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Fridrich A, Salinas-Saaverda M, Kozlolvski I, Surm JM, Chrysostomou E, Tripathi AM, Frank U, Moran Y. An ancient pan-cnidarian microRNA regulates stinging capsule biogenesis in Nematostella vectensis. Cell Rep 2023; 42:113072. [PMID: 37676763 PMCID: PMC10548089 DOI: 10.1016/j.celrep.2023.113072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 07/12/2023] [Accepted: 08/18/2023] [Indexed: 09/09/2023] Open
Abstract
An ancient evolutionary innovation of a novel cell type, the stinging cell (cnidocyte), appeared >600 million years ago in the phylum Cnidaria (sea anemones, corals, hydroids, and jellyfish). A complex bursting nano-injector of venom, the cnidocyst, is embedded in cnidocytes and enables cnidarians to paralyze their prey and predators, contributing to this phylum's evolutionary success. In this work, we show that post-transcriptional regulation by a pan-cnidarian microRNA, miR-2022, is essential for biogenesis of these cells in the sea anemone Nematostella vectensis. By manipulation of miR-2022 levels in a transgenic reporter line of cnidocytes, followed by transcriptomics, single-cell data analysis, prey paralysis assays, and cell sorting of transgenic cnidocytes, we reveal that miR-2022 enables cnidocyte biogenesis in Nematostella, while exhibiting a conserved expression domain with its targets in cnidocytes of other cnidarian species. Thus, here we revealed a functional basis to the conservation of one of nature's most ancient microRNAs.
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Affiliation(s)
- Arie Fridrich
- Department of Ecology Evolution and Behavior, Faculty of Science, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel; Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna, Austria.
| | | | - Itamar Kozlolvski
- Department of Ecology Evolution and Behavior, Faculty of Science, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Joachim M Surm
- Department of Ecology Evolution and Behavior, Faculty of Science, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | | | - Abhinandan M Tripathi
- Department of Ecology Evolution and Behavior, Faculty of Science, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Uri Frank
- Centre for Chromosome Biology, University of Galway, Galway, Ireland
| | - Yehu Moran
- Department of Ecology Evolution and Behavior, Faculty of Science, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
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Hulett RE, Gehrke AR, Gompers A, Rivera-López C, Srivastava M. A wound-induced differentiation trajectory for neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.10.540286. [PMID: 37214981 PMCID: PMC10197691 DOI: 10.1101/2023.05.10.540286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Animals capable of whole-body regeneration can replace any missing cell type and regenerate fully-functional new organs, de novo . The regeneration of a new brain requires the formation of diverse neuronal cell types and their assembly into an organized structure and correctly-wired circuits. Recent work in various regenerative animals has revealed transcriptional programs required for the differentiation of distinct neuronal subpopulations, however how these transcriptional programs are initiated upon amputation remains unknown. Here, we focused on the highly regenerative acoel worm, Hofstenia miamia , to study wound-induced transcriptional regulatory events that lead to the production of neurons. Footprinting analysis using chromatin accessibility data on an improved genome assembly revealed that binding sites for the NFY transcription factor complex were significantly bound during regeneration, showing a dynamic increase in binding within one hour upon amputation specifically in tail fragments, which will regenerate a new brain. Strikingly, NFY targets were highly enriched for genes with neuronal functional. Single-cell transcriptome analysis combined with functional studies identified sox4 + stem cells as the likely progenitor population for multiple neuronal subtypes. Further, we found that wound-induced sox4 expression is likely under direct transcriptional control by NFY, uncovering a mechanism for how early wound-induced binding of a transcriptional regulator results in the initiation of a neuronal differentiation pathway. Highlights A new chromosome-scale assembly for Hofstenia enables comprehensive analysis of transcription factor binding during regeneration NFY motifs become dynamically bound by 1hpa in regenerating tail fragments, particularly in the loci of neural genes A sox4 + neural-specialized stem cell is identified using scRNA-seq sox4 is wound-induced and required for differentiation of multiple neural cell types NFY regulates wound-induced expression of sox4 during regeneration.
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Single-cell atavism reveals an ancient mechanism of cell type diversification in a sea anemone. Nat Commun 2023; 14:885. [PMID: 36797294 PMCID: PMC9935875 DOI: 10.1038/s41467-023-36615-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 02/09/2023] [Indexed: 02/18/2023] Open
Abstract
Cnidocytes are the explosive stinging cells unique to cnidarians (corals, jellyfish, etc). Specialized for prey capture and defense, cnidocytes comprise a group of over 30 morphologically and functionally distinct cell types. These unusual cells are iconic examples of biological novelty but the developmental mechanisms driving diversity of the stinging apparatus are poorly characterized, making it challenging to understand the evolutionary history of stinging cells. Using CRISPR/Cas9-mediated genome editing in the sea anemone Nematostella vectensis, we show that a single transcription factor (NvSox2) acts as a binary switch between two alternative stinging cell fates. Knockout of NvSox2 causes a transformation of piercing cells into ensnaring cells, which are common in other species of sea anemone but appear to have been silenced in N. vectensis. These results reveal an unusual case of single-cell atavism and expand our understanding of the diversification of cell type identity.
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Abstract
Neurons are the fundamental building blocks of nervous systems. It appears intuitive that the human brain is made up of hundreds, if not thousands different types of neurons. Conversely, the seemingly diffuse nerve net of Cnidaria is often assumed to be simple. However, evidence that the Cnidaria nervous system is indeed simple is sparse. Recent technical advances make it possible to assess the diversity and function of neurons with unprecedented resolution. Transgenic animals expressing genetically encoded Calcium sensors allow direct physiological assessments of neural responses within the nerve net and provide insight into the spatial organization of the nervous system. Moreover, response and activity patterns allow the characterization of cell types on a functional level. Molecular and genetic identities on the other hand can be assessed combining single-cell transcriptomic analysis with correlations of gene expression in defined neurons. Here I review recent advances on these two experimental strategies focusing on Hydra, Nematostella, and Clytia.
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Affiliation(s)
- Simon G Sprecher
- Department of Biology, University of Fribourg, Fribourg, Switzerland
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5
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A novel regulatory gene promotes novel cell fate by suppressing ancestral fate in the sea anemone Nematostella vectensis. Proc Natl Acad Sci U S A 2022; 119:e2113701119. [PMID: 35500123 PMCID: PMC9172639 DOI: 10.1073/pnas.2113701119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In this study, we demonstrate how a new cell type can arise through duplication of an ancestral cell type followed by functional divergence of the new daughter cell. Specifically, we show that stinging cells in a cnidarian (namely, a sea anemone) emerged by duplication of an ancestral neuron followed by inhibition of the RFamide neuropeptide it once secreted. This finding is evidence that stinging cells evolved from a specific subtype of neurons and suggests other neuronal subtypes may have been coopted for other novel secretory functions. Cnidocytes (i.e., stinging cells) are an unequivocally novel cell type used by cnidarians (i.e., corals, jellyfish, and their kin) to immobilize prey. Although they are known to share a common evolutionary origin with neurons, the developmental program that promoted the emergence of cnidocyte fate is not known. Using functional genomics in the sea anemone, Nematostella vectensis, we show that cnidocytes develop by suppression of neural fate in a subset of neurons expressing RFamide. We further show that a single regulatory gene, a C2H2-type zinc finger transcription factor (ZNF845), coordinates both the gain of novel (cnidocyte-specific) traits and the inhibition of ancestral (neural) traits during cnidocyte development and that this gene arose by domain shuffling in the stem cnidarian. Thus, we report a mechanism by which a truly novel regulatory gene (ZNF845) promotes the development of a truly novel cell type (cnidocyte) through duplication of an ancestral cell lineage (neuron) and inhibition of its ancestral identity (RFamide).
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Chrysostomou E, Febrimarsa, DuBuc T, Frank U. Gene Manipulation in Hydractinia. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2450:419-436. [PMID: 35359321 DOI: 10.1007/978-1-0716-2172-1_22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The ability to regenerate lost body parts is irregularly distributed among animals, with substantial differences in regenerative potential between and within metazoan phyla. It is widely believed that regenerative animal clades inherited some aspects of their capacity to regenerate from their common ancestors but have also evolved new mechanisms that are not shared with other regenerative animals. Therefore, to gain a broad understanding of animal regenerative mechanisms and evolution, a broad sampling approach is necessary. Unfortunately, only few regenerative animals have been established as laboratory models with protocols for functional gene studies. Here, we describe the methods to establish transgenic individuals of the marine cnidarian Hydractinia. We also provide methods for transient gene expression manipulation without modifying the genome of the animals.
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Affiliation(s)
- Eleni Chrysostomou
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Febrimarsa
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Timothy DuBuc
- Biology Department, Swarthmore College, Swarthmore, PA, USA
| | - Uri Frank
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland.
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7
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Gahan JM, Kouzel IU, Jansen KO, Burkhardt P, Rentzsch F. Histone demethylase Lsd1 is required for the differentiation of neural cells in Nematostella vectensis. Nat Commun 2022; 13:465. [PMID: 35075108 PMCID: PMC8786827 DOI: 10.1038/s41467-022-28107-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 11/26/2021] [Indexed: 12/21/2022] Open
Abstract
Chromatin regulation is a key process in development but its contribution to the evolution of animals is largely unexplored. Chromatin is regulated by a diverse set of proteins, which themselves are tightly regulated in a cell/tissue-specific manner. Using the cnidarian Nematostella vectensis as a basal metazoan model, we explore the function of one such chromatin regulator, Lysine specific demethylase 1 (Lsd1). We generated an endogenously tagged allele and show that NvLsd1 expression is developmentally regulated and higher in differentiated neural cells than their progenitors. We further show, using a CRISPR/Cas9 generated mutant that loss of NvLsd1 leads to developmental abnormalities. This includes the almost complete loss of differentiated cnidocytes, cnidarian-specific neural cells, as a result of a cell-autonomous requirement for NvLsd1. Together this suggests that the integration of chromatin modifying proteins into developmental regulation predates the split of the cnidarian and bilaterian lineages and constitutes an ancient feature of animal development. The evolutionary point where chromatin modifier function integrated into regulation of specific cell types is unclear. In the cnidarian Nematostella vectensis, the authors here show that lysine specific demethylase Lsd1 is developmentally regulated and required for normal development including cnidocyte differentiation.
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Affiliation(s)
- James M Gahan
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgt 55, 5006, Bergen, Norway.
| | - Ian U Kouzel
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgt 55, 5006, Bergen, Norway
| | - Kamilla Ormevik Jansen
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgt 55, 5006, Bergen, Norway
| | - Pawel Burkhardt
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgt 55, 5006, Bergen, Norway
| | - Fabian Rentzsch
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgt 55, 5006, Bergen, Norway. .,Department for Biological Sciences, University of Bergen, Thormøhlensgt 53, 5006, Bergen, Norway.
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8
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Chrysostomou E, Flici H, Gornik SG, Salinas-Saavedra M, Gahan JM, McMahon ET, Thompson K, Hanley S, Kilcoyne M, Schnitzler CE, Gonzalez P, Baxevanis AD, Frank U. A cellular and molecular analysis of SoxB-driven neurogenesis in a cnidarian. eLife 2022; 11:78793. [PMID: 35608899 PMCID: PMC9173746 DOI: 10.7554/elife.78793] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 05/23/2022] [Indexed: 01/09/2023] Open
Abstract
Neurogenesis is the generation of neurons from stem cells, a process that is regulated by SoxB transcription factors (TFs) in many animals. Although the roles of these TFs are well understood in bilaterians, how their neural function evolved is unclear. Here, we use Hydractinia symbiolongicarpus, a member of the early-branching phylum Cnidaria, to provide insight into this question. Using a combination of mRNA in situ hybridization, transgenesis, gene knockdown, transcriptomics, and in vivo imaging, we provide a comprehensive molecular and cellular analysis of neurogenesis during embryogenesis, homeostasis, and regeneration in this animal. We show that SoxB genes act sequentially at least in some cases. Stem cells expressing Piwi1 and Soxb1, which have broad developmental potential, become neural progenitors that express Soxb2 before differentiating into mature neural cells. Knockdown of SoxB genes resulted in complex defects in embryonic neurogenesis. Hydractinia neural cells differentiate while migrating from the aboral to the oral end of the animal, but it is unclear whether migration per se or exposure to different microenvironments is the main driver of their fate determination. Our data constitute a rich resource for studies aiming at addressing this question, which is at the heart of understanding the origin and development of animal nervous systems.
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Affiliation(s)
- Eleni Chrysostomou
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
| | - Hakima Flici
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
| | - Sebastian G Gornik
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
| | - Miguel Salinas-Saavedra
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
| | - James M Gahan
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
| | - Emma T McMahon
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
| | - Kerry Thompson
- Centre for Microscopy and Imaging, Discipline of Anatomy, National University of Ireland, GalwayGalwayIreland
| | - Shirley Hanley
- National Centre for Biomedical Engineering Science, National University of Ireland, GalwayGalwayIreland
| | - Michelle Kilcoyne
- Carbohydrate Signalling Group, Microbiology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
| | - Christine E Schnitzler
- Whitney Laboratory for Marine Bioscience, University of FloridaSt. Augustine, FloridaUnited States,Department of Biology, University of FloridaGainesville, FloridaUnited States
| | - Paul Gonzalez
- Computational and Statistical Genomics Branch, Division of Intramural Research, National Human Genome Research Institute, National Institutes of HealthBethesda, MarylandUnited States
| | - Andreas D Baxevanis
- Computational and Statistical Genomics Branch, Division of Intramural Research, National Human Genome Research Institute, National Institutes of HealthBethesda, MarylandUnited States
| | - Uri Frank
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
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Pillai A, Gungi A, Reddy PC, Galande S. Epigenetic Regulation in Hydra: Conserved and Divergent Roles. Front Cell Dev Biol 2021; 9:663208. [PMID: 34041242 PMCID: PMC8141815 DOI: 10.3389/fcell.2021.663208] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 04/13/2021] [Indexed: 12/12/2022] Open
Abstract
Transitions in gene regulatory processes responsible for the emergence of specialized cell types and spatiotemporal regulation of developmental signaling prior to the divergence of Cnidaria and Bilateria are poorly understood. As a sister group of Bilateria, the phylum Cnidaria can provide significant insights into these processes. Among the cnidarians, hydrae have been studied for >250 years to comprehend the mechanisms underlying their unique immortality and robust regenerative capacity. Studies on Hydra spp. and other pre-bilaterians alike have advanced our understanding of the evolutionary underpinnings governing eumetazoan tissue development, homeostasis, and regeneration. In addition to its regenerative potential, Hydra exhibits continuously active axial patterning due to its peculiar tissue dynamics. These distinctive physiological processes necessitate large scale gene expression changes that are governed by the multitude of epigenetic mechanisms operating in cells. This review highlights the contemporary knowledge of epigenetic regulation in Hydra with contemporary studies from other members of Cnidaria, as well as the interplay between regulatory mechanisms wherever demonstrated. The studies covered in the scope of this review reveal both ancestral and divergent roles played by conserved epigenetic mechanisms with emphasis on transcriptional regulation. Additionally, single-cell transcriptomics data was mined to predict the physiological relevance of putative gene regulatory components, which is in agreement with published findings and yielded insights into the possible functions of the gene regulatory mechanisms that are yet to be deciphered in Hydra, such as DNA methylation. Finally, we delineate potentially rewarding epigenetics research avenues that can further leverage the unique biology of Hydra.
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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, India
| | - Sanjeev Galande
- Centre of Excellence in Epigenetics, Department of Biology, Indian Institute of Science Education and Research, Pune, India
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10
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The transcriptome of anterior regeneration in earthworm Eudrilus eugeniae. Mol Biol Rep 2020; 48:259-283. [PMID: 33306150 DOI: 10.1007/s11033-020-06044-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/28/2020] [Indexed: 12/25/2022]
Abstract
The oligochaete earthworm, Eudrilus eugeniae is capable of regenerating both anterior and posterior segments. The present study focuses on the transcriptome analysis of earthworm E. eugeniae to identify and functionally annotate the key genes supporting the anterior blastema formation and regulating the anterior regeneration of the worm. The Illumina sequencing generated a total of 91,593,182 raw reads which were assembled into 105,193 contigs using CLC genomics workbench. In total, 40,946 contigs were annotated against the NCBI nr and SwissProt database and among them, 15,702 contigs were assigned to 14,575 GO terms. Besides a total of 9389 contigs were mapped to 416 KEGG biological pathways. The RNA-Seq comparison study identified 10,868 differentially expressed genes (DEGs) and of them, 3986 genes were significantly upregulated in the anterior regenerated blastema tissue samples of the worm. The GO enrichment analysis showed angiogenesis and unfolded protein binding as the top enriched functions and the pathway enrichment analysis denoted TCA cycle as the most significantly enriched pathway associated with the upregulated gene dataset of the worm. The identified DEGs and their function and pathway information can be effectively utilized further to interpret the key cellular, genetic and molecular events associated with the regeneration of the worm.
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11
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Gene knockdown via electroporation of short hairpin RNAs in embryos of the marine hydroid Hydractinia symbiolongicarpus. Sci Rep 2020; 10:12806. [PMID: 32732955 PMCID: PMC7393174 DOI: 10.1038/s41598-020-69489-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 07/13/2020] [Indexed: 11/08/2022] Open
Abstract
Analyzing gene function in a broad range of research organisms is crucial for understanding the biological functions of genes and their evolution. Recent studies have shown that short hairpin RNAs (shRNAs) can induce gene-specific knockdowns in two cnidarian species. We have developed a detailed, straightforward, and scalable method to deliver shRNAs into fertilized eggs of the hydrozoan cnidarian Hydractinia symbiolongicarpus via electroporation, yielding effective gene-targeted knockdowns that can last throughout embryogenesis. Our electroporation protocol allows for the transfection of shRNAs into hundreds of fertilized H. symbiolongicarpus eggs simultaneously with minimal embryo death and no long-term harmful consequences on the developing animals. We show RT-qPCR and detailed phenotypic evidence of our method successfully inducing effective knockdowns of an exogenous gene (eGFP) and an endogenous gene (Nanos2), as well as knockdown confirmation by RT-qPCR of two other endogenous genes. We also provide visual confirmation of successful shRNA transfection inside embryos through electroporation. Our detailed protocol for electroporation of shRNAs in H. symbiolongicarpus embryos constitutes an important experimental resource for the hydrozoan community while also serving as a successful model for the development of similar methods for interrogating gene function in other marine invertebrates.
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12
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Zancolli G, Casewell NR. Venom Systems as Models for Studying the Origin and Regulation of Evolutionary Novelties. Mol Biol Evol 2020; 37:2777-2790. [DOI: 10.1093/molbev/msaa133] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Abstract
A central goal in biology is to determine the ways in which evolution repeats itself. One of the most remarkable examples in nature of convergent evolutionary novelty is animal venom. Across diverse animal phyla, various specialized organs and anatomical structures have evolved from disparate developmental tissues to perform the same function, that is, produce and deliver a cocktail of potent molecules to subdue prey or predators. Venomous organisms therefore offer unique opportunities to investigate the evolutionary processes of convergence of key adaptive traits, and the molecular mechanisms underlying the emergence of novel genes, cells, and tissues. Indeed, some venomous species have already proven to be highly amenable as models for developmental studies, and recent work with venom gland organoids provides manipulatable systems for directly testing important evolutionary questions. Here, we provide a synthesis of the current knowledge that could serve as a starting point for the establishment of venom systems as new models for evolutionary and molecular biology. In particular, we highlight the potential of various venomous species for the study of cell differentiation and cell identity, and the regulatory dynamics of rapidly evolving, highly expressed, tissue-specific, gene paralogs. We hope that this review will encourage researchers to look beyond traditional study organisms and consider venom systems as useful tools to explore evolutionary novelties.
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Affiliation(s)
- Giulia Zancolli
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Nicholas R Casewell
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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13
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Characterization of gonad differentially expressed SoxB2 genes in mud crab Scylla paramamosain. Gene 2020; 740:144507. [DOI: 10.1016/j.gene.2020.144507] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 01/26/2020] [Accepted: 02/21/2020] [Indexed: 12/25/2022]
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14
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Frank U, Nicotra ML, Schnitzler CE. The colonial cnidarian Hydractinia. EvoDevo 2020; 11:7. [PMID: 32226598 PMCID: PMC7098123 DOI: 10.1186/s13227-020-00151-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 03/12/2020] [Indexed: 11/27/2022] Open
Abstract
Hydractinia, a genus of colonial marine cnidarians, has been used as a model organism for developmental biology and comparative immunology for over a century. It was this animal where stem cells and germ cells were first studied. However, protocols for efficient genetic engineering have only recently been established by a small but interactive community of researchers. The animal grows well in the lab, spawns daily, and its relatively short life cycle allows genetic studies. The availability of genomic tools and resources opens further opportunities for research using this animal. Its accessibility to experimental manipulation, growth- and cellular-plasticity, regenerative ability, and resistance to aging and cancer place Hydractinia as an emerging model for research in many biological and environmental disciplines.
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Affiliation(s)
- Uri Frank
- 1Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Matthew L Nicotra
- 2Departments of Surgery and Immunology, Center for Evolutionary Biology and Medicine, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA 15261 USA
| | - Christine E Schnitzler
- 3Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 320803 USA.,4Department of Biology, University of Florida, Gainesville, FL 32611 USA
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DuBuc TQ, Schnitzler CE, Chrysostomou E, McMahon ET, Febrimarsa, Gahan JM, Buggie T, Gornik SG, Hanley S, Barreira SN, Gonzalez P, Baxevanis AD, Frank U. Transcription factor AP2 controls cnidarian germ cell induction. Science 2020; 367:757-762. [PMID: 32054756 PMCID: PMC7025884 DOI: 10.1126/science.aay6782] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 12/06/2019] [Indexed: 12/18/2022]
Abstract
Clonal animals do not sequester a germ line during embryogenesis. Instead, they have adult stem cells that contribute to somatic tissues or gametes. How germ fate is induced in these animals, and whether this process is related to bilaterian embryonic germline induction, is unknown. We show that transcription factor AP2 (Tfap2), a regulator of mammalian germ lines, acts to commit adult stem cells, known as i-cells, to the germ cell fate in the clonal cnidarian Hydractinia symbiolongicarpus Tfap2 mutants lacked germ cells and gonads. Transplanted wild-type cells rescued gonad development but not germ cell induction in Tfap2 mutants. Forced expression of Tfap2 in i-cells converted them to germ cells. Therefore, Tfap2 is a regulator of germ cell commitment across germ line-sequestering and germ line-nonsequestering animals.
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Affiliation(s)
- Timothy Q DuBuc
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Christine E Schnitzler
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Eleni Chrysostomou
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Emma T McMahon
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Febrimarsa
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - James M Gahan
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Tara Buggie
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Sebastian G Gornik
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Shirley Hanley
- National Centre for Biomedical Engineering Science, National University of Ireland Galway, Galway, Ireland
| | - Sofia N Barreira
- Computational and Statistical Genomics Branch, Division of Intramural Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Paul Gonzalez
- Computational and Statistical Genomics Branch, Division of Intramural Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Andreas D Baxevanis
- Computational and Statistical Genomics Branch, Division of Intramural Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Uri Frank
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland.
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Funayama N, Frank U. Meeting Report on “At the Roots of Bilaterian Complexity: Insights from Early Emerging Metazoans,” Tutzing (Germany) September 16–19, 2019. Bioessays 2019; 42:e1900236. [DOI: 10.1002/bies.201900236] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 12/05/2019] [Indexed: 12/27/2022]
Affiliation(s)
- Noriko Funayama
- Department of Biophysics, Graduate School of ScienceKyoto University Kitashirakawaoiwake, Sakyo‐ku Kyoto 606‐8502 Japan
| | - Uri Frank
- Centre for Chromosome BiologySchool of Natural SciencesNational University of Ireland Galway University Road Galway H91 W2TYIreland
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17
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Boundary maintenance in the ancestral metazoan Hydra depends on histone acetylation. Dev Biol 2019; 458:200-214. [PMID: 31738910 DOI: 10.1016/j.ydbio.2019.11.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 11/04/2019] [Accepted: 11/12/2019] [Indexed: 12/24/2022]
Abstract
Much of boundary formation during development remains to be understood, despite being a defining feature of many animal taxa. Axial patterning of Hydra, a member of the ancient phylum Cnidaria which diverged prior to the bilaterian radiation, involves a steady-state of production and loss of tissue, and is dependent on an organizer located in the upper part of the head. We show that the sharp boundary separating tissue in the body column from head and foot tissue depends on histone acetylation. Histone deacetylation disrupts the boundary by affecting numerous developmental genes including Wnt components and prevents stem cells from entering the position dependent differentiation program. Overall, our results suggest that reversible histone acetylation is an ancient regulatory mechanism for partitioning the body axis into domains with specific identity, which was present in the common ancestor of cnidarians and bilaterians, at least 600 million years ago.
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18
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Zondag L, M Clarke R, Wilson MJ. Histone deacetylase activity is required for Botrylloides leachii whole-body regeneration. ACTA ACUST UNITED AC 2019; 222:jeb.203620. [PMID: 31253711 DOI: 10.1242/jeb.203620] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 06/24/2019] [Indexed: 12/13/2022]
Abstract
The colonial tunicate Botrylloides leachii is exceptional at regenerating from a piece of vascular tunic after loss of all adults from the colony. Previous transcriptome analyses indicate a brief period of healing before regeneration of a new adult (zooid) in as little as 8-10 days. However, there is little understanding of how the resulting changes to gene expression, required to drive regeneration, are initiated and how the overall process is regulated. Rapid changes to transcription often occur in response to chromatin changes, mediated by histone modifications such as histone acetylation. Here, we investigated a group of key epigenetic modifiers, histone deacetylases (HDAC), which are known to play an important role in many biological processes such as development, healing and regeneration. Through our transcriptome data, we identified and quantified the expression levels of HDAC and histone acetyltransferase enzymes during whole-body regeneration (WBR). To determine whether HDAC activity is required for WBR, we inhibited its action using valproic acid and trichostatin A. HDAC inhibition prevented the final morphological changes normally associated with WBR and resulted in aberrant gene expression. Botrylloides leachii genes including Slit2, TGF-β, Piwi and Fzd4 all showed altered mRNA levels upon HDAC inhibition in comparison with the control samples. Additionally, atypical expression of Bl_Piwi was found in immunocytes upon HDAC inhibition. Together, these results show that HDAC function, specifically HDAC I/IIa class enzymes, are vital for B. leachii to undergo WBR successfully.
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Affiliation(s)
- Lisa Zondag
- Developmental Biology and Genomics Laboratory, Department of Anatomy, Otago School of Medical Sciences, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | - Rebecca M Clarke
- Developmental Biology and Genomics Laboratory, Department of Anatomy, Otago School of Medical Sciences, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | - Megan J Wilson
- Developmental Biology and Genomics Laboratory, Department of Anatomy, Otago School of Medical Sciences, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
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19
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Rentzsch F, Juliano C, Galliot B. Modern genomic tools reveal the structural and cellular diversity of cnidarian nervous systems. Curr Opin Neurobiol 2019; 56:87-96. [PMID: 30654234 DOI: 10.1016/j.conb.2018.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/10/2018] [Accepted: 12/11/2018] [Indexed: 12/11/2022]
Abstract
Cnidarians shared a common ancestor with bilaterians more than 600 million years ago. This sister group relationship gives them an informative phylogenetic position for understanding the fascinating morphological and molecular cell type diversity of bilaterian nervous systems. Moreover, cnidarians display novel features such as endodermal neurogenesis and independently evolved centralizations, which provide a platform for understanding the evolution of nervous system innovations. In recent years, the application of modern genomic tools has significantly advanced our understanding of cnidarian nervous system structure and function. For example, transgenic reporter lines and gene knockdown experiments in several cnidarian species reveal a significant degree of conservation in the neurogenesis gene regulatory program, while single cell RNA sequencing projects are providing a much deeper understanding of cnidarian neural cell type diversity. At the level of neural function, the physiological properties of ion channels have been described and calcium imaging of the nervous system in whole animals has allowed for the identification of neural circuits underlying specific behaviours. Cnidarians have arrived in the modern era of molecular neurobiology and are primed to provide exciting new insights into the early evolution of nervous systems.
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Affiliation(s)
- Fabian Rentzsch
- Sars Centre for Marine Molecular Biology, Norway; Department for Biological Sciences, University of Bergen, Norway.
| | - Celina Juliano
- Department of Molecular and Cellular Biology, University of California Davis, CA 95616, United States.
| | - Brigitte Galliot
- Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Switzerland.
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20
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Babonis LS, DeBiasse MB, Francis WR, Christianson LM, Moss AG, Haddock SHD, Martindale MQ, Ryan JF. Integrating Embryonic Development and Evolutionary History to Characterize Tentacle-Specific Cell Types in a Ctenophore. Mol Biol Evol 2018; 35:2940-2956. [PMID: 30169705 PMCID: PMC6278862 DOI: 10.1093/molbev/msy171] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The origin of novel traits can promote expansion into new niches and drive speciation. Ctenophores (comb jellies) are unified by their possession of a novel cell type: the colloblast, an adhesive cell found only in the tentacles. Although colloblast-laden tentacles are fundamental for prey capture among ctenophores, some species have tentacles lacking colloblasts and others have lost their tentacles completely. We used transcriptomes from 36 ctenophore species to identify gene losses that occurred specifically in lineages lacking colloblasts and tentacles. We cross-referenced these colloblast- and tentacle-specific candidate genes with temporal RNA-Seq during embryogenesis in Mnemiopsis leidyi and found that both sets of candidates are preferentially expressed during tentacle morphogenesis. We also demonstrate significant upregulation of candidates from both data sets in the tentacle bulb of adults. Both sets of candidates were enriched for an N-terminal signal peptide and protein domains associated with secretion; among tentacle candidates we also identified orthologs of cnidarian toxin proteins, presenting tantalizing evidence that ctenophore tentacles may secrete toxins along with their adhesive. Finally, using cell lineage tracing, we demonstrate that colloblasts and neurons share a common progenitor, suggesting the evolution of colloblasts involved co-option of a neurosecretory gene regulatory network. Together these data offer an initial glimpse into the genetic architecture underlying ctenophore cell-type diversity.
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Affiliation(s)
- Leslie S Babonis
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL
| | - Melissa B DeBiasse
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL
| | - Warren R Francis
- Monterey Bay Aquarium Research Institute (MBARI), Moss Landing, CA
| | | | - Anthony G Moss
- Department of Biological Sciences, Auburn University, Auburn, AL
| | | | - Mark Q Martindale
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL
| | - Joseph F Ryan
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL
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21
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Flici H, Frank U. Inhibition of SoxB2 or HDACs suppresses Hydractinia head regeneration by affecting blastema formation. Commun Integr Biol 2018; 11:1-5. [PMID: 30083285 PMCID: PMC6067865 DOI: 10.1080/19420889.2018.1450032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 03/06/2018] [Indexed: 10/28/2022] Open
Abstract
Regeneration has long been known to occur in the cnidarian Hydractinia. This process refers to its ability to regrow structures, i.e a head, lost by injury, a phenomenon that depends on the migration of proliferative cells to the site of injury, and the formation of a blastema, a mass of undifferentiated cells that will restore the missing head tissues. In our study, we showed that members of SoxB transcription factors and HDACs are involved in the regulation of Hydractinia neurogenesis in tissue homeostasis and regeneration. Particularly, we revealed that knockdown of SoxB2 or Hdac2 (a class I HDAC) knockdown, or inhibition of HDAC activity, suppress head regeneration. Here, we show that SoxB2 knockdown, or the inhibition of HDACs activity by TSA, a HDAC Class I and II inhibitor, interfere with head regeneration by affecting the migration of proliferative cells and the formation of a proliferative blastema.
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Affiliation(s)
- Hakima Flici
- Centre for Chromosome Biology (CCB), School of Natural Sciences, National University of Ireland, Galway H91 CF50, Ireland
| | - Uri Frank
- Centre for Chromosome Biology (CCB), School of Natural Sciences, National University of Ireland, Galway H91 CF50, Ireland
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22
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Demyanenko S, Neginskaya M, Berezhnaya E. Expression of Class I Histone Deacetylases in Ipsilateral and Contralateral Hemispheres after the Focal Photothrombotic Infarction in the Mouse Brain. Transl Stroke Res 2017; 9:471-483. [PMID: 29218547 DOI: 10.1007/s12975-017-0595-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/27/2017] [Accepted: 11/28/2017] [Indexed: 12/19/2022]
Abstract
Histone acetylation and deacetylation are among the most important epigenetic processes that regulate gene expression. Nonselective inhibitors of histone deacetylases (HDAC) can protect brain cells during ischemia and stroke. However, which HDAC isoform is involved in this effect is unknown. Some isoforms of histone deacetylases (HDACs) protect brain cells after ischemia, whereas others can promote their death. Most studies consider early periods (1-24 h) after stroke, whereas little is known on the involvement of HDACs during recovery after stroke. In this study, cellular and intracellular rearrangement of class I HDACs (HDAC1, HDAC2, HDAC3, HDAC8) was investigated at late periods after photothrombotic infarction (PTI) of the mouse sensorimotor cortex in intact tissue that surrounds the ischemia core, in the corresponding region of the contralateral hemisphere, and in the hippocampus. Each HDAC isoform had a specific pattern of expression and intracellular distribution in neurons and astrocytes at different periods after the ischemia. We did not observe ischemia-induced changes in the subcellular localization of HDACs under study. Three days after the PTI, the expression of HDAC2 was increased in neurons of the damaged hemisphere. The activity of HDAC2 and HDAC8 was elevated 7 days after the ischemia both in neurons and astrocytes of the studied brain structures; the activity of HDAC8 was also increased 14 days after the ischemia. It is notable that the expression of class I HDACs in the intact hemisphere changes in the same way as their expression in the living tissue of the damaged hemisphere. HDAC1 was found both in the nuclei and cytoplasm of the brain cells; HDAC2 was predominantly localized in the nuclei, and HDAC8 was predominantly observed in the cytoplasm. This in addition to the regulation of gene transcription indicates nontranscriptional activity of HDAC1 and HDAC8 during recovery of the brain tissue after the ischemia. HDAC2 and HDAC8 were identified as potential mediators in an early recovery period after stroke, suggesting that selective inhibitors and activators of HDACs can be considered for therapeutic approaches in this period.
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Affiliation(s)
- Svetlana Demyanenko
- Laboratory of Molecular Neurobiology, Academy of Biology and Biotechnology, Southern Federal University, prospect Stachki 194/1, Rostov-on-Don, 344090, Russia.
| | - Maria Neginskaya
- Laboratory of Molecular Neurobiology, Academy of Biology and Biotechnology, Southern Federal University, prospect Stachki 194/1, Rostov-on-Don, 344090, Russia
| | - Elena Berezhnaya
- Laboratory of Molecular Neurobiology, Academy of Biology and Biotechnology, Southern Federal University, prospect Stachki 194/1, Rostov-on-Don, 344090, Russia
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23
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Babonis LS, Martindale MQ. PaxA, but not PaxC, is required for cnidocyte development in the sea anemone Nematostella vectensis. EvoDevo 2017; 8:14. [PMID: 28878874 PMCID: PMC5584322 DOI: 10.1186/s13227-017-0077-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 08/16/2017] [Indexed: 12/25/2022] Open
Abstract
Background Pax genes are a family of conserved transcription factors that regulate many aspects of developmental morphogenesis, notably the development of ectodermal sensory structures including eyes. Nematostella vectensis, the starlet sea anemone, has numerous Pax orthologs, many of which are expressed early during embryogenesis. The function of Pax genes in this eyeless cnidarian is unknown. Results Here, we show that PaxA, but not PaxC, plays a critical role in the development of cnidocytes in N. vectensis. Knockdown of PaxA results in a loss of developing cnidocytes and downregulation of numerous cnidocyte-specific genes, including a variant of the transcription factor Mef2. We also demonstrate that the co-expression of Mef2 in a subset of the PaxA-expressing cells is associated with the development with a second lineage of cnidocytes and show that knockdown of the neural progenitor gene SoxB2 results in downregulation of expression of PaxA, Mef2, and several cnidocyte-specific genes. Because PaxA is not co-expressed with SoxB2 at any time during cnidocyte development, we propose a simple model for cnidogenesis whereby a SoxB2-expressing progenitor cell population undergoes division to give rise to PaxA-expressing cnidocytes, some of which also express Mef2. Discussion The role of PaxA in cnidocyte development among hydrozoans has not been studied, but the conserved role of SoxB2 in regulating the fate of a progenitor cell that gives rise to neurons and cnidocytes in Nematostella and Hydractinia echinata suggests that this SoxB2/PaxA pathway may well be conserved across cnidarians.
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Affiliation(s)
- Leslie S Babonis
- Whitney Laboratory for Marine Bioscience, University of Florida, 9505 Ocean Shore Blvd, St. Augustine, FL 32080 USA
| | - Mark Q Martindale
- Whitney Laboratory for Marine Bioscience, University of Florida, 9505 Ocean Shore Blvd, St. Augustine, FL 32080 USA.,Department of Biology, University of Florida, Gainesville, FL 32611 USA
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24
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Gahan JM, Schnitzler CE, DuBuc TQ, Doonan LB, Kanska J, Gornik SG, Barreira S, Thompson K, Schiffer P, Baxevanis AD, Frank U. Functional studies on the role of Notch signaling in Hydractinia development. Dev Biol 2017; 428:224-231. [PMID: 28601529 DOI: 10.1016/j.ydbio.2017.06.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/06/2017] [Accepted: 06/06/2017] [Indexed: 11/19/2022]
Abstract
The function of Notch signaling was previously studied in two cnidarians, Hydra and Nematostella, representing the lineages Hydrozoa and Anthozoa, respectively. Using pharmacological inhibition in Hydra and a combination of pharmacological and genetic approaches in Nematostella, it was shown in both animals that Notch is required for tentacle morphogenesis and for late stages of stinging cell maturation. Surprisingly, a role for Notch in neural development, which is well documented in bilaterians, was evident in embryonic Nematostella but not in adult Hydra. Adult neurogenesis in the latter seemed to be unaffected by DAPT, a drug that inhibits Notch signaling. To address this apparent discrepancy, we studied the role of Notch in Hydractinia echinata, an additional hydrozoan, in all life stages. Using CRISPR-Cas9 mediated mutagenesis, transgenesis, and pharmacological interference we show that Notch is dispensable for Hydractinia normal neurogenesis in all life stages but is required for the maturation of stinging cells and for tentacle morphogenesis. Our results are consistent with a conserved role for Notch in morphogenesis and nematogenesis across Cnidaria, and a lineage-specific loss of Notch dependence in neurogenesis in hydrozoans.
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Affiliation(s)
- James M Gahan
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Christine E Schnitzler
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 320803, USA; Department of Biology, University of Florida, Gainesville, FL 32611, USA; Division of Intramural Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Timothy Q DuBuc
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Liam B Doonan
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Justyna Kanska
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Sebastian G Gornik
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Sofia Barreira
- Division of Intramural Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Kerry Thompson
- Centre for Microscopy and Imaging, Discipline of Anatomy, School of Medicine, National University of Ireland, Galway, Galway, Ireland
| | - Philipp Schiffer
- Department for Genetics Environment and Evolution, University College London, London, UK
| | - Andreas D Baxevanis
- Division of Intramural Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Uri Frank
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland.
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