1
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Sakagami K, Igawa T, Saikawa K, Sakaguchi Y, Hossain N, Kato C, Kinemori K, Suzuki N, Suzuki M, Kawaguchi A, Ochi H, Tajika Y, Ogino H. Development of a heat-stable alkaline phosphatase reporter system for cis-regulatory analysis and its application to 3D digital imaging of Xenopus embryonic tissues. Dev Growth Differ 2024; 66:256-265. [PMID: 38439617 DOI: 10.1111/dgd.12919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 02/16/2024] [Accepted: 02/19/2024] [Indexed: 03/06/2024]
Abstract
Xenopus is one of the essential model systems for studying vertebrate development. However, one drawback of this system is that, because of the opacity of Xenopus embryos, 3D imaging analysis is limited to surface structures, explant cultures, and post-embryonic tadpoles. To develop a technique for 3D tissue/organ imaging in whole Xenopus embryos, we identified optimal conditions for using placental alkaline phosphatase (PLAP) as a transgenic reporter and applied it to the correlative light microscopy and block-face imaging (CoMBI) method for visualization of PLAP-expressing tissues/organs. In embryos whose endogenous alkaline phosphatase activities were heat-inactivated, PLAP staining visualized various tissue-specific enhancer/promoter activities in a manner consistent with green fluorescent protein (GFP) fluorescence. Furthermore, PLAP staining appeared to be more sensitive than GFP fluorescence as a reporter, and the resulting expression patterns were not mosaic, in striking contrast to the mosaic staining pattern of β-galactosidase expressed from the lacZ gene that was introduced by the same transgenesis method. Owing to efficient penetration of alkaline phosphatase substrates, PLAP activity was detected in deep tissues, such as the developing brain, spinal cord, heart, and somites, by whole-mount staining. The stained embryos were analyzed by the CoMBI method, resulting in the digital reconstruction of 3D images of the PLAP-expressing tissues. These results demonstrate the efficacy of the PLAP reporter system for detecting enhancer/promoter activities driving deep tissue expression and its combination with the CoMBI method as a powerful approach for 3D digital imaging analysis of specific tissue/organ structures in Xenopus embryos.
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Affiliation(s)
- Kiyo Sakagami
- Department of Animal Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Japan
| | - Takeshi Igawa
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Kaori Saikawa
- Department of Animal Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Japan
| | - Yusuke Sakaguchi
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Nusrat Hossain
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
| | - Chiho Kato
- Department of Animal Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Japan
| | - Kazuhito Kinemori
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Nanoka Suzuki
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Makoto Suzuki
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Akane Kawaguchi
- Department of Genomics and Evolutionary Biology, National Institute of Genetics, Shizuoka, Japan
| | - Haruki Ochi
- Institute for Promotion of Medical Science Research, Faculty of Medicine, Yamagata University, Yamagata, Japan
| | - Yuki Tajika
- Department of Radiological Technology, Gunma Prefectural College of Health Sciences, Maebashi, Japan
| | - Hajime Ogino
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
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2
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Liu J, Zhang C. Xenopus cell-free extracts and their applications in cell biology study. BIOPHYSICS REPORTS 2023; 9:195-205. [PMID: 38516620 PMCID: PMC10951473 DOI: 10.52601/bpr.2023.230016] [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: 09/27/2023] [Accepted: 12/05/2023] [Indexed: 03/23/2024] Open
Abstract
Xenopus has proven to be a remarkably versatile model organism in the realm of biological research for numerous years, owing to its straightforward maintenance in laboratory settings and its abundant provision of ample-sized oocytes, eggs, and embryos. The cell cycle of these oocytes, eggs, and early embryos exhibits synchrony, and extracts derived from these cells serve various research purposes. Many fundamental concepts in biochemistry, cell biology, and development have been elucidated through the use of cell-free extracts derived from Xenopus cells. Over the past few decades, a wide array of cell-free extracts has been prepared from oocytes, eggs, and early embryos of different Xenopus species at varying cell cycle stages. Each of these extracts possesses distinct characteristics. This review provides a concise overview of the Xenopus species employed in laboratory research, the diverse types of cell-free extracts available, and their respective properties. Furthermore, this review delves into the extensive investigation of spindle assembly in Xenopus egg extracts, underscoring the versatility and potency of these cell-free systems in the realm of cell biology.
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Affiliation(s)
- Junjun Liu
- Department of Biological Sciences, California State Polytechnic University, Pomona, CA 91768, USA
| | - Chuanmao Zhang
- The Academy for Cell and Life Health, Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China
- The Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing 100871, China
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3
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Reyes YM, Robinson SA, De Silva AO, Brinovcar C, Trudeau VL. Exposure to the synthetic phenolic antioxidant 4,4'-thiobis(6-t-butyl-m-cresol) disrupts early development in the frog Silurana tropicalis. CHEMOSPHERE 2022; 291:132814. [PMID: 34774609 DOI: 10.1016/j.chemosphere.2021.132814] [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: 08/11/2021] [Revised: 11/01/2021] [Accepted: 11/04/2021] [Indexed: 06/13/2023]
Abstract
Many chemicals in commonly used household and industrial products are being released into the environment, yet their toxicity is poorly understood. The synthetic phenolic antioxidant, 4,4'-thiobis(6-t-butyl-m-cresol) (CAS 96-69-5; TBBC) is present in many common products made of rubber and plastic. Yet, this phenolic antioxidant has not been tested for potential toxicity and developmental disruption in amphibians, a sensitive and susceptible class. We investigated whether acute and chronic exposure to TBBC would interfere with thyroid hormone-dependent developmental processes in the frog Silurana tropicalis and thus affect its early life-stage development. We exposed S. tropicalis embryos at the Nieuwkoop-Faber (NF) 9-10 stage to TBBC at nominal concentrations (0, 25, 50, 75, 100, 200 and 400 μg/L) to determine the 96h lethal concentrations and sublethal effects. We conducted a chronic exposure starting at stage NF47-48 to three sublethal TBBC nominal concentrations (0, 0.002, 0.1 and 5 μg/L) for 48-52 days to evaluate effects on growth and metamorphosis. The 96h lethal and effective (malformations) TBBC concentrations (LC50 and EC50) were 70.5 and 76.5 μg/L, respectively. Acute exposure to all TBBC concentrations affected S. tropicalis growth and was lethal at 200 and 400 μg/L. Chronic exposure to sublethal TBBC concentrations reduced body size by 8% at 5 μg/L and body mass by 17% at 0.002 μg/L when metamorphosis was completed. This study demonstrates that TBBC is toxic, induces malformations and inhibits tadpole growth after acute and chronic exposures. These findings call for further investigations on the mode of actions of TBBC and related antioxidants for developmental disruption in amphibians.
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Affiliation(s)
- Yol Monica Reyes
- Department of Biology, University of Ottawa, 30 Marie-Curie Private, Ottawa, ON K1N 9B4, Canada.
| | - Stacey A Robinson
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Science Directorate, Science and Technology Branch, Environment and Climate Change Canada, 1125 Colonel By Drive, Ottawa, Ontario, K1S 5B6, Canada.
| | - Amila O De Silva
- Aquatics Contaminants Research Division, Water Science and Technology Directorate, Science and Technology Branch, Environment and Climate Change Canada, 867 Lakeshore Rd, Burlington, Ontario, L7S 1A1, Canada.
| | - Cassandra Brinovcar
- Aquatics Contaminants Research Division, Water Science and Technology Directorate, Science and Technology Branch, Environment and Climate Change Canada, 867 Lakeshore Rd, Burlington, Ontario, L7S 1A1, Canada.
| | - Vance L Trudeau
- Department of Biology, University of Ottawa, 30 Marie-Curie Private, Ottawa, ON K1N 9B4, Canada.
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4
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Maciej-Hulme ML, Dubaissi E, Shao C, Zaia J, Amaya E, Flitsch SL, Merry CLR. Selective Inhibition of Heparan Sulphate and Not Chondroitin Sulphate Biosynthesis by a Small, Soluble Competitive Inhibitor. Int J Mol Sci 2021; 22:ijms22136988. [PMID: 34209670 PMCID: PMC8269443 DOI: 10.3390/ijms22136988] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/16/2021] [Accepted: 06/19/2021] [Indexed: 11/29/2022] Open
Abstract
The glycosaminoglycan, heparan sulphate (HS), orchestrates many developmental processes. Yet its biological role has not yet fully been elucidated. Small molecule chemical inhibitors can be used to perturb HS function and these compounds provide cheap alternatives to genetic manipulation methods. However, existing chemical inhibition methods for HS also interfere with chondroitin sulphate (CS), complicating data interpretation of HS function. Herein, a simple method for the selective inhibition of HS biosynthesis is described. Using endogenous metabolic sugar pathways, Ac4GalNAz produces UDP-GlcNAz, which can target HS synthesis. Cell treatment with Ac4GalNAz resulted in defective chain elongation of the polymer and decreased HS expression. Conversely, no adverse effect on CS production was observed. The inhibition was transient and dose-dependent, affording rescue of HS expression after removal of the unnatural azido sugar. The utility of inhibition is demonstrated in cell culture and in whole organisms, demonstrating that this small molecule can be used as a tool for HS inhibition in biological systems.
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Affiliation(s)
- Marissa L. Maciej-Hulme
- Materials Science Centre, School of Materials, The University of Manchester, Grosvenor St., Manchester M1 7HS, UK
- Correspondence: (M.L.M.-H.); (C.L.R.M.)
| | - Eamon Dubaissi
- Division of Cell Matrix Biology & Regenerative Medicine, Faculty of Biology, Medicine and Health, Michael Smith Building, The University of Manchester, Oxford Road, Manchester M13 9PT, UK; (E.D.); (E.A.)
| | - Chun Shao
- Center for Biomedical Mass Spectrometry, Boston University School of Medicine, 670 Albany Street, Boston, MA 02118, USA; (C.S.); (J.Z.)
| | - Joseph Zaia
- Center for Biomedical Mass Spectrometry, Boston University School of Medicine, 670 Albany Street, Boston, MA 02118, USA; (C.S.); (J.Z.)
| | - Enrique Amaya
- Division of Cell Matrix Biology & Regenerative Medicine, Faculty of Biology, Medicine and Health, Michael Smith Building, The University of Manchester, Oxford Road, Manchester M13 9PT, UK; (E.D.); (E.A.)
| | - Sabine L. Flitsch
- School of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK;
| | - Catherine L. R. Merry
- Materials Science Centre, School of Materials, The University of Manchester, Grosvenor St., Manchester M1 7HS, UK
- Correspondence: (M.L.M.-H.); (C.L.R.M.)
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5
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Abstract
Understanding how to promote organ and appendage regeneration is a key goal of regenerative medicine. The frog, Xenopus, can achieve both scar-free healing and tissue regeneration during its larval stages, although it predominantly loses these abilities during metamorphosis and adulthood. This transient regenerative capacity, alongside their close evolutionary relationship with humans, makes Xenopus an attractive model to uncover the mechanisms underlying functional regeneration. Here, we present an overview of Xenopus as a key model organism for regeneration research and highlight how studies of Xenopus have led to new insights into the mechanisms governing regeneration.
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Affiliation(s)
- Lauren S Phipps
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Lindsey Marshall
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Karel Dorey
- Division of Developmental Biology and Medicine, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Enrique Amaya
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
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6
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Shibata Y, Wen L, Okada M, Shi YB. Organ-Specific Requirements for Thyroid Hormone Receptor Ensure Temporal Coordination of Tissue-Specific Transformations and Completion of Xenopus Metamorphosis. Thyroid 2020; 30:300-313. [PMID: 31854240 PMCID: PMC7047119 DOI: 10.1089/thy.2019.0366] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background: Thyroid hormone (triiodothyronine [T3]) is essential for the development throughout vertebrates. Anuran metamorphosis mimics mammalian postembryonic development, a period around birth when plasma T3 level peaks and many organs/tissues mature into their adult forms. Compared with the uterus-enclosed mammalian embryos, tadpoles can be easily manipulated to study the roles of T3 and T3 receptors (TRs) in tissue remodeling and adult organ development. We and others have previously knocked out TRα or TRβ in the diploid anuran Xenopus tropicalis and reported distinct effects of the two receptor knockouts on metamorphosis. However, animals lacking either TRα or TRβ can complete metamorphosis and develop into reproductive adults. Methods: We have generated TRα and TRβ double knockout animals and carried out molecular and morphological analyses to determine if TR is required for Xenopus development. Results: We found that the TR double knockout tadpoles do not respond to T3, supporting the view that there are no other TR genes in X. tropicalis and that TR is essential for mediating the effects of T3 in vivo. Surprisingly, the double knockout tadpoles are able to initiate metamorphosis and accomplish many metamorphic changes, such as limb development. However, all double knockout tadpoles stall and eventually die at stage 61, the climax of metamorphosis, before tail resorption takes place. Analyses of the knockout tadpoles at stage 61 revealed various developmental abnormalities, including precocious ossification and extra vertebrae. Conclusions: Our data indicate that TRs are not required for the initiation of metamorphosis but is essential for the completion of metamorphosis. Furthermore, the differential effects of TR knockout on different organs/tissues suggest tissue-specific roles for TR to control temporal coordination and progression of metamorphosis in various organs.
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Affiliation(s)
- Yuki Shibata
- Section on Molecular Morphogenesis, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Luan Wen
- Section on Molecular Morphogenesis, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Morihiro Okada
- Section on Molecular Morphogenesis, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Yun-Bo Shi
- Section on Molecular Morphogenesis, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
- Address correspondence to: Yun-Bo Shi, PhD, Section on Molecular Morphogenesis, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
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7
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Zhu S, Wu X, Fu H, Ye C, Chen M, Jiang Z, Ji G. Modeling of Genome-Wide Polyadenylation Signals in Xenopus tropicalis. Front Genet 2019; 10:647. [PMID: 31333724 PMCID: PMC6616101 DOI: 10.3389/fgene.2019.00647] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 06/18/2019] [Indexed: 12/22/2022] Open
Abstract
Alternative polyadenylation (APA) is an important post-transcriptional modification event to process messenger RNA (mRNA) for transcriptional termination, transport, and translation. In the present study, we characterized poly(A) signals in Xenopus tropicalis using 70,918 highly confident poly(A) sites derived from 16,511 protein-coding genes to understand their roles in the regulation of embryo development and gender difference. We examined potential factors, including the gene length, the number of introns in a gene, and the intron length, that may affect the prevalence of APA. We observed 12 prominent poly(A) signal patterns, which accounted for approximately 92% of total APA sites in Xenopus tropicalis. Among them, three patterns are specific to X. tropicalis, so they are absent in other animals such as humans or mice. We catalogued APA sites based on their genomic regions and developed a bioinformatics pipeline to identify over-represented signal patterns for each class. Then the schema of cis elements for APA sites in each genomic region was proposed. More importantly, APA usage is dramatically dynamic in embryos along five developmental stages and well-coordinated with the maternal-to-zygotic transition event. We used an entropy-based method to identify developmental stage-specific APA sites and identified significant signal patterns around specific sites and constitutive sites. We found that the APA frequency in different genomic regions varies with developmental stages and that those sites located in intron or coding sequence regions contribute most to the dynamics of gene expression during developmental stages. This study deciphers the characteristics and poly(A) signal patterns for both canonical APA sites and non-canonical APA sites across different developmental stages and gender dimorphisms in X. tropicalis, providing new insights into the dynamic regulation of distal and proximal APA.
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Affiliation(s)
- Sheng Zhu
- Department of Automation, Xiamen University, Xiamen, China.,National Institute for Data Science in Health and Medicine, Xiamen University, Xiamen, China
| | - Xiaohui Wu
- Department of Automation, Xiamen University, Xiamen, China.,National Institute for Data Science in Health and Medicine, Xiamen University, Xiamen, China.,Innovation Center for Cell Signaling Network, Xiamen University, Xiamen, China
| | - Hongjuan Fu
- Department of Automation, Xiamen University, Xiamen, China
| | - Congting Ye
- National Institute for Data Science in Health and Medicine, Xiamen University, Xiamen, China.,Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, China
| | - Moliang Chen
- Department of Automation, Xiamen University, Xiamen, China
| | - Zhihua Jiang
- Department of Animal Sciences and Center for Reproductive Biology, Washington State University, Pullman, WA, United States
| | - Guoli Ji
- Department of Automation, Xiamen University, Xiamen, China.,National Institute for Data Science in Health and Medicine, Xiamen University, Xiamen, China.,Innovation Center for Cell Signaling Network, Xiamen University, Xiamen, China
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8
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Babošová M, Vašeková P, Porhajašová JI, Noskovič J. Influence of temperature on reproduction and length of metamorphosis in Xenopus laevis (Amphibia: Anura). EUROPEAN ZOOLOGICAL JOURNAL 2018. [DOI: 10.1080/24750263.2018.1450456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- M. Babošová
- Department of Environmental and Zoology, Faculty of Agrobiology and Food Resources, Slovak University of Agriculture, Nitra, Slovak Republic
| | - P. Vašeková
- Department of Environmental and Zoology, Faculty of Agrobiology and Food Resources, Slovak University of Agriculture, Nitra, Slovak Republic
| | - J. I. Porhajašová
- Department of Environmental and Zoology, Faculty of Agrobiology and Food Resources, Slovak University of Agriculture, Nitra, Slovak Republic
| | - J. Noskovič
- Department of Environmental and Zoology, Faculty of Agrobiology and Food Resources, Slovak University of Agriculture, Nitra, Slovak Republic
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9
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Wlizla M, McNamara S, Horb ME. Generation and Care of Xenopus laevis and Xenopus tropicalis Embryos. Methods Mol Biol 2018; 1865:19-32. [PMID: 30151756 DOI: 10.1007/978-1-4939-8784-9_2] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Robust and efficient protocols for fertilization and early embryo care of Xenopus laevis and Xenopus tropicalis are essential for experimental success, as well as maintenance and propagation of precious animal stocks. The rapid growth of the National Xenopus Resource has required effective implementation and optimization of these protocols. Here, we discuss the procedures used at the National Xenopus Resource, which we found helpful for generation and early upkeep of Xenopus embryos and tadpoles.
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Affiliation(s)
- Marcin Wlizla
- National Xenopus Resource, Marine Biological Laboratory, Woods Hole, MA, USA
| | - Sean McNamara
- National Xenopus Resource, Marine Biological Laboratory, Woods Hole, MA, USA
| | - Marko E Horb
- National Xenopus Resource, Marine Biological Laboratory, Woods Hole, MA, USA.
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10
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Wen L, Fu L, Shi YB. Histone methyltransferase Dot1L is a coactivator for thyroid hormone receptor during Xenopus development. FASEB J 2017; 31:4821-4831. [PMID: 28739643 DOI: 10.1096/fj.201700131r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 07/05/2017] [Indexed: 12/18/2022]
Abstract
Histone modifications are associated with transcriptional regulation by diverse transcription factors. Genome-wide correlation studies have revealed that histone activation marks and repression marks are associated with activated and repressed gene expression, respectively. Among the histone activation marks is histone H3 K79 methylation, which is carried out by only a single methyltransferase, disruptor of telomeric silencing-1-like (DOT1L). We have been studying thyroid hormone (T3)-dependent amphibian metamorphosis in two highly related species, the pseudo-tetraploid Xenopus laevis and diploid Xenopus tropicalis, as a model for postembryonic development, a period around birth in mammals that is difficult to study. We previously showed that H3K79 methylation levels are induced at T3 target genes during natural and T3-induced metamorphosis and that Dot1L is itself a T3 target gene. These suggest that T3 induces Dot1L expression, and Dot1L in turn functions as a T3 receptor (TR) coactivator to promote vertebrate development. We show here that in cotransfection studies or in the reconstituted frog oocyte in vivo transcription system, overexpression of Dot1L enhances gene activation by TR in the presence of T3. Furthermore, making use of the ability to carry out transgenesis in X. laevis and gene knockdown in X. tropicalis, we demonstrate that endogenous Dot1L is critical for T3-induced activation of endogenous TR target genes while transgenic Dot1L enhances endogenous TR function in premetamorphic tadpoles in the presence of T3. Our studies thus for the first time provide complementary gain- and loss-of functional evidence in vivo for a cofactor, Dot1L, in gene activation by TR during vertebrate development.-Wen, L., Fu, L., Shi, Y.-B. Histone methyltransferase Dot1L is a coactivator for thyroid hormone receptor during Xenopus development.
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Affiliation(s)
- Luan Wen
- Section on Molecular Morphogenesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Liezhen Fu
- Section on Molecular Morphogenesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Yun-Bo Shi
- Section on Molecular Morphogenesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
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11
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Wen L, Shibata Y, Su D, Fu L, Luu N, Shi YB. Thyroid Hormone Receptor α Controls Developmental Timing and Regulates the Rate and Coordination of Tissue-Specific Metamorphosis in Xenopus tropicalis. Endocrinology 2017; 158:1985-1998. [PMID: 28324024 PMCID: PMC5460924 DOI: 10.1210/en.2016-1953] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 03/09/2017] [Indexed: 12/25/2022]
Abstract
Thyroid hormone (T3) receptors (TRs) mediate the effects of T3 on organ metabolism and animal development. There are two TR genes, TRα and TRβ, in all vertebrates. During animal development, TRα expression is activated earlier than zygotic T3 synthesis and secretion into the plasma, implicating a developmental role of TRα both in the presence and absence of T3. Using T3-dependent amphibian metamorphosis as a model, we previously proposed a dual-function model for TRs, in particular TRα, during development. That is, unliganded TR represses the expression of T3-inducible genes during premetamorphosis to ensure proper animal growth and prevent premature metamorphosis, whereas during metamorphosis, liganded TR activates target gene transcription to promote the transformation of the tadpole into a frog. To determine if TRα has such a dual function, we generated homozygous TRα-knockout animal lines. We show that, indeed, TRα knockout affects both premetamorphic animal development and metamorphosis. Surprisingly, we observed that TRα is not essential for amphibian metamorphosis, given that homozygous knockout animals complete metamorphosis within a similar time period after fertilization as their wild-type siblings. On the other hand, the timing of metamorphosis for different organs is altered by the knockout; limb metamorphosis occurs earlier, whereas intestinal metamorphosis is completed later than in wild-type siblings. Thus, our studies have demonstrated a critical role of endogenous TRα, not only in regulating both the timing and rate of metamorphosis, but also in coordinating temporal metamorphosis of different organs.
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Affiliation(s)
- Luan Wen
- Section on Molecular Morphogenesis, Program on Cell Regulation and Metabolism, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Yuki Shibata
- Section on Molecular Morphogenesis, Program on Cell Regulation and Metabolism, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Dan Su
- Section on Molecular Morphogenesis, Program on Cell Regulation and Metabolism, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Liezhen Fu
- Section on Molecular Morphogenesis, Program on Cell Regulation and Metabolism, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Nga Luu
- Section on Molecular Morphogenesis, Program on Cell Regulation and Metabolism, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Yun-Bo Shi
- Section on Molecular Morphogenesis, Program on Cell Regulation and Metabolism, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
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12
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Shi Z, Tian D, Xin H, Lian J, Guo X, Chen Y. Targeted integration of genes in Xenopus tropicalis. Genesis 2017; 55. [PMID: 28095621 DOI: 10.1002/dvg.23006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Revised: 11/17/2016] [Accepted: 11/19/2016] [Indexed: 11/06/2022]
Abstract
With the successful establishment of both targeted gene disruption and integration methods in the true diploid frog Xenopus tropicalis, this excellent vertebrate genetic model now is making a unique contribution to modelling human diseases. Here, we summarize our efforts on establishing homologous recombination-mediated targeted integration in Xenopus tropicalis, the usefulness, and limitation of targeted integration via the homology-independent strategy, and future directions on how to further improve targeted gene integration in Xenopus tropicalis.
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Affiliation(s)
- Zhaoying Shi
- Shenzhen Key Laboratory of Cell Microenvironment, Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Dandan Tian
- Shenzhen Key Laboratory of Cell Microenvironment, Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Huhu Xin
- Shenzhen Key Laboratory of Cell Microenvironment, Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Jingru Lian
- Shenzhen Key Laboratory of Cell Microenvironment, Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Xiaogang Guo
- DanStem, University of Copenhagen, 3B Blegdamsvej, DK-2200, Copenhagen N, Denmark
| | - Yonglong Chen
- Shenzhen Key Laboratory of Cell Microenvironment, Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
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13
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A balance of Mad and Myc expression dictates larval cell apoptosis and adult stem cell development during Xenopus intestinal metamorphosis. Cell Death Dis 2017; 8:e2787. [PMID: 28492553 PMCID: PMC5520718 DOI: 10.1038/cddis.2017.198] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 02/24/2017] [Accepted: 04/03/2017] [Indexed: 11/29/2022]
Abstract
The Myc/Mad/Max network has long been shown to be an important factor in regulating cell proliferation, death and differentiation in diverse cell types. In general, Myc–Max heterodimers activate target gene expression to promote cell proliferation, although excess of c-Myc can also induce apoptosis. In contrast, Mad competes against Myc to form Mad–Max heterodimers that bind to the same target genes to repress their expression and promote differentiation. The role of the Myc/Mad/Max network during vertebrate development, especially, the so-called postembryonic development, a period around birth in mammals, is unclear. Using thyroid hormone (T3)-dependent Xenopus metamorphosis as a model, we show here that Mad1 is induced by T3 in the intestine during metamorphosis when larval epithelial cell death and adult epithelial stem cell development take place. More importantly, we demonstrate that Mad1 is expressed in the larval cells undergoing apoptosis, whereas c-Myc is expressed in the proliferating adult stem cells during intestinal metamorphosis, suggesting that Mad1 may have a role in cell death during development. By using transcription activator-like effector nuclease-mediated gene-editing technology, we have generated Mad1 knockout Xenopus animals. This has revealed that Mad1 is not essential for embryogenesis or metamorphosis. On the other hand, consistent with its spatiotemporal expression profile, Mad1 knockout leads to reduced larval epithelial apoptosis but surprisingly also results in increased adult stem cell proliferation. These findings not only reveal a novel role of Mad1 in regulating developmental cell death but also suggest that a balance of Mad and Myc controls cell fate determination during adult organ development.
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Luu N, Fu L, Fujimoto K, Shi YB. Direct Regulation of Histidine Ammonia-Lyase 2 Gene by Thyroid Hormone in the Developing Adult Intestinal Stem Cells. Endocrinology 2017; 158:1022-1033. [PMID: 28323994 PMCID: PMC5460799 DOI: 10.1210/en.2016-1558] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 01/26/2017] [Indexed: 02/06/2023]
Abstract
Most vertebrate organs use adult stem cells to maintain homeostasis and ensure proper repair when damaged. How such organ-specific stem cells are formed during vertebrate development is largely unexplored. We have been using the thyroid hormone (T3)-dependent amphibian metamorphosis to address this issue. Early studies in Xenopus laevis have shown that intestinal remodeling involves complete degeneration of the larval epithelium and de novo formation of adult stem cells through dedifferentiation of some larval epithelial cells. We have further discovered that the histidine ammonia-lyase (HAL; also known as histidase or histidinase)-2 gene is strongly and specifically activated by T3 in the proliferating adult stem cells of the intestine during metamorphosis, implicating a role of histidine catabolism in the development of adult intestinal stem cells. To determine the mechanism by which T3 regulates the HAL2 gene, we have carried out bioinformatics analysis and discovered a putative T3 response element (TRE) in the HAL2 gene. Importantly, we show that this TRE is bound by T3 receptor (TR) in the intestine during metamorphosis. The TRE is capable of binding to the heterodimer of TR and 9-cis retinoic acid receptor (RXR) in vitro and mediate transcriptional activation by liganded TR/RXR in frog oocytes. More importantly, the HAL2 promoter containing the TRE can drive T3-dependent reporter gene expression to mimic endogenous HAL2 expression in transgenic animals. Our results suggest that the TRE mediates the induction of HAL2 gene by T3 in the developing adult intestinal stem cells during metamorphosis.
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Affiliation(s)
- Nga Luu
- Section on Molecular Morphogenesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Liezhen Fu
- Section on Molecular Morphogenesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Kenta Fujimoto
- Section on Molecular Morphogenesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Yun-Bo Shi
- Section on Molecular Morphogenesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
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Using Xenopus Embryos to Study Transcriptional and Posttranscriptional Gene Regulatory Mechanisms of Intermediate Filaments. Methods Enzymol 2016; 568:635-60. [DOI: 10.1016/bs.mie.2015.07.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
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Simons M, Alitalo K, Annex BH, Augustin HG, Beam C, Berk BC, Byzova T, Carmeliet P, Chilian W, Cooke JP, Davis GE, Eichmann A, Iruela-Arispe ML, Keshet E, Sinusas AJ, Ruhrberg C, Woo YJ, Dimmeler S. State-of-the-Art Methods for Evaluation of Angiogenesis and Tissue Vascularization: A Scientific Statement From the American Heart Association. Circ Res 2015; 116:e99-132. [PMID: 25931450 DOI: 10.1161/res.0000000000000054] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Cao Y. Germ layer formation during Xenopus embryogenesis: the balance between pluripotency and differentiation. SCIENCE CHINA-LIFE SCIENCES 2015; 58:336-42. [DOI: 10.1007/s11427-015-4799-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 12/30/2014] [Indexed: 12/31/2022]
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Abstract
Thyroid hormone (T3) affects adult metabolism and postembryonic development in vertebrates. T3 functions mainly via binding to its receptors (TRs) to regulate gene expression. There are 2 TR genes, TRα and TRβ, with TRα more ubiquitously expressed. During development, TRα expression appears earlier than T3 synthesis and secretion into the plasma. This and the ability of TRs to regulate gene expression both in the presence and absence of T3 have indicated a role for unliganded TR during vertebrate development. On the other hand, it has been difficult to study the role of unliganded TR during development in mammals because of the difficulty to manipulate the uterus-enclosed, late-stage embryos. Here we use amphibian development as a model to address this question. We have designed transcriptional activator-like effector nucleases (TALENs) to mutate the TRα gene in Xenopus tropicalis. We show that knockdown of TRα enhances tadpole growth in premetamorphic tadpoles, in part because of increased growth hormone gene expression. More importantly, the knockdown also accelerates animal development, with the knockdown animals initiating metamorphosis at a younger age and with a smaller body size. On the other hand, such tadpoles are resistant to exogenous T3 treatment and have delayed natural metamorphosis. Thus, our studies not only have directly demonstrated a critical role of endogenous TRα in mediating the metamorphic effect of T3 but also revealed novel functions of unliganded TRα during postembryonic development, that is, regulating both tadpole growth rate and the timing of metamorphosis.
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Affiliation(s)
- Luan Wen
- Section on Molecular Morphogenesis, Program on Cell Regulation and Metabolism, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
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19
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Schmitt SM, Gull M, Brändli AW. Engineering Xenopus embryos for phenotypic drug discovery screening. Adv Drug Deliv Rev 2014; 69-70:225-46. [PMID: 24576445 DOI: 10.1016/j.addr.2014.02.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 02/13/2014] [Accepted: 02/14/2014] [Indexed: 02/08/2023]
Abstract
Many rare human inherited diseases remain untreatable despite the fact that the disease causing genes are known and adequate mouse disease models have been developed. In vivo phenotypic drug screening relies on isolating drug candidates by their ability to produce a desired therapeutic phenotype in whole organisms. Embryos of zebrafish and Xenopus frogs are abundant, small and free-living. They can be easily arrayed in multi-well dishes and treated with small organic molecules. With the development of novel genome modification tools, such a zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and CRISPR/Cas, it is now possible to efficiently engineer non-mammalian models of inherited human diseases. Here, we will review the rapid progress made in adapting these novel genome editing tools to Xenopus. The advantages of Xenopus embryos as in vivo models to study human inherited diseases will be presented and their utility for drug discovery screening will be discussed. Being a tetrapod, Xenopus complements zebrafish as an indispensable non-mammalian animal model for the study of human disease pathologies and the discovery of novel therapeutics for inherited diseases.
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Kurabayashi A, Kakehashi R, Tazawa I, Haramoto Y, Oshima T, Ito Y, Sumida M. Improved Transport of the Model Amphibian,Xenopus tropicalis, and Its Viable Temperature for Transport. CURRENT HERPETOLOGY 2014. [DOI: 10.5358/hsj.33.75] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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21
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Luu N, Wen L, Fu L, Fujimoto K, Shi YB, Sun G. Differential regulation of two histidine ammonia-lyase genes during Xenopus development implicates distinct functions during thyroid hormone-induced formation of adult stem cells. Cell Biosci 2013; 3:43. [PMID: 24499573 PMCID: PMC3874607 DOI: 10.1186/2045-3701-3-43] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 10/30/2013] [Indexed: 11/16/2022] Open
Abstract
Background Organ-specific, adult stem cells are essential for organ-homeostasis and tissue repair and regeneration. The formation of such stem cells during vertebrate development remains to be investigated. Frog metamorphosis offers an excellent opportunity to study the formation of adult stem cells as this process involves essentially the transformations of all larval tissues/organs into the adult form. Of particular interest is the remodeling of the intestine. Early studies in Xenopus laevis have shown that this process involves complete degeneration of the larval epithelium and de novo formation of adult stem cells through dedifferentiation of some larval epithelial cells. A major advantage of this metamorphosis model is its total dependence on thyroid hormone (T3). In an effort to identify genes that are important for stem cell development, we have previously carried out tissue-specific microarray analysis of intestinal gene expression during Xenopus laevis metamorphosis. Results We report the detailed characterization of one of the genes thus identified, the histidine ammonia-lyase (HAL) gene, which encodes an enzyme known as histidase or histidinase. We show that there are two duplicated HAL genes, HAL1 and HAL2, in both Xenopus laevis and Xenopus tropicalis, a highly related but diploid species. Interestingly, only HAL2 is highly upregulated by T3 and appears to be specifically expressed in the adult intestinal progenitor/stem cells while HAL1 is not expressed in the intestine during metamorphosis. Furthermore, when analyzed in whole animals, HAL1 appears to be expressed only during embryogenesis but not metamorphosis while the opposite appears to be true for HAL2. Conclusions Our results suggest that the duplicated HAL genes have distinct functions with HAL2 likely involved in the formation and/or proliferation of the adult stem cells during metamorphosis.
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Affiliation(s)
- Nga Luu
- Section on Molecular Morphogenesis, Program in Cellular Regulation and Metabolism (PCRM), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), 18 Library Dr., 20892 Bethesda, Maryland, USA
| | - Luan Wen
- Section on Molecular Morphogenesis, Program in Cellular Regulation and Metabolism (PCRM), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), 18 Library Dr., 20892 Bethesda, Maryland, USA
| | - Liezhen Fu
- Section on Molecular Morphogenesis, Program in Cellular Regulation and Metabolism (PCRM), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), 18 Library Dr., 20892 Bethesda, Maryland, USA
| | - Kenta Fujimoto
- Section on Molecular Morphogenesis, Program in Cellular Regulation and Metabolism (PCRM), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), 18 Library Dr., 20892 Bethesda, Maryland, USA.,Present address: Division of Gene Structure and Function, Research Center for Genomic Medicine, Saitama Medical University, 1397-1 Yamane, 350-1241 Hidaka-shi, Saitama, Japan
| | - Yun-Bo Shi
- Section on Molecular Morphogenesis, Program in Cellular Regulation and Metabolism (PCRM), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), 18 Library Dr., 20892 Bethesda, Maryland, USA
| | - Guihong Sun
- School of Basic Medical Sciences, Wuhan University, 430072 Wuhan, P.R. China
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Pratt KG, Khakhalin AS. Modeling human neurodevelopmental disorders in the Xenopus tadpole: from mechanisms to therapeutic targets. Dis Model Mech 2013; 6:1057-65. [PMID: 23929939 PMCID: PMC3759326 DOI: 10.1242/dmm.012138] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The Xenopus tadpole model offers many advantages for studying the molecular, cellular and network mechanisms underlying neurodevelopmental disorders. Essentially every stage of normal neural circuit development, from axon outgrowth and guidance to activity-dependent homeostasis and refinement, has been studied in the frog tadpole, making it an ideal model to determine what happens when any of these stages are compromised. Recently, the tadpole model has been used to explore the mechanisms of epilepsy and autism, and there is mounting evidence to suggest that diseases of the nervous system involve deficits in the most fundamental aspects of nervous system function and development. In this Review, we provide an update on how tadpole models are being used to study three distinct types of neurodevelopmental disorders: diseases caused by exposure to environmental toxicants, epilepsy and seizure disorders, and autism.
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Affiliation(s)
- Kara G. Pratt
- University of Wyoming, 1000 E University Avenue, Laramie, WY 82071, USA
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Shi YB, Matsuura K, Fujimoto K, Wen L, Fu L. Thyroid hormone receptor actions on transcription in amphibia: The roles of histone modification and chromatin disruption. Cell Biosci 2012; 2:42. [PMID: 23256597 PMCID: PMC3562205 DOI: 10.1186/2045-3701-2-42] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 11/21/2012] [Indexed: 01/14/2023] Open
Abstract
Thyroid hormone (T3) plays diverse roles in adult organ function and during vertebrate development. The most important stage of mammalian development affected by T3 is the perinatal period when plasma T3 level peaks. Amphibian metamorphosis resembles this mammalian postembryonic period and is absolutely dependent on T3. The ability to easily manipulate this process makes it an ideal model to study the molecular mechanisms governing T3 action during vertebrate development. T3 functions mostly by regulating gene expression through T3 receptors (TRs). Studies in vitro, in cell cultures and reconstituted frog oocyte transcription system have revealed that TRs can both activate and repress gene transcription in a T3-dependent manner and involve chromatin disruption and histone modifications. These changes are accompanied by the recruitment of diverse cofactor complexes. More recently, genetic studies in mouse and frog have provided strong evidence for a role of cofactor complexes in T3 signaling in vivo. Molecular studies on amphibian metamorphosis have also revealed that developmental gene regulation by T3 involves histone modifications and the disruption of chromatin structure at the target genes as evidenced by the loss of core histones, arguing that chromatin remodeling is an important mechanism for gene activation by liganded TR during vertebrate development.
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Affiliation(s)
- Yun-Bo Shi
- Section on Molecular Morphogenesis, Program in Cellular Regulation and Metabolism (PCRM), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland, 20892, USA.
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24
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Ishibashi S, Cliffe R, Amaya E. Highly efficient bi-allelic mutation rates using TALENs in Xenopus tropicalis. Biol Open 2012; 1:1273-6. [PMID: 23408158 PMCID: PMC3558749 DOI: 10.1242/bio.20123228] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 10/09/2012] [Indexed: 01/01/2023] Open
Abstract
In the past decade, Xenopus tropicalis has emerged as a powerful new amphibian genetic model system, which offers all of the experimental advantages of its larger cousin, Xenopus laevis. Here we investigated the efficiency of transcription activator-like effector nucleases (TALENs) for generating targeted mutations in endogenous genes in X. tropicalis. For our analysis we targeted the tyrosinase (oculocutaneous albinism IA) (tyr) gene, which is required for the production of skin pigments, such as melanin. We injected mRNA encoding TALENs targeting the first exon of the tyr gene into two-cell-stage embryos. Surprisingly, we found that over 90% of the founder animals developed either partial or full albinism, suggesting that the TALENs induced bi-allelic mutations in the tyr gene at very high frequency in the F0 animals. Furthermore, mutations tyr gene were efficiently transmitted into the F1 progeny, as evidenced by the generation of albino offspring. These findings have far reaching implications in our quest to develop efficient reverse genetic approaches in this emerging amphibian model.
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Affiliation(s)
- Shoko Ishibashi
- The Healing Foundation Centre, Faculty of Life Sciences, University of Manchester , Oxford Road, Manchester M13 9PT , UK
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25
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Cytological and morphological analyses reveal distinct features of intestinal development during Xenopus tropicalis metamorphosis. PLoS One 2012; 7:e47407. [PMID: 23071801 PMCID: PMC3468569 DOI: 10.1371/journal.pone.0047407] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 09/14/2012] [Indexed: 01/29/2023] Open
Abstract
Background The formation and/or maturation of adult organs in vertebrates often takes place during postembryonic development, a period around birth in mammals when thyroid hormone (T3) levels are high. The T3-dependent anuran metamorphosis serves as a model to study postembryonic development. Studies on the remodeling of the intestine during Xenopus (X.) laevis metamorphosis have shown that the development of the adult intestine involves de novo formation of adult stem cells in a process controlled by T3. On the other hand, X. tropicalis, highly related to X. laevis, offers a number of advantages for studying developmental mechanisms, especially at genome-wide level, over X. laevis, largely due to its shorter life cycle and sequenced genome. To establish X. tropicalis intestinal metamorphosis as a model for adult organogenesis, we analyzed the morphological and cytological changes in X. tropicalis intestine during metamorphosis. Methodology/Principal Findings We observed that in X. tropicalis, the premetamorphic intestine was made of mainly a monolayer of larval epithelial cells surrounded by little connective tissue except in the single epithelial fold, the typhlosole. During metamorphosis, the larval epithelium degenerates and adult epithelium develops to form a multi-folded structure with elaborate connective tissue and muscles. Interestingly, typhlosole, which is likely critical for adult epithelial development, is present along the entire length of the small intestine in premetamorphic tadpoles, in contrast to X. laevis, where it is present only in the anterior 1/3. T3-treatment induces intestinal remodeling, including the shortening of the intestine and the typhlosole, just like in X. laevis. Conclusions/Significance Our observations indicate that the intestine undergoes similar metamorphic changes in X. laevis and X. tropicalis, making it possible to use the large amount of information available on X. laevis intestinal metamorphosis and the genome sequence information and genetic advantages of X. tropicalis to dissect the pathways governing adult intestinal development.
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Clulow J, Clulow S, Guo J, French AJ, Mahony MJ, Archer M. Optimisation of an oviposition protocol employing human chorionic and pregnant mare serum gonadotropins in the barred frog Mixophyes fasciolatus (Myobatrachidae). Reprod Biol Endocrinol 2012; 10:60. [PMID: 22909256 PMCID: PMC3488330 DOI: 10.1186/1477-7827-10-60] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 08/03/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Protocols for the hormonal induction of ovulation and oviposition are essential tools for managing threatened amphibians with assisted reproduction, but responses vary greatly between species and even broad taxon groups. Consequently, it is necessary to assess effectiveness of such protocols in representative species when new taxa become targets for induction. The threatened genus Mixophyes (family Myobatrachidae) has amongst the highest proportion of endangered species of all the Australian amphibians. This study developed and optimised the induction of oviposition in a non-threatened member of this taxon, the great barred frog (Mixophyes fasciolatus). METHODS Gravid female M. fasciolatus were induced to oviposit on one or more occasions by administration of human chorionic gonadotropin (hCG) with or without priming with pregnant mare serum gonadotropin (PMSG). Treatments involved variations in hormone doses and combinations (administered via injection into the dorsal lymph sacs), and timing of administration. Pituitary homogenates from an unrelated bufonid species (Rhinella marina) were also examined with hCG. RESULTS When injected alone, hCG (900 to 1400 IU) induced oviposition. However, priming with two time dependent doses of PMSG (50 IU, 25 IU) increased responses, with lower doses of hCG (200 IU). Priming increased response rates in females from around 30% (hCG alone) to more than 50% (p = 0.035), and up to 67%. Increasing the interval between the first PMSG dose and first hCG dose from 3 to 6 days also produced significant improvement (p<0.001). Heterologous pituitary extracts administered with hCG were no more effective than hCG alone (p = 0.628). CONCLUSIONS This study found that M. fasciolatus is amongst the few amphibian species (including Xenopus (Silurana) and some bufonids) that respond well to the induction of ovulation utilising mammalian gonadotropins (hCG). The optimal protocol for M. fasciolatus involved two priming doses of PMSG (50 IU and 25 IU) administered at 6 and 4 days respectively, prior to two doses of hCG (100 IU), 24 hours apart. This study is also the first to demonstrate in an amphibian species that responds to mammalian gonadotropins that an increase in the ovulation rate occurs after priming with a gonadotropin (PMSG) with FSH activity.
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Affiliation(s)
- John Clulow
- School of Environmental and Life Sciences, University of Newcastle, Callaghan Drive, Callaghan, NSW, 2308, Australia
| | - Simon Clulow
- School of Environmental and Life Sciences, University of Newcastle, Callaghan Drive, Callaghan, NSW, 2308, Australia
| | - Jitong Guo
- Inner Mongolia Saikexing Reproductive Biotechnology Co., Ltd. 6 F, Mengniu Dairy R&D Center, Shengle Economic Zone of Helingeer County, Hohhot, 011517, Inner Mongolia, People's Republic of China
| | - Andrew J French
- Centre for Animal Biotechnology, Faculty of Veterinary Science, The University of Melbourne, Parkville, 3010, VIC, Australia
| | - Michael J Mahony
- School of Environmental and Life Sciences, University of Newcastle, Callaghan Drive, Callaghan, NSW, 2308, Australia
| | - Michael Archer
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, 2052, Australia
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Ishibashi S, Kroll KL, Amaya E. Generating transgenic frog embryos by restriction enzyme mediated integration (REMI). Methods Mol Biol 2012; 917:185-203. [PMID: 22956089 DOI: 10.1007/978-1-61779-992-1_11] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Here we present a protocol for generating transgenic embryos in Xenopus laevis and Xenopus tropicalis. The method includes three steps: (1) The preparation of high-speed egg extracts, which facilitates the replacement of protamines in sperm nuclei with nucleosomes and decondenses the chromatin of sperm nuclei; (2) The isolation of sperm nuclei; and (3) The mixing of sperm nuclei, restriction enzyme, and high-speed extract in vitro, following by nuclear transplantation into unfertilized eggs to generate the transgenic embryos. This procedure generates non-mosaic transgenic embryos at high frequency and efficiency.
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Affiliation(s)
- Shoko Ishibashi
- The Healing Foundation Centre, The Faculty of Life Sciences, University of Manchester, Manchester, England, UK
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28
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Abstract
Xenopus tropicalis was introduced as a model system for genetic, and then genomic research, in the early 1990s, complementing work on the widely used model organism Xenopus laevis. Its shorter generation time and diploid genome has facilitated a number of experimental approaches. It has permitted multigenerational experiments (e.g., preparation of transgenic lines and generation of mutant lines) that have added powerful approaches for research by the Xenopus community. As a diploid animal, its simpler genome was sequenced before X. laevis, and has provided a highly valuable resource indispensable for all Xenopus researchers. As more sophisticated transgenic technologies for manipulating gene expression are developed, and mutations, particularly null mutations, are identified in widely studied genes involved in critical cellular and developmental processes, researchers will increasingly turn to X. tropicalis for definitive analysis of complex genetic pathways. This chapter describes the historical and conceptual development of X. tropicalis as a genetic and genomic model system for higher vertebrate development.
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Affiliation(s)
- Robert M Grainger
- Department of Biology, University of Virginia, Charlottesville, VA, USA.
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29
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Kelley CM, Yergeau DA, Zhu H, Kuliyev E, Mead PE. Xenopus transgenics: methods using transposons. Methods Mol Biol 2012; 917:231-43. [PMID: 22956092 DOI: 10.1007/978-1-61779-992-1_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
The generation of transgenic animals is an essential tool for many genetic strategies. DNA "cut-and-paste" transposon systems can be used to efficiently modify the Xenopus genome. The DNA transposon substrate, harbored on a circularized plasmid, is co-injected into fertilized Xenopus embryos at the one-cell stage together with mRNA encoding the cognate transposase enzyme. The cellular machinery rapidly translates the exogenous mRNA to produce active transposase enzyme that catalyzes excision of the transposon substrate from the plasmid and stable integration into the genomic DNA.
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Affiliation(s)
- Clair M Kelley
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN, USA
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30
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Kurth T, Weiche S, Vorkel D, Kretschmar S, Menge A. Histology of plastic embedded amphibian embryos and larvae. Genesis 2011; 50:235-50. [DOI: 10.1002/dvg.20821] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 10/27/2011] [Accepted: 10/28/2011] [Indexed: 12/27/2022]
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Duarte-Guterman P, Ryan MJ, Hogan NS, Trudeau VL. Developmental Profiles and Thyroid Hormone Regulation of Brain Transcripts in Frogs: A Species Comparison with Emphasis on Physalaemus pustulosus. BRAIN, BEHAVIOR AND EVOLUTION 2011; 79:98-112. [DOI: 10.1159/000331265] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 07/20/2011] [Indexed: 01/18/2023]
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32
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Harland RM, Grainger RM. Xenopus research: metamorphosed by genetics and genomics. Trends Genet 2011; 27:507-15. [PMID: 21963197 PMCID: PMC3601910 DOI: 10.1016/j.tig.2011.08.003] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 08/25/2011] [Accepted: 08/25/2011] [Indexed: 01/18/2023]
Abstract
Research using Xenopus takes advantage of large, abundant eggs and readily manipulated embryos in addition to conserved cellular, developmental and genomic organization with mammals. Research on Xenopus has defined key principles of gene regulation and signal transduction, embryonic induction, morphogenesis and patterning as well as cell cycle regulation. Genomic and genetic advances in this system, including the development of Xenopus tropicalis as a genetically tractable complement to the widely used Xenopus laevis, capitalize on the classical strengths and wealth of achievements. These attributes provide the tools to tackle the complex biological problems of the new century, including cellular reprogramming, organogenesis, regeneration, gene regulatory networks and protein interactions controlling growth and development, all of which provide insights into a multitude of human diseases and their potential treatments.
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Affiliation(s)
- Richard M Harland
- Department of Molecular and Cell Biology, Center for Integrative Genomics, University of California Berkeley, CA 94720, USA
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Love NR, Chen Y, Bonev B, Gilchrist MJ, Fairclough L, Lea R, Mohun TJ, Paredes R, Zeef LAH, Amaya E. Genome-wide analysis of gene expression during Xenopus tropicalis tadpole tail regeneration. BMC DEVELOPMENTAL BIOLOGY 2011; 11:70. [PMID: 22085734 PMCID: PMC3247858 DOI: 10.1186/1471-213x-11-70] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2011] [Accepted: 11/15/2011] [Indexed: 01/08/2023]
Abstract
Background The molecular mechanisms governing vertebrate appendage regeneration remain poorly understood. Uncovering these mechanisms may lead to novel therapies aimed at alleviating human disfigurement and visible loss of function following injury. Here, we explore tadpole tail regeneration in Xenopus tropicalis, a diploid frog with a sequenced genome. Results We found that, like the traditionally used Xenopus laevis, the Xenopus tropicalis tadpole has the capacity to regenerate its tail following amputation, including its spinal cord, muscle, and major blood vessels. We examined gene expression using the Xenopus tropicalis Affymetrix genome array during three phases of regeneration, uncovering more than 1,000 genes that are significantly modulated during tail regeneration. Target validation, using RT-qPCR followed by gene ontology (GO) analysis, revealed a dynamic regulation of genes involved in the inflammatory response, intracellular metabolism, and energy regulation. Meta-analyses of the array data and validation by RT-qPCR and in situ hybridization uncovered a subset of genes upregulated during the early and intermediate phases of regeneration that are involved in the generation of NADP/H, suggesting that these pathways may be important for proper tail regeneration. Conclusions The Xenopus tropicalis tadpole is a powerful model to elucidate the genetic mechanisms of vertebrate appendage regeneration. We have produced a novel and substantial microarray data set examining gene expression during vertebrate appendage regeneration.
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Affiliation(s)
- Nick R Love
- Faculty of Life Sciences, University of Manchester, UK
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Fremont-Rahl JJ, Ek C, Williamson HR, Small PLC, Fox JG, Muthupalani S. Mycobacterium liflandii outbreak in a research colony of Xenopus (Silurana) tropicalis frogs. Vet Pathol 2010; 48:856-67. [PMID: 21118799 DOI: 10.1177/0300985810388520] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A research colony of Xenopus (Silurana) tropicalis frogs presented with nodular and ulcerative skin lesions. Additional consistent gross findings included splenomegaly with multiple tan-yellow nodular foci in the spleen and liver of diseased frogs. Copious acid-fast positive bacteria were present in touch impression smears of spleen, skin, and livers of diseased frogs. Histologically, necrotizing and granulomatous dermatitis, splenitis, and hepatitis with numerous acid-fast bacilli were consistently present, indicative of systemic mycobacteriosis. Infrequently, granulomatous inflammation was noted in the lungs, pancreas, coelomic membranes, and rarely reproductive organs. Ultrastructurally, both extracellular bacilli and intracellular bacilli within macrophages were identified. Frogs in the affected room were systematically depopulated, and control measures were initiated. Cultured mycobacteria from affected organs were identified and genetically characterized as Mycobacterium liflandii by polymerase chain reaction amplification of the enoyl reductase domain and specific variable numbers of tandem repeats. In recent years, M. liflandii has had a devastating impact on research frog colonies throughout the United States. This detailed report with ultrastructural description of M. liflandii aids in further understanding of this serious disease in frogs.
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Abstract
Lens regeneration among vertebrates is basically restricted to some amphibians. The most notable cases are the ones that occur in premetamorphic frogs and in adult newts. Frogs and newts regenerate their lens in very different ways. In frogs the lens is regenerated by transdifferentiation of the cornea and is limited only to a time before metamorphosis. On the other hand, regeneration in newts is mediated by transdifferentiation of the pigment epithelial cells of the dorsal iris and is possible in adult animals as well. Thus, the study of both systems could provide important information about the process. Molecular tools have been developed in frogs and recently also in newts. Thus, the process has been studied at the molecular and cellular levels. A synthesis describing both systems was long due. In this review we describe the process in both Xenopus and the newt. The known molecular mechanisms are described and compared.
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Affiliation(s)
- Jonathan J Henry
- Department of Cell and Developmental Biology, University of Illinois, Urbana, IL 61801, USA.
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Langlois VS, Duarte-Guterman P, Ing S, Pauli BD, Cooke GM, Trudeau VL. Fadrozole and finasteride exposures modulate sex steroid- and thyroid hormone-related gene expression in Silurana (Xenopus) tropicalis early larval development. Gen Comp Endocrinol 2010; 166:417-27. [PMID: 19917284 DOI: 10.1016/j.ygcen.2009.11.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 11/03/2009] [Accepted: 11/10/2009] [Indexed: 11/19/2022]
Abstract
Steroidogenic enzymes and their steroid products play critical roles during gonadal differentiation in amphibians; however their roles during embryogenesis remain unclear. The objective of this study was to investigate the expression and activity of aromatase (cyp19; estrogen synthase) and 5 beta-reductase (srd5 beta; 5 beta-dihydrotestosterone synthase) during amphibian embryogenesis. Expression and activity profiles of cyp19 and srd5 beta were first established during Silurana (Xenopus) tropicalis embryogenesis from Nieuwkoop-Faber (NF) stage 2 (2-cell stage; 1h post-fertilization) to NF stage 46 (beginning of feeding; 72 h post-fertilization). Exposures to fadrozole (an aromatase inhibitor; 0.5, 1.0 and 2.0 microM) and finasteride (a putative 5-reductase inhibitor; 25, 50 and 100 microM) were designed to assess the consequences of inhibiting these enzymes on gene expression in early amphibian larval development. Exposed embryos showed changes in both enzyme activities and sex steroid- and thyroid hormone-related gene expression. Fadrozole treatment inhibited cyp19 activity and increased androgen receptor and thyroid hormone receptor (alpha and beta) mRNAs. Finasteride treatment inhibited srd5 beta (activity and mRNA), decreased cyp19 mRNA and activity levels and increased estrogen receptor alpha mRNA. Both treatments altered the expression of deiodinases (thyroid hormone metabolizing enzymes). We conclude that cyp19 and srd5 beta are active in early embryogenesis and larval development in Silurana tropicalis and their inhibition affected transcription of genes associated with the thyroid and reproductive axes.
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Affiliation(s)
- Valérie S Langlois
- Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
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Duarte-Guterman P, Langlois VS, Pauli BD, Trudeau VL. Expression and T3 regulation of thyroid hormone- and sex steroid-related genes during Silurana (Xenopus) tropicalis early development. Gen Comp Endocrinol 2010; 166:428-35. [PMID: 20015451 DOI: 10.1016/j.ygcen.2009.12.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 12/01/2009] [Accepted: 12/05/2009] [Indexed: 11/26/2022]
Abstract
In amphibians, thyroid hormones (THs) are the primary regulators of metamorphosis; however, their physiological role during embryogenesis remains unclear. First, we established complete developmental profiles for TH receptors (tr alpha and tr beta), deiodinases (dio; types 1, 2, 3), estrogen receptors (er alpha and er beta) and androgen receptor (ar) mRNA levels during embryogenesis and early larval stages in Silurana (Xenopus) tropicalis (from Nieuwkoop and Faber (NF) stage 2 until NF 46). Real-time RT-PCR analyses in whole embryos and larvae revealed that all transcripts except tr alpha were detected throughout development; tr alpha only appears after gastrulation. The first significant increase in the expression of tralpha and tr beta was observed before hatching, between NF 21 and NF 27 (2.5- and 11-fold, respectively). In order to test if these genes could be regulated by THs during early larval development, embryos were exposed to triiodothyronine (T3; 0.5, 5.0, 50 nM) from NF 27 to NF 46. T3 exposure caused a dose-dependent increase relative to control in the expression of tr alpha, tr beta, dio (types 2 and 3), ar, and 5 alpha-reductase type 1 in whole larvae. These results indicate that in S. tropicalis, tr and dio can be induced by T3 as early as NF 46, a response that had only been characterized later during frog metamorphosis. In addition, T3 also affected androgen-related gene expression, supporting our hypothesis that THs are involved in male development in frogs.
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Affiliation(s)
- Paula Duarte-Guterman
- Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
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Kurth T, Berger J, Wilsch-Bräuninger M, Kretschmar S, Cerny R, Schwarz H, Löfberg J, Piendl T, Epperlein HH. Electron Microscopy of the Amphibian Model Systems Xenopus laevis and Ambystoma mexicanum. Methods Cell Biol 2010; 96:395-423. [DOI: 10.1016/s0091-679x(10)96017-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Abstract
Vertebrate eyes begin as a small patch of cells at the most anterior end of the early brain called the eye field. If these cells are removed from an amphibian embryo, the eyes do not form. If the eye field is transplanted to another location on the embryo or cultured in a dish, it forms eyes. These simple cut and paste experiments were performed at the beginning of the last century and helped to define the embryonic origin of the vertebrate eye. The genes necessary for eye field specification and eventual eye formation, by contrast, have only recently been identified. These genes and the molecular mechanisms regulating the initial formation of the Xenopus laevis eye field are the subjects of this review.
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Affiliation(s)
- Michael E Zuber
- Center for Vision Research, SUNY Eye Institute, Departments of Ophthalmology and Biochemistry & Molecular Biology, Upstate Medical University, Syracuse, New York, USA
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Yergeau DA, Johnson Hamlet MR, Kuliyev E, Zhu H, Doherty JR, Archer TD, Subhawong AP, Valentine MB, Kelley CM, Mead PE. Transgenesis in Xenopus using the Sleeping Beauty transposon system. Dev Dyn 2009; 238:1727-43. [PMID: 19517568 DOI: 10.1002/dvdy.21994] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Transposon-based integration systems have been widely used for genetic manipulation of invertebrate and plant model systems. In the past decade, these powerful tools have begun to be used in vertebrates for transgenesis, insertional mutagenesis, and gene therapy applications. Sleeping Beauty (SB) is a member of Tc1/mariner class of transposases and is derived from an inactive form of the gene isolated from Atlantic salmon. SB has been used extensively in human cell lines and in whole animal vertebrate model systems such as the mouse, rat, and zebrafish. In this study, we describe the use of SB in the diploid frog Xenopus tropicalis to generate stable transgenic lines. SB transposon transgenes integrate into the X. tropicalis genome by a noncanonical process and are passed through the germline. We compare the activity of SB in this model organism with that of Tol2, a hAT (hobo, Ac1, TAM)-like transposon system.
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Affiliation(s)
- Donald A Yergeau
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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Khokha MK, Krylov V, Reilly MJ, Gall JG, Bhattacharya D, Cheung CYJ, Kaufman S, Lam DK, Macha J, Ngo C, Prakash N, Schmidt P, Tlapakova T, Trivedi T, Tumova L, Abu-Daya A, Geach T, Vendrell E, Ironfield H, Sinzelle L, Sater AK, Wells DE, Harland RM, Zimmerman LB. Rapid gynogenetic mapping of Xenopus tropicalis mutations to chromosomes. Dev Dyn 2009; 238:1398-46. [PMID: 19441086 DOI: 10.1002/dvdy.21965] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Pilot forward genetic screens in Xenopus tropicalis have isolated over 60 recessive mutations. Here we present a simple method for mapping mutations to chromosomes using gynogenesis and centromeric markers. When coupled with available genomic resources, gross mapping facilitates evaluation of candidate genes as well as higher resolution linkage studies. Using gynogenesis, we have mapped the genetic locations of the 10 X. tropicalis centromeres, and performed fluorescence in situ hybridization to validate these locations cytologically. We demonstrate the use of this very small set of centromeric markers to map mutations efficiently to specific chromosomes. Developmental Dynamics 238:1398-1406, 2009. (c) 2009 Wiley-Liss, Inc.
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Affiliation(s)
- Mustafa K Khokha
- Department of Pediatrics and Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
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Chen Y, Costa RMB, Love NR, Soto X, Roth M, Paredes R, Amaya E. C/EBPalpha initiates primitive myelopoiesis in pluripotent embryonic cells. Blood 2009; 114:40-8. [PMID: 19420355 PMCID: PMC3747498 DOI: 10.1182/blood-2008-11-189159] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The molecular mechanisms that underlie the development of primitive myeloid cells in vertebrate embryos are not well understood. Here we characterize the role of cebpa during primitive myeloid cell development in Xenopus. We show that cebpa is one of the first known hematopoietic genes expressed in the embryo. Loss- and gain-of-function studies show that it is both necessary and sufficient for the development of functional myeloid cells. In addition, we show that cebpa misexpression leads to the precocious induction of myeloid cell markers in pluripotent prospective ectodermal cells, without the cells transitioning through a general mesodermal state. Finally, we use live imaging to show that cebpa-expressing cells exhibit many attributes of terminally differentiated myeloid cells, such as highly active migratory behavior, the ability to quickly and efficiently migrate toward wounds and phagocytose bacteria, and the ability to enter the circulation. Thus, C/EPBalpha is the first known single factor capable of initiating an entire myelopoiesis pathway in pluripotent cells in the embryo.
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Affiliation(s)
- Yaoyao Chen
- The Healing Foundation Centre, Michael Smith Building, Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, United Kingdom
| | - Ricardo M. B. Costa
- The Healing Foundation Centre, Michael Smith Building, Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, United Kingdom
| | - Nick R. Love
- The Healing Foundation Centre, Michael Smith Building, Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, United Kingdom
| | - Ximena Soto
- The Healing Foundation Centre, Michael Smith Building, Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, United Kingdom
| | - Martin Roth
- The Healing Foundation Centre, Michael Smith Building, Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, United Kingdom
| | - Roberto Paredes
- The Healing Foundation Centre, Michael Smith Building, Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, United Kingdom
| | - Enrique Amaya
- The Healing Foundation Centre, Michael Smith Building, Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, United Kingdom
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Oka T, Miyahara M, Yamamoto J, Mitsui N, Fujii T, Tooi O, Kashiwagi K, Takase M, Kashiwagi A, Iguchi T. Application of metamorphosis assay to a native Japanese amphibian species, Rana rugosa, for assessing effects of thyroid system affecting chemicals. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2009; 72:1400-1405. [PMID: 19394694 DOI: 10.1016/j.ecoenv.2009.03.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 03/27/2009] [Accepted: 03/30/2009] [Indexed: 05/27/2023]
Abstract
The aims of this study were to assess the utility of a metamorphosis assay for detecting thyroid hormone-disrupting chemicals using Rana rugosa, a domestic frog species in Japan, and to compare species differences in sensitivity to thyroxine (T(4)) and propylthiouracil (PTU) among R. rugosa, Xenopus laevis and Xenopus (Silurana) tropicalis. Tadpoles of R. rugosa (TK stages III/IV) were exposed to standard test chemicals for acceleration (T(4)) and inhibition (PTU) of metamorphosis for 28 days in semi-static condition and total body length and developmental stage (TK stage) were recorded every week. T(4) (0.61 and 2.24 microg/L in actual concentrations) and PTU (19.73, 76.83, and 155.67 mg/L in actual concentrations) induced significant acceleration and inhibition of metamorphosis, respectively. The present results indicate that the metamorphosis assay is successfully applied to the domestic frog species, R. rugosa, suggesting this assay can be used for the assessment of chemicals on ecological impacts in wild frog species.
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Affiliation(s)
- Tomohiro Oka
- Institute of Environmental Ecology, IDEA Consultants, Inc, Yaizu, Shizuoka, Japan
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Sánchez-Morgado JM, Gallagher A, Johnson LK. Mycobacterium gordonae infection in a colony of African clawed frogs (Xenopus tropicalis). Lab Anim 2009; 43:300-3. [DOI: 10.1258/la.2008.008035] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Mycobacterium gordonae is an occasional human pathogen associated with cutaneous infections and nodular granulomatous skin lesions. A case of cutaneous nodular infection caused by M. gordonae in a colony of African clawed frogs ( Xenopus tropicalis) is described and confirms this organism to be an opportunistic frog pathogen.
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Affiliation(s)
- José M Sánchez-Morgado
- Biological Services, MRC–National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Alec Gallagher
- Biological Services, MRC–National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Linda K Johnson
- Histopathology, Pathology Department Bldg 57, Veterinary Laboratories Agency, New Haw, Addlestone, Surrey KT15 3NB, UK
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Ogino H, Ochi H. Resources and transgenesis techniques for functional genomics in Xenopus. Dev Growth Differ 2009; 51:387-401. [PMID: 19382936 DOI: 10.1111/j.1440-169x.2009.01098.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Recent developments in genomic resources and high-throughput transgenesis techniques have allowed Xenopus to 'metamorphose' from a classic model for embryology to a leading-edge experimental system for functional genomics. This process has incorporated the fast-breeding diploid frog, Xenopus tropicalis, as a new model-system for vertebrate genomics and genetics. Sequencing of the X. tropicalis genome is nearly complete, and its comparison with mammalian sequences offers a reliable guide for the genome-wide prediction of cis-regulatory elements. Unique cDNA sets have been generated for both X. tropicalis and X. laevis, which have facilitated non-redundant, systematic gene expression screening and comprehensive gene expression analysis. A variety of transgenesis techniques are available for both X. laevis and X. tropicalis, and the appropriate procedure may be chosen depending on the purpose for which it is required. Effective use of these resources and techniques will help to reveal the overall picture of the complex wiring of gene regulatory networks that control vertebrate development.
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Affiliation(s)
- Hajime Ogino
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, Japan.
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Wang X, Matsuda H, Shi YB. Developmental regulation and function of thyroid hormone receptors and 9-cis retinoic acid receptors during Xenopus tropicalis metamorphosis. Endocrinology 2008; 149:5610-8. [PMID: 18635662 PMCID: PMC2584584 DOI: 10.1210/en.2008-0751] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Amphibian metamorphosis serves as an excellent model to study T3 function during postembryonic development in vertebrate due to its total dependence on T3. Earlier molecular studies in the model species Xenopus laevis have led to a number of important in vivo findings on the function and mechanisms of T3 receptor (TR) action during vertebrate development. However, the lack of genomic sequence information, its tetraploid genome, and lengthy developmental cycle hinder further analyses on TR functions. In this regard, the highly related species, Xenopus tropicalis, is much more advantageous. Toward developing X. tropicalis for genome-wide and genetic studies of TR function, we analyzed the expression profiles of TRs and their heterodimerization partners, retinoid X receptors (RXRs) or 9-cis retinoic acid receptors. We show that their expression correlates with transformations in different organs and that TR/RXR heterodimers are capable of repressing and activating gene expression in vivo in the absence and presence of T3, respectively. We further demonstrate that TRs are bound to endogenous target genes in X. tropicalis tadpoles. Our results thus support a role of TRs in mediating the metamorphic effects of T3 in X. tropicalis. More importantly, the similarities in the expression and function between X. tropicalis and X. laevis TRs and RXRs as demonstrated by our study also pave the way to take advantages of existing morphological, molecular, and cellular knowledge of X. laevis development and the genetic and sequence superiority of X. tropicalis to dissect the molecular pathways governing tissue/organ-specific transformations during vertebrate postembryonic development.
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Affiliation(s)
- Xuedong Wang
- Section on Molecular Morphogenesis, Laboratory of Gene Regulation and Development, Program on Cell Regulation and Metabolism, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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Chesneau A, Sachs LM, Chai N, Chen Y, Pasquier LD, Loeber J, Pollet N, Reilly M, Weeks DL, Bronchain OJ. Transgenesis procedures in Xenopus. Biol Cell 2008; 100:503-21. [PMID: 18699776 PMCID: PMC2967756 DOI: 10.1042/bc20070148] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Stable integration of foreign DNA into the frog genome has been the purpose of several studies aimed at generating transgenic animals or producing mutations of endogenous genes. Inserting DNA into a host genome can be achieved in a number of ways. In Xenopus, different strategies have been developed which exhibit specific molecular and technical features. Although several of these technologies were also applied in various model organizms, the attributes of each method have rarely been experimentally compared. Investigators are thus confronted with a difficult choice to discriminate which method would be best suited for their applications. To gain better understanding, a transgenesis workshop was organized by the X-omics consortium. Three procedures were assessed side-by-side, and the results obtained are used to illustrate this review. In addition, a number of reagents and tools have been set up for the purpose of gene expression and functional gene analyses. This not only improves the status of Xenopus as a powerful model for developmental studies, but also renders it suitable for sophisticated genetic approaches. Twenty years after the first reported transgenic Xenopus, we review the state of the art of transgenic research, focusing on the new perspectives in performing genetic studies in this species.
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Affiliation(s)
- Albert Chesneau
- Laboratoire Evolution et Développement, Université Paris Sud, F-91405 Orsay cedex, France
- CNRS UMR 8080, F-91405 Orsay, France
| | - Laurent M. Sachs
- Département Régulation, Développement et Diversité Moléculaire, MNHN USM 501, CNRS UMR 5166, CP32, 7 rue Cuvier, 75231 Paris cedex 05, France
| | - Norin Chai
- Muséum National d’Histoire Naturelle, Ménagerie du Jardin des Plantes, 57 rue Cuvier, 75005 Paris, France
| | - Yonglong Chen
- Georg-August-Universitat Gottingen, Zentrum Biochemie und Molekular Zellbiologie, Abteilung Entwicklungsbiochemie, 37077 Gottingen, Germany
- Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Science City, 510663 Guangzhou, People’s Republic of China
| | - Louis Du Pasquier
- Institute of Zoology and Evolutionary Biology, University of Basel, Vesalgasse 1, CH-4051 Basel, Switzerland
| | - Jana Loeber
- Georg-August-Universitat Gottingen, Zentrum Biochemie und Molekular Zellbiologie, Abteilung Entwicklungsbiochemie, 37077 Gottingen, Germany
| | - Nicolas Pollet
- Laboratoire Evolution et Développement, Université Paris Sud, F-91405 Orsay cedex, France
- CNRS UMR 8080, F-91405 Orsay, France
| | - Michael Reilly
- Division of Developmental Biology, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, U.K
| | - Daniel L. Weeks
- Department of Biochemistry, Bowen Science Building, University of Iowa, Iowa City, IA 52242, U.S.A
| | - Odile J. Bronchain
- Laboratoire Evolution et Développement, Université Paris Sud, F-91405 Orsay cedex, France
- CNRS UMR 8080, F-91405 Orsay, France
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48
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Affiliation(s)
- Shoko Ishibashi
- The Healing Foundation Centre, Michael Smith Building, Faculty of Life Sciences, University of Manchester, Manchester, UK
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49
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Bowes JB, Snyder KA, Segerdell E, Gibb R, Jarabek C, Noumen E, Pollet N, Vize PD. Xenbase: a Xenopus biology and genomics resource. Nucleic Acids Res 2007; 36:D761-7. [PMID: 17984085 PMCID: PMC2238855 DOI: 10.1093/nar/gkm826] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Xenbase (www.xenbase.org) is a model organism database integrating a diverse array of biological and genomic data on the frogs, Xenopus laevis and Xenopus (Silurana) tropicalis. Data is collected from other databases, high-throughput screens and the scientific literature and integrated into a number of database modules covering subjects such as community, literature, gene and genomic analysis. Gene pages are automatically assembled from data piped from the Entrez Gene, Gurdon Institute, JGI, Metazome, MGI, OMIM, PubMed, Unigene, Zfin, commercial suppliers and others. These data are then supplemented with in-house annotation. Xenbase has implemented the Gbrowse genome browser and also provides a BLAST service that allows users to specifically search either laevis or tropicalis DNA or protein targets. A table of Xenopus gene synonyms has been implemented and allows the genome, genes, publications and high-throughput gene expression data to be seamlessly integrated with other Xenopus data and to external database resources, making the wealth of developmental and functional data from the frog available to the broader research community.
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Affiliation(s)
- Jeff B Bowes
- Department of Computer Science, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada
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Ogino H, McConnell WB, Grainger RM. High-throughput transgenesis in Xenopus using I-SceI meganuclease. Nat Protoc 2007; 1:1703-10. [PMID: 17487153 DOI: 10.1038/nprot.2006.208] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In this report we describe an easy, highly efficient transgenesis method for Xenopus. The method is very simple; a commercially available meganuclease, I-SceI, is incubated with a transgene construct carrying its recognition sites, and is subsequently microinjected into fertilized eggs. Approximately 30% (in Xenopus tropicalis) or 20% (in Xenopus laevis) of injected embryos exhibit non-mosaic, promoter-dependent transgene expression, and transgenes from the founder animals are transmitted to offspring. The method is compatible with mRNA or antisense morpholino oligonucleotide injection, and these secondary reagents can be introduced simultaneously or sequentially with a transgene to test their interaction. This high-throughput transgenic technique will be a powerful tool for studying the complex wiring of regulatory networks at the genome-wide level, as well as for facilitating genetic studies in the rapidly breeding diploid frog, X. tropicalis.
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Affiliation(s)
- Hajime Ogino
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904, USA
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