1
|
Ishii R, Yoshida M, Suzuki N, Ogino H, Suzuki M. X-ray micro-computed tomography of Xenopus tadpole reveals changes in brain ventricular morphology during telencephalon regeneration. Dev Growth Differ 2023; 65:300-310. [PMID: 37477433 DOI: 10.1111/dgd.12881] [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: 05/09/2023] [Revised: 06/26/2023] [Accepted: 06/30/2023] [Indexed: 07/22/2023]
Abstract
Xenopus tadpoles serve as an exceptional model organism for studying post-embryonic development in vertebrates. During post-embryonic development, large-scale changes in tissue morphology, including organ regeneration and metamorphosis, occur at the organ level. However, understanding these processes in a three-dimensional manner remains challenging. In this study, the use of X-ray micro-computed tomography (microCT) for the three-dimensional observation of the soft tissues of Xenopus tadpoles was explored. The findings revealed that major organs, such as the brain, heart, and kidneys, could be visualized with high contrast by phosphotungstic acid staining following fixation with Bouin's solution. Then, the changes in brain shape during telencephalon regeneration were analyzed as the first example of utilizing microCT to study organ regeneration in Xenopus tadpoles, and it was found that the size of the amputated telencephalon recovered to >80% of its original length within approximately 1 week. It was also observed that the ventricles tended to shrink after amputation and maintained this state for at least 3 days. This shrinkage was transient, as the ventricles expanded to exceed their original size within the following week. Temporary shrinkage and expansion of the ventricles, which were also observed in transgenic or fluorescent dye-injected tadpoles with telencephalon amputation, may be significant in tissue homeostasis in response to massive brain injury and subsequent repair and regeneration. This established method will improve experimental analyses in developmental biology and medical science using Xenopus tadpoles.
Collapse
Affiliation(s)
- Riona Ishii
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Mana Yoshida
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Nanoka Suzuki
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Hajime Ogino
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Makoto Suzuki
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| |
Collapse
|
2
|
Chen P, Levy DL. Regulation of organelle size and organization during development. Semin Cell Dev Biol 2023; 133:53-64. [PMID: 35148938 PMCID: PMC9357868 DOI: 10.1016/j.semcdb.2022.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/20/2022] [Accepted: 02/01/2022] [Indexed: 12/11/2022]
Abstract
During early embryogenesis, as cells divide in the developing embryo, the size of intracellular organelles generally decreases to scale with the decrease in overall cell size. Organelle size scaling is thought to be important to establish and maintain proper cellular function, and defective scaling may lead to impaired development and disease. However, how the cell regulates organelle size and organization are largely unanswered questions. In this review, we summarize the process of size scaling at both the cell and organelle levels and discuss recently discovered mechanisms that regulate this process during early embryogenesis. In addition, we describe how some recently developed techniques and Xenopus as an animal model can be used to investigate the underlying mechanisms of size regulation and to uncover the significance of proper organelle size scaling and organization.
Collapse
Affiliation(s)
- Pan Chen
- Institute of Biochemistry and Molecular Biology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, China.
| | - Daniel L Levy
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA.
| |
Collapse
|
3
|
Choi B, Kim H, Jang J, Park S, Jung H. Development and Degeneration of Retinal Ganglion Cell Axons in Xenopus tropicalis. Mol Cells 2022; 45:846-854. [PMID: 36380734 PMCID: PMC9676988 DOI: 10.14348/molcells.2022.0081] [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: 05/13/2022] [Accepted: 06/15/2022] [Indexed: 11/18/2022] Open
Abstract
Neurons make long-distance connections via their axons, and the accuracy and stability of these connections are crucial for brain function. Research using various animal models showed that the molecular and cellular mechanisms underlying the assembly and maintenance of neuronal circuitry are highly conserved in vertebrates. Therefore, to gain a deeper understanding of brain development and maintenance, an efficient vertebrate model is required, where the axons of a defined neuronal cell type can be genetically manipulated and selectively visualized in vivo. Placental mammals pose an experimental challenge, as time-consuming breeding of genetically modified animals is required due to their in utero development. Xenopus laevis, the most commonly used amphibian model, offers comparative advantages, since their embryos ex utero during which embryological manipulations can be performed. However, the tetraploidy of the X. laevis genome makes them not ideal for genetic studies. Here, we use Xenopus tropicalis, a diploid amphibian species, to visualize axonal pathfinding and degeneration of a single central nervous system neuronal cell type, the retinal ganglion cell (RGC). First, we show that RGC axons follow the developmental trajectory previously described in X. laevis with a slightly different timeline. Second, we demonstrate that co-electroporation of DNA and/or oligonucleotides enables the visualization of gene function-altered RGC axons in an intact brain. Finally, using this method, we show that the axon-autonomous, Sarm1-dependent axon destruction program operates in X. tropicalis. Taken together, the present study demonstrates that the visual system of X. tropicalis is a highly efficient model to identify new molecular mechanisms underlying axon guidance and survival.
Collapse
Affiliation(s)
- Boyoon Choi
- Department of Anatomy, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Hyeyoung Kim
- Department of Anatomy, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Jungim Jang
- Department of Anatomy, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Sihyeon Park
- Department of Anatomy, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Hosung Jung
- Department of Anatomy, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul 03722, Korea
| |
Collapse
|
4
|
Zhang M, Wilson SS, Casey KM, Thomson PE, Zlatow AL, Langlois VS, Green SL. Degenerative Osteoarthropathy in Laboratory Housed Xenopus (Silurana) tropicalis. Comp Med 2021; 71:512-520. [PMID: 34794532 DOI: 10.30802/aalas-cm-21-000061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In this case study, 15 adult laboratory Xenopus (Silurana) tropicalis (7 adult males and 8 adult females) were examined for nodular enlargements of the clawed digits (digits 0, I, II, and III) on the hind feet. Radiographs showed smoothly margined, rounded, peripherally mineralized lesions arising from the distal phalanges of digits 0-III with osteoproductive and osteolytic components in all frogs. Micro computed tomography (microCT) scans further revealed interphalangeal (IP), metacarpophalangeal (MCP), and metatarsophalangeal (MTP) joint osteoarthritis characterized by periarticular new bone formation, rounded mineral foci both peripherally and centrally within the joints, and more rarely, linear mineralization palmar/plantar to the joints in the flexor tendons. In the nonclawed digits, the shape of the distal phalanx was variably distorted and both subluxation and malangulation of IP joints were identified. Histologically, nodules corresponded to a peripheral rim of mature cortical bone surrounding central adipose tissue, scattered hematopoietic elements, and residual bone of the distal phalanx. Occasionally, the peripheral rim of cortical bone extended proximally to encompass the distal aspect of adjacent phalanx. MCP, MTP and IP joint spaces of most digits exhibited widespread osteoarthritis characterized by periarticular cartilaginous or osseous metaplasia, bony remodeling, and less frequently, granulomatous osteomyelitis. Nutritional analyses of the feed did not indicate imbalances nor were the lesions consistent with metabolic bone disease. The exact etiopathogenesis of these lesions is unknown; however, we hypothesize that the osteoarthritic changes are due to a combination of the frogs' mature age, the unique structure of the Xenopus spp. claw, genetics and biomechanical forces on the digits and distal phalanges of the hind feet.
Collapse
Affiliation(s)
- Mingyun Zhang
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford, California
| | - Sabrina S Wilson
- Diagnostic Imaging Service, William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, California
| | - Kerriann M Casey
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford, California
| | - Paisley E Thomson
- Institut National de la Recherche Scientifique (INRS) - Centre Eau Terre Environnement, Quebec, QC, Canada
| | - Anne L Zlatow
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford, California
| | - Valerie S Langlois
- Institut National de la Recherche Scientifique (INRS) - Centre Eau Terre Environnement, Quebec, QC, Canada
| | - Sherril L Green
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford, California;,
| |
Collapse
|
5
|
Coppenrath K, Tavares ALP, Shaidani NI, Wlizla M, Moody SA, Horb M. Generation of a new six1-null line in Xenopus tropicalis for study of development and congenital disease. Genesis 2021; 59:e23453. [PMID: 34664392 DOI: 10.1002/dvg.23453] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/02/2021] [Accepted: 09/04/2021] [Indexed: 12/15/2022]
Abstract
The vertebrate Six (Sine oculis homeobox) family of homeodomain transcription factors plays critical roles in the development of several organs. Six1 plays a central role in cranial placode development, including the precursor tissues of the inner ear, as well as other cranial sensory organs and the kidney. In humans, mutations in SIX1 underlie some cases of Branchio-oto-renal (BOR) syndrome, which is characterized by moderate-to-severe hearing loss. We utilized CRISPR/Cas9 technology to establish a six1 mutant line in Xenopus tropicalis that is available to the research community. We demonstrate that at larval stages, the six1-null animals show severe disruptions in gene expression of putative Six1 target genes in the otic vesicle, cranial ganglia, branchial arch, and neural tube. At tadpole stages, six1-null animals display dysmorphic Meckel's, ceratohyal, and otic capsule cartilage morphology. This mutant line will be of value for the study of the development of several organs as well as congenital syndromes that involve these tissues.
Collapse
Affiliation(s)
- Kelsey Coppenrath
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus Resource, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Andre L P Tavares
- Department of Anatomy and Cell Biology, George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA
| | - Nikko-Ideen Shaidani
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus Resource, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Marcin Wlizla
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus Resource, Marine Biological Laboratory, Woods Hole, Massachusetts, USA.,Embryology Department, Charles River Laboratories, Wilmington, Massachusetts, USA
| | - Sally A Moody
- Department of Anatomy and Cell Biology, George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA
| | - Marko Horb
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus Resource, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| |
Collapse
|
6
|
Mangus LM, França MS, Shivaprasad HL, Wolf JC. Research-Relevant Background Lesions and Conditions in Common Avian and Aquatic Species. ILAR J 2021; 62:169-202. [PMID: 33782706 DOI: 10.1093/ilar/ilab008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 11/18/2020] [Accepted: 12/20/2020] [Indexed: 12/20/2022] Open
Abstract
Non-mammalian vertebrates including birds, fish, and amphibians have a long history of contributing to ground-breaking scientific discoveries. Because these species offer several experimental advantages over higher vertebrates and share extensive anatomic and genetic homology with their mammalian counterparts, they remain popular animal models in a variety of fields such as developmental biology, physiology, toxicology, drug discovery, immunology, toxicology, and infectious disease. As with all animal models, familiarity with the anatomy, physiology, and spontaneous diseases of these species is necessary for ensuring animal welfare, as well as accurate interpretation and reporting of study findings. Working with avian and aquatic species can be especially challenging in this respect due to their rich diversity and array of unique adaptations. Here, we provide an overview of the research-relevant anatomic features, non-infectious conditions, and infectious diseases that impact research colonies of birds and aquatic animals, including fish and Xenopus species.
Collapse
Affiliation(s)
- Lisa M Mangus
- Department of Molecular and Comparative Pathobiology, Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Monique S França
- Poultry Diagnostic and Research Center, The University of Georgia, Athens, Georgia, USA
| | - H L Shivaprasad
- California Animal Health and Food Safety Laboratory System, University of California, Davis, Tulare, California, USA
| | - Jeffrey C Wolf
- Experimental Pathology Laboratories, Inc., Sterling, Virginia, USA
| |
Collapse
|
7
|
Exner CRT, Willsey HR. Xenopus leads the way: Frogs as a pioneering model to understand the human brain. Genesis 2021; 59:e23405. [PMID: 33369095 PMCID: PMC8130472 DOI: 10.1002/dvg.23405] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/12/2020] [Accepted: 12/14/2020] [Indexed: 12/20/2022]
Abstract
From its long history in the field of embryology to its recent advances in genetics, Xenopus has been an indispensable model for understanding the human brain. Foundational studies that gave us our first insights into major embryonic patterning events serve as a crucial backdrop for newer avenues of investigation into organogenesis and organ function. The vast array of tools available in Xenopus laevis and Xenopus tropicalis allows interrogation of developmental phenomena at all levels, from the molecular to the behavioral, and the application of CRISPR technology has enabled the investigation of human disorder risk genes in a higher-throughput manner. As the only major tetrapod model in which all developmental stages are easily manipulated and observed, frogs provide the unique opportunity to study organ development from the earliest stages. All of these features make Xenopus a premier model for studying the development of the brain, a notoriously complex process that demands an understanding of all stages from fertilization to organogenesis and beyond. Importantly, core processes of brain development are conserved between Xenopus and human, underlining the advantages of this model. This review begins by summarizing discoveries made in amphibians that form the cornerstones of vertebrate neurodevelopmental biology and goes on to discuss recent advances that have catapulted our understanding of brain development in Xenopus and in relation to human development and disease. As we engage in a new era of patient-driven gene discovery, Xenopus offers exceptional potential to uncover conserved biology underlying human brain disorders and move towards rational drug design.
Collapse
Affiliation(s)
- Cameron R T Exner
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, 94143, USA
| | - Helen Rankin Willsey
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, 94143, USA
| |
Collapse
|
8
|
Willsey HR, Exner CRT, Xu Y, Everitt A, Sun N, Wang B, Dea J, Schmunk G, Zaltsman Y, Teerikorpi N, Kim A, Anderson AS, Shin D, Seyler M, Nowakowski TJ, Harland RM, Willsey AJ, State MW. Parallel in vivo analysis of large-effect autism genes implicates cortical neurogenesis and estrogen in risk and resilience. Neuron 2021; 109:788-804.e8. [PMID: 33497602 DOI: 10.1016/j.neuron.2021.01.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 12/02/2020] [Accepted: 01/04/2021] [Indexed: 12/29/2022]
Abstract
Gene Ontology analyses of autism spectrum disorders (ASD) risk genes have repeatedly highlighted synaptic function and transcriptional regulation as key points of convergence. However, these analyses rely on incomplete knowledge of gene function across brain development. Here we leverage Xenopus tropicalis to study in vivo ten genes with the strongest statistical evidence for association with ASD. All genes are expressed in developing telencephalon at time points mapping to human mid-prenatal development, and mutations lead to an increase in the ratio of neural progenitor cells to maturing neurons, supporting previous in silico systems biological findings implicating cortical neurons in ASD vulnerability, but expanding the range of convergent functions to include neurogenesis. Systematic chemical screening identifies that estrogen, via Sonic hedgehog signaling, rescues this convergent phenotype in Xenopus and human models of brain development, suggesting a resilience factor that may mitigate a range of ASD genetic risks.
Collapse
Affiliation(s)
- Helen Rankin Willsey
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Cameron R T Exner
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Yuxiao Xu
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Amanda Everitt
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA; Institute for Neurodegenerative Diseases, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Nawei Sun
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA; Institute for Neurodegenerative Diseases, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Belinda Wang
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA; Institute for Neurodegenerative Diseases, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Jeanselle Dea
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Galina Schmunk
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA; Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Yefim Zaltsman
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA; Institute for Neurodegenerative Diseases, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Nia Teerikorpi
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA; Institute for Neurodegenerative Diseases, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Albert Kim
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Aoife S Anderson
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - David Shin
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA; Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Meghan Seyler
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA; Institute for Neurodegenerative Diseases, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Tomasz J Nowakowski
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA; Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Richard M Harland
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - A Jeremy Willsey
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA; Institute for Neurodegenerative Diseases, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA; Quantitative Biosciences Institute (QBI), University of California, San Francisco, San Francisco, CA 94143, USA.
| | - Matthew W State
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA; Quantitative Biosciences Institute (QBI), University of California, San Francisco, San Francisco, CA 94143, USA; Langley Porter Psychiatric Institute, University of California, San Francisco, San Francisco, CA 94143, USA.
| |
Collapse
|
9
|
Kakebeen AD, Chitsazan AD, Wills AE. Tissue disaggregation and isolation of specific cell types from transgenic Xenopus appendages for transcriptional analysis by FACS. Dev Dyn 2020; 250:1381-1392. [PMID: 33137227 DOI: 10.1002/dvdy.268] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/10/2020] [Accepted: 10/26/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Xenopus embryos and tadpoles are versatile models for embryological, cell biological, and regenerative studies. Genomic and transcriptomic approaches have been increasingly employed in these frogs. Most of these genome-wide analyses have profiled tissues in bulk, but there are many scenarios where isolation of single cells may be advantageous, including isolation of a preferred cell type, or generation of a single-cell suspension for applications such as scRNA-Seq. RESULTS Here we present a protocol for the disaggregation of complex tail and limb bud tissue, and use cell type-specific fluorescence in transgenic X. tropicalis appendages to isolate specific cell populations using fluorescence activated cell sorting (FACS). Our protocol addresses a specific challenge in Xenopus embryos and tadpoles: the storage of maternal yolk platelets in each cell, which can introduce light scatter and thereby false positives into FACS analysis. CONCLUSIONS Here we gate against both nontransgenic and ubiquitously transgenic animals to reduce both false positives and false negatives. We use the Xtr.Tg(pax6:GFP;cryga:RFP;actc1:RFP)Papal transgenic line as a test case to demonstrate that nucleic acid preparations made from sorted cells are high quality and specific. We anticipate this method will be adaptable to study various cell types that have transgenic reporter lines to better profile cell types of interest.
Collapse
Affiliation(s)
- Anneke Dixie Kakebeen
- Department of Biochemistry, University of Washington Seattle, Seattle, Washington, USA
| | - Alexander Daniel Chitsazan
- Oregon Health Sciences Center For Early Detection Advanced Research Center (CEDAR), Portland, Oregon, USA
| | | |
Collapse
|
10
|
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.
Collapse
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
| |
Collapse
|
11
|
Sterner ZR, Shewade LH, Mertz KM, Sturgeon SM, Buchholz DR. Glucocorticoid receptor is required for survival through metamorphosis in the frog Xenopus tropicalis. Gen Comp Endocrinol 2020; 291:113419. [PMID: 32032606 DOI: 10.1016/j.ygcen.2020.113419] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/23/2020] [Accepted: 02/03/2020] [Indexed: 02/07/2023]
Abstract
Stress hormones, also known as glucocorticoids, are critical for survival at birth in mammals due at least in part to their importance in lung maturation. However, because air breathing is not always required for amphibian survival and because stress hormones have no known developmental impact except to modulate the developmental actions of thyroid hormone (TH), the requirement for stress hormone signaling during metamorphosis is not well understoodi. Here, we produced a glucocorticoid receptor knockout (GRKO) Xenopus line with a frameshift mutation in the first exon of the glucocorticoid receptor. Induction by exogenous corticosterone (CORT, the frog stress hormone) of the CORT response genes, klf9 (Krüppel-like factor 9, also regulated by TH) and ush1g (Usher's syndrome 1G), was completely abrogated in GRKO tadpoles. Surprisingly, GRKO tadpoles developed faster than wild-type tadpoles until forelimb emergence and then developed more slowly until their death at the climax of metamorphosis. Growth rate was not affected in GRKO tadpoles, but they achieved a smaller maximum size. Gene expression analysis of the TH response genes, thrb (TH receptor beta) and klf9 showed reduced expression in the tail at metamorphic climax consistent with the reduced development rate. These results indicate that glucocorticoid receptor is required for survival through metamorphosis and support dual roles for GR signaling in control of developmental rate.
Collapse
Affiliation(s)
- Zachary R Sterner
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Leena H Shewade
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Kala M Mertz
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Savannah M Sturgeon
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Daniel R Buchholz
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States.
| |
Collapse
|
12
|
Wesley CC, Mishra S, Levy DL. Organelle size scaling over embryonic development. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2020; 9:e376. [PMID: 32003549 DOI: 10.1002/wdev.376] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 12/19/2019] [Accepted: 01/08/2020] [Indexed: 12/13/2022]
Abstract
Cell division without growth results in progressive cell size reductions during early embryonic development. How do the sizes of intracellular structures and organelles scale with cell size and what are the functional implications of such scaling relationships? Model organisms, in particular Caenorhabditis elegans worms, Drosophila melanogaster flies, Xenopus laevis frogs, and Mus musculus mice, have provided insights into developmental size scaling of the nucleus, mitotic spindle, and chromosomes. Nuclear size is regulated by nucleocytoplasmic transport, nuclear envelope proteins, and the cytoskeleton. Regulators of microtubule dynamics and chromatin compaction modulate spindle and mitotic chromosome size scaling, respectively. Developmental scaling relationships for membrane-bound organelles, like the endoplasmic reticulum, Golgi, mitochondria, and lysosomes, have been less studied, although new imaging approaches promise to rectify this deficiency. While models that invoke limiting components and dynamic regulation of assembly and disassembly can account for some size scaling relationships in early embryos, it will be exciting to investigate the contribution of newer concepts in cell biology such as phase separation and interorganellar contacts. With a growing understanding of the underlying mechanisms of organelle size scaling, future studies promise to uncover the significance of proper scaling for cell function and embryonic development, as well as how aberrant scaling contributes to disease. This article is categorized under: Establishment of Spatial and Temporal Patterns > Regulation of Size, Proportion, and Timing Early Embryonic Development > Fertilization to Gastrulation Comparative Development and Evolution > Model Systems.
Collapse
Affiliation(s)
- Chase C Wesley
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming
| | - Sampada Mishra
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming
| | - Daniel L Levy
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming
| |
Collapse
|
13
|
Franz-Odendaal TA, Hockman D. Non-model organisms and unique approaches are needed for the future of evo-devo. Dev Dyn 2019; 248:618-619. [PMID: 31215704 DOI: 10.1002/dvdy.71] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
| | - Dorit Hockman
- Division of Cell Biology, Department of Human Biology, Neuroscience Institute, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| |
Collapse
|