal.pone.0004231] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Accepted: 12/05/2008] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The early evolution and diversification of Hox-related genes in eumetazoans has been the subject of conflicting hypotheses concerning the evolutionary conservation of their role in axial patterning and the pre-bilaterian origin of the Hox and ParaHox clusters. The diversification of Hox/ParaHox genes clearly predates the origin of bilaterians. However, the existence of a "Hox code" predating the cnidarian-bilaterian ancestor and supporting the deep homology of axes is more controversial. This assumption was mainly based on the interpretation of Hox expression data from the sea anemone, but growing evidence from other cnidarian taxa puts into question this hypothesis. METHODOLOGY/PRINCIPAL FINDINGS Hox, ParaHox and Hox-related genes have been investigated here by phylogenetic analysis and in situ hybridisation in Clytia hemisphaerica, an hydrozoan species with medusa and polyp stages alternating in the life cycle. Our phylogenetic analyses do not support an origin of ParaHox and Hox genes by duplication of an ancestral ProtoHox cluster, and reveal a diversification of the cnidarian HOX9-14 genes into three groups called A, B, C. Among the 7 examined genes, only those belonging to the HOX9-14 and the CDX groups exhibit a restricted expression along the oral-aboral axis during development and in the planula larva, while the others are expressed in very specialised areas at the medusa stage. CONCLUSIONS/SIGNIFICANCE Cross species comparison reveals a strong variability of gene expression along the oral-aboral axis and during the life cycle among cnidarian lineages. The most parsimonious interpretation is that the Hox code, collinearity and conservative role along the antero-posterior axis are bilaterian innovations.
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Affiliation(s)
- Roxane Chiori
- UPMC Univ Paris 06, UMR 7138 CNRS UPMC MNHN IRD, Case 05, Paris, France
| | - Muriel Jager
- UPMC Univ Paris 06, UMR 7138 CNRS UPMC MNHN IRD, Case 05, Paris, France
| | - Elsa Denker
- Sars International Centre for Marine Molecular Biology, Bergen, Norway
| | | | | | - Hervé Le Guyader
- UPMC Univ Paris 06, UMR 7138 CNRS UPMC MNHN IRD, Case 05, Paris, France
| | - Michaël Manuel
- UPMC Univ Paris 06, UMR 7138 CNRS UPMC MNHN IRD, Case 05, Paris, France
| | - Eric Quéinnec
- UPMC Univ Paris 06, UMR 7138 CNRS UPMC MNHN IRD, Case 05, Paris, France
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Ryan JF, Mazza ME, Pang K, Matus DQ, Baxevanis AD, Martindale MQ, Finnerty JR. Pre-bilaterian origins of the Hox cluster and the Hox code: evidence from the sea anemone, Nematostella vectensis. PLoS One 2007; 2:e153. [PMID: 17252055 PMCID: PMC1779807 DOI: 10.1371/journal.pone.0000153] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2006] [Accepted: 11/30/2006] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Hox genes were critical to many morphological innovations of bilaterian animals. However, early Hox evolution remains obscure. Phylogenetic, developmental, and genomic analyses on the cnidarian sea anemone Nematostella vectensis challenge recent claims that the Hox code is a bilaterian invention and that no "true" Hox genes exist in the phylum Cnidaria. METHODOLOGY/PRINCIPAL FINDINGS Phylogenetic analyses of 18 Hox-related genes from Nematostella identify putative Hox1, Hox2, and Hox9+ genes. Statistical comparisons among competing hypotheses bolster these findings, including an explicit consideration of the gene losses implied by alternate topologies. In situ hybridization studies of 20 Hox-related genes reveal that multiple Hox genes are expressed in distinct regions along the primary body axis, supporting the existence of a pre-bilaterian Hox code. Additionally, several Hox genes are expressed in nested domains along the secondary body axis, suggesting a role in "dorsoventral" patterning. CONCLUSIONS/SIGNIFICANCE A cluster of anterior and posterior Hox genes, as well as ParaHox cluster of genes evolved prior to the cnidarian-bilaterian split. There is evidence to suggest that these clusters were formed from a series of tandem gene duplication events and played a role in patterning both the primary and secondary body axes in a bilaterally symmetrical common ancestor. Cnidarians and bilaterians shared a common ancestor some 570 to 700 million years ago, and as such, are derived from a common body plan. Our work reveals several conserved genetic components that are found in both of these diverse lineages. This finding is consistent with the hypothesis that a set of developmental rules established in the common ancestor of cnidarians and bilaterians is still at work today.
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Affiliation(s)
- Joseph F. Ryan
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
- Genome Technology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Maureen E. Mazza
- Department of Biology, Boston University, Boston, Massachusetts, United States of America
| | - Kevin Pang
- Kewalo Marine Laboratory, Pacific Bioscience Research Center, University of Hawaii, Honolulu, Hawaii, United States of America
| | - David Q. Matus
- Kewalo Marine Laboratory, Pacific Bioscience Research Center, University of Hawaii, Honolulu, Hawaii, United States of America
| | - Andreas D. Baxevanis
- Genome Technology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mark Q. Martindale
- Kewalo Marine Laboratory, Pacific Bioscience Research Center, University of Hawaii, Honolulu, Hawaii, United States of America
| | - John R. Finnerty
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
- Department of Biology, Boston University, Boston, Massachusetts, United States of America
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