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Abu-Daya A, Godwin A. CRISPR/Cas9 Gene Disruption Studies in F 0 Xenopus Tadpoles: Understanding Development and Disease in the Frog. Methods Mol Biol 2023; 2633:111-130. [PMID: 36853461 DOI: 10.1007/978-1-0716-3004-4_10] [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: 03/01/2023]
Abstract
CRISPR/Cas9 has become the favorite method for gene knockouts in a range of vertebrate model organisms due to its ease of use and versatility. Gene-specific guide RNAs can be designed to a unique genomic sequence and used to target the Cas9 endonuclease, which causes a double-stranded break at the desired locus. Repair of the breaks through non-homologous end joining often results in the deletion or insertion of several nucleotides, which frequently result in nonsense mutations. Xenopus frogs have long been an excellent model organism in which to study gene function, and they have proven to be useful in gene-editing experiments, especially the diploid species, X. tropicalis. In this chapter, we present our protocols for gene disruption in Xenopus, which we regularly use to investigate developmental processes and model human genetic disease.
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Affiliation(s)
- Anita Abu-Daya
- European Xenopus Resource Centre, University of Portsmouth, Portsmouth, UK.
| | - Annie Godwin
- European Xenopus Resource Centre, University of Portsmouth, Portsmouth, UK.
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2
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I-SceI-Mediated Transgenesis in Xenopus. Cold Spring Harb Protoc 2022; 2022:Pdb.prot107011. [PMID: 35135888 DOI: 10.1101/pdb.prot107011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Transgenic frogs can be very efficiently generated using I-SceI meganuclease, a nuclease with an 18-bp recognition site. The desired transgene must be flanked by I-SceI sites, in either a plasmid or a polymerase chain reaction (PCR) product. After a short in vitro digestion with the meganuclease, the complete reaction is injected into fertilized eggs, where the enzyme mediates genomic integration by an unknown mechanism. Posttransgenesis development is typically normal, and up to 70% of the embryos integrate the transgene.
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3
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Macken WL, Godwin A, Wheway G, Stals K, Nazlamova L, Ellard S, Alfares A, Aloraini T, AlSubaie L, Alfadhel M, Alajaji S, Wai HA, Self J, Douglas AGL, Kao AP, Guille M, Baralle D. Biallelic variants in COPB1 cause a novel, severe intellectual disability syndrome with cataracts and variable microcephaly. Genome Med 2021; 13:34. [PMID: 33632302 PMCID: PMC7908744 DOI: 10.1186/s13073-021-00850-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 02/11/2021] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Coat protein complex 1 (COPI) is integral in the sorting and retrograde trafficking of proteins and lipids from the Golgi apparatus to the endoplasmic reticulum (ER). In recent years, coat proteins have been implicated in human diseases known collectively as "coatopathies". METHODS Whole exome or genome sequencing of two families with a neuro-developmental syndrome, variable microcephaly and cataracts revealed biallelic variants in COPB1, which encodes the beta-subunit of COPI (β-COP). To investigate Family 1's splice donor site variant, we undertook patient blood RNA studies and CRISPR/Cas9 modelling of this variant in a homologous region of the Xenopus tropicalis genome. To investigate Family 2's missense variant, we studied cellular phenotypes of human retinal epithelium and embryonic kidney cell lines transfected with a COPB1 expression vector into which we had introduced Family 2's mutation. RESULTS We present a new recessive coatopathy typified by severe developmental delay and cataracts and variable microcephaly. A homozygous splice donor site variant in Family 1 results in two aberrant transcripts, one of which causes skipping of exon 8 in COPB1 pre-mRNA, and a 36 amino acid in-frame deletion, resulting in the loss of a motif at a small interaction interface between β-COP and β'-COP. Xenopus tropicalis animals with a homologous mutation, introduced by CRISPR/Cas9 genome editing, recapitulate features of the human syndrome including microcephaly and cataracts. In vitro modelling of the COPB1 c.1651T>G p.Phe551Val variant in Family 2 identifies defective Golgi to ER recycling of this mutant β-COP, with the mutant protein being retarded in the Golgi. CONCLUSIONS This adds to the growing body of evidence that COPI subunits are essential in brain development and human health and underlines the utility of exome and genome sequencing coupled with Xenopus tropicalis CRISPR/Cas modelling for the identification and characterisation of novel rare disease genes.
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Affiliation(s)
- William L Macken
- Wessex Clinical Genetics Service, Princess Anne Hospital, University Hospital Southampton NHS Foundation Trust, Coxford Rd, Southampton, SO165YA, UK
| | - Annie Godwin
- European Xenopus Resource Centre, University of Portsmouth School of Biological Sciences, King Henry Building, King Henry I Street, Portsmouth, PO1 2DY, UK
| | - Gabrielle Wheway
- Faculty of Medicine, University of Southampton, Duthie Building, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK
| | - Karen Stals
- Exeter Genomics Laboratory, Level 3 RILD building, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, EX2 5DW, UK
| | - Liliya Nazlamova
- Faculty of Medicine, University of Southampton, Duthie Building, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK
| | - Sian Ellard
- Exeter Genomics Laboratory, Level 3 RILD building, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, EX2 5DW, UK
- University of Exeter Medical School, RILD building, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, EX2 5DW, UK
| | - Ahmed Alfares
- Department of Pediatrics, College of Medicine, Qassim University, Qassim, Saudi Arabia
- Department of Pathology and Laboratory Medicine, King Abdulaziz Medical City, Riyadh, Saudi Arabia
| | - Taghrid Aloraini
- Department of Pathology and Laboratory Medicine, King Abdulaziz Medical City, Riyadh, Saudi Arabia
| | - Lamia AlSubaie
- Division of Genetics, Department of Pediatrics, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia
- King Abdullah International Medical Research Centre, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | - Majid Alfadhel
- Division of Genetics, Department of Pediatrics, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia
- King Abdullah International Medical Research Centre, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia
- King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | - Sulaiman Alajaji
- King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia
- Division of Allergy and Clinical Immunology, Department of Pediatrics, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | - Htoo A Wai
- Faculty of Medicine, University of Southampton, Duthie Building, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK
| | - Jay Self
- Faculty of Medicine, University of Southampton, Duthie Building, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK
| | - Andrew G L Douglas
- Wessex Clinical Genetics Service, Princess Anne Hospital, University Hospital Southampton NHS Foundation Trust, Coxford Rd, Southampton, SO165YA, UK
- Faculty of Medicine, University of Southampton, Duthie Building, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK
| | - Alexander P Kao
- Zeiss Global Centre, School of Mechanical and Design Engineering, University of Portsmouth, Portsmouth, PO1 3DJ, UK
| | - Matthew Guille
- European Xenopus Resource Centre, University of Portsmouth School of Biological Sciences, King Henry Building, King Henry I Street, Portsmouth, PO1 2DY, UK.
| | - Diana Baralle
- Wessex Clinical Genetics Service, Princess Anne Hospital, University Hospital Southampton NHS Foundation Trust, Coxford Rd, Southampton, SO165YA, UK.
- Faculty of Medicine, University of Southampton, Duthie Building, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK.
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4
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Martin SA, Page SJ, Piccinni MZ, Guille MJ. Confirming Antibody Specificity in Xenopus. Cold Spring Harb Protoc 2020; 2020:pdb.prot105601. [PMID: 33037077 DOI: 10.1101/pdb.prot105601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Verifying that a new antibody recognizes its target can be difficult. In this protocol, expression of a target protein in Xenopus embryos is either knocked down using CRISPR-Cas9 technology (for zygotic proteins) or enhanced by microinjection of a synthetic mRNA (for maternal proteins). Western blotting analysis is then performed. If the antibody recognizes the target protein, the western blot will show a relatively weak band for CRISPR-injected embryos and a relatively strong band for RNA-injected embryos. This represents a straightforward, powerful strategy for confirming antibody specificity in Xenopus.
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Affiliation(s)
- Sian A Martin
- Molecular Embryology Laboratory, University of Portsmouth, Portsmouth, Hampshire PO1 2DY, United Kingdom
| | - Suzannah J Page
- Molecular Embryology Laboratory, University of Portsmouth, Portsmouth, Hampshire PO1 2DY, United Kingdom
| | - Maya Z Piccinni
- European Xenopus Resource Centre, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, Hampshire PO1 2DY, United Kingdom
| | - Matthew J Guille
- Molecular Embryology Laboratory, University of Portsmouth, Portsmouth, Hampshire PO1 2DY, United Kingdom; .,European Xenopus Resource Centre, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, Hampshire PO1 2DY, United Kingdom
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Cobley JN, Noble A, Jimenez-Fernandez E, Valdivia Moya MT, Guille M, Husi H. Catalyst-free Click PEGylation reveals substantial mitochondrial ATP synthase sub-unit alpha oxidation before and after fertilisation. Redox Biol 2019; 26:101258. [PMID: 31234016 PMCID: PMC6597785 DOI: 10.1016/j.redox.2019.101258] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 06/10/2019] [Accepted: 06/15/2019] [Indexed: 12/21/2022] Open
Abstract
Using non-reducing Western blotting to assess protein thiol redox state is challenging because most reduced and oxidised forms migrate at the same molecular weight and are, therefore, indistinguishable. While copper catalysed Click chemistry can be used to ligate a polyethylene glycol (PEG) moiety termed Click PEGylation to mass shift the reduced or oxidised form as desired, the potential for copper catalysed auto-oxidation is problematic. Here we define a catalyst-free trans-cyclooctene-methyltetrazine (TCO-Tz) inverse electron demand Diels Alder chemistry approach that affords rapid (k ~2000 M−1 s−1), selective and bio-orthogonal Click PEGylation. We used TCO-Tz Click PEGylation to investigate how fertilisation impacts reversible mitochondrial ATP synthase F1-Fo sub-unit alpha (ATP-α-F1) oxidation—an established molecular correlate of impaired enzyme activity—in Xenopus laevis. TCO-Tz Click PEGylation studies reveal substantial (~65%) reversible ATP-α-F1 oxidation at evolutionary conserved cysteine residues (i.e., C244 and C294) before and after fertilisation. A single thiol is, however, preferentially oxidised likely due to greater solvent exposure during the catalytic cycle. Selective reduction experiments show that: S-glutathionylation accounts for ~50–60% of the reversible oxidation observed, making it the dominant oxidative modification type. Intermolecular disulphide bonds may also contribute due to their relative stability. Substantial reversible ATP-α-F1 oxidation before and after fertilisation is biologically meaningful because it implies low mitochondrial F1-Fo ATP synthase activity. Catalyst-free TCO-Tz Click PEGylation is a valuable new tool to interrogate protein thiol redox state in health and disease. Catalyst-free TCO-Tz Click PEGylation can assess protein thiol redox state. ATP-α-F1 is substantially oxidised before and after fertilisation. S-glutathionylation is the dominant oxidative modification type. A single thiol is preferentially oxidised due to greater solvent exposure. Catalyst-free TCO-Tz Click PEGylation is a valuable new tool.
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Affiliation(s)
- James N Cobley
- Free Radical Research Group, University of the Highlands and Islands, Centre for Health Sciences, Inverness, IV2 3JH, UK.
| | - Anna Noble
- European Xenopus Resource Centre, University of Portsmouth, School of Biological Sciences, King Henry Building, Portsmouth, PO1 2DY, UK
| | - Eduardo Jimenez-Fernandez
- Free Radical Research Group, University of the Highlands and Islands, Centre for Health Sciences, Inverness, IV2 3JH, UK
| | - Manuel-Thomas Valdivia Moya
- Free Radical Research Group, University of the Highlands and Islands, Centre for Health Sciences, Inverness, IV2 3JH, UK
| | - Matthew Guille
- European Xenopus Resource Centre, University of Portsmouth, School of Biological Sciences, King Henry Building, Portsmouth, PO1 2DY, UK
| | - Holger Husi
- Free Radical Research Group, University of the Highlands and Islands, Centre for Health Sciences, Inverness, IV2 3JH, UK
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Pearl E, Morrow S, Noble A, Lerebours A, Horb M, Guille M. An optimized method for cryogenic storage of Xenopus sperm to maximise the effectiveness of research using genetically altered frogs. Theriogenology 2017; 92:149-155. [PMID: 28237331 PMCID: PMC5340284 DOI: 10.1016/j.theriogenology.2017.01.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 10/26/2016] [Accepted: 01/04/2017] [Indexed: 02/06/2023]
Abstract
Cryogenic storage of sperm from genetically altered Xenopus improves cost effectiveness and animal welfare associated with their use in research; currently it is routine for X. tropicalis but not reliable for X. laevis. Here we compare directly the three published protocols for Xenopus sperm freeze-thaw and determine whether sperm storage temperature, method of testes maceration and delays in the freezing protocols affect successful fertilisation and embryo development in X. laevis. We conclude that the protocol is robust and that the variability observed in fertilisation rates is due to differences between individuals. We show that the embryos made from the frozen-thawed sperm are normal and that the adults they develop into are reproductively indistinguishable from others in the colony. This opens the way for using cryopreserved sperm to distribute dominant genetically altered (GA) lines, potentially saving travel-induced stress to the male frogs, reducing their numbers used and making Xenopus experiments more cost effective. Xenopus cryopreservation is robust using an optimized method. Success is dependent on the quality of animals from which the sperm are taken. Frozen sperm may now be used to distribute lines and wild-type male gametes around the world.
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Affiliation(s)
- Esther Pearl
- National Xenopus Resource, 7 MBL Street, Woods Hole, MA, 02543, USA
| | - Sean Morrow
- European Xenopus Resource Centre, Institute of Biomedical and Biomolecular Sciences, University of Portsmouth, Portsmouth, PO1 2DT, UK
| | - Anna Noble
- European Xenopus Resource Centre, Institute of Biomedical and Biomolecular Sciences, University of Portsmouth, Portsmouth, PO1 2DT, UK
| | - Adelaide Lerebours
- School of Biological Sciences, University of Portsmouth, Portsmouth, PO1 2DY, UK
| | - Marko Horb
- National Xenopus Resource, 7 MBL Street, Woods Hole, MA, 02543, USA
| | - Matthew Guille
- European Xenopus Resource Centre, Institute of Biomedical and Biomolecular Sciences, University of Portsmouth, Portsmouth, PO1 2DT, UK; School of Biological Sciences, University of Portsmouth, Portsmouth, PO1 2DY, UK.
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7
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Nogueira JM, Hawrot K, Sharpe C, Noble A, Wood WM, Jorge EC, Goldhamer DJ, Kardon G, Dietrich S. The emergence of Pax7-expressing muscle stem cells during vertebrate head muscle development. Front Aging Neurosci 2015; 7:62. [PMID: 26042028 PMCID: PMC4436886 DOI: 10.3389/fnagi.2015.00062] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 04/10/2015] [Indexed: 12/13/2022] Open
Abstract
Pax7 expressing muscle stem cells accompany all skeletal muscles in the body and in healthy individuals, efficiently repair muscle after injury. Currently, the in vitro manipulation and culture of these cells is still in its infancy, yet muscle stem cells may be the most promising route toward the therapy of muscle diseases such as muscular dystrophies. It is often overlooked that muscular dystrophies affect head and body skeletal muscle differently. Moreover, these muscles develop differently. Specifically, head muscle and its stem cells develop from the non-somitic head mesoderm which also has cardiac competence. To which extent head muscle stem cells retain properties of the early head mesoderm and might even be able to switch between a skeletal muscle and cardiac fate is not known. This is due to the fact that the timing and mechanisms underlying head muscle stem cell development are still obscure. Consequently, it is not clear at which time point one should compare the properties of head mesodermal cells and head muscle stem cells. To shed light on this, we traced the emergence of head muscle stem cells in the key vertebrate models for myogenesis, chicken, mouse, frog and zebrafish, using Pax7 as key marker. Our study reveals a common theme of head muscle stem cell development that is quite different from the trunk. Unlike trunk muscle stem cells, head muscle stem cells do not have a previous history of Pax7 expression, instead Pax7 expression emerges de-novo. The cells develop late, and well after the head mesoderm has committed to myogenesis. We propose that this unique mechanism of muscle stem cell development is a legacy of the evolutionary history of the chordate head mesoderm.
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Affiliation(s)
- Julia Meireles Nogueira
- School of Pharmacy and Biomedical Sciences, Institute for Biomedical and Biomolecular Science, University of Portsmouth Portsmouth, UK ; Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais Belo Horizonte, Brazil
| | - Katarzyna Hawrot
- School of Pharmacy and Biomedical Sciences, Institute for Biomedical and Biomolecular Science, University of Portsmouth Portsmouth, UK
| | - Colin Sharpe
- School of Biological Sciences, Institute for Biomedical and Biomolecular Science, University of Portsmouth Portsmouth, UK
| | - Anna Noble
- European Xenopus Resource Centre, School of Biological Sciences, University of Portsmouth Portsmouth, UK
| | - William M Wood
- Department of Molecular and Cell Biology, University of Connecticut Stem Cell Institute, University of Connecticut Storrs, CT, USA
| | - Erika C Jorge
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais Belo Horizonte, Brazil
| | - David J Goldhamer
- Department of Molecular and Cell Biology, University of Connecticut Stem Cell Institute, University of Connecticut Storrs, CT, USA
| | - Gabrielle Kardon
- Department of Human Genetics, University of Utah Salt Lake City, UT, USA
| | - Susanne Dietrich
- School of Pharmacy and Biomedical Sciences, Institute for Biomedical and Biomolecular Science, University of Portsmouth Portsmouth, UK
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The nuclear F-actin interactome of Xenopus oocytes reveals an actin-bundling kinesin that is essential for meiotic cytokinesis. EMBO J 2013; 32:1886-902. [PMID: 23727888 PMCID: PMC3981176 DOI: 10.1038/emboj.2013.108] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Accepted: 04/23/2013] [Indexed: 11/09/2022] Open
Abstract
Nuclei of Xenopus laevis oocytes grow 100 000-fold larger in volume than a typical somatic nucleus and require an unusual intranuclear F-actin scaffold for mechanical stability. We now developed a method for mapping F-actin interactomes and identified a comprehensive set of F-actin binders from the oocyte nuclei. Unexpectedly, the most prominent interactor was a novel kinesin termed NabKin (Nuclear and meiotic actin-bundling Kinesin). NabKin not only binds microtubules but also F-actin structures, such as the intranuclear actin bundles in prophase and the contractile actomyosin ring during cytokinesis. The interaction between NabKin and F-actin is negatively regulated by Importin-β and is responsive to spatial information provided by RanGTP. Disconnecting NabKin from F-actin during meiosis caused cytokinesis failure and egg polyploidy. We also found actin-bundling activity in Nabkin's somatic paralogue KIF14, which was previously shown to be essential for somatic cell division. Our data are consistent with the notion that NabKin/KIF14 directly link microtubules with F-actin and that such link is essential for cytokinesis. The presence and role of actin filaments in cell nuclei remains incompletely understood. A proteomics approach now reveals a highly distinct set of F-actin-binding proteins in the nucleus, including a novel kinesin family member.
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9
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Ng KP, Cheung F, Lee KAW. A transcription assay for EWS oncoproteins in Xenopus oocytes. Protein Cell 2010; 1:927-34. [PMID: 21204019 DOI: 10.1007/s13238-010-0114-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Accepted: 09/18/2010] [Indexed: 11/29/2022] Open
Abstract
Aberrant chromosomal fusion of the Ewing's sarcoma oncogene (EWS) to several different cellular partners produces the Ewing's family of oncoproteins (EWS-fusion-proteins, EFPs) and associated tumors (EFTs). EFPs are potent transcriptional activators, dependent on the N-terminal region of EWS (the EWS-activation-domain, EAD) and this function is thought to be central to EFT oncogenesis and maintenance. Thus EFPs are promising therapeutic targets, but detailed molecular studies will be pivotal for exploring this potential. Such studies have so far largely been restricted to intact mammalian cells while recent evidence has indicated that a mammalian cell-free transcription system may not support bona fide EAD function. Therefore, the lack of manipulatable assays for the EAD presents a significant barrier to progress. Using Xenopus laevis oocytes we describe a plasmid-based micro-injection assay that supports efficient, bona fide EAD transcriptional activity and hence provides a new vehicle for molecular dissection of the EAD.
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Affiliation(s)
- King Pan Ng
- Department of Biology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon Hong Kong, China
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Wallingford JB. Preparation of fixed Xenopus embryos for confocal imaging. Cold Spring Harb Protoc 2010; 2010:pdb.prot5426. [PMID: 20439413 DOI: 10.1101/pdb.prot5426] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Although live imaging of embryonic development is a powerful approach, it is often essential to use immunostaining or in situ hybridization to reveal structures or to localize proteins or gene expression patterns. For these approaches, fixed embryos must be used, and Xenopus offers many advantages. Xenopus is a vertebrate tetrapod closely related to mammals. The large size of their embryos makes them ideal for imaging patterns of gene expression during development. Also, individual Xenopus embryonic cells are larger than those of other vertebrate models, making them suitable for imaging cell morphology and subcellular processes. Xenopus embryos are amenable to simple manipulations of gene function, including knockdown and misexpression, and the large numbers of embryos produced allow even an inexperienced researcher to perform such manipulations on hundreds of embryos per day. Transgenesis is quite effective as well. Finally, because the fate map of Xenopus embryos is stereotypical, simple targeted microinjections can reliably deliver reagents into specific tissues and cell types for gene manipulation or for imaging. To improve image quality for fixed specimens, the pigment of the Xenopus embryo can be removed by bleaching. Also, although Xenopus embryos are opaque because of the large amounts of yolk stored in each cell, they can easily be rendered transparent using a process called clearing. This protocol describes the methods for bleaching and clearing Xenopus embryos, as well as a simple procedure for vibratome sectioning. These approaches are effective for imaging embryos and cells following immunostaining or in situ hybridization.
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Affiliation(s)
- John B Wallingford
- Howard Hughes Medical Institute and Section of Molecular Cell and Developmental Biology, University of Texas, Austin, TX 78712, USA.
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Kieserman EK, Lee C, Gray RS, Park TJ, Wallingford JB. High-magnification in vivo imaging of Xenopus embryos for cell and developmental biology. Cold Spring Harb Protoc 2010; 2010:pdb.prot5427. [PMID: 20439414 DOI: 10.1101/pdb.prot5427] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Embryos of the frog Xenopus laevis are an ideal model system for in vivo imaging of dynamic biological processes, from the inner workings of individual cells to the reshaping of tissues during embryogenesis. Their externally developing embryos are more amenable to in vivo analysis than internally developing mammalian embryos, and the large size of the embryos make them particularly suitable for time-lapse analysis of tissue-level morphogenetic events. In addition, individual cells in Xenopus embryos are larger than those in other vertebrate models, making them ideal for imaging cell behavior and subcellular processes (e.g., following the dynamics of fluorescent fusion proteins in living or fixed cells and tissues). Xenopus embryos are amenable to simple manipulations of gene function, including knockdown and misexpression, and the large number of embryos available allows even an inexperienced researcher to perform hundreds of such manipulations per day. Transgenesis is quite effective as well. Finally, because the fate map of Xenopus embryos is stereotypical, simple targeted microinjections can reliably deliver reagents into specific tissues and cell types for gene manipulation or for imaging. Although yolk opacity can hinder deep imaging in intact embryos, almost any cell in the early embryo can be placed into organotypic culture, such that the cells of interest are directly apposed to the cover glass. Furthermore, live imaging techniques can be complemented with immunostaining and in situ hybridization approaches in fixed tissues. This protocol describes methods for labeling and high-magnification time-lapse imaging of cell biological and developmental processes in Xenopus embryos by confocal microscopy.
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Affiliation(s)
- Esther K Kieserman
- Howard Hughes Medical Institute and Section of Molecular Cell and Developmental Biology, University of Texas, Austin, TX 78712, USA
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Kang X, Chao D, Gu Q, Ding G, Wang Y, Balboni G, Lazarus LH, Xia Y. delta-Opioid receptors protect from anoxic disruption of Na+ homeostasis via Na+ channel regulation. Cell Mol Life Sci 2009; 66:3505-16. [PMID: 19756387 PMCID: PMC3061309 DOI: 10.1007/s00018-009-0136-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 08/03/2009] [Accepted: 08/18/2009] [Indexed: 12/30/2022]
Abstract
Hypoxic/ischemic disruption of ionic homeostasis is a critical trigger of neuronal injury/death in the brain. There is, however, no promising strategy against such pathophysiologic change to protect the brain from hypoxic/ischemic injury. Here, we present a novel finding that activation of delta-opioid receptors (DOR) reduced anoxic Na+ influx in the mouse cortex, which was completely blocked by DOR antagonism with naltrindole. Furthermore, we co-expressed DOR and Na+ channels in Xenopus oocytes and showed that DOR expression and activation indeed play an inhibitory role in Na+ channel regulation by decreasing the amplitude of sodium currents and increasing activation threshold of Na+ channels. Our results suggest that DOR protects from anoxic disruption of Na+ homeostasis via Na+ channel regulation. These data may potentially have significant impacts on understanding the intrinsic mechanism of neuronal responses to stress and provide clues for better solutions of hypoxic/ischemic encephalopathy, and for the exploration of acupuncture mechanism since acupuncture activates opioid system.
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Affiliation(s)
- Xuezhi Kang
- Shanghai Research Center for Acupuncture and Meridians, Shanghai, China
| | - Dongman Chao
- Yale University School of Medicine, 333 Cedar Street, LMP 3107, New Haven, CT 06520 USA
| | - Quanbao Gu
- Shanghai Research Center for Acupuncture and Meridians, Shanghai, China
| | - Guanghong Ding
- Shanghai Research Center for Acupuncture and Meridians, Shanghai, China
| | - Yingwei Wang
- Shanghai Jiaotong University College of Medicine, Shanghai, China
| | | | - Lawrence H. Lazarus
- National Institute of Environmental Health Sciences, Research Triangle Park, USA
| | - Ying Xia
- Yale University School of Medicine, 333 Cedar Street, LMP 3107, New Haven, CT 06520 USA
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δ-opioid Receptor induced inhibition of sodium channel function. JOURNAL OF ACUPUNCTURE AND TUINA SCIENCE 2008. [DOI: 10.1007/s11726-008-0276-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Cazanove O, Batut J, Scarlett G, Mumford K, Elgar S, Thresh S, Neant I, Moreau M, Guille M. Methylation of Xilf3 by Xprmt1b Alters Its DNA, but Not RNA, Binding Activity. Biochemistry 2008; 47:8350-7. [DOI: 10.1021/bi7008486] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ophelie Cazanove
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
| | - Julie Batut
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
| | - Garry Scarlett
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
| | - Katherine Mumford
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
| | - Stuart Elgar
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
| | - Sarah Thresh
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
| | - Isabelle Neant
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
| | - Marc Moreau
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
| | - Matthew Guille
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
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15
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Friedeberg C, Scarlett G, McGeeghan J, Abu-daya A, Guille M, Kneale G. Identification of a structural and functional domain in xNAP1 involved in protein-protein interactions. Nucleic Acids Res 2006; 34:4893-9. [PMID: 16982648 PMCID: PMC1635243 DOI: 10.1093/nar/gkl434] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
xNAP1 (Xenopus nucleosome assembly protein) belongs to the family of nucleosome assembly proteins (NAPs) and shares 92% identity with human and mouse NAP1. NAPs have been reported to have a role in nucleosome assembly, cell cycle regulation, cell proliferation and transcriptional control, although the precise function of NAP1 is still not clear. Here we report the identification of a putative domain of xNAP1 by limited proteolysis. This domain has been mapped in the xNAP1 protein sequence to residues 38–282 and thus lacks the acidic sequences at the N- and C-termini. We have studied this domain and related fragments in vitro and by a functional assay involving over-expression of the protein in Xenopus laevis embryos. Analytical ultracentrifugation shows that removal of the acidic N- and C-terminal regions does not prevent the formation of larger multimers, which are predominantly hexadecamers. Injection of mRNA encoding the full-length xNAP1 or the putative domain and other related constructs into Xenopus embryos gave identical phenotypes. These results are discussed in relation to protein–protein interactions between NAP1 octamers and a possible ‘squelching’ mechanism.
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Affiliation(s)
| | | | | | | | | | - Geoff Kneale
- To whom correspondence should be addressed. Tel: 0044 2392 842678; Fax: 0044 2392 842053;
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16
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Abu-Daya A, Steer WM, Trollope AF, Friedeberg CE, Patient RK, Thorne AW, Guille MJ. Zygotic nucleosome assembly protein-like 1 has a specific, non-cell autonomous role in hematopoiesis. Blood 2005; 106:514-20. [PMID: 15811954 DOI: 10.1182/blood-2005-02-0598] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nucleosome assembly proteins (NAPs) bind core histones, facilitate chromatin remodeling, and can act as transcriptional coactivators. We previously described the isolation of a Xenopus NAP1-like (xNAP1L) cDNA, which encodes a member of this protein family. Its zygotic expression is restricted to neural cells, the outer cells of the ventral blood island (VBIs), and the ectoderm overlying the blood precursors. Here, we report that depletion of zygotic xNAP1L in embryos produces no obvious morphologic phenotype, but ablates alpha-globin mRNA expression in the VBIs. Transcript levels of the hematopoietic precursor genes SCL and Xaml (Runx-1) are also reduced in the VBIs. SCL expression can be rescued by injection of xNAP1L mRNA into the ectoderm, showing that the effect of xNAP1L can be non-cell autonomous. Fli1 and Hex, genes expressed in hemangioblasts but subsequently endothelial markers, were unaffected, suggesting that xNAP1L is required for the hematopoietic lineage specifically. Our data are consistent with a requirement for xNAP1L upstream of SCL, and injection of SCL mRNA into xNAP1L-depleted embryos rescues alpha-globin expression. Thus, xNAP1L, which belongs to a family of proteins previously believed to have general roles, has a specific function in hematopoiesis.
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Affiliation(s)
- Anita Abu-Daya
- School of Biological Sciences, Institute of Biomedical and Biomolecular Science, University of Portsmouth, Portsmouth PO1 2DT, United Kingdom
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17
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Scarlett GP, Elgar SJ, Cary PD, Noble AM, Orford RL, Kneale GG, Guille MJ. Intact RNA-binding domains are necessary for structure-specific DNA binding and transcription control by CBTF122 during Xenopus development. J Biol Chem 2004; 279:52447-55. [PMID: 15452137 DOI: 10.1074/jbc.m406107200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CBTF122 is a subunit of the Xenopus CCAAT box transcription factor complex and a member of a family of double-stranded RNA-binding proteins that function in both transcriptional and post-transcriptional control. Here we identify a region of CBTF122 containing the double-stranded RNA-binding domains that is capable of binding either RNA or DNA. We show that these domains bind A-form DNA in preference to B-form DNA and that the -59 to -31 region of the GATA-2 promoter (an in vivo target of CCAAT box transcription factor) adopts a partial A-form structure. Mutations in the RNA-binding domains that inhibit RNA binding also affect DNA binding in vitro. In addition, these mutations alter the ability of CBTF122 fusions with engrailed transcription repressor and VP16 transcription activator domains to regulate transcription of the GATA-2 gene in vivo. These data support the hypothesis that the double-stranded RNA-binding domains of this family of proteins are important for their DNA binding both in vitro and in vivo.
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Affiliation(s)
- Garry P Scarlett
- Institute of Biomedical and Biomolecular Sciences, University of Portsmouth, Portsmouth, PO1 2DT, UK
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18
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Brzostowski J, Robinson C, Orford R, Elgar S, Scarlett G, Peterkin T, Malartre M, Kneale G, Wormington M, Guille M. RNA-dependent cytoplasmic anchoring of a transcription factor subunit during Xenopus development. EMBO J 2000; 19:3683-93. [PMID: 10899122 PMCID: PMC313978 DOI: 10.1093/emboj/19.14.3683] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2000] [Revised: 05/30/2000] [Accepted: 05/30/2000] [Indexed: 11/14/2022] Open
Abstract
The CCAAT box transcription factor (CBTF) is a multimeric transcription factor that activates expression of the haematopoietic regulatory factor, GATA-2. The 122 kDa subunit of this complex, CBTF(122), is cytoplasmic in fertilized Xenopus eggs and subsequently translocates to the nucleus prior to activation of zygotic GATA-2 transcription at gastrulation. Here we present data suggesting both a role for CBTF(122) prior to its nuclear translocation and the mechanism that retains it in the cytoplasm before the midblastula transition (MBT). CBTF(122) and its variant CBTF(98) are associated with translationally quiescent mRNP complexes. We show that CBTF(122) RNA binding activity is both necessary and sufficient for its cytoplasmic retention during early development. The introduction of an additional nuclear localization signal to CBTF(122) is insufficient to overcome this retention, suggesting that RNA binding acts as a cytoplasmic anchor for CBTF(122). Destruction of endogenous RNA by microinjection of RNase promotes premature nuclear translocation of CBTF(122). Thus, the nuclear translocation of CBTF(122) at the MBT is likely to be coupled to the degradation of maternal mRNA that occurs at that stage.
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Affiliation(s)
- J Brzostowski
- Department of Biology, University of Virginia, Gilmer Hall, Charlottesville, VA 22903-2477, USA
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