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Tandon P, Conlon F, Furlow JD, Horb ME. Expanding the genetic toolkit in Xenopus: Approaches and opportunities for human disease modeling. Dev Biol 2017; 426:325-335. [PMID: 27109192 PMCID: PMC5074924 DOI: 10.1016/j.ydbio.2016.04.009] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/23/2016] [Accepted: 04/12/2016] [Indexed: 11/29/2022]
Abstract
The amphibian model Xenopus, has been used extensively over the past century to study multiple aspects of cell and developmental biology. Xenopus offers advantages of a non-mammalian system, including high fecundity, external development, and simple housing requirements, with additional advantages of large embryos, highly conserved developmental processes, and close evolutionary relationship to higher vertebrates. There are two main species of Xenopus used in biomedical research, Xenopus laevis and Xenopus tropicalis; the common perception is that both species are excellent models for embryological and cell biological studies, but only Xenopus tropicalis is useful as a genetic model. The recent completion of the Xenopus laevis genome sequence combined with implementation of genome editing tools, such as TALENs (transcription activator-like effector nucleases) and CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR associated nucleases), greatly facilitates the use of both Xenopus laevis and Xenopus tropicalis for understanding gene function in development and disease. In this paper, we review recent advances made in Xenopus laevis and Xenopus tropicalis with TALENs and CRISPR-Cas and discuss the various approaches that have been used to generate knockout and knock-in animals in both species. These advances show that both Xenopus species are useful for genetic approaches and in particular counters the notion that Xenopus laevis is not amenable to genetic manipulations.
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Affiliation(s)
- Panna Tandon
- University of North Carolina McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280, United States.
| | - Frank Conlon
- University of North Carolina McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280, United States
| | - J David Furlow
- Deparment of Neurobiology, Physiology and Behavior, University of California, Davis, CA 95616, United States
| | - Marko E Horb
- National Xenopus Resource and Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02543, United States.
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Igawa T, Watanabe A, Suzuki A, Kashiwagi A, Kashiwagi K, Noble A, Guille M, Simpson DE, Horb ME, Fujii T, Sumida M. Inbreeding Ratio and Genetic Relationships among Strains of the Western Clawed Frog, Xenopus tropicalis. PLoS One 2015. [PMID: 26222540 PMCID: PMC4519292 DOI: 10.1371/journal.pone.0133963] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The Western clawed frog, Xenopus tropicalis, is a highly promising model amphibian, especially in developmental and physiological research, and as a tool for understanding disease. It was originally found in the West African rainforest belt, and was introduced to the research community in the 1990s. The major strains thus far known include the Nigerian and Ivory Coast strains. However, due to its short history as an experimental animal, the genetic relationship among the various strains has not yet been clarified, and establishment of inbred strains has not yet been achieved. Since 2003 the Institute for Amphibian Biology (IAB), Hiroshima University has maintained stocks of multiple X. tropicalis strains and conducted consecutive breeding as part of the National BioResource Project. In the present study we investigated the inbreeding ratio and genetic relationship of four inbred strains at IAB, as well as stocks from other institutions, using highly polymorphic microsatellite markers and mitochondrial haplotypes. Our results show successive reduction of heterozygosity in the genome of the IAB inbred strains. The Ivory Coast strains clearly differed from the Nigerian strains genetically, and three subgroups were identified within both the Nigerian and Ivory Coast strains. It is noteworthy that the Ivory Coast strains have an evolutionary divergent genetic background. Our results serve as a guide for the most effective use of X. tropicalis strains, and the long-term maintenance of multiple strains will contribute to further research efforts.
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Affiliation(s)
- Takeshi Igawa
- Institute for Amphibian Biology, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
- * E-mail:
| | - Ai Watanabe
- Institute for Amphibian Biology, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Atsushi Suzuki
- Institute for Amphibian Biology, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Akihiko Kashiwagi
- Institute for Amphibian Biology, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Keiko Kashiwagi
- Institute for Amphibian Biology, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Anna Noble
- School of Biological Sciences, Institute of Biomedical and Biomolecular Science, University of Portsmouth, Portsmouth, United Kingdom
| | - Matt Guille
- School of Biological Sciences, Institute of Biomedical and Biomolecular Science, University of Portsmouth, Portsmouth, United Kingdom
| | - David E. Simpson
- The Wellcome Trust/Cancer Research UK Gurdon Institute, The Henry Wellcome Building of Cancer and Developmental Biology, University of Cambridge, Cambridge, United Kingdom
| | - Marko E. Horb
- Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus Resource, Marine Biological Laboratory, Woods Hole, MA, United States of America
| | - Tamotsu Fujii
- Department of Health Sciences, Faculty of Human Culture & Science, Prefectural University of Hiroshima, Hiroshima, Japan
| | - Masayuki Sumida
- Institute for Amphibian Biology, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
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Abu-Daya A, Khokha MK, Zimmerman LB. The hitchhiker's guide to Xenopus genetics. Genesis 2012; 50:164-75. [PMID: 22344745 DOI: 10.1002/dvg.22007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 12/19/2011] [Accepted: 12/23/2011] [Indexed: 01/12/2023]
Abstract
A decade after the human genome sequence, most vertebrate gene functions remain poorly understood, limiting benefits to human health from rapidly advancing genomic technologies. Systematic in vivo functional analysis is ideally suited to the experimentally accessible Xenopus embryo, which combines embryological accessibility with a broad range of transgenic, biochemical, and gain-of-function assays. The diploid X. tropicalis adds loss-of-function genetics and enhanced genomics to this repertoire. In the last decade, diverse phenotypes have been recovered from genetic screens, mutations have been cloned, and reverse genetics in the form of TILLING and targeted gene editing have been established. Simple haploid genetics and gynogenesis and the very large number of embryos produced streamline screening and mapping. Improved genomic resources and the revolution in high-throughput sequencing are transforming mutation cloning and reverse genetic approaches. The combination of loss-of-function mutant backgrounds with the diverse array of conventional Xenopus assays offers a uniquely flexible platform for analysis of gene function in vertebrate development.
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Affiliation(s)
- Anita Abu-Daya
- Division of Developmental Biology, MRC-National Institute for Medical Research, Mill Hill, London, United Kingdom
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Abstract
The pipid frog Xenopus tropicalis has emerged as a powerful new model system for combining genetic and genomic analysis of tetrapod development with robust embryological, molecular, and biochemical assays. Its early development closely resembles that of its well-understood relative X. laevis, from which techniques and reagents can be readily transferred. In contrast to the tetraploid X. laevis, X. tropicalis has a compact diploid genome with strong synteny to those of amniotes. Recently, advances in high-throughput sequencing together with solution-hybridization whole-exome enrichment technology offer powerful strategies for cloning novel mutations as well as reverse genetic identification of sequence lesions in specific genes of interest. Further advantages include the wide range of functional and molecular assays available, the large number of embryos/meioses produced, and the ease of haploid genetics and gynogenesis. The addition of these genetic tools to X. tropicalis provides a uniquely flexible platform for analysis of gene function in vertebrate development.
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Affiliation(s)
- Timothy J. Geach
- National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA United Kingdom
| | | | - Lyle B. Zimmerman
- National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA United Kingdom
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