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Willsey HR, Seaby EG, Godwin A, Ennis S, Guille M, Grainger RM. Modelling human genetic disorders in Xenopus tropicalis. Dis Model Mech 2024; 17:dmm050754. [PMID: 38832520 PMCID: PMC11179720 DOI: 10.1242/dmm.050754] [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] [Indexed: 06/05/2024] Open
Abstract
Recent progress in human disease genetics is leading to rapid advances in understanding pathobiological mechanisms. However, the sheer number of risk-conveying genetic variants being identified demands in vivo model systems that are amenable to functional analyses at scale. Here we provide a practical guide for using the diploid frog species Xenopus tropicalis to study many genes and variants to uncover conserved mechanisms of pathobiology relevant to human disease. We discuss key considerations in modelling human genetic disorders: genetic architecture, conservation, phenotyping strategy and rigour, as well as more complex topics, such as penetrance, expressivity, sex differences and current challenges in the field. As the patient-driven gene discovery field expands significantly, the cost-effective, rapid and higher throughput nature of Xenopus make it an essential member of the model organism armamentarium for understanding gene function in development and in relation to disease.
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Affiliation(s)
- Helen Rankin Willsey
- Department of Psychiatry and Behavioral Sciences, Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA 94158, USA
- Chan Zuckerberg Biohub - San Francisco, San Francisco, CA 94518, USA
| | - Eleanor G Seaby
- Genomic Informatics Group, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| | - Annie Godwin
- European Xenopus Resource Centre (EXRC), School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, UK
| | - Sarah Ennis
- Genomic Informatics Group, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| | - Matthew Guille
- European Xenopus Resource Centre (EXRC), School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, UK
| | - Robert M Grainger
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
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Neal SJ, Rajasekaran A, Jusić N, Taylor L, Read M, Alfandari D, Pignoni F, Moody SA. Using Xenopus to discover new candidate genes involved in BOR and other congenital hearing loss syndromes. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2024; 342:212-240. [PMID: 37830236 PMCID: PMC11014897 DOI: 10.1002/jez.b.23222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 08/15/2023] [Accepted: 09/14/2023] [Indexed: 10/14/2023]
Abstract
Hearing in infants is essential for brain development, acquisition of verbal language skills, and development of social interactions. Therefore, it is important to diagnose hearing loss soon after birth so that interventions can be provided as early as possible. Most newborns in the United States are screened for hearing deficits and commercially available next-generation sequencing hearing loss panels often can identify the causative gene, which may also identify congenital defects in other organs. One of the most prevalent autosomal dominant congenital hearing loss syndromes is branchio-oto-renal syndrome (BOR), which also presents with defects in craniofacial structures and the kidney. Currently, mutations in three genes, SIX1, SIX5, and EYA1, are known to be causative in about half of the BOR patients that have been tested. To uncover new candidate genes that could be added to congenital hearing loss genetic screens, we have combined the power of Drosophila mutants and protein biochemical assays with the embryological advantages of Xenopus, a key aquatic animal model with a high level of genomic similarity to human, to identify potential Six1 transcriptional targets and interacting proteins that play a role during otic development. We review our transcriptomic, yeast 2-hybrid, and proteomic approaches that have revealed a large number of new candidates. We also discuss how we have begun to identify how Six1 and co-factors interact to direct developmental events necessary for normal otic development.
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Affiliation(s)
- Scott J. Neal
- Department of Neuroscience and Physiology, Upstate Medical University, Syracuse, NY, USA
| | - Anindita Rajasekaran
- Department of Neuroscience and Physiology, Upstate Medical University, Syracuse, NY, USA
| | - Nisveta Jusić
- Department of Neuroscience and Physiology, Upstate Medical University, Syracuse, NY, USA
| | - Louis Taylor
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA, USA
| | - Mai Read
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA, USA
| | - Dominique Alfandari
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA, USA
| | - Francesca Pignoni
- Department of Neuroscience and Physiology, Upstate Medical University, Syracuse, NY, USA
| | - Sally A. Moody
- Department of Anatomy and Cell Biology, George Washington University, School of Medicine and Health Sciences, Washington, DC, USA
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Castro Colabianchi AM, González Pérez NG, Franchini LF, López SL. A maternal dorsoventral prepattern revealed by an asymmetric distribution of ventralizing molecules before fertilization in Xenopus laevis. Front Cell Dev Biol 2024; 12:1365705. [PMID: 38572484 PMCID: PMC10987785 DOI: 10.3389/fcell.2024.1365705] [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: 01/04/2024] [Accepted: 03/07/2024] [Indexed: 04/05/2024] Open
Abstract
The establishment of the embryonic dorsoventral axis in Xenopus occurs when the radial symmetry around the egg's animal-vegetal axis is broken to give rise to the typical symmetry of Bilaterians. We have previously shown that the Notch1 protein is ventrally enriched during early embryogenesis in Xenopus laevis and zebrafish and exerts ventralizing activity through β-Catenin destabilization and the positive regulation of ventral center genes in X. laevis. These findings led us to further investigate when these asymmetries arise. In this work, we show that the asymmetrical distribution of Notch1 protein and mRNA precedes cortical rotation and even fertilization in X. laevis. Moreover, we found that in unfertilized eggs transcripts encoded by the ventralizing gene bmp4 are also asymmetrically distributed in the animal hemisphere and notch1 transcripts accumulate consistently on the same side of the eccentric maturation point. Strikingly, a Notch1 asymmetry orthogonal to the animal-vegetal axis appears during X. laevis oogenesis. Thus, we show for the first time a maternal bias in the distribution of molecules that are later involved in ventral patterning during embryonic axialization, strongly supporting the hypothesis of a dorsoventral prepattern or intrinsic bilaterality of Xenopus eggs before fertilization.
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Affiliation(s)
- Aitana M. Castro Colabianchi
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Biología Celular e Histología / 1° U.A. Departamento de Histología, Embriología, Biología Celular y Genética, Laboratorio de Embriología Molecular “Prof. Dr. Andrés E. Carrasco”, Buenos Aires, Argentina
- CONICET–Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencias “Prof. E. De Robertis” (IBCN), Buenos Aires, Argentina
| | - Nicolás G. González Pérez
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Biología Celular e Histología / 1° U.A. Departamento de Histología, Embriología, Biología Celular y Genética, Laboratorio de Embriología Molecular “Prof. Dr. Andrés E. Carrasco”, Buenos Aires, Argentina
- CONICET–Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencias “Prof. E. De Robertis” (IBCN), Buenos Aires, Argentina
| | - Lucía F. Franchini
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI) “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Silvia L. López
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Biología Celular e Histología / 1° U.A. Departamento de Histología, Embriología, Biología Celular y Genética, Laboratorio de Embriología Molecular “Prof. Dr. Andrés E. Carrasco”, Buenos Aires, Argentina
- CONICET–Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencias “Prof. E. De Robertis” (IBCN), Buenos Aires, Argentina
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Wen Y, Zhao J, Zhang R, Liu F, Chen X, Wu D, Wang M, Liu C, Su P, Meng P, Zhang Y, Gao X, Wang L, Wang H, Zhou J. Identification and characterization of human hematopoietic mesoderm. SCIENCE CHINA. LIFE SCIENCES 2024; 67:320-331. [PMID: 37870675 DOI: 10.1007/s11427-022-2374-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 05/17/2023] [Indexed: 10/24/2023]
Abstract
The embryonic mesoderm comprises heterogeneous cell subpopulations with distinct lineage biases. It is unclear whether a bias for the human hematopoietic lineage emerges at this early developmental stage. In this study, we integrated single-cell transcriptomic analyses of human mesoderm cells from embryonic stem cells and embryos, enabling us to identify and define the molecular features of human hematopoietic mesoderm (HM) cells biased towards hematopoietic lineages. We discovered that BMP4 plays an essential role in HM specification and can serve as a marker for HM cells. Mechanistically, BMP4 acts as a downstream target of HDAC1, which modulates the expression of BMP4 by deacetylating its enhancer. Inhibition of HDAC significantly enhances HM specification and promotes subsequent hematopoietic cell differentiation. In conclusion, our study identifies human HM cells and describes new mechanisms for human hematopoietic development.
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Affiliation(s)
- Yuqi Wen
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
- CAMS Center for Stem Cell Medicine, PUMC Department of Stem Cell and Regenerative Medicine, Tianjin, 300020, China
| | - Jingjing Zhao
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
- CAMS Center for Stem Cell Medicine, PUMC Department of Stem Cell and Regenerative Medicine, Tianjin, 300020, China
| | - Runqing Zhang
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
- CAMS Center for Stem Cell Medicine, PUMC Department of Stem Cell and Regenerative Medicine, Tianjin, 300020, China
| | - Fan Liu
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
- CAMS Center for Stem Cell Medicine, PUMC Department of Stem Cell and Regenerative Medicine, Tianjin, 300020, China
| | - Xiaoyuan Chen
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
- CAMS Center for Stem Cell Medicine, PUMC Department of Stem Cell and Regenerative Medicine, Tianjin, 300020, China
| | - Dan Wu
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
- CAMS Center for Stem Cell Medicine, PUMC Department of Stem Cell and Regenerative Medicine, Tianjin, 300020, China
| | - Mengge Wang
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
- CAMS Center for Stem Cell Medicine, PUMC Department of Stem Cell and Regenerative Medicine, Tianjin, 300020, China
| | - Cuicui Liu
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
- CAMS Center for Stem Cell Medicine, PUMC Department of Stem Cell and Regenerative Medicine, Tianjin, 300020, China
| | - Pei Su
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
- CAMS Center for Stem Cell Medicine, PUMC Department of Stem Cell and Regenerative Medicine, Tianjin, 300020, China
| | - Panpan Meng
- Division of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou, 510006, China
| | - Yiyue Zhang
- Division of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou, 510006, China
| | - Xin Gao
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
- CAMS Center for Stem Cell Medicine, PUMC Department of Stem Cell and Regenerative Medicine, Tianjin, 300020, China
| | - Lu Wang
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
- CAMS Center for Stem Cell Medicine, PUMC Department of Stem Cell and Regenerative Medicine, Tianjin, 300020, China
| | - Hongtao Wang
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China.
- Tianjin Institutes of Health Science, Tianjin, 301600, China.
- CAMS Center for Stem Cell Medicine, PUMC Department of Stem Cell and Regenerative Medicine, Tianjin, 300020, China.
| | - Jiaxi Zhou
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China.
- Tianjin Institutes of Health Science, Tianjin, 301600, China.
- CAMS Center for Stem Cell Medicine, PUMC Department of Stem Cell and Regenerative Medicine, Tianjin, 300020, China.
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Slack J. The organizer: What it meant, and still means, to developmental biology. Curr Top Dev Biol 2023; 157:1-42. [PMID: 38556456 DOI: 10.1016/bs.ctdb.2023.12.001] [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] [Indexed: 04/02/2024]
Abstract
This article is about how the famous organizer experiment has been perceived since it was first published in 1924. The experiment involves the production of a secondary embryo under the influence of a graft of a dorsal lip from an amphibian gastrula to a host embryo. The early experiments of Spemann and his school gave rise to a view that the whole early amphibian embryo was "indifferent" in terms of determination, except for a special region called "the organizer". This was viewed mainly as an agent of neural induction, also having the ability to generate an anteroposterior body pattern. Early biochemical efforts to isolate a factor emitted by the organizer were not successful but culminated in the definition of "neuralizing (N)" and "mesodermalizing (M)" factors present in a wide variety of animal tissues. By the 1950s this view became crystallized as a "two gradient" model involving the N and M factors, which explained the anteroposterior patterning effect. In the 1970s, the phenomenon of mesoderm induction was characterized as a process occurring before the commencement of gastrulation. Reinvestigation of the organizer effect using lineage labels gave rise to a more precise definition of the sequence of events. Since the 1980s, modern research using the tools of molecular biology, combined with microsurgery, has explained most of the processes involved. The organizer graft should now be seen as an experiment which involves multiple interactions: dorsoventral polarization following fertilization, mesoderm induction, the dorsalizing signal responsible for neuralization and dorsoventral patterning of the mesoderm, and additional factors responsible for anteroposterior patterning.
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Affiliation(s)
- Jonathan Slack
- Department of Life Sciences, University of Bath, Bath, United Kingdom.
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Edri T, Cohen D, Shabtai Y, Fainsod A. Alcohol induces neural tube defects by reducing retinoic acid signaling and promoting neural plate expansion. Front Cell Dev Biol 2023; 11:1282273. [PMID: 38116205 PMCID: PMC10728305 DOI: 10.3389/fcell.2023.1282273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 11/22/2023] [Indexed: 12/21/2023] Open
Abstract
Introduction: Neural tube defects (NTDs) are among the most debilitating and common developmental defects in humans. The induction of NTDs has been attributed to abnormal folic acid (vitamin B9) metabolism, Wnt and BMP signaling, excess retinoic acid (RA), dietary components, environmental factors, and many others. In the present study we show that reduced RA signaling, including alcohol exposure, induces NTDs. Methods: Xenopus embryos were exposed to pharmacological RA biosynthesis inhibitors to study the induction of NTDs. Embryos were treated with DEAB, citral, or ethanol, all of which inhibit the biosynthesis of RA, or injected to overexpress Cyp26a1 to reduce RA. NTD induction was studied using neural plate and notochord markers together with morphological analysis. Expression of the neuroectodermal regulatory network and cell proliferation were analyzed to understand the morphological malformations of the neural plate. Results: Reducing RA signaling levels using retinaldehyde dehydrogenase inhibitors (ethanol, DEAB, and citral) or Cyp26a1-driven degradation efficiently induce NTDs. These NTDs can be rescued by providing precursors of RA. We mapped this RA requirement to early gastrula stages during the induction of neural plate precursors. This reduced RA signaling results in abnormal expression of neural network genes, including the neural plate stem cell maintenance genes, geminin, and foxd4l1.1. This abnormal expression of neural network genes results in increased proliferation of neural precursors giving rise to an expanded neural plate. Conclusion: We show that RA signaling is required for neural tube closure during embryogenesis. RA signaling plays a very early role in the regulation of proliferation and differentiation of the neural plate soon after the induction of neural progenitors during gastrulation. RA signaling disruption leads to the induction of NTDs through the mis regulation of the early neuroectodermal network, leading to increased proliferation resulting in the expansion of the neural plate. Ethanol exposure induces NTDs through this mechanism involving reduced RA levels.
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Affiliation(s)
| | | | | | - Abraham Fainsod
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
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Baxi AB, Li J, Quach VM, Nemes P. Cell Lineage-Guided Microanalytical Mass Spectrometry Reveals Increased Energy Metabolism and Reactive Oxygen Species in the Vertebrate Organizer. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.07.548174. [PMID: 37461553 PMCID: PMC10350060 DOI: 10.1101/2023.07.07.548174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2024]
Abstract
Molecular understanding of the vertebrate Organizer, a tissue center critical for inductive signaling during gastrulation, has so far been limited to transcripts and some proteins due to limitations in detection and sensitivity. The Spemann-Mangold Organizer (SMO) in the South African Clawed Frog ( X. laevis ), a popular model of development, has long been discovered to induce the patterning of the central nervous system. Molecular screens on the tissue have identified several genes, such as goosecoid, chordin, and noggin, with independent ability to establish a body axis. A comprehensive study of proteins and metabolites produced in the SMO and their functional roles has been lacking. Here, we pioneer a deep discovery proteomic and targeted metabolomic screen of the SMO in comparison to the rest of the embryo using liquid chromatography high-resolution mass spectrometry (HRMS). Quantification of ∼4,600 proteins and a panel of metabolites documented differential expression for ∼450 proteins and multiple intermediates of energy metabolism in the SMO. Upregulation of oxidative phosphorylation (OXPHOS) and redox regulatory proteins gave rise to elevated oxidative stress and an accumulation of reactive oxygen species in the Organizer. Imaging experiments corroborated these findings, discovering enrichment of hydrogen peroxide in the SMO tissue. Chemical perturbation of the redox gradient affected mesoderm involution during early tissue movements of gastrulation. HRMS expands the bioanalytical toolbox of cell and developmental biology, providing previously unavailable information on molecular classes to challenge and refine our classical understanding of the Organizer and its function during early patterning of the embryo.
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Guille M, Grainger R. Genetics and Gene Editing Methods in Xenopus laevis and Xenopus tropicalis. Cold Spring Harb Protoc 2023; 2023:pdb.top107045. [PMID: 36283837 DOI: 10.1101/pdb.top107045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Our understanding of biological systems has for many years been heavily influenced by experimental approaches that exploit genetic methods. These include gain-of-function experiments that overexpress transgenes or ectopically express injected RNA and loss-of-function experiments that knock out genes or knock down RNAs. Here, we review how these methods have been applied in Xenopus frogs and introduce a variety of protocols for genetic manipulation of Xenopus laevis and Xenopus tropicalis.
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Affiliation(s)
- Matthew Guille
- European Xenopus Resource Centre, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2UP, United Kingdom
| | - Robert Grainger
- Department of Biology, University of Virginia, Charlottesville, Virginia 22903, USA
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Cervino AS, Collodel MG, Lopez IA, Hochbaum D, Hukriede NA, Cirio MC. Xenopus Ssbp2 is required for embryonic pronephros morphogenesis and terminal differentiation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.15.537039. [PMID: 37090653 PMCID: PMC10120741 DOI: 10.1101/2023.04.15.537039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
The nephron, functional unit of the vertebrate kidney, is specialized in metabolic wastes excretion and body fluids osmoregulation. Given the high evolutionary conservation of gene expression and segmentation patterning between mammalian and amphibian nephrons, the Xenopus laevis pronephric kidney offers a simplified model for studying nephrogenesis. The Lhx1 transcription factor plays several roles during embryogenesis, regulating target genes expression by forming multiprotein complexes with LIM binding protein 1 (Ldb1). However, few Lhx1-Ldb1 cofactors have been identified for kidney organogenesis. By tandem-affinity purification from kidney-induced Xenopus animal caps, we identified s ingle- s tranded DNA b inding p rotein 2 (Ssbp2) interacts with the Ldb1-Lhx1 complex. Ssbp2 is expressed in the Xenopus pronephros, and knockdown prevents normal morphogenesis and differentiation of the glomus and the convoluted renal tubules. We demonstrate a role for a member of the Ssbp family in kidney organogenesis and provide evidence of a fundamental function for the Ldb1-Lhx1-Ssbp transcriptional complexes in embryonic development.
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Durant-Vesga J, Suzuki N, Ochi H, Le Bouffant R, Eschstruth A, Ogino H, Umbhauer M, Riou JF. Retinoic acid control of pax8 during renal specification of Xenopus pronephros involves hox and meis3. Dev Biol 2023; 493:17-28. [PMID: 36279927 DOI: 10.1016/j.ydbio.2022.10.009] [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: 07/12/2022] [Revised: 10/12/2022] [Accepted: 10/13/2022] [Indexed: 11/16/2022]
Abstract
Development of the Xenopus pronephros relies on renal precursors grouped at neurula stage into a specific region of dorso-lateral mesoderm called the kidney field. Formation of the kidney field at early neurula stage is dependent on retinoic (RA) signaling acting upstream of renal master transcriptional regulators such as pax8 or lhx1. Although lhx1 might be a direct target of RA-mediated transcriptional activation in the kidney field, how RA controls the emergence of the kidney field remains poorly understood. In order to better understand RA control of renal specification of the kidney field, we have performed a transcriptomic profiling of genes affected by RA disruption in lateral mesoderm explants isolated prior to the emergence of the kidney field and cultured at different time points until early neurula stage. Besides genes directly involved in pronephric development (pax8, lhx1, osr2, mecom), hox (hoxa1, a3, b3, b4, c5 and d1) and the hox co-factor meis3 appear as a prominent group of genes encoding transcription factors (TFs) downstream of RA. Supporting the idea of a role of meis3 in the kidney field, we have observed that meis3 depletion results in a severe inhibition of pax8 expression in the kidney field. Meis3 depletion only marginally affects expression of lhx1 and aldh1a2 suggesting that meis3 principally acts upstream of pax8. Further arguing for a role of meis3 and hox in the control of pax8, expression of a combination of meis3, hoxb4 and pbx1 in animal caps induces pax8 expression, but not that of lhx1. The same combination of TFs is also able to transactivate a previously identified pax8 enhancer, Pax8-CNS1. Mutagenesis of potential PBX-Hox binding motifs present in Pax8-CNS1 further allows to identify two of them that are necessary for transactivation. Finally, we have tested deletions of regulatory sequences in reporter assays with a previously characterized transgene encompassing 36.5 kb of the X. tropicalis pax8 gene that allows expression of a truncated pax8-GFP fusion protein recapitulating endogenous pax8 expression. This transgene includes three conserved pax8 enhancers, Pax8-CNS1, Pax8-CNS2 and Pax8-CNS3. Deletion of Pax8-CNS1 alone does not affect reporter expression, but deletion of a 3.5 kb region encompassing Pax8-CNS1 and Pax8-CNS2 results in a severe inhibition of reporter expression both in the otic placode and kidney field domains.
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Affiliation(s)
- Jennifer Durant-Vesga
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, IBPS, Laboratoire de Biologie Du Développement, UMR7622, 9, Quai Saint-Bernard, 75252, Paris, Cedex05, France
| | - Nanoka Suzuki
- Institute for Promotion of Medical Science Research, Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan; Amphibian Research Center / Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagami-yama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
| | - Haruki Ochi
- Institute for Promotion of Medical Science Research, Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan
| | - Ronan Le Bouffant
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, IBPS, Laboratoire de Biologie Du Développement, UMR7622, 9, Quai Saint-Bernard, 75252, Paris, Cedex05, France
| | - Alexis Eschstruth
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, IBPS, Laboratoire de Biologie Du Développement, UMR7622, 9, Quai Saint-Bernard, 75252, Paris, Cedex05, France
| | - Hajime Ogino
- Amphibian Research Center / Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagami-yama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
| | - Muriel Umbhauer
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, IBPS, Laboratoire de Biologie Du Développement, UMR7622, 9, Quai Saint-Bernard, 75252, Paris, Cedex05, France
| | - Jean-François Riou
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, IBPS, Laboratoire de Biologie Du Développement, UMR7622, 9, Quai Saint-Bernard, 75252, Paris, Cedex05, France.
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11
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Favarolo MB, Revinski DR, Garavaglia MJ, López SL. Nodal and churchill1 position the expression of a notch ligand during Xenopus germ layer segregation. Life Sci Alliance 2022; 5:5/12/e202201693. [PMID: 36180230 PMCID: PMC9604498 DOI: 10.26508/lsa.202201693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 09/13/2022] [Accepted: 09/14/2022] [Indexed: 11/24/2022] Open
Abstract
Churchill and Nodal signaling, which participate in vertebrates’ germ layer induction, position a domain of Delta/Notch activity, which refines germ layer boundaries during frog gastrulation. In vertebrates, Nodal signaling plays a major role in endomesoderm induction, but germ layer delimitation is poorly understood. In avian embryos, the neural/mesoderm boundary is controlled by the transcription factor CHURCHILL1, presumably through the repressor ZEB2, but there is scarce knowledge about its role in other vertebrates. During amphibian gastrulation, Delta/Notch signaling refines germ layer boundaries in the marginal zone, but it is unknown the place this pathway occupies in the network comprising Churchill1 and Nodal. Here, we show that Xenopus churchill1 is expressed in the presumptive neuroectoderm at mid-blastula transition and during gastrulation, upregulates zeb2, prevents dll1 expression in the neuroectoderm, and favors neuroectoderm over endomesoderm development. Nodal signaling prevents dll1 expression in the endoderm but induces it in the presumptive mesoderm, from where it activates Notch1 and its target gene hes4 in the non-involuting marginal zone. We propose a model where Nodal and Churchill1 position Dll1/Notch1/Hes4 domains in the marginal zone, ensuring the delimitation between mesoderm and neuroectoderm.
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Affiliation(s)
- María Belén Favarolo
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Biología Celular e Histología/1° U.A. Departamento de Histología, Embriología, Biología Celular y Genética, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" (IBCN), Laboratorio de Embriología Molecular "Prof. Dr. Andrés E. Carrasco", Buenos Aires, Argentina
| | - Diego R Revinski
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Biología Celular e Histología/1° U.A. Departamento de Histología, Embriología, Biología Celular y Genética, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" (IBCN), Laboratorio de Embriología Molecular "Prof. Dr. Andrés E. Carrasco", Buenos Aires, Argentina
| | - Matías J Garavaglia
- Laboratorio de Bioinsumos, Instituto de Biotecnología, Universidad Nacional de Hurlingham, Buenos Aires, Argentina
| | - Silvia L López
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Biología Celular e Histología/1° U.A. Departamento de Histología, Embriología, Biología Celular y Genética, Buenos Aires, Argentina .,CONICET-Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" (IBCN), Laboratorio de Embriología Molecular "Prof. Dr. Andrés E. Carrasco", Buenos Aires, Argentina
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12
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Shiraki T, Hayashi T, Ozue J, Watanabe M. Appropriate Amounts and Activity of the Wilms' Tumor Suppressor Gene, wt1, Are Required for Normal Pronephros Development of Xenopus Embryos. J Dev Biol 2022; 10:jdb10040046. [PMID: 36412640 PMCID: PMC9680428 DOI: 10.3390/jdb10040046] [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: 08/17/2022] [Revised: 10/23/2022] [Accepted: 10/27/2022] [Indexed: 12/14/2022] Open
Abstract
The Wilms' tumor suppressor gene, wt1, encodes a zinc finger-containing transcription factor that binds to a GC-rich motif and regulates the transcription of target genes. wt1 was first identified as a tumor suppressor gene in Wilms' tumor, a pediatric kidney tumor, and has been implicated in normal kidney development. The WT1 protein has transcriptional activation and repression domains and acts as a transcriptional activator or repressor, depending on the target gene and context. In Xenopus, an ortholog of wt1 has been isolated and shown to be expressed in the developing embryonic pronephros. To investigate the role of wt1 in pronephros development in Xenopus embryos, we mutated wt1 by CRISPR/Cas9 and found that the expression of pronephros marker genes was reduced. In reporter assays in which known WT1 binding sequences were placed upstream of the luciferase gene, WT1 activated transcription of the luciferase gene. The injection of wild-type or artificially altered transcriptional activity of wt1 mRNA disrupted the expression of pronephros marker genes in the embryos. These results suggest that the appropriate amounts and activity of WT1 protein are required for normal pronephros development in Xenopus embryos.
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Affiliation(s)
- Taisei Shiraki
- Graduate School of Sciences and Technology for Innovation, Tokushima University, 1-1 Minamijosanjima-Cho, Tokushima 770-8054, Japan
| | - Takuma Hayashi
- Graduate School of Sciences and Technology for Innovation, Tokushima University, 1-1 Minamijosanjima-Cho, Tokushima 770-8054, Japan
| | - Jotaro Ozue
- Graduate School of Sciences and Technology for Innovation, Tokushima University, 1-1 Minamijosanjima-Cho, Tokushima 770-8054, Japan
| | - Minoru Watanabe
- Graduate School of Sciences and Technology for Innovation, Tokushima University, 1-1 Minamijosanjima-Cho, Tokushima 770-8054, Japan
- Institute of Liberal Arts and Sciences, Tokushima University, 1-1 Minamijosanjima-Cho, Tokushima 770-8054, Japan
- Correspondence: ; Tel.: +81-088-656-7253
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13
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Gur M, Edri T, Moody SA, Fainsod A. Retinoic Acid is Required for Normal Morphogenetic Movements During Gastrulation. Front Cell Dev Biol 2022; 10:857230. [PMID: 35531100 PMCID: PMC9068879 DOI: 10.3389/fcell.2022.857230] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 03/21/2022] [Indexed: 11/23/2022] Open
Abstract
Retinoic acid (RA) is a central regulatory signal that controls numerous developmental processes in vertebrate embryos. Although activation of Hox expression is considered one of the earliest functions of RA signaling in the embryo, there is evidence that embryos are poised to initiate RA signaling just before gastrulation begins, and manipulations of the RA pathway have been reported to show gastrulation defects. However, which aspects of gastrulation are affected have not been explored in detail. We previously showed that partial inhibition of RA biosynthesis causes a delay in the rostral migration of some of the earliest involuting cells, the leading edge mesendoderm (LEM) and the prechordal mesoderm (PCM). Here we identify several detrimental gastrulation defects resulting from inhibiting RA biosynthesis by three different treatments. RA reduction causes a delay in the progression through gastrulation as well as the rostral migration of the goosecoid-positive PCM cells. RA inhibition also hampered the elongation of explanted dorsal marginal zones, the compaction of the blastocoel, and the length of Brachet’s cleft, all of which indicate an effect on LEM/PCM migration. The cellular mechanisms underlying this deficit were shown to include a reduced deposition of fibronectin along Brachet’s cleft, the substrate for their migration, as well as impaired separation of the blastocoel roof and involuting mesoderm, which is important for the formation of Brachet’s cleft and successful LEM/PCM migration. We further show reduced non-canonical Wnt signaling activity and altered expression of genes in the Ephrin and PDGF signaling pathways, both of which are required for the rostral migration of the LEM/PCM, following RA reduction. Together, these experiments demonstrate that RA signaling performs a very early function critical for the progression of gastrulation morphogenetic movements.
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Affiliation(s)
- Michal Gur
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tamir Edri
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Sally A. Moody
- Department of Anatomy and Cell Biology, School of Medicine and Health Sciences, George Washington University, Washington, DC, United States
- *Correspondence: Sally A. Moody, ; Abraham Fainsod,
| | - Abraham Fainsod
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
- *Correspondence: Sally A. Moody, ; Abraham Fainsod,
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14
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Blackiston D, Lederer E, Kriegman S, Garnier S, Bongard J, Levin M. A cellular platform for the development of synthetic living machines. Sci Robot 2021; 6:6/52/eabf1571. [PMID: 34043553 DOI: 10.1126/scirobotics.abf1571] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 03/08/2021] [Indexed: 12/18/2022]
Abstract
Robot swarms have, to date, been constructed from artificial materials. Motile biological constructs have been created from muscle cells grown on precisely shaped scaffolds. However, the exploitation of emergent self-organization and functional plasticity into a self-directed living machine has remained a major challenge. We report here a method for generation of in vitro biological robots from frog (Xenopus laevis) cells. These xenobots exhibit coordinated locomotion via cilia present on their surface. These cilia arise through normal tissue patterning and do not require complicated construction methods or genomic editing, making production amenable to high-throughput projects. The biological robots arise by cellular self-organization and do not require scaffolds or microprinting; the amphibian cells are highly amenable to surgical, genetic, chemical, and optical stimulation during the self-assembly process. We show that the xenobots can navigate aqueous environments in diverse ways, heal after damage, and show emergent group behaviors. We constructed a computational model to predict useful collective behaviors that can be elicited from a xenobot swarm. In addition, we provide proof of principle for a writable molecular memory using a photoconvertible protein that can record exposure to a specific wavelength of light. Together, these results introduce a platform that can be used to study many aspects of self-assembly, swarm behavior, and synthetic bioengineering, as well as provide versatile, soft-body living machines for numerous practical applications in biomedicine and the environment.
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Affiliation(s)
| | - Emma Lederer
- Allen Discovery Center at Tufts University, Medford, MA 02155, USA
| | - Sam Kriegman
- Department of Computer Science, University of Vermont, Burlington, VT 05405, USA
| | - Simon Garnier
- Federated Department of Biological Sciences, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - Joshua Bongard
- Department of Computer Science, University of Vermont, Burlington, VT 05405, USA
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA 02155, USA. .,Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA
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15
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Abstract
The endoderm is the innermost germ layer that forms the linings of the respiratory and gastrointestinal tracts, and their associated organs, during embryonic development. Xenopus embryology experiments have provided fundamental insights into how the endoderm develops in vertebrates, including the critical role of TGFβ-signaling in endoderm induction,elucidating the gene regulatory networks controlling germ layer development and the key molecular mechanisms regulating endoderm patterning and morphogenesis. With new genetic, genomic, and imaging approaches, Xenopus is now routinely used to model human disease, discover mechanisms underlying endoderm organogenesis, and inform differentiation protocols for pluripotent stem cell differentiation and regenerative medicine applications. In this chapter, we review historical and current discoveries of endoderm development in Xenopus, then provide examples of modeling human disease and congenital defects of endoderm-derived organs using Xenopus.
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Affiliation(s)
- Nicole A Edwards
- Division of Developmental Biology, Center for Stem Cell and Organoid Medicine, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.
| | - Aaron M Zorn
- Division of Developmental Biology, Center for Stem Cell and Organoid Medicine, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States.
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16
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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.
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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
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17
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Kakebeen AD, Huebner RJ, Shindo A, Kwon K, Kwon T, Wills AE, Wallingford JB. A temporally resolved transcriptome for developing "Keller" explants of the Xenopus laevis dorsal marginal zone. Dev Dyn 2021; 250:717-731. [PMID: 33368695 DOI: 10.1002/dvdy.289] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/20/2020] [Accepted: 11/30/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Explanted tissues from vertebrate embryos reliably develop in culture and have provided essential paradigms for understanding embryogenesis, from early embryological investigations of induction, to the extensive study of Xenopus animal caps, to the current studies of mammalian gastruloids. Cultured explants of the Xenopus dorsal marginal zone ("Keller" explants) serve as a central paradigm for studies of convergent extension cell movements, yet we know little about the global patterns of gene expression in these explants. RESULTS In an effort to more thoroughly develop this important model system, we provide here a time-resolved bulk transcriptome for developing Keller explants. CONCLUSIONS The dataset reported here provides a useful resource for those using Keller explants for studies of morphogenesis and provide genome-scale insights into the temporal patterns of gene expression in an important tissue when explanted and grown in culture.
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Affiliation(s)
- Anneke D Kakebeen
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Robert J Huebner
- Department of Molecular Biosciences, University of Texas, Austin, Texas, USA
| | - Asako Shindo
- Division of Biological Science, Nagoya University, Nagoya, Japan
| | - Kujin Kwon
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, (UNIST), Ulsan, Republic of Korea
| | - Taejoon Kwon
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, (UNIST), Ulsan, Republic of Korea.,Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan, Republic of Korea
| | - Andrea E Wills
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - John B Wallingford
- Department of Molecular Biosciences, University of Texas, Austin, Texas, USA
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18
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Walentek P. Xenopus epidermal and endodermal epithelia as models for mucociliary epithelial evolution, disease, and metaplasia. Genesis 2021; 59:e23406. [PMID: 33400364 DOI: 10.1002/dvg.23406] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 11/08/2022]
Abstract
The Xenopus embryonic epidermis is a powerful model to study mucociliary biology, development, and disease. Particularly, the Xenopus system is being used to elucidate signaling pathways, transcription factor functions, and morphogenetic mechanisms regulating cell fate specification, differentiation and cell function. Thereby, Xenopus research has provided significant insights into potential underlying molecular mechanisms for ciliopathies and chronic airway diseases. Recent studies have also established the embryonic epidermis as a model for mucociliary epithelial remodeling, multiciliated cell trans-differentiation, cilia loss, and mucus secretion. Additionally, the tadpole foregut epithelium is lined by a mucociliary epithelium, which shows remarkable features resembling mammalian airway epithelia, including its endodermal origin and a variable cell type composition along the proximal-distal axis. This review aims to summarize the advantages of the Xenopus epidermis for mucociliary epithelial biology and disease modeling. Furthermore, the potential of the foregut epithelium as novel mucociliary model system is being highlighted. Additional perspectives are presented on how to expand the range of diseases that can be modeled in the frog system, including proton pump inhibitor-associated pneumonia as well as metaplasia in epithelial cells of the airway and the gastroesophageal region.
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Affiliation(s)
- Peter Walentek
- Renal Division, Department of Medicine, University Hospital Freiburg, Freiburg University Faculty of Medicine, Freiburg, Germany.,CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
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19
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20
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Horb M, Wlizla M, Abu-Daya A, McNamara S, Gajdasik D, Igawa T, Suzuki A, Ogino H, Noble A, Robert J, James-Zorn C, Guille M. Xenopus Resources: Transgenic, Inbred and Mutant Animals, Training Opportunities, and Web-Based Support. Front Physiol 2019; 10:387. [PMID: 31073289 PMCID: PMC6497014 DOI: 10.3389/fphys.2019.00387] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 03/21/2019] [Indexed: 02/06/2023] Open
Abstract
Two species of the clawed frog family, Xenopus laevis and X. tropicalis, are widely used as tools to investigate both normal and disease-state biochemistry, genetics, cell biology, and developmental biology. To support both frog specialist and non-specialist scientists needing access to these models for their research, a number of centralized resources exist around the world. These include centers that hold live and frozen stocks of transgenic, inbred and mutant animals and centers that hold molecular resources. This infrastructure is supported by a model organism database. Here, we describe much of this infrastructure and encourage the community to make the best use of it and to guide the resource centers in developing new lines and libraries.
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Affiliation(s)
- Marko Horb
- National Xenopus Resource, Marine Biological Laboratory, Woods Hole, MA, United States
| | - Marcin Wlizla
- National Xenopus Resource, Marine Biological Laboratory, Woods Hole, MA, United States
| | - Anita Abu-Daya
- European Xenopus Resource Centre, Portsmouth, United Kingdom
| | - Sean McNamara
- National Xenopus Resource, Marine Biological Laboratory, Woods Hole, MA, United States
| | - Dominika Gajdasik
- School of Biological Sciences, King Henry Building, Portsmouth, United Kingdom
| | - Takeshi Igawa
- Amphibian Research Center, Hiroshima University, Higashihiroshima, Japan
| | - Atsushi Suzuki
- Amphibian Research Center, Hiroshima University, Higashihiroshima, Japan
| | - Hajime Ogino
- Amphibian Research Center, Hiroshima University, Higashihiroshima, Japan
| | - Anna Noble
- European Xenopus Resource Centre, Portsmouth, United Kingdom
| | | | - Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Christina James-Zorn
- Xenbase, Division of Developmental Biology, Cincinnati Children's Research Foundation, Cincinnati, OH, United States
| | - Matthew Guille
- European Xenopus Resource Centre, Portsmouth, United Kingdom.,School of Biological Sciences, King Henry Building, Portsmouth, United Kingdom
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21
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Blackburn ATM, Miller RK. Modeling congenital kidney diseases in Xenopus laevis. Dis Model Mech 2019; 12:12/4/dmm038604. [PMID: 30967415 PMCID: PMC6505484 DOI: 10.1242/dmm.038604] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Congenital anomalies of the kidney and urinary tract (CAKUT) occur in ∼1/500 live births and are a leading cause of pediatric kidney failure. With an average wait time of 3-5 years for a kidney transplant, the need is high for the development of new strategies aimed at reducing the incidence of CAKUT and preserving renal function. Next-generation sequencing has uncovered a significant number of putative causal genes, but a simple and efficient model system to examine the function of CAKUT genes is needed. Xenopus laevis (frog) embryos are well-suited to model congenital kidney diseases and to explore the mechanisms that cause these developmental defects. Xenopus has many advantages for studying the kidney: the embryos develop externally and are easily manipulated with microinjections, they have a functional kidney in ∼2 days, and 79% of identified human disease genes have a verified ortholog in Xenopus. This facilitates high-throughput screening of candidate CAKUT-causing genes. In this Review, we present the similarities between Xenopus and mammalian kidneys, highlight studies of CAKUT-causing genes in Xenopus and describe how common kidney diseases have been modeled successfully in this model organism. Additionally, we discuss several molecular pathways associated with kidney disease that have been studied in Xenopus and demonstrate why it is a useful model for studying human kidney diseases. Summary: Understanding how congenital kidney diseases arise is imperative to their treatment. Using Xenopus as a model will aid in elucidating kidney development and congenital kidney diseases.
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Affiliation(s)
- Alexandria T M Blackburn
- Pediatric Research Center, Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA.,The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Program in Genetics and Epigenetics, Houston, TX 77030, USA
| | - Rachel K Miller
- Pediatric Research Center, Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA .,The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Program in Genetics and Epigenetics, Houston, TX 77030, USA.,The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Program in Biochemistry and Cell Biology Houston, Houston, TX 77030, USA.,Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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22
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Abstract
The individual blastomeres of Xenopus two- to 32-cell embryos have been fate mapped. This work identified the precursors of most of the embryonic cell types, tissues and organs; however, the maps do not reveal the cell interactions or signaling pathways that are required for establishing cell fates. This protocol describes an explant culture approach for culturing blastomeres in isolation to test whether a cell's fate has been determined. Cleavage blastomeres can be cultured in a simple salt medium without added factors because they contain intracellular yolk platelets, which provide an intrinsic energy source. This method allows one to test whether an isolated blastomere can produce specific cell types or express tissue-specific genes independent of interactions with other cells or specific signaling pathways. The role of cell-cell interactions can be revealed by co-culturing different sets of blastomeres. One can identify the molecules that are required for those cell fates by applying knockdown approaches to the isolated cell. One also can determine the developmental time at which cell fates are committed by explanting blastomere lineages at different stages.
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Affiliation(s)
- Sally A Moody
- Department of Anatomy and Regenerative Biology, George Washington University, Washington, DC 20037
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23
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Moody SA. Cleavage Blastomere Deletion and Transplantation to Test Cell Fate Commitment in Xenopus. Cold Spring Harb Protoc 2019; 2019:pdb.prot097311. [PMID: 29769398 DOI: 10.1101/pdb.prot097311] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Fate maps identify the precursors of an organ, and tracing the members of a blastomere lineage over time shows how its descendants come to populate that organ. The fates of the individual blastomeres of the two- to 32-cell Xenopus embryo have been fully mapped to reveal which cells are the major contributors to various cell types, tissues, and organs. However, because these fate maps were produced in the normal embryo, they do not reveal whether a precursor blastomere is competent to give rise to additional tissues or is already committed to its fate-mapped repertoire of descendants. To identify the mechanisms by which a cell's fate is committed, one needs to expose the cell to different experimental environments. If the cell's fate is determined, it will express its normal fate or gene expression profile in novel environments, whereas if it is not yet determined it will express different fates or gene expression profiles when exposed to novel external factors or neighboring cells. This protocol describes two techniques for testing cell fate commitment: single cell deletion and single cell transplantation. Deleting a blastomere allows one to test whether the deleted cell is required for the remaining cells to produce their normal, specific cell fates. Transplanting a blastomere to a novel location in a host embryo allows one to test whether the transplanted cell is committed to produce its normal fate-mapped repertoire, or whether it is still competent to respond to novel cell-cell interactions.
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Affiliation(s)
- Sally A Moody
- Department of Anatomy and Regenerative Biology, George Washington University, Washington, DC 20037
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24
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Favarolo MB, López SL. Notch signaling in the division of germ layers in bilaterian embryos. Mech Dev 2018; 154:122-144. [PMID: 29940277 DOI: 10.1016/j.mod.2018.06.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/08/2018] [Accepted: 06/18/2018] [Indexed: 01/09/2023]
Abstract
Bilaterian embryos are triploblastic organisms which develop three complete germ layers (ectoderm, mesoderm, and endoderm). While the ectoderm develops mainly from the animal hemisphere, there is diversity in the location from where the endoderm and the mesoderm arise in relation to the animal-vegetal axis, ranging from endoderm being specified between the ectoderm and mesoderm in echinoderms, and the mesoderm being specified between the ectoderm and the endoderm in vertebrates. A common feature is that part of the mesoderm segregates from an ancient bipotential endomesodermal domain. The process of segregation is noisy during the initial steps but it is gradually refined. In this review, we discuss the role of the Notch pathway in the establishment and refinement of boundaries between germ layers in bilaterians, with special focus on its interaction with the Wnt/β-catenin pathway.
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Affiliation(s)
- María Belén Favarolo
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Biología Celular y Neurociencias "Prof. E. De Robertis" (IBCN), Facultad de Medicina, Laboratorio de Embriología Molecular "Prof. Dr. Andrés E. Carrasco", Buenos Aires, Argentina
| | - Silvia L López
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Biología Celular y Neurociencias "Prof. E. De Robertis" (IBCN), Facultad de Medicina, Laboratorio de Embriología Molecular "Prof. Dr. Andrés E. Carrasco", Buenos Aires, Argentina.
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25
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Hox and Wnt pattern the primary body axis of an anthozoan cnidarian before gastrulation. Nat Commun 2018; 9:2007. [PMID: 29789526 PMCID: PMC5964151 DOI: 10.1038/s41467-018-04184-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 04/06/2018] [Indexed: 11/17/2022] Open
Abstract
Hox gene transcription factors are important regulators of positional identity along the anterior–posterior axis in bilaterian animals. Cnidarians (e.g., sea anemones, corals, and hydroids) are the sister group to the Bilateria and possess genes related to both anterior and central/posterior class Hox genes. Here we report a previously unrecognized domain of Hox expression in the starlet sea anemone, Nematostella vectensis, beginning at early blastula stages. We explore the relationship of two opposing Hox genes (NvAx6/NvAx1) expressed on each side of the blastula during early development. Functional perturbation reveals that NvAx6 and NvAx1 not only regulate their respective expression domains, but also interact with Wnt genes to pattern the entire oral–aboral axis. These findings suggest an ancient link between Hox/Wnt patterning during axis formation and indicate that oral–aboral domains are likely established during blastula formation in anthozoan cnidarians. Hox genes regulate anterior–posterior axis formation but their role in cnidarians is unclear. Here, the authors disrupt Hox genes NvAx1 and NvAx6 in the starlet sea anemone, Nematostella vectensis, showing antagonist function in patterning the oral–aboral axis and a link to Wnt signaling.
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Embryonic regeneration by relocalization of the Spemann organizer during twinning in Xenopus. Proc Natl Acad Sci U S A 2018; 115:E4815-E4822. [PMID: 29686106 PMCID: PMC6003488 DOI: 10.1073/pnas.1802749115] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The formation of identical twins from a single egg has fascinated developmental biologists for a very long time. Previous work had shown that Xenopus blastulae bisected along the dorsal-ventral (D-V) midline (i.e., the sagittal plane) could generate twins but at very low frequencies. Here, we have improved this method by using an eyelash knife and changing saline solutions, reaching frequencies of twinning of 50% or more. This allowed mechanistic analysis of the twinning process. We unexpectedly observed that the epidermis of the resulting twins was asymmetrically pigmented at the tailbud stage of regenerating tadpoles. This pigment was entirely of maternal (oocyte) origin. Bisecting the embryo generated a large wound, which closed from all directions within 60 minutes, bringing cells normally fated to become Spemann organizer in direct contact with predicted ventral-most cells. Lineage-tracing analyses at the four-cell stage showed that in regenerating embryos midline tissues originated from the dorsal half, while the epidermis was entirely of ventral origin. Labeling of D-V segments at the 16-cell stage showed that the more pigmented epidermis originated from the ventral-most cells, while the less-pigmented epidermis arose from the adjoining ventral segment. This suggested a displacement of the organizer by 90°. Studies with the marker Chordin and phospho-Smad1/5/8 showed that in half embryos a new D-V gradient is intercalated at the site of the missing half. The displacement of self-organizing morphogen gradients uncovered here may help us understand not only twin formation in amphibians, but also rare cases of polyembryony.
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Abstract
Organizers, which comprise groups of cells with the ability to instruct adjacent cells into specific states, represent a key principle in developmental biology. The concept was first introduced by Spemann and Mangold, who showed that there is a cellular population in the newt embryo that elicits the development of a secondary axis from adjacent cells. Similar experiments in chicken and rabbit embryos subsequently revealed groups of cells with similar instructive potential. In birds and mammals, organizer activity is often associated with a structure known as the node, which has thus been considered a functional homologue of Spemann's organizer. Here, we take an in-depth look at the structure and function of organizers across species and note that, whereas the amphibian organizer is a contingent collection of elements, each performing a specific function, the elements of organizers in other species are dispersed in time and space. This observation urges us to reconsider the universality and meaning of the organizer concept. Summary: This Review re-evaluates the notion of Spemann's organizer as identified in amphibians, highlighting the spatiotemporal dispersion of equivalent elements in mouse and the key influence of responsiveness to organizer signals.
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Affiliation(s)
| | - Ben Steventon
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
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Onjiko RM, Plotnick DO, Moody SA, Nemes P. Metabolic Comparison of Dorsal versus Ventral Cells Directly in the Live 8-cell Frog Embryo by Microprobe Single-cell CE-ESI-MS. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2017; 9:4964-4970. [PMID: 29062391 PMCID: PMC5650250 DOI: 10.1039/c7ay00834a] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Single-cell mass spectrometry (MS) empowers the characterization of metabolomic changes as cells differentiate to different tissues during early embryogenesis. Using whole-cell dissection and capillary electrophoresis electrospray ionization (CE-ESI) MS, we recently uncovered metabolic cell-to-cell differences in the 8- and 16-cell embryo of the South African clawed frog (Xenopus laevis), raising the question whether metabolic cell heterogeneity is also detectable across the dorsal-ventral axis of the 8-cell embryo. Here, we tested this hypothesis directly in the live embryo by quantifying single-cell metabolism between the left dorsal-animal (D1L) and left ventral-animal (V1L) cell pairs in the same embryo using microprobe single-cell CE-ESI-MS in the positive ion mode. After quantifying ~70 molecular features, including 52 identified metabolites, that were reproducibly detected in both cells among n = 5 different embryos, we employed supervised multivariate data analysis based on partial least squares discriminant analysis (PLSDA) to compare metabolism between the cell types. Statistical analysis revealed that asparagine, glycine betaine, and a yet-unidentified molecule were statistically significantly enriched in the D1L cell compared to V1L (p < 0.05 and fold change ≥ 1.5). These results demonstrate that cells derived from the same hemisphere (animal pole) harbor different metabolic activity along the dorsal-ventral axis as early as the 8-cell stage. Apart from providing new evidence of metabolic cell heterogeneity during early embryogenesis, this study demonstrates that microprobe single-cell CE-ESI-MS enables the analysis of multiple single cells in the same live vertebrate embryo.
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Affiliation(s)
- Rosemary M. Onjiko
- Department of Chemistry, The George Washington University, Washington DC, 20052
| | - David O. Plotnick
- Department of Chemistry, The George Washington University, Washington DC, 20052
| | - Sally A. Moody
- Department of Anatomy and Regenerative Biology, The George Washington University, Washington DC, 20052
| | - Peter Nemes
- Department of Chemistry, The George Washington University, Washington DC, 20052
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29
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Ratzan W, Falco R, Salanga C, Salanga M, Horb ME. Generation of a Xenopus laevis F1 albino J strain by genome editing and oocyte host-transfer. Dev Biol 2017; 426:188-193. [PMID: 26993591 PMCID: PMC5025372 DOI: 10.1016/j.ydbio.2016.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 02/27/2016] [Accepted: 03/02/2016] [Indexed: 10/22/2022]
Abstract
Completion of the Xenopus laevis genome sequence from inbred J strain animals has facilitated the generation of germline mutant X. laevis using targeted genome editing. In the last few years, numerous reports have demonstrated that TALENs are able to induce mutations in F0 Xenopus embryos, but none has demonstrated germline transmission of such mutations in X. laevis. In this report we used the oocyte host-transfer method to generate mutations in both tyrosinase homeologs and found highly-penetrant germline mutations; in contrast, embryonic injections yielded few germline mutations. We also compared the distribution of mutations in several F0 somatic tissues and germ cells and found that the majority of mutations in each tissue were different. These results establish that X. laevis J strain animals are very useful for generating germline mutations and that the oocyte host-transfer method is an efficient technique for generating mutations in both homeologs.
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Affiliation(s)
- Wil Ratzan
- National Xenopus Resource and Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Rosalia Falco
- National Xenopus Resource and Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Cristy Salanga
- National Xenopus Resource and Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Matthew Salanga
- National Xenopus Resource and Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Marko E Horb
- National Xenopus Resource and Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02543, USA.
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30
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Lombard-Banek C, Portero EP, Onjiko RM, Nemes P. New-generation mass spectrometry expands the toolbox of cell and developmental biology. Genesis 2017; 55. [PMID: 28095647 DOI: 10.1002/dvg.23012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 12/01/2016] [Accepted: 12/03/2016] [Indexed: 12/12/2022]
Abstract
Systems cell biology understanding of development requires characterization of all the molecules produced in the biological system. Decades of research and new-generation sequencing provided functional information on key genes and transcripts. However, there is less information available on how differential gene expression translates into the domains of functionally important proteins, peptides, and metabolites, and how changes in these molecules impact development. Mass spectrometry (MS) is the current technology of choice for the detection and quantification of large numbers of proteins and metabolites, because it requires no use of antibodies, functional probes, or a priori knowledge of molecules produced in the system. This review focuses on recent technologies that have improved MS sensitivity for proteins and metabolites and enabled new functionalities to assess their temporal and spatial changes during vertebrate embryonic development. This review highlights case studies, in which new-generation MS tools have enabled the study of hundreds-to-thousands of proteins and metabolites in tissues, cell populations, and single cells in model systems of vertebrate development, particularly the frog (Xenopus), zebrafish, and mouse. New-generation MS expands the toolbox of cell and developmental studies, raising exciting potentials to advance basic and translational research in the life sciences.
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Affiliation(s)
| | - Erika P Portero
- Department of Chemistry, The George Washington University, Washington, DC, 20052
| | - Rosemary M Onjiko
- Department of Chemistry, The George Washington University, Washington, DC, 20052
| | - Peter Nemes
- Department of Chemistry, The George Washington University, Washington, DC, 20052
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31
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Onjiko RM, Portero EP, Moody SA, Nemes P. In Situ Microprobe Single-Cell Capillary Electrophoresis Mass Spectrometry: Metabolic Reorganization in Single Differentiating Cells in the Live Vertebrate (Xenopus laevis) Embryo. Anal Chem 2017; 89:7069-7076. [PMID: 28434226 DOI: 10.1021/acs.analchem.7b00880] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Knowledge of single-cell metabolism would provide a powerful look into cell activity changes as cells differentiate to all the tissues of the vertebrate embryo. However, single-cell mass spectrometry technologies have not yet been made compatible with complex three-dimensional changes and rapidly decreasing cell sizes during early development of the embryo. Here, we bridge this technological gap by integrating capillary microsampling, microscale metabolite extraction, and capillary electrophoresis electrospray ionization mass spectrometry (CE-ESI-MS) to enable direct metabolic analysis of identified cells in the live frog embryo (Xenopus laevis). Microprobe CE-ESI-MS of <0.02% of the single-cell content allowed us to detect ∼230 different molecular features (positive ion mode), including 70 known metabolites, in single dorsal and ventral cells in 8-to-32-cell embryos. Relative quantification followed by multivariate and statistical analysis of the data found that microsampling enhanced detection sensitivity compared to whole-cell dissection by minimizing chemical interferences and ion suppression effects from the culture media. In addition, higher glutathione/oxidized glutathione ratios suggested that microprobed cells exhibited significantly lower oxidative stress than those dissected from the embryo. Fast (5 s/cell) and scalable microsampling with minimal damage to cells in the 8-cell embryo enabled duplicate and triplicate metabolic analysis of the same cell, which surprisingly continued to divide to the 16-cell stage. Last, we used microprobe single-cell CE-ESI-MS to uncover previously unknown reorganization of the single-cell metabolome as the dorsal progenitor cell from the 8-cell embryo formed the neural tissue fated clone through divisions to the 32-cell embryo, peering, for the first time, into the formation of metabolic single-cell heterogeneity during early development of a vertebrate embryo.
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Affiliation(s)
- Rosemary M Onjiko
- Department of Chemistry and ‡Department of Anatomy and Regenerative Biology, The George Washington University , Washington, D.C., 20052, United States
| | - Erika P Portero
- Department of Chemistry and ‡Department of Anatomy and Regenerative Biology, The George Washington University , Washington, D.C., 20052, United States
| | - Sally A Moody
- Department of Chemistry and ‡Department of Anatomy and Regenerative Biology, The George Washington University , Washington, D.C., 20052, United States
| | - Peter Nemes
- Department of Chemistry and ‡Department of Anatomy and Regenerative Biology, The George Washington University , Washington, D.C., 20052, United States
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32
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Jackson TR, Kim HY, Balakrishnan UL, Stuckenholz C, Davidson LA. Spatiotemporally Controlled Mechanical Cues Drive Progenitor Mesenchymal-to-Epithelial Transition Enabling Proper Heart Formation and Function. Curr Biol 2017; 27:1326-1335. [PMID: 28434863 DOI: 10.1016/j.cub.2017.03.065] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 02/14/2017] [Accepted: 03/27/2017] [Indexed: 10/19/2022]
Abstract
During early cardiogenesis, bilateral fields of mesenchymal heart progenitor cells (HPCs) move from the anterior lateral plate mesoderm to the ventral midline, undergoing a mesenchymal-to-epithelial transition (MET) en route to forming a single epithelial sheet. Through tracking of tissue-level deformations in the heart-forming region (HFR) as well as movement trajectories and traction generation of individual HPCs, we find that the onset of MET correlates with a peak in mechanical stress within the HFR and changes in HPC migratory behaviors. Small-molecule inhibitors targeting actomyosin contractility reveal a temporally specific requirement of bulk tissue compliance to regulate heart development and MET. Targeting mutant constructs to modulate contractility and compliance in the underlying endoderm, we find that MET in HPCs can be accelerated in response to microenvironmental stiffening and can be inhibited by softening. To test whether MET in HPCs was responsive to purely physical mechanical cues, we mimicked a high-stress state by injecting an inert oil droplet to generate high strain in the HFR, demonstrating that exogenously applied stress was sufficient to drive MET. MET-induced defects in anatomy result in defined functional lesions in the larval heart, implicating mechanical signaling and MET in the etiology of congenital heart defects. From this integrated analysis of HPC polarity and mechanics, we propose that normal heart development requires bilateral HPCs to undergo a critical behavioral and phenotypic transition on their way to the ventral midline, and that this transition is driven in response to the changing mechanical properties of their endoderm substrate.
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Affiliation(s)
- Timothy R Jackson
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Hye Young Kim
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Uma L Balakrishnan
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Carsten Stuckenholz
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Lance A Davidson
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Developmental Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15260, USA; Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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33
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Toolbox in a tadpole: Xenopus for kidney research. Cell Tissue Res 2017; 369:143-157. [PMID: 28401306 DOI: 10.1007/s00441-017-2611-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 03/09/2017] [Indexed: 01/14/2023]
Abstract
Xenopus is a versatile model organism increasingly used to study organogenesis and genetic diseases. The rapid embryonic development, targeted injections, loss- and gain-of-function experiments and an increasing supply of tools for functional in vivo analysis are unique advantages of the Xenopus system. Here, we review the vast array of methods available that have facilitated its transition into a translational model. We will focus primarily on how these methods have been employed in the study of kidney development, renal function and kidney disease. Future advances in the fields of genome editing, imaging and quantitative 'omics approaches are likely to enable exciting and novel applications for Xenopus to deepen our understanding of core principles of renal development and molecular mechanisms of human kidney disease. Thus, using Xenopus in clinically relevant research diversifies the narrowing pool of "standard" model organisms and provides unique opportunities for translational research.
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34
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Tseng WC, Munisha M, Gutierrez JB, Dougan ST. Establishment of the Vertebrate Germ Layers. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 953:307-381. [PMID: 27975275 DOI: 10.1007/978-3-319-46095-6_7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The process of germ layer formation is a universal feature of animal development. The germ layers separate the cells that produce the internal organs and tissues from those that produce the nervous system and outer tissues. Their discovery in the early nineteenth century transformed embryology from a purely descriptive field into a rigorous scientific discipline, in which hypotheses could be tested by observation and experimentation. By systematically addressing the questions of how the germ layers are formed and how they generate overall body plan, scientists have made fundamental contributions to the fields of evolution, cell signaling, morphogenesis, and stem cell biology. At each step, this work was advanced by the development of innovative methods of observing cell behavior in vivo and in culture. Here, we take an historical approach to describe our current understanding of vertebrate germ layer formation as it relates to the long-standing questions of developmental biology. By comparing how germ layers form in distantly related vertebrate species, we find that highly conserved molecular pathways can be adapted to perform the same function in dramatically different embryonic environments.
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Affiliation(s)
- Wei-Chia Tseng
- Department of Cellular Biology, University of Georgia, Athens, GA, 30602, USA
| | - Mumingjiang Munisha
- Department of Cellular Biology, University of Georgia, Athens, GA, 30602, USA
| | - Juan B Gutierrez
- Department of Mathematics, University of Georgia, Athens, GA, 30602, USA.,Institute of Bioinformatics, University of Georgia, Athens, GA, 30602, USA
| | - Scott T Dougan
- Department of Cellular Biology, University of Georgia, Athens, GA, 30602, USA.
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35
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Cooperation Between T-Box Factors Regulates the Continuous Segregation of Germ Layers During Vertebrate Embryogenesis. Curr Top Dev Biol 2017; 122:117-159. [DOI: 10.1016/bs.ctdb.2016.07.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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36
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A Matter of the Heart: The African Clawed Frog Xenopus as a Model for Studying Vertebrate Cardiogenesis and Congenital Heart Defects. J Cardiovasc Dev Dis 2016; 3:jcdd3020021. [PMID: 29367567 PMCID: PMC5715680 DOI: 10.3390/jcdd3020021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 05/25/2016] [Accepted: 05/30/2016] [Indexed: 12/20/2022] Open
Abstract
The African clawed frog, Xenopus, is a valuable non-mammalian model organism to investigate vertebrate heart development and to explore the underlying molecular mechanisms of human congenital heart defects (CHDs). In this review, we outline the similarities between Xenopus and mammalian cardiogenesis, and provide an overview of well-studied cardiac genes in Xenopus, which have been associated with congenital heart conditions. Additionally, we highlight advantages of modeling candidate genes derived from genome wide association studies (GWAS) in Xenopus and discuss commonly used techniques.
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37
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Aiello NM, Stanger BZ. Echoes of the embryo: using the developmental biology toolkit to study cancer. Dis Model Mech 2016; 9:105-14. [PMID: 26839398 PMCID: PMC4770149 DOI: 10.1242/dmm.023184] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The hallmark of embryonic development is regulation - the tendency for cells to find their way into organized and 'well behaved' structures - whereas cancer is characterized by dysregulation and disorder. At face value, cancer biology and developmental biology would thus seem to have little to do with each other. But if one looks beneath the surface, embryos and cancers share a number of cellular and molecular features. Embryos arise from a single cell and undergo rapid growth involving cell migration and cell-cell interactions: features that are also seen in the context of cancer. Consequently, many of the experimental tools that have been used to study embryogenesis for over a century are well-suited to studying cancer. This article will review the similarities between embryogenesis and cancer progression and discuss how some of the concepts and techniques used to understand embryos are now being adapted to provide insight into tumorigenesis, from the origins of cancer cells to metastasis.
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Affiliation(s)
- Nicole M Aiello
- Departments of Medicine and Cell and Developmental Biology, Abramson Family Cancer Research Institute, and Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA
| | - Ben Z Stanger
- Departments of Medicine and Cell and Developmental Biology, Abramson Family Cancer Research Institute, and Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA
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38
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Kimelman D. Tales of Tails (and Trunks): Forming the Posterior Body in Vertebrate Embryos. Curr Top Dev Biol 2016; 116:517-36. [PMID: 26970638 DOI: 10.1016/bs.ctdb.2015.12.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A major question in developmental biology is how the early embryonic axes are established. Recent studies using different model organisms and mammalian in vitro systems have revealed the surprising result that most of the early posterior embryonic body forms from a Wnt-regulated bipotential neuromesodermal progenitor population that escapes early germ layer patterning. Part of the regulatory network that drives the maintenance and differentiation of these progenitors has recently been determined, but much remains to be discovered. This review discusses some of the common features present in all vertebrates, as well as unique aspects that different species utilize to establish their anterior-posterior (A-P) axis.
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Affiliation(s)
- David Kimelman
- Department of Biochemistry, University of Washington, Seattle, Washington, USA.
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39
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Abstract
The nature of cells in early embryos may be respecified simply by exposure to inducing factors. In later stage embryos, determined cell populations do not respond to inducing factors but may be respecified by other stimuli, especially the introduction of specific transcription factors. Fully differentiated cell types are hard to respecify by any method, but some degree of success can be achieved using selected combinations of transcription factors, and this may have clinical significance in the future.
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40
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Klein SL, Moody SA. When Family History Matters: The Importance of Lineage Analyses and Fate Maps for Explaining Animal Development. Curr Top Dev Biol 2016; 117:93-112. [PMID: 26969974 DOI: 10.1016/bs.ctdb.2015.10.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2023]
Abstract
Initial interest in understanding how the fertilized egg becomes a multicellular animal suggested two possible answers: either the embryo came from preformed components or it arose through epigenetic processes. Extensive research during the past few decades has identified aspects of development that depend on preformed elements, such as cytoplasmic components and a cell's lineage; it also has identified aspects that depend on epigenetic processes, such as cell interactions and morphogen gradients. These advances have depended on understanding embryonic cell lineage and cell fate. This essay explains how lineage analysis and fate mapping have contributed to our current understanding of embryonic development.
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Affiliation(s)
- Steven L Klein
- Department of Anatomy and Regenerative Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Sally A Moody
- Department of Anatomy and Regenerative Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC, USA.
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41
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Carmel MS, Kahane N, Oberman F, Miloslavski R, Sela-Donenfeld D, Kalcheim C, Yisraeli JK. A Novel Role for VICKZ Proteins in Maintaining Epithelial Integrity during Embryogenesis. PLoS One 2015; 10:e0136408. [PMID: 26317350 PMCID: PMC4552865 DOI: 10.1371/journal.pone.0136408] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 08/04/2015] [Indexed: 12/31/2022] Open
Abstract
Background VICKZ (IGF2BP1,2,3/ZBP1/Vg1RBP/IMP1,2,3) proteins bind RNA and help regulate many RNA-mediated processes. In the midbrain region of early chick embryos, VICKZ is expressed in the neural folds and along the basal surface of the neural epithelium, but, upon neural tube closure, is down-regulated in prospective cranial neural crest (CNC) cells, concomitant with their emigration and epithelial-to-mesenchymal transition (EMT). Electroporation of constructs that modulate cVICKZ expression demonstrates that this down-regulation is both necessary and sufficient for CNC EMT. These results suggest that VICKZ down-regulation in CNC cell-autonomously promotes EMT and migration. Reduction of VICKZ throughout the embryo, however, inhibits CNC migration non-cell-autonomously, as judged by transplantation experiments in Xenopus embryos. Results and Conclusions Given the positive role reported for VICKZ proteins in promoting cell migration of chick embryo fibroblasts and many types of cancer cells, we have begun to look for specific mRNAs that could mediate context-specific differences. We report here that the laminin receptor, integrin alpha 6, is down-regulated in the dorsal neural tube when CNC cells emigrate, this process is mediated by cVICKZ, and integrin alpha 6 mRNA is found in VICKZ ribonucleoprotein complexes. Significantly, prolonged inhibition of cVICKZ in either the neural tube or the nascent dermomyotome sheet, which also dynamically expresses cVICKZ, induces disruption of these epithelia. These data point to a previously unreported role for VICKZ in maintaining epithelial integrity.
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Affiliation(s)
- Michal Shoshkes Carmel
- Department of Developmental Biology and Cancer Research, The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nitza Kahane
- Department of Medical Neurobiology, IMRIC, The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Froma Oberman
- Department of Developmental Biology and Cancer Research, The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Rachel Miloslavski
- Department of Developmental Biology and Cancer Research, The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Dalit Sela-Donenfeld
- Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, 76100, Rehovot, Israel
| | - Chaya Kalcheim
- Department of Medical Neurobiology, IMRIC, The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Joel K. Yisraeli
- Department of Developmental Biology and Cancer Research, The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
- * E-mail:
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42
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Shi Z, Wang F, Cui Y, Liu Z, Guo X, Zhang Y, Deng Y, Zhao H, Chen Y. Heritable CRISPR/Cas9‐mediated targeted integration in
Xenopus tropicalis. FASEB J 2015; 29:4914-23. [DOI: 10.1096/fj.15-273425] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 08/03/2015] [Indexed: 01/03/2023]
Affiliation(s)
- Zhaoying Shi
- Chinese Academy of Sciences Key Laboratory of Regenerative Biology and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative MedicineSouth China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of SciencesGuangzhouGuangdongChina
- Shenzhen Key Laboratory of Cell MicroenvironmentDepartment of BiologySouth University of Science and Technology of ChinaShenzhenGuangdongChina
| | - Fengqin Wang
- Chinese Academy of Sciences Key Laboratory of Regenerative Biology and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative MedicineSouth China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of SciencesGuangzhouGuangdongChina
- School of Life SciencesAnhui UniversityHefeiAnhuiChina
| | - Yan Cui
- Chinese Academy of Sciences Key Laboratory of Regenerative Biology and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative MedicineSouth China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of SciencesGuangzhouGuangdongChina
- University of Chinese Academy of SciencesBeijingChina
| | - Zhongzhen Liu
- School of Biomedical Sciences, Faculty of MedicineThe Chinese University of Hong Kong, ShatinNew TerritoriesHong KongChina
| | - Xiaogang Guo
- Chinese Academy of Sciences Key Laboratory of Regenerative Biology and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative MedicineSouth China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of SciencesGuangzhouGuangdongChina
| | - Yanqi Zhang
- Chinese Academy of Sciences Key Laboratory of Regenerative Biology and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative MedicineSouth China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of SciencesGuangzhouGuangdongChina
- University of Chinese Academy of SciencesBeijingChina
| | - Yi Deng
- Shenzhen Key Laboratory of Cell MicroenvironmentDepartment of BiologySouth University of Science and Technology of ChinaShenzhenGuangdongChina
| | - Hui Zhao
- School of Biomedical Sciences, Faculty of MedicineThe Chinese University of Hong Kong, ShatinNew TerritoriesHong KongChina
- Shenzhen Research InstituteThe Chinese University of Hong KongShenzhenGuangdongChina
| | - Yonglong Chen
- Chinese Academy of Sciences Key Laboratory of Regenerative Biology and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative MedicineSouth China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of SciencesGuangzhouGuangdongChina
- Shenzhen Key Laboratory of Cell MicroenvironmentDepartment of BiologySouth University of Science and Technology of ChinaShenzhenGuangdongChina
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43
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Abstract
The use of Xenopus embryonic skin as a model system for the development of ciliated epithelia is well established. This tissue is comprised of numerous cell types, most notably the multiciliated cells (MCCs) that each contain approximately 150 motile cilia. At the base of each cilium lies the centriole-based structure called the basal body. Centriole biogenesis is typically restricted to two new centrioles per cell cycle, each templating from an existing "mother" centriole. In contrast, MCCs are post-mitotic cells in which the majority of centrioles arise "de novo" without templating from a mother centriole, instead, these centrioles nucleate from an electron-dense structure termed the deuterostome. How centriole number is regulated in these cells and the mechanism by which the deuterosome templates nascent centrioles is still poorly understood. Here, we describe methods for regulating MCC cell fate as well as for visualizing and manipulating centriole biogenesis.
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Affiliation(s)
- Siwei Zhang
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Brian J Mitchell
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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44
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Single-cell mass spectrometry reveals small molecules that affect cell fates in the 16-cell embryo. Proc Natl Acad Sci U S A 2015; 112:6545-50. [PMID: 25941375 DOI: 10.1073/pnas.1423682112] [Citation(s) in RCA: 149] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Spatial and temporal changes in molecular expression are essential to embryonic development, and their characterization is critical to understand mechanisms by which cells acquire different phenotypes. Although technological advances have made it possible to quantify expression of large molecules during embryogenesis, little information is available on metabolites, the ultimate indicator of physiological activity of the cell. Here, we demonstrate that single-cell capillary electrophoresis-electrospray ionization mass spectrometry is able to test whether differential expression of the genome translates to the domain of metabolites between single embryonic cells. Dissection of three different cell types with distinct tissue fates from 16-cell embryos of the South African clawed frog (Xenopus laevis) and microextraction of their metabolomes enabled the identification of 40 metabolites that anchored interconnected central metabolic networks. Relative quantitation revealed that several metabolites were differentially active between the cell types in the wild-type, unperturbed embryos. Altering postfertilization cytoplasmic movements that perturb dorsal development confirmed that these three cells have characteristic small-molecular activity already at cleavage stages as a result of cell type and not differences in pigmentation, yolk content, cell size, or position in the embryo. Changing the metabolite concentration caused changes in cell movements at gastrulation that also altered the tissue fates of these cells, demonstrating that the metabolome affects cell phenotypes in the embryo.
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45
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Zhang X, Cheong SM, Amado NG, Reis AH, MacDonald BT, Zebisch M, Jones EY, Abreu JG, He X. Notum is required for neural and head induction via Wnt deacylation, oxidation, and inactivation. Dev Cell 2015; 32:719-30. [PMID: 25771893 PMCID: PMC4375027 DOI: 10.1016/j.devcel.2015.02.014] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 02/17/2015] [Accepted: 02/17/2015] [Indexed: 11/21/2022]
Abstract
Secreted Wnt morphogens are essential for embryogenesis and homeostasis and require a lipid/palmitoleoylate modification for receptor binding and activity. Notum is a secreted Wnt antagonist that belongs to the α/β hydrolase superfamily, but its mechanism of action and roles in vertebrate embryogenesis are not fully understood. Here, we report that Notum hydrolyzes the Wnt palmitoleoylate adduct extracellularly, resulting in inactivated Wnt proteins that form oxidized oligomers incapable of receptor binding. Thus, Notum is a Wnt deacylase, and palmitoleoylation is obligatory for the Wnt structure that maintains its active monomeric conformation. Notum is expressed in naive ectoderm and neural plate in Xenopus and is required for neural and head induction. These findings suggest that Notum is a prerequisite for the "default" neural fate and that distinct mechanisms of Wnt inactivation by the Tiki protease in the Organizer and the Notum deacylase in presumptive neuroectoderm orchestrate vertebrate brain development.
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Affiliation(s)
- Xinjun Zhang
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Seong-Moon Cheong
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Nathalia G Amado
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Alice H Reis
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Bryan T MacDonald
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Matthias Zebisch
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - E Yvonne Jones
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Jose Garcia Abreu
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Xi He
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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46
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Abstract
Cilia are key organelles in development and homeostasis. The ever-expanding complement of cilia associated proteins necessitates rapid and tractable models for in vivo functional investigation. Xenopus laevis provides an attractive model for such studies, having multiple ciliated populations, including primary and multiciliated tissues. The rapid external development of Xenopus and the large cells make it an especially excellent platform for imaging studies. Here we present embryological and cell biological methods for the investigation of cilia structure and function in X. laevis, with a focus on quantitative live and fixed imaging.
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47
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FoxA4 favours notochord formation by inhibiting contiguous mesodermal fates and restricts anterior neural development in Xenopus embryos. PLoS One 2014; 9:e110559. [PMID: 25343614 PMCID: PMC4208771 DOI: 10.1371/journal.pone.0110559] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 09/24/2014] [Indexed: 11/19/2022] Open
Abstract
In vertebrates, the embryonic dorsal midline is a crucial signalling centre that patterns the surrounding tissues during development. Members of the FoxA subfamily of transcription factors are expressed in the structures that compose this centre. Foxa2 is essential for dorsal midline development in mammals, since knock-out mouse embryos lack a definitive node, notochord and floor plate. The related gene foxA4 is only present in amphibians. Expression begins in the blastula -chordin and -noggin expressing centre (BCNE) and is later restricted to the dorsal midline derivatives of the Spemann's organiser. It was suggested that the early functions of mammalian foxa2 are carried out by foxA4 in frogs, but functional experiments were needed to test this hypothesis. Here, we show that some important dorsal midline functions of mammalian foxa2 are exerted by foxA4 in Xenopus. We provide new evidence that the latter prevents the respecification of dorsal midline precursors towards contiguous fates, inhibiting prechordal and paraxial mesoderm development in favour of the notochord. In addition, we show that foxA4 is required for the correct regionalisation and maintenance of the central nervous system. FoxA4 participates in constraining the prospective rostral forebrain territory during neural specification and is necessary for the correct segregation of the most anterior ectodermal derivatives, such as the cement gland and the pituitary anlagen. Moreover, the early expression of foxA4 in the BCNE (which contains precursors of the whole forebrain and most of the midbrain and hindbrain) is directly required to restrict anterior neural development.
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48
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Gentsch GE, Smith JC. Investigating physical chromatin associations across the Xenopus genome by chromatin immunoprecipitation. Cold Spring Harb Protoc 2014; 2014:2014/5/pdb.prot080614. [PMID: 24786504 DOI: 10.1101/pdb.prot080614] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Chromatin immunoprecipitation (ChIP) combined with genomic analysis techniques provide a global snapshot of protein-DNA interactions in the context of chromatin, yielding insights into which genomic loci might be regulated by the DNA-associated protein under investigation. This protocol describes how to perform ChIP on intact or dissected Xenopus embryos. The ChIP-isolated DNA fragments are suitable for high-throughput sequencing (ChIP-Seq) or for quantitative PCR (ChIP-qPCR). In this protocol, embryonic tissue is harvested from Xenopus tropicalis or Xenopus laevis at the developmental stage of interest, and DNA-associated proteins are immobilized to their endogenous genomic binding sites with formaldehyde. Nuclei are extracted from embryos and subjected to sonication so as to shear the chromatin to a size that allows sufficient positional resolution of protein binding to genomic DNA. Chromatin fragments bound by the protein of interest are immunoprecipitated using antibody-coupled beads, washed under high-stringency conditions, and stripped from the beads with anionic detergents. The chemical cross-links are reversed, and the coimmunoprecipitated DNA is purified. The resulting DNA fragments can be analyzed by qPCR or used to create a ChIP-Seq library. General advice for qPCR and for making ChIP-Seq libraries is offered, and approaches for analyzing ChIP-Seq data are outlined.
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Affiliation(s)
- George E Gentsch
- Division of Systems Biology, National Institute for Medical Research, London NW7 1AA, United Kingdom
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49
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Geach TJ, Faas L, Devader C, Gonzalez-Cordero A, Tabler JM, Brunsdon H, Isaacs HV, Dale L. An essential role for LPA signalling in telencephalon development. Development 2014; 141:940-9. [PMID: 24496630 DOI: 10.1242/dev.104901] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Lysophosphatidic acid (LPA) has wide-ranging effects on many different cell types, acting through G-protein-coupled receptors such as LPAR6. We show that Xenopus lpar6 is expressed from late blastulae and is enriched in the mesoderm and dorsal ectoderm of early gastrulae. Expression in gastrulae is an early response to FGF signalling. Transcripts for lpar6 are enriched in the neural plate of Xenopus neurulae and loss of function caused forebrain defects, with reduced expression of telencephalic markers (foxg1, emx1 and nkx2-1). Midbrain (en2) and hindbrain (egr2) markers were unaffected. Foxg1 expression requires LPAR6 within ectoderm and not mesoderm. Head defects caused by LPAR6 loss of function were enhanced by co-inhibiting FGF signalling, with defects extending into the hindbrain (en2 and egr2 expression reduced). This is more severe than expected from simple summation of individual defects, suggesting that LPAR6 and FGF have overlapping or partially redundant functions in the anterior neural plate. We observed similar defects in forebrain development in loss-of-function experiments for ENPP2, an enzyme involved in the synthesis of extracellular LPA. Our study demonstrates a role for LPA in early forebrain development.
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Affiliation(s)
- Timothy J Geach
- Department of Cell and Developmental Biology, University College London, Anatomy Building, Gower Street, London, WC1E 6BT, UK
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50
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Vandenberg LN, Lemire JM, Levin M. It's never too early to get it Right: A conserved role for the cytoskeleton in left-right asymmetry. Commun Integr Biol 2013; 6:e27155. [PMID: 24505508 PMCID: PMC3912007 DOI: 10.4161/cib.27155] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 11/08/2013] [Accepted: 11/11/2013] [Indexed: 01/08/2023] Open
Abstract
For centuries, scientists and physicians have been captivated by the consistent left-right (LR) asymmetry of the heart, viscera, and brain. A recent study implicated tubulin proteins in establishing laterality in several experimental models, including asymmetric chemosensory receptor expression in C. elegans neurons, polarization of HL-60 human neutrophil-like cells in culture, and asymmetric organ placement in Xenopus. The same mutations that randomized asymmetry in these diverse systems also affect chirality in Arabidopsis, revealing a remarkable conservation of symmetry-breaking mechanisms among kingdoms. In Xenopus, tubulin mutants only affected LR patterning very early, suggesting that this axis is established shortly after fertilization. This addendum summarizes and extends the knowledge of the cytoskeleton's role in the patterning of the LR axis. Results from many species suggest a conserved role for the cytoskeleton as the initiator of asymmetry, and indicate that symmetry is first broken during early embryogenesis by an intracellular process.
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Affiliation(s)
- Laura N Vandenberg
- Biology Department; Center for Regenerative and Developmental Biology; Tufts University; Medford, MA USA ; Current affiliation: Department of Public Health; Division of Environmental Health Sciences; University of Massachusetts, Amherst; Amherst, MA USA
| | - Joan M Lemire
- Biology Department; Center for Regenerative and Developmental Biology; Tufts University; Medford, MA USA
| | - Michael Levin
- Biology Department; Center for Regenerative and Developmental Biology; Tufts University; Medford, MA USA
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