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Tate HM, Barone V, Schrankel CS, Hamdoun A, Lyons DC. Localization and origins of juvenile skeletogenic cells in the sea urchin Lytechinuspictus. Dev Biol 2024; 514:12-27. [PMID: 38862087 DOI: 10.1016/j.ydbio.2024.05.012] [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: 07/22/2023] [Revised: 05/10/2024] [Accepted: 05/16/2024] [Indexed: 06/13/2024]
Abstract
The development of the sea urchin larval body plan is well understood from extensive studies of embryonic patterning. However, fewer studies have investigated the late larval stages during which the unique pentaradial adult body plan develops. Previous work on late larval development highlights major tissue changes leading up to metamorphosis, but the location of specific cell types during juvenile development is less understood. Here, we improve on technical limitations by applying highly sensitive hybridization chain reaction fluorescent in situ hybridization (HCR-FISH) to the fast-developing and transparent sea urchin Lytechinus pictus, with a focus on skeletogenic cells. First, we show that HCR-FISH can be used in L. pictus to precisely localize skeletogenic cells in the rudiment. In doing so, we provide a detailed staging scheme for the appearance of skeletogenic cells around the rudiment prior to and during biomineralization and show that many skeletogenic cells unassociated with larval rods localize outside of the rudiment prior to localizing inside. Second, we show that downstream biomineralization genes have similar expression patterns during larval and juvenile skeletogenesis, suggesting some conservation of skeletogenic mechanisms during development between stages. Third, we find co-expression of blastocoelar and skeletogenic cell markers around juvenile skeleton located outside of the rudiment, which is consistent with data showing that cells from the non-skeletogenic mesoderm embryonic lineage contribute to the juvenile skeletogenic cell lineage. This work sets the foundation for subsequent studies of other cell types in the late larva of L. pictus to better understand juvenile body plan development, patterning, and evolution.
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Affiliation(s)
- Heidi M Tate
- Scripps Institution of Oceanography, UC San Diego, La Jolla, CA, USA
| | - Vanessa Barone
- Scripps Institution of Oceanography, UC San Diego, La Jolla, CA, USA
| | - Catherine S Schrankel
- Scripps Institution of Oceanography, UC San Diego, La Jolla, CA, USA; San Diego State University, San Diego, CA, USA
| | - Amro Hamdoun
- Scripps Institution of Oceanography, UC San Diego, La Jolla, CA, USA
| | - Deirdre C Lyons
- Scripps Institution of Oceanography, UC San Diego, La Jolla, CA, USA.
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Telmer CA, Karimi K, Chess MM, Agalakov S, Arshinoff BI, Lotay V, Wang DZ, Chu S, Pells TJ, Vize PD, Hinman VF, Ettensohn CA. Echinobase: a resource to support the echinoderm research community. Genetics 2024; 227:iyae002. [PMID: 38262680 DOI: 10.1093/genetics/iyae002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 12/27/2023] [Indexed: 01/25/2024] Open
Abstract
Echinobase (www.echinobase.org) is a model organism knowledgebase serving as a resource for the community that studies echinoderms, a phylum of marine invertebrates that includes sea urchins and sea stars. Echinoderms have been important experimental models for over 100 years and continue to make important contributions to environmental, evolutionary, and developmental studies, including research on developmental gene regulatory networks. As a centralized resource, Echinobase hosts genomes and collects functional genomic data, reagents, literature, and other information for the community. This third-generation site is based on the Xenbase knowledgebase design and utilizes gene-centric pages to minimize the time and effort required to access genomic information. Summary gene pages display gene symbols and names, functional data, links to the JBrowse genome browser, and orthology to other organisms and reagents, and tabs from the Summary gene page contain more detailed information concerning mRNAs, proteins, diseases, and protein-protein interactions. The gene pages also display 1:1 orthologs between the fully supported species Strongylocentrotus purpuratus (purple sea urchin), Lytechinus variegatus (green sea urchin), Patiria miniata (bat star), and Acanthaster planci (crown-of-thorns sea star). JBrowse tracks are available for visualization of functional genomic data from both fully supported species and the partially supported species Anneissia japonica (feather star), Asterias rubens (sugar star), and L. pictus (painted sea urchin). Echinobase serves a vital role by providing researchers with annotated genomes including orthology, functional genomic data aligned to the genomes, and curated reagents and data. The Echinoderm Anatomical Ontology provides a framework for standardizing developmental data across the phylum, and knowledgebase content is formatted to be findable, accessible, interoperable, and reusable by the research community.
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Affiliation(s)
- Cheryl A Telmer
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Kamran Karimi
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada T2N 1N4
| | - Macie M Chess
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Sergei Agalakov
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada T2N 1N4
| | - Bradley I Arshinoff
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada T2N 1N4
| | - Vaneet Lotay
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada T2N 1N4
| | - Dong Zhuo Wang
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada T2N 1N4
| | - Stanley Chu
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada T2N 1N4
| | - Troy J Pells
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada T2N 1N4
| | - Peter D Vize
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada T2N 1N4
| | - Veronica F Hinman
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Charles A Ettensohn
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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Stoeltje L, Luc JK, Haddad T, Schrankel CS. The roles of ABCB1/P-glycoprotein drug transporters in regulating gut microbes and inflammation: insights from animal models, old and new. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230074. [PMID: 38497255 PMCID: PMC10945405 DOI: 10.1098/rstb.2023.0074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 02/13/2024] [Indexed: 03/19/2024] Open
Abstract
Commensal enteric bacteria have evolved systems that enable growth in the ecologic niche of the host gastrointestinal tract. Animals evolved parallel mechanisms to survive the constant exposure to bacteria and their metabolic by-products. We propose that drug transporters encompass a crucial system to managing the gut microbiome. Drug transporters are present in the apical surface of gut epithelia. They detoxify cells from small molecules and toxins (xenobiotics) in the lumen. Here, we review what is known about commensal structure in the absence of the transporter ABCB1/P-glycoprotein in mammalian models. Knockout or low-activity alleles of ABCB1 lead to dysbiosis, Crohn's disease and ulcerative colitis in mammals. However, the exact function of ABCB1 in these contexts remain unclear. We highlight emerging models-the zebrafish Danio rerio and sea urchin Lytechinus pictus-that are poised to help dissect the fundamental mechanisms of ATP-binding cassette (ABC) transporters in the tolerance of commensal and pathogenic communities in the gut. We and others hypothesize that ABCB1 plays a direct role in exporting inflammatory bacterial products from host epithelia. Interdisciplinary work in this research area will lend novel insight to the transporter-mediated pathways that impact microbiome community structure and accelerate the pathogenesis of inflammatory bowel disease when perturbed. This article is part of the theme issue 'Sculpting the microbiome: how host factors determine and respond to microbial colonization'.
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Affiliation(s)
- Lauren Stoeltje
- Department of Biology, San Diego State University, 5500 Campanile Drive, Life Sciences North, Room 321, San Diego, CA 92182, USA
| | - Jenna K. Luc
- Department of Biology, San Diego State University, 5500 Campanile Drive, Life Sciences North, Room 321, San Diego, CA 92182, USA
| | - Timothaus Haddad
- Department of Biology, San Diego State University, 5500 Campanile Drive, Life Sciences North, Room 321, San Diego, CA 92182, USA
| | - Catherine S. Schrankel
- Department of Biology, San Diego State University, 5500 Campanile Drive, Life Sciences North, Room 321, San Diego, CA 92182, USA
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Vacquier VD, Hamdoun A. Cold storage and cryopreservation methods for spermatozoa of the sea urchins Lytechinus pictus and Strongylocentrotus purpuratus. Dev Dyn 2024. [PMID: 38340021 DOI: 10.1002/dvdy.691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/06/2023] [Accepted: 12/10/2023] [Indexed: 02/12/2024] Open
Abstract
BACKGROUND Sea urchins have contributed greatly to knowledge of fertilization, embryogenesis, and cell biology. However, until now, they have not been genetic model organisms because of their long generation times and lack of tools for husbandry and gene manipulation. We recently established the sea urchin Lytechinus pictus, as a multigenerational model Echinoderm, because of its relatively short generation time of 4-6 months and ease of laboratory culture. To take full advantage of this new multigenerational species, methods are needed to biobank and share genetically modified L. pictus sperm. RESULTS Here, we describe a method, based on sperm ion physiology that maintains L. pictus and Strongylocentrotus purpuratus sperm fertilizable for at least 5-10 weeks when stored at 0°C. We also describe a new method to cryopreserve sperm of both species. Sperm of both species can be frozen and thawed at least twice and still give rise to larvae that undergo metamorphosis. CONCLUSIONS The simple methods we describe work well for both species, achieving >90% embryo development and producing larvae that undergo metamorphosis to juvenile adults. We hope that these methods will be useful to others working on marine invertebrate sperm.
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Affiliation(s)
- Victor D Vacquier
- Center for Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
| | - Amro Hamdoun
- Center for Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
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Nesbit KT, Shikuma NJ. Future research directions of the model marine tubeworm Hydroides elegans and synthesis of developmental staging of the complete life cycle. Dev Dyn 2023; 252:1391-1400. [PMID: 37227089 PMCID: PMC10674040 DOI: 10.1002/dvdy.628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 05/02/2023] [Accepted: 05/07/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND The biofouling marine tube worm, Hydroides elegans, is an indirect developing polychaete with significance as a model organism for questions in developmental biology and the evolution of host-microbe interactions. However, a complete description of the life cycle from fertilization through sexual maturity remains scattered in the literature, and lacks standardization. RESULTS AND DISCUSSION Here, we present a unified staging scheme synthesizing the major morphological changes that occur during the entire life cycle of the animal. These data represent a complete record of the life cycle, and serve as a foundation for connecting molecular changes with morphology. CONCLUSIONS The present synthesis and associated staging scheme are especially timely as this system gains traction within research communities. Characterizing the Hydroides life cycle is essential for investigating the molecular mechanisms that drive major developmental transitions, like metamorphosis, in response to bacteria.
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Affiliation(s)
- Katherine T. Nesbit
- Molecular Biology Division, San Diego State University, 5500 Campanile Drive, San Diego CA, 92182
| | - Nicholas J. Shikuma
- Molecular Biology Division, San Diego State University, 5500 Campanile Drive, San Diego CA, 92182
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de Santiago WGA, Muñoz-Alvarez AI, Díaz-Martínez JP, Benítez-Villalobos F. Resemblances in the early development of two sea urchins: Toxopneustes roseus (Euechinoidea: Echinacea) and Rhyncholampas pacificus (Euechinoidea: Irregularia) from different habitats in the southern Mexican Pacific. Dev Biol 2023; 499:1-9. [PMID: 37085002 DOI: 10.1016/j.ydbio.2023.04.005] [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: 11/17/2022] [Revised: 04/10/2023] [Accepted: 04/18/2023] [Indexed: 04/23/2023]
Abstract
Sea urchins play a key role in the marine environment, contributing to maintain a balance in benthic ecosystems. Toxopneustes roseus acts as a regulator of rhodolith beds and is a key species as a bioturbation promoter, while Rhyncholampas pacificus moderates the detritus content of sediment through various mechanisms and contributes to accelerating the circulation of organic matter. However, nothing is known about their early development, so the objective of this research is to characterize the embryonic and larval development of specimens of the two species from the southern Mexican Pacific and identify the causes that produce their differences. The embryonic development of T. roseus lasted approximately 20 h; the echinopluteus larva appeared at 23 h and culminated in around 12 days with an eight-armed larva. Metamorphosis was reached at 18 days. The embryonic development of R. pacificus lasted about 15 h; the larva emerged at 20 h and culminated in about two days with an eight-armed larva. The metamorphosis was completed in 9 days. The reproductive output of both species determines their development time and the structure of their larvae; therefore, the energy of R. pacificus is invested in reaching metamorphosis earlier to ensure that its larvae, which are not very abundant, settle and recruit to the population. Regarding T. roseus, the longest permanence in the plankton is efficiently maintained by its numerous larvae through the presence of mobile arms and the shift of the swimming function to the epauletes. This is the first work that characterizes the early development of a species of the genus Toxopneustes and of the only living species of the genus Ryncholampas. The information generated in this work is essential to gaining knowledge about these groups of echinoids, especially the effect of the environment on their early development.
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Affiliation(s)
- Walter Germán Alonso de Santiago
- División de Estudios de Posgrado, Universidad del Mar (UMAR), Campus Puerto Ángel, Distrito de San Pedro Pochutla, Puerto Ángel, Oaxaca, C.P. 70902, Mexico; Laboratorio de Ecología del Desarrollo, Universidad del Mar (UMAR), Campus Puerto Ángel, Distrito de San Pedro Pochutla, Puerto Ángel, Oaxaca, C.P. 70902, Mexico
| | - Astrid Itzel Muñoz-Alvarez
- Laboratorio de Ecología del Desarrollo, Universidad del Mar (UMAR), Campus Puerto Ángel, Distrito de San Pedro Pochutla, Puerto Ángel, Oaxaca, C.P. 70902, Mexico
| | - Julia Patricia Díaz-Martínez
- Laboratorio de Ecología del Desarrollo, Universidad del Mar (UMAR), Campus Puerto Ángel, Distrito de San Pedro Pochutla, Puerto Ángel, Oaxaca, C.P. 70902, Mexico
| | - Francisco Benítez-Villalobos
- Laboratorio de Ecología del Desarrollo, Universidad del Mar (UMAR), Campus Puerto Ángel, Distrito de San Pedro Pochutla, Puerto Ángel, Oaxaca, C.P. 70902, Mexico; Instituto de Recursos, Universidad del Mar (UMAR), Campus Puerto Ángel, Distrito de San Pedro Pochutla, Puerto Ángel, Oaxaca, C.P. 70902, Mexico.
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Vyas H, Schrankel CS, Espinoza JA, Mitchell KL, Nesbit KT, Jackson E, Chang N, Lee Y, Warner J, Reitzel A, Lyons DC, Hamdoun A. Generation of a homozygous mutant drug transporter (ABCB1) knockout line in the sea urchin Lytechinus pictus. Development 2022; 149:275601. [PMID: 35666622 PMCID: PMC9245184 DOI: 10.1242/dev.200644] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 05/05/2022] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Sea urchins are premier model organisms for the study of early development. However, the lengthy generation times of commonly used species have precluded application of stable genetic approaches. Here, we use the painted sea urchin Lytechinus pictus to address this limitation and to generate a homozygous mutant sea urchin line. L. pictus has one of the shortest generation times of any currently used sea urchin. We leveraged this advantage to generate a knockout mutant of the sea urchin homolog of the drug transporter ABCB1, a major player in xenobiotic disposition for all animals. Using CRISPR/Cas9, we generated large fragment deletions of ABCB1 and used these readily detected deletions to rapidly genotype and breed mutant animals to homozygosity in the F2 generation. The knockout larvae are produced according to expected Mendelian distribution, exhibit reduced xenobiotic efflux activity and can be grown to maturity. This study represents a major step towards more sophisticated genetic manipulation of the sea urchin and the establishment of reproducible sea urchin animal resources.
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Affiliation(s)
- Himanshu Vyas
- Center for Marine Biotechnology and Biomedicine 1 , , , La Jolla, CA 92093-0202 , USA
- Scripps Institution of Oceanography 1 , , , La Jolla, CA 92093-0202 , USA
- University of California San Diego 1 , , , La Jolla, CA 92093-0202 , USA
| | - Catherine S. Schrankel
- Center for Marine Biotechnology and Biomedicine 1 , , , La Jolla, CA 92093-0202 , USA
- Scripps Institution of Oceanography 1 , , , La Jolla, CA 92093-0202 , USA
- University of California San Diego 1 , , , La Jolla, CA 92093-0202 , USA
| | - Jose A. Espinoza
- Center for Marine Biotechnology and Biomedicine 1 , , , La Jolla, CA 92093-0202 , USA
- Scripps Institution of Oceanography 1 , , , La Jolla, CA 92093-0202 , USA
- University of California San Diego 1 , , , La Jolla, CA 92093-0202 , USA
| | - Kasey L. Mitchell
- Center for Marine Biotechnology and Biomedicine 1 , , , La Jolla, CA 92093-0202 , USA
- Scripps Institution of Oceanography 1 , , , La Jolla, CA 92093-0202 , USA
- University of California San Diego 1 , , , La Jolla, CA 92093-0202 , USA
| | - Katherine T. Nesbit
- Center for Marine Biotechnology and Biomedicine 1 , , , La Jolla, CA 92093-0202 , USA
- Scripps Institution of Oceanography 1 , , , La Jolla, CA 92093-0202 , USA
- University of California San Diego 1 , , , La Jolla, CA 92093-0202 , USA
| | - Elliot Jackson
- Center for Marine Biotechnology and Biomedicine 1 , , , La Jolla, CA 92093-0202 , USA
- Scripps Institution of Oceanography 1 , , , La Jolla, CA 92093-0202 , USA
- University of California San Diego 1 , , , La Jolla, CA 92093-0202 , USA
| | - Nathan Chang
- Center for Marine Biotechnology and Biomedicine 1 , , , La Jolla, CA 92093-0202 , USA
- Scripps Institution of Oceanography 1 , , , La Jolla, CA 92093-0202 , USA
- University of California San Diego 1 , , , La Jolla, CA 92093-0202 , USA
| | - Yoon Lee
- Center for Marine Biotechnology and Biomedicine 1 , , , La Jolla, CA 92093-0202 , USA
- Scripps Institution of Oceanography 1 , , , La Jolla, CA 92093-0202 , USA
- University of California San Diego 1 , , , La Jolla, CA 92093-0202 , USA
| | - Jacob Warner
- University of North Carolina Wilmington 2 Department of Biology and Marine Biology , , Wilmington, NC 28403-5915 , USA
| | - Adam Reitzel
- University of North Carolina Charlotte 3 Department of Biological Sciences , , Charlotte, NC 28223-0001 , USA
| | - Deirdre C. Lyons
- Center for Marine Biotechnology and Biomedicine 1 , , , La Jolla, CA 92093-0202 , USA
- Scripps Institution of Oceanography 1 , , , La Jolla, CA 92093-0202 , USA
- University of California San Diego 1 , , , La Jolla, CA 92093-0202 , USA
| | - Amro Hamdoun
- Center for Marine Biotechnology and Biomedicine 1 , , , La Jolla, CA 92093-0202 , USA
- Scripps Institution of Oceanography 1 , , , La Jolla, CA 92093-0202 , USA
- University of California San Diego 1 , , , La Jolla, CA 92093-0202 , USA
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Warner JF, Lord JW, Schreiter SA, Nesbit KT, Hamdoun A, Lyons DC. Chromosomal-Level Genome Assembly of the Painted Sea Urchin Lytechinus pictus: A Genetically Enabled Model System for Cell Biology and Embryonic Development. Genome Biol Evol 2021; 13:evab061. [PMID: 33769486 PMCID: PMC8085125 DOI: 10.1093/gbe/evab061] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2021] [Indexed: 02/06/2023] Open
Abstract
The painted urchin Lytechinus pictus is a sea urchin in the family Toxopneustidae and one of several sea urchin species that are routinely used as an experimental research organism. Recently, L. pictus has emerged as a tractable model system for establishing transgenic sea urchin lines due to its amenability to long term laboratory culture. We present the first published genome of L. pictus. This chromosomal-level assembly was generated using Illumina sequencing in conjunction with Oxford Nanopore Technologies long read sequencing and HiC chromatin conformation capture sequencing. The 998.9-Mb assembly exhibits high contiguity and has a scaffold length N50 of 46.0 Mb with 97% of the sequence assembled into 19 chromosomal-length scaffolds. These 19 scaffolds exhibit a high degree of synteny compared with the 19 chromosomes of a related species Lytechinus variegatus. Ab initio and transcript evidence gene modeling, combined with sequence homology, identified 28,631 gene models that capture 92% of BUSCO orthologs. This annotation strategy was validated by manual curation of gene models for the ABC transporter superfamily, which confirmed the completeness and accuracy of the annotations. Thus, this genome assembly, in conjunction with recent high contiguity assemblies of related species, positions L. pictus as an exceptional model system for comparative functional genomics and it will be a key resource for the developmental, toxicological, and ecological biology scientific communities.
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Affiliation(s)
- Jacob F Warner
- Department of Biology and Marine Biology, University of North Carolina Wilmington, North Carolina, USA
| | - James W Lord
- Department of Biology and Marine Biology, University of North Carolina Wilmington, North Carolina, USA
| | - Samantha A Schreiter
- Department of Biology and Marine Biology, University of North Carolina Wilmington, North Carolina, USA
| | - Katherine T Nesbit
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
| | - Amro Hamdoun
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
| | - Deirdre C Lyons
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
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Nesbit KT, Hamdoun A. Embryo, larval, and juvenile staging of Lytechinus pictus from fertilization through sexual maturation. Dev Dyn 2020; 249:1334-1346. [PMID: 32644271 DOI: 10.1002/dvdy.223] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 06/17/2020] [Accepted: 06/21/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Sea urchin embryos have been used for more than a century in the study of fertilization and early development. However, several of the species used, such as Strongylocentrotus purpuratus, have long generation times making them suboptimal for transgenerational studies. RESULTS Here, we present an overview of the development of a rapidly developing echinoderm species, Lytechinus pictus, from fertilization through sexual maturation. When grown at room temperature (20°C) embryos complete the first cell cycle in 90 minutes, followed by subsequent cleavages every 45 minutes, leading to hatching at 9 hours postfertilization (hpf). The swimming embryos gastrulate from 12 to 36 hpf and produce the cells which subsequently give rise to the larval skeleton and immunocytes. Larvae begin to feed at 2 days and metamorphose by 3 weeks. Juveniles reach sexual maturity at 4 to 6 months of age, depending on individual growth rate. CONCLUSIONS This staging scheme lays a foundation for future studies in L. pictus, which share many of the attractive features of other urchins but have the key advantage of rapid development to sexual maturation. This is significant for multigenerational and genetic studies newly enabled by CRISPR-CAS mediated gene editing.
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Affiliation(s)
- Katherine T Nesbit
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
| | - Amro Hamdoun
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
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