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Johnson HK, Wahl SE, Sesay F, Litovchick L, Dickinson AJ. Dyrk1a is required for craniofacial development in Xenopus laevis. Dev Biol 2024; 511:63-75. [PMID: 38621649 DOI: 10.1016/j.ydbio.2024.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 03/29/2024] [Accepted: 04/11/2024] [Indexed: 04/17/2024]
Abstract
Loss of function variations in the dual specificity tyrosine-phosphorylation-regulated kinase 1 A (DYRK1A) gene are associated with craniofacial malformations in humans. Here we characterized the effects of deficient DYRK1A in craniofacial development using a developmental model, Xenopus laevis. Dyrk1a mRNA and protein were expressed throughout the developing head and both were enriched in the branchial arches which contribute to the face and jaw. Consistently, reduced Dyrk1a function, using dyrk1a morpholinos and pharmacological inhibitors, resulted in orofacial malformations including hypotelorism, altered mouth shape, slanted eyes, and narrower face accompanied by smaller jaw cartilage and muscle. Inhibition of Dyrk1a function resulted in misexpression of key craniofacial regulators including transcription factors and members of the retinoic acid signaling pathway. Two such regulators, sox9 and pax3 are required for neural crest development and their decreased expression corresponds with smaller neural crest domains within the branchial arches. Finally, we determined that the smaller size of the faces, jaw elements and neural crest domains in embryos deficient in Dyrk1a could be explained by increased cell death and decreased proliferation. This study is the first to provide insight into why craniofacial birth defects might arise in humans with variants of DYRK1A.
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Affiliation(s)
| | - Stacey E Wahl
- Department of Biology, Virginia Commonwealth University, Richmond, VA, USA
| | - Fatmata Sesay
- Department of Internal Medicine, Division of Hematology, Oncology and Palliative Care, Virginia Commonwealth University, Richmond, VA, USA
| | - Larisa Litovchick
- Department of Internal Medicine, Division of Hematology, Oncology and Palliative Care, Virginia Commonwealth University, Richmond, VA, USA; Massey Comprehensive Cancer Center, Richmond, VA, USA
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2
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Johnson HK, Wahl SE, Sesay F, Litovchick L, Dickinson AJ. Dyrk1a is required for craniofacial development in Xenopus laevis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.13.575394. [PMID: 38260562 PMCID: PMC10802584 DOI: 10.1101/2024.01.13.575394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Loss of function mutations in the dual specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A) gene are associated with craniofacial malformations in humans. Here we characterized the effects of deficient DYRK1A in craniofacial development using a developmental model, Xenopus laevis . Dyrk1a mRNA and protein was expressed throughout the developing head and was enriched in the branchial arches which contribute to the face and jaw. Consistently, reduced Dyrk1a function, using dyrk1a morpholinos and pharmacological inhibitors, resulted in orofacial malformations including hypotelorism, altered mouth shape, slanted eyes, and narrower face accompanied by smaller jaw cartilage and muscle. Inhibition of Dyrk1a function resulted in misexpression of key craniofacial regulators including transcription factors and members of the retinoic acid signaling pathway. Two such regulators, sox9 and pax3 are required for neural crest development and their decreased expression corresponds with smaller neural crest domains within the branchial arches. Finally, we determined that the smaller size of the faces, jaw elements and neural crest domains in embryos deficient in Dyrk1a could be explained by increased cell death and decreased proliferation. This study is the first to provide insight into why craniofacial birth defects might arise in humans with DYRK1A mutations.
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3
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Dickinson AJG. Jak2 and Jaw Muscles Are Required for Buccopharyngeal Membrane Perforation during Mouth Development. J Dev Biol 2023; 11:24. [PMID: 37367478 DOI: 10.3390/jdb11020024] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/23/2023] [Accepted: 05/28/2023] [Indexed: 06/28/2023] Open
Abstract
The mouth is a central feature of our face, without which we could not eat, breathe, or communicate. A critical and early event in mouth formation is the creation of a "hole" which connects the digestive system and the external environment. This hole, which has also been called the primary or embryonic mouth in vertebrates, is initially covered by a 1-2 cell layer thick structure called the buccopharyngeal membrane. When the buccopharyngeal membrane does not rupture, it impairs early mouth functions and may also lead to further craniofacial malformations. Using a chemical screen in an animal model (Xenopus laevis) and genetic data from humans, we determined that Janus kinase 2 (Jak2) has a role in buccopharyngeal membrane rupture. We have determined that decreased Jak2 function, using antisense morpholinos or a pharmacological antagonist, caused a persistent buccopharyngeal membrane as well as the loss of jaw muscles. Surprisingly, we observed that the jaw muscle compartments were connected to the oral epithelium that is continuous with the buccopharyngeal membrane. Severing such connections resulted in buccopharyngeal membrane buckling and persistence. We also noted puncta accumulation of F-actin, an indicator of tension, in the buccopharyngeal membrane during perforation. Taken together, the data has led us to a hypothesis that muscles are required to exert tension across the buccopharyngeal membrane, and such tension is necessary for its perforation.
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Affiliation(s)
- Amanda J G Dickinson
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284, USA
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4
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Lansdon LA, Dickinson A, Arlis S, Liu H, Hlas A, Hahn A, Bonde G, Long A, Standley J, Tyryshkina A, Wehby G, Lee NR, Daack-Hirsch S, Mohlke K, Girirajan S, Darbro BW, Cornell RA, Houston DW, Murray JC, Manak JR. Genome-wide analysis of copy-number variation in humans with cleft lip and/or cleft palate identifies COBLL1, RIC1, and ARHGEF38 as clefting genes. Am J Hum Genet 2023; 110:71-91. [PMID: 36493769 PMCID: PMC9892779 DOI: 10.1016/j.ajhg.2022.11.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 11/18/2022] [Indexed: 12/13/2022] Open
Abstract
Cleft lip with or without cleft palate (CL/P) is a common birth defect with a complex, heterogeneous etiology. It is well established that common and rare sequence variants contribute to the formation of CL/P, but the contribution of copy-number variants (CNVs) to cleft formation remains relatively understudied. To fill this knowledge gap, we conducted a large-scale comparative analysis of genome-wide CNV profiles of 869 individuals from the Philippines and 233 individuals of European ancestry with CL/P with three primary goals: first, to evaluate whether differences in CNV number, amount of genomic content, or amount of coding genomic content existed within clefting subtypes; second, to assess whether CNVs in our cohort overlapped with known Mendelian clefting loci; and third, to identify unestablished Mendelian clefting genes. Significant differences in CNVs across cleft types or in individuals with non-syndromic versus syndromic clefts were not observed; however, several CNVs in our cohort overlapped with known syndromic and non-syndromic Mendelian clefting loci. Moreover, employing a filtering strategy relying on population genetics data that rare variants are on the whole more deleterious than common variants, we identify several CNV-associated gene losses likely driving non-syndromic clefting phenotypes. By prioritizing genes deleted at a rare frequency across multiple individuals with clefts yet enriched in our cohort of individuals with clefts compared to control subjects, we identify COBLL1, RIC1, and ARHGEF38 as clefting genes. CRISPR-Cas9 mutagenesis of these genes in Xenopus laevis and Danio rerio yielded craniofacial dysmorphologies, including clefts analogous to those seen in human clefting disorders.
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Affiliation(s)
- Lisa A Lansdon
- Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA; Department of Biology, University of Iowa, Iowa City, IA 52242, USA; Interdisciplinary Genetics Program, University of Iowa, Iowa City, IA 52242, USA; Department of Pathology and Laboratory Medicine, Children's Mercy Kansas City, Kansas City, MO 64108, USA; Department of Pathology, University of Missouri - Kansas City School of Medicine, Kansas City, MO 64108, USA
| | | | - Sydney Arlis
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Huan Liu
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Arman Hlas
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Alyssa Hahn
- Interdisciplinary Genetics Program, University of Iowa, Iowa City, IA 52242, USA
| | - Greg Bonde
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Abby Long
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Jennifer Standley
- Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA
| | | | - George Wehby
- College of Public Health, University of Iowa, Iowa City, IA 52242, USA
| | - Nanette R Lee
- Office of Population Studies Foundation, Inc., University of San Carlos, Cebu City, Philippines
| | | | - Karen Mohlke
- University of North Carolina, Chapel Hill, NC 27514, USA
| | | | - Benjamin W Darbro
- Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA; Interdisciplinary Genetics Program, University of Iowa, Iowa City, IA 52242, USA
| | - Robert A Cornell
- Interdisciplinary Genetics Program, University of Iowa, Iowa City, IA 52242, USA; Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Douglas W Houston
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA; Interdisciplinary Genetics Program, University of Iowa, Iowa City, IA 52242, USA
| | - Jeffrey C Murray
- Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA; Interdisciplinary Genetics Program, University of Iowa, Iowa City, IA 52242, USA
| | - J Robert Manak
- Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA; Department of Biology, University of Iowa, Iowa City, IA 52242, USA; Interdisciplinary Genetics Program, University of Iowa, Iowa City, IA 52242, USA.
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Lasser M, Bolduc J, Murphy L, O'Brien C, Lee S, Girirajan S, Lowery LA. 16p12.1 Deletion Orthologs are Expressed in Motile Neural Crest Cells and are Important for Regulating Craniofacial Development in Xenopus laevis. Front Genet 2022; 13:833083. [PMID: 35401697 PMCID: PMC8987115 DOI: 10.3389/fgene.2022.833083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 03/09/2022] [Indexed: 12/03/2022] Open
Abstract
Copy number variants (CNVs) associated with neurodevelopmental disorders are characterized by extensive phenotypic heterogeneity. In particular, one CNV was identified in a subset of children clinically diagnosed with intellectual disabilities (ID) that results in a hemizygous deletion of multiple genes at chromosome 16p12.1. In addition to ID, individuals with this deletion display a variety of symptoms including microcephaly, seizures, cardiac defects, and growth retardation. Moreover, patients also manifest severe craniofacial abnormalities, such as micrognathia, cartilage malformation of the ears and nose, and facial asymmetries; however, the function of the genes within the 16p12.1 region have not been studied in the context of vertebrate craniofacial development. The craniofacial tissues affected in patients with this deletion all derive from the same embryonic precursor, the cranial neural crest, leading to the hypothesis that one or more of the 16p12.1 genes may be involved in regulating neural crest cell (NCC)-related processes. To examine this, we characterized the developmental role of the 16p12.1-affected gene orthologs, polr3e, mosmo, uqcrc2, and cdr2, during craniofacial morphogenesis in the vertebrate model system, Xenopus laevis. While the currently-known cellular functions of these genes are diverse, we find that they share similar expression patterns along the neural tube, pharyngeal arches, and later craniofacial structures. As these genes show co-expression in the pharyngeal arches where NCCs reside, we sought to elucidate the effect of individual gene depletion on craniofacial development and NCC migration. We find that reduction of several 16p12.1 genes significantly disrupts craniofacial and cartilage formation, pharyngeal arch migration, as well as NCC specification and motility. Thus, we have determined that some of these genes play an essential role during vertebrate craniofacial patterning by regulating specific processes during NCC development, which may be an underlying mechanism contributing to the craniofacial defects associated with the 16p12.1 deletion.
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Affiliation(s)
- Micaela Lasser
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Jessica Bolduc
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Luke Murphy
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Caroline O'Brien
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Sangmook Lee
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Santhosh Girirajan
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, State College, PA, United States
| | - Laura Anne Lowery
- Alfred B. Nobel Section of Hematology and Medical Oncology, Boston University School of Medicine and Boston Medical Center, Boston, MA, United States
- *Correspondence: Laura Anne Lowery,
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6
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Dickinson AJG, Turner SD, Wahl S, Kennedy AE, Wyatt BH, Howton DA. E-liquids and vanillin flavoring disrupts retinoic acid signaling and causes craniofacial defects in Xenopus embryos. Dev Biol 2022; 481:14-29. [PMID: 34543654 PMCID: PMC8665092 DOI: 10.1016/j.ydbio.2021.09.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 09/08/2021] [Accepted: 09/11/2021] [Indexed: 01/03/2023]
Abstract
Environmental teratogens such as smoking are known risk factors for developmental disorders such as cleft palate. While smoking rates have declined, a new type of smoking, called vaping is on the rise. Vaping is the use of e-cigarettes to vaporize and inhale an e-liquid containing nicotine and food-like flavors. There is the potential that, like smoking, vaping could also pose a danger to the developing human. Rather than waiting for epidemiological and mammalian studies, we have turned to an aquatic developmental model, Xenopus laevis, to more quickly assess whether e-liquids contain teratogens that could lead to craniofacial malformations. Xenopus, like zebrafish, has the benefit of being a well-established developmental model and has also been effective in predicting whether a chemical could be a teratogen. We have determined that embryonic exposure to dessert flavored e-liquids can cause craniofacial abnormalities, including an orofacial cleft in Xenopus. To better understand the underlying mechanisms contributing to these defects, transcriptomic analysis of the facial tissues of embryos exposed to a representative dessert flavored e-liquid vapor extract was performed. Analysis of differentially expressed genes in these embryos revealed several genes associated with retinoic acid metabolism or the signaling pathway. Consistently, retinoic acid receptor inhibition phenocopied the craniofacial defects as those embryos exposed to the vapor extract of the e-liquid. Such malformations also correlated with a group of common differentially expressed genes, two of which are associated with midface birth defects in humans. Further, e-liquid exposure sensitized embryos to forming craniofacial malformations when they already had depressed retinoic acid signaling. Moreover, 13-cis-retinoic acid treatment could significantly reduce the e-liquid induced malformation in the midface. Such results suggest the possibility of an interaction between retinoic acid signaling and e-liquid exposure. One of the most popular and concentrated flavoring chemicals in dessert flavored e-liquids is vanillin. Xenopus embryos exposed to this chemical closely resembled embryos exposed to dessert-like e-liquids and a retinoic acid receptor antagonist. In summary, we determined that e-liquid chemicals, in particular vanillin, can cause craniofacial defects potentially by dysregulating retinoic acid signaling. This work warrants the evaluation of vanillin and other such flavoring additives in e-liquids on mammalian development.
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Affiliation(s)
| | - Stephen D Turner
- Department of Public Health Sciences, University of Virginia School of Medicine, Charlottesville, VA, USA; Signature Science LLC, Charlottesville, VA, USA
| | - Stacey Wahl
- Research and Education Department, Tompkins-McCaw Library for the Health Sciences, Virginia Commonwealth University, Richmond, VA, USA
| | - Allyson E Kennedy
- Directorate for Computer and Information Science and Engineering, National Science Foundation, Alexandria, VA, USA
| | - Brent H Wyatt
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, 27607, USA
| | - Deborah A Howton
- Department of Biology, Virginia Commonwealth University, Richmond, VA, USA
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7
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Abstract
The endoderm is the innermost germ layer that forms the linings of the respiratory and gastrointestinal tracts, and their associated organs, during embryonic development. Xenopus embryology experiments have provided fundamental insights into how the endoderm develops in vertebrates, including the critical role of TGFβ-signaling in endoderm induction,elucidating the gene regulatory networks controlling germ layer development and the key molecular mechanisms regulating endoderm patterning and morphogenesis. With new genetic, genomic, and imaging approaches, Xenopus is now routinely used to model human disease, discover mechanisms underlying endoderm organogenesis, and inform differentiation protocols for pluripotent stem cell differentiation and regenerative medicine applications. In this chapter, we review historical and current discoveries of endoderm development in Xenopus, then provide examples of modeling human disease and congenital defects of endoderm-derived organs using Xenopus.
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Affiliation(s)
- Nicole A Edwards
- Division of Developmental Biology, Center for Stem Cell and Organoid Medicine, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.
| | - Aaron M Zorn
- Division of Developmental Biology, Center for Stem Cell and Organoid Medicine, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States.
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8
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Wyatt BH, Raymond TO, Lansdon LA, Darbro BW, Murray JC, Manak JR, Dickinson AJG. Using an aquatic model, Xenopus laevis, to uncover the role of chromodomain 1 in craniofacial disorders. Genesis 2021; 59:e23394. [PMID: 32918369 PMCID: PMC10701884 DOI: 10.1002/dvg.23394] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/04/2020] [Accepted: 08/08/2020] [Indexed: 12/14/2022]
Abstract
The chromodomain family member chromodomain 1 (CHD1) has been shown to have numerous critical molecular functions including transcriptional regulation, splicing, and DNA repair. Complete loss of function of this gene is not compatible with life. On the other hand, missense and copy number variants of CHD1 can result in intellectual disabilities and craniofacial malformations in human patients including cleft palate and Pilarowski-Bjornsson Syndrome. We have used the aquatic developmental model organism Xenopus laevis, to determine a specific role for Chd1 in such cranioafcial disorders. Protein and gene knockdown techniques in Xenopus, including antisense oligos and mosaic Crispr/Cas9-mediated mutagenesis, recapitulated the craniofacial defects observed in humans. Further analysis indicated that embryos deficient in Chd1 had defects in cranial neural crest development and jaw cartilage morphology. Additionally, flow cytometry and immunohistochemistry revealed that decreased Chd1 resulted in increased in apoptosis in the developing head. Together, these experiments demonstrate that Chd1 is critical for fundamental processes and cell survival in craniofacial development. We also presented evidence that Chd1 is regulated by retinoic acid signaling during craniofacial development. Expression levels of chd1 mRNA, specifically in the head, were increased by RAR agonist exposure and decreased upon antagonist treatment. Subphenotypic levels of an RAR antagonist and Chd1 morpholinos synergized to result in orofacial defects. Further, RAR DNA binding sequences (RAREs) were detected in chd1 regulatory regions by bioinformatic analysis. In summary, by combining human genetics and experiments in an aquatic model we now have a better understanding of the role of CHD1 in craniofacial disorders.
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Affiliation(s)
- Brent H. Wyatt
- Department of Biology, Virginia Commonwealth University, Richmond, Virginia
| | - Thomas O. Raymond
- Department of Biology, Virginia Commonwealth University, Richmond, Virginia
| | - Lisa A. Lansdon
- Department of Biology, University of Iowa, Iowa City, Iowa
- Department of Pathology and Laboratory Medicine, Children’s Mercy Hospital, Kansas City, Missouri
| | | | | | - John Robert Manak
- Department of Biology, University of Iowa, Iowa City, Iowa
- Department of Pediatrics, University of Iowa, Iowa City, Iowa
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9
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Walentek P. Xenopus epidermal and endodermal epithelia as models for mucociliary epithelial evolution, disease, and metaplasia. Genesis 2021; 59:e23406. [PMID: 33400364 DOI: 10.1002/dvg.23406] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 11/08/2022]
Abstract
The Xenopus embryonic epidermis is a powerful model to study mucociliary biology, development, and disease. Particularly, the Xenopus system is being used to elucidate signaling pathways, transcription factor functions, and morphogenetic mechanisms regulating cell fate specification, differentiation and cell function. Thereby, Xenopus research has provided significant insights into potential underlying molecular mechanisms for ciliopathies and chronic airway diseases. Recent studies have also established the embryonic epidermis as a model for mucociliary epithelial remodeling, multiciliated cell trans-differentiation, cilia loss, and mucus secretion. Additionally, the tadpole foregut epithelium is lined by a mucociliary epithelium, which shows remarkable features resembling mammalian airway epithelia, including its endodermal origin and a variable cell type composition along the proximal-distal axis. This review aims to summarize the advantages of the Xenopus epidermis for mucociliary epithelial biology and disease modeling. Furthermore, the potential of the foregut epithelium as novel mucociliary model system is being highlighted. Additional perspectives are presented on how to expand the range of diseases that can be modeled in the frog system, including proton pump inhibitor-associated pneumonia as well as metaplasia in epithelial cells of the airway and the gastroesophageal region.
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Affiliation(s)
- Peter Walentek
- Renal Division, Department of Medicine, University Hospital Freiburg, Freiburg University Faculty of Medicine, Freiburg, Germany.,CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
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10
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Lasser M, Pratt B, Monahan C, Kim SW, Lowery LA. The Many Faces of Xenopus: Xenopus laevis as a Model System to Study Wolf-Hirschhorn Syndrome. Front Physiol 2019; 10:817. [PMID: 31297068 PMCID: PMC6607408 DOI: 10.3389/fphys.2019.00817] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 06/11/2019] [Indexed: 01/09/2023] Open
Abstract
Wolf–Hirschhorn syndrome (WHS) is a rare developmental disorder characterized by intellectual disability and various physical malformations including craniofacial, skeletal, and cardiac defects. These phenotypes, as they involve structures that are derived from the cranial neural crest, suggest that WHS may be associated with abnormalities in neural crest cell (NCC) migration. This syndrome is linked with assorted mutations on the short arm of chromosome 4, most notably the microdeletion of a critical genomic region containing several candidate genes. However, the function of these genes during embryonic development, as well as the cellular and molecular mechanisms underlying the disorder, are still unknown. The model organism Xenopus laevis offers a number of advantages for studying WHS. With the Xenopus genome sequenced, genetic manipulation strategies can be readily designed in order to alter the dosage of the WHS candidate genes. Moreover, a variety of assays are available for use in Xenopus to examine how manipulation of WHS genes leads to changes in the development of tissue and organ systems affected in WHS. In this review article, we highlight the benefits of using X. laevis as a model system for studying human genetic disorders of development, with a focus on WHS.
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Affiliation(s)
- Micaela Lasser
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Benjamin Pratt
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Connor Monahan
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Seung Woo Kim
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Laura Anne Lowery
- Department of Biology, Boston College, Chestnut Hill, MA, United States
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11
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Mills A, Bearce E, Cella R, Kim SW, Selig M, Lee S, Lowery LA. Wolf-Hirschhorn Syndrome-Associated Genes Are Enriched in Motile Neural Crest Cells and Affect Craniofacial Development in Xenopus laevis. Front Physiol 2019; 10:431. [PMID: 31031646 PMCID: PMC6474402 DOI: 10.3389/fphys.2019.00431] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 03/28/2019] [Indexed: 01/08/2023] Open
Abstract
Wolf-Hirschhorn Syndrome (WHS) is a human developmental disorder arising from a hemizygous perturbation, typically a microdeletion, on the short arm of chromosome four. In addition to pronounced intellectual disability, seizures, and delayed growth, WHS presents with a characteristic facial dysmorphism and varying prevalence of microcephaly, micrognathia, cartilage malformation in the ear and nose, and facial asymmetries. These affected craniofacial tissues all derive from a shared embryonic precursor, the cranial neural crest (CNC), inviting the hypothesis that one or more WHS-affected genes may be critical regulators of neural crest development or migration. To explore this, we characterized expression of multiple genes within or immediately proximal to defined WHS critical regions, across the span of craniofacial development in the vertebrate model system Xenopus laevis. This subset of genes, whsc1, whsc2, letm1, and tacc3, are diverse in their currently-elucidated cellular functions; yet we find that their expression demonstrates shared tissue-specific enrichment within the anterior neural tube, migratory neural crest, and later craniofacial structures. We examine the ramifications of this by characterizing craniofacial development and neural crest migration following individual gene depletion. We observe that several WHS-associated genes significantly impact facial patterning, cartilage formation, neural crest motility in vivo and in vitro, and can separately contribute to forebrain scaling. Thus, we have determined that numerous genes within and surrounding the defined WHS critical regions potently impact craniofacial patterning, suggesting their role in WHS presentation may stem from essential functions during neural crest-derived tissue formation.
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Affiliation(s)
- Alexandra Mills
- Biology Department, Boston College, Chestnut Hill, MA, United States
| | - Elizabeth Bearce
- Biology Department, Boston College, Chestnut Hill, MA, United States
| | - Rachael Cella
- Biology Department, Boston College, Chestnut Hill, MA, United States
| | - Seung Woo Kim
- Biology Department, Boston College, Chestnut Hill, MA, United States
| | - Megan Selig
- Biology Department, Boston College, Chestnut Hill, MA, United States
| | - Sangmook Lee
- Biology Department, Boston College, Chestnut Hill, MA, United States
| | - Laura Anne Lowery
- Biology Department, Boston College, Chestnut Hill, MA, United States
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12
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Nenni MJ, Fisher ME, James-Zorn C, Pells TJ, Ponferrada V, Chu S, Fortriede JD, Burns KA, Wang Y, Lotay VS, Wang DZ, Segerdell E, Chaturvedi P, Karimi K, Vize PD, Zorn AM. Xenbase: Facilitating the Use of Xenopus to Model Human Disease. Front Physiol 2019; 10:154. [PMID: 30863320 PMCID: PMC6399412 DOI: 10.3389/fphys.2019.00154] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 02/08/2019] [Indexed: 01/02/2023] Open
Abstract
At a fundamental level most genes, signaling pathways, biological functions and organ systems are highly conserved between man and all vertebrate species. Leveraging this conservation, researchers are increasingly using the experimental advantages of the amphibian Xenopus to model human disease. The online Xenopus resource, Xenbase, enables human disease modeling by curating the Xenopus literature published in PubMed and integrating these Xenopus data with orthologous human genes, anatomy, and more recently with links to the Online Mendelian Inheritance in Man resource (OMIM) and the Human Disease Ontology (DO). Here we review how Xenbase supports disease modeling and report on a meta-analysis of the published Xenopus research providing an overview of the different types of diseases being modeled in Xenopus and the variety of experimental approaches being used. Text mining of over 50,000 Xenopus research articles imported into Xenbase from PubMed identified approximately 1,000 putative disease- modeling articles. These articles were manually assessed and annotated with disease ontologies, which were then used to classify papers based on disease type. We found that Xenopus is being used to study a diverse array of disease with three main experimental approaches: cell-free egg extracts to study fundamental aspects of cellular and molecular biology, oocytes to study ion transport and channel physiology and embryo experiments focused on congenital diseases. We integrated these data into Xenbase Disease Pages to allow easy navigation to disease information on external databases. Results of this analysis will equip Xenopus researchers with a suite of experimental approaches available to model or dissect a pathological process. Ideally clinicians and basic researchers will use this information to foster collaborations necessary to interrogate the development and treatment of human diseases.
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Affiliation(s)
- Mardi J Nenni
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Malcolm E Fisher
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Christina James-Zorn
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Troy J Pells
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Virgilio Ponferrada
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Stanley Chu
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Joshua D Fortriede
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Kevin A Burns
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Ying Wang
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Vaneet S Lotay
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Dong Zhou Wang
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Erik Segerdell
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, United States
| | - Praneet Chaturvedi
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Kamran Karimi
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Peter D Vize
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Aaron M Zorn
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
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13
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Reynolds K, Kumari P, Sepulveda Rincon L, Gu R, Ji Y, Kumar S, Zhou CJ. Wnt signaling in orofacial clefts: crosstalk, pathogenesis and models. Dis Model Mech 2019; 12:12/2/dmm037051. [PMID: 30760477 PMCID: PMC6398499 DOI: 10.1242/dmm.037051] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Diverse signaling cues and attendant proteins work together during organogenesis, including craniofacial development. Lip and palate formation starts as early as the fourth week of gestation in humans or embryonic day 9.5 in mice. Disruptions in these early events may cause serious consequences, such as orofacial clefts, mainly cleft lip and/or cleft palate. Morphogenetic Wnt signaling, along with other signaling pathways and transcription regulation mechanisms, plays crucial roles during embryonic development, yet the signaling mechanisms and interactions in lip and palate formation and fusion remain poorly understood. Various Wnt signaling and related genes have been associated with orofacial clefts. This Review discusses the role of Wnt signaling and its crosstalk with cell adhesion molecules, transcription factors, epigenetic regulators and other morphogenetic signaling pathways, including the Bmp, Fgf, Tgfβ, Shh and retinoic acid pathways, in orofacial clefts in humans and animal models, which may provide a better understanding of these disorders and could be applied towards prevention and treatments.
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Affiliation(s)
- Kurt Reynolds
- Department of Biochemistry and Molecular Medicine, University of California at Davis, School of Medicine, Sacramento, CA 95817, USA.,Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis, School of Medicine, Sacramento, CA 95817, USA.,Biochemistry, Molecular, Cellular, and Developmental Biology (BMCDB) Graduate Group, University of California, Davis, CA 95616, USA
| | - Priyanka Kumari
- Department of Biochemistry and Molecular Medicine, University of California at Davis, School of Medicine, Sacramento, CA 95817, USA.,Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis, School of Medicine, Sacramento, CA 95817, USA
| | - Lessly Sepulveda Rincon
- Department of Biochemistry and Molecular Medicine, University of California at Davis, School of Medicine, Sacramento, CA 95817, USA.,Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis, School of Medicine, Sacramento, CA 95817, USA
| | - Ran Gu
- Department of Biochemistry and Molecular Medicine, University of California at Davis, School of Medicine, Sacramento, CA 95817, USA.,Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis, School of Medicine, Sacramento, CA 95817, USA
| | - Yu Ji
- Department of Biochemistry and Molecular Medicine, University of California at Davis, School of Medicine, Sacramento, CA 95817, USA.,Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis, School of Medicine, Sacramento, CA 95817, USA.,Biochemistry, Molecular, Cellular, and Developmental Biology (BMCDB) Graduate Group, University of California, Davis, CA 95616, USA
| | - Santosh Kumar
- Department of Biochemistry and Molecular Medicine, University of California at Davis, School of Medicine, Sacramento, CA 95817, USA.,Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis, School of Medicine, Sacramento, CA 95817, USA
| | - Chengji J Zhou
- Department of Biochemistry and Molecular Medicine, University of California at Davis, School of Medicine, Sacramento, CA 95817, USA .,Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis, School of Medicine, Sacramento, CA 95817, USA.,Biochemistry, Molecular, Cellular, and Developmental Biology (BMCDB) Graduate Group, University of California, Davis, CA 95616, USA
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14
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Transcriptome analysis of Xenopus orofacial tissues deficient in retinoic acid receptor function. BMC Genomics 2018; 19:795. [PMID: 30390632 PMCID: PMC6215681 DOI: 10.1186/s12864-018-5186-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 10/18/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Development of the face and mouth is orchestrated by a large number of transcription factors, signaling pathways and epigenetic regulators. While we know many of these regulators, our understanding of how they interact with each other and implement changes in gene expression during orofacial development is still in its infancy. Therefore, this study focuses on uncovering potential cooperation between transcriptional regulators and one important signaling pathway, retinoic acid, during development of the midface. RESULTS Transcriptome analyses was performed on facial tissues deficient for retinoic acid receptor function at two time points in development; early (35 hpf) just after the neural crest migrates and facial tissues are specified and later (60 hpf) when the mouth has formed and facial structures begin to differentiate. Functional and network analyses revealed that retinoic acid signaling could cooperate with novel epigenetic factors and calcium-NFAT signaling during early orofacial development. At the later stage, retinoic acid may work with WNT and BMP and regulate homeobox containing transcription factors. Finally, there is an overlap in genes dysregulated in Xenopus embryos with median clefts with human genes associated with similar orofacial defects. CONCLUSIONS This study uncovers novel signaling pathways required for orofacial development as well as pathways that could interact with retinoic acid signaling during the formation of the face. We show that frog faces are an important tool for studying orofacial development and birth defects.
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15
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Lansdon LA, Darbro BW, Petrin AL, Hulstrand AM, Standley JM, Brouillette RB, Long A, Mansilla MA, Cornell RA, Murray JC, Houston DW, Manak JR. Identification of Isthmin 1 as a Novel Clefting and Craniofacial Patterning Gene in Humans. Genetics 2018; 208:283-296. [PMID: 29162626 PMCID: PMC5753863 DOI: 10.1534/genetics.117.300535] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 11/20/2017] [Indexed: 12/26/2022] Open
Abstract
Orofacial clefts are one of the most common birth defects, affecting 1-2 per 1000 births, and have a complex etiology. High-resolution array-based comparative genomic hybridization has increased the ability to detect copy number variants (CNVs) that can be causative for complex diseases such as cleft lip and/or palate. Utilizing this technique on 97 nonsyndromic cleft lip and palate cases and 43 cases with cleft palate only, we identified a heterozygous deletion of Isthmin 1 in one affected case, as well as a deletion in a second case that removes putative 3' regulatory information. Isthmin 1 is a strong candidate for clefting, as it is expressed in orofacial structures derived from the first branchial arch and is also in the same "synexpression group" as fibroblast growth factor 8 and sprouty RTK signaling antagonist 1a and 2, all of which have been associated with clefting. CNVs affecting Isthmin 1 are exceedingly rare in control populations, and Isthmin 1 scores as a likely haploinsufficiency locus. Confirming its role in craniofacial development, knockdown or clustered randomly interspaced short palindromic repeats/Cas9-generated mutation of isthmin 1 in Xenopus laevis resulted in mild to severe craniofacial dysmorphologies, with several individuals presenting with median clefts. Moreover, knockdown of isthmin 1 produced decreased expression of LIM homeobox 8, itself a gene associated with clefting, in regions of the face that pattern the maxilla. Our study demonstrates a successful pipeline from CNV identification of a candidate gene to functional validation in a vertebrate model system, and reveals Isthmin 1 as both a new human clefting locus as well as a key craniofacial patterning gene.
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Affiliation(s)
- Lisa A Lansdon
- Department of Pediatrics
- Department of Biology
- Interdisciplinary Graduate Program in Genetics
| | - Benjamin W Darbro
- Department of Pediatrics
- Interdisciplinary Graduate Program in Genetics
| | - Aline L Petrin
- Department of Pediatrics
- College of Dentistry, University of Iowa, Iowa 52242 and
| | | | | | | | | | | | - Robert A Cornell
- Interdisciplinary Graduate Program in Genetics
- Department of Anatomy and Cell Biology, and
| | - Jeffrey C Murray
- Department of Pediatrics
- Department of Biology
- Department of Anatomy and Cell Biology, and
- Interdisciplinary Graduate Program in Genetics
- College of Dentistry, University of Iowa, Iowa 52242 and
| | | | - J Robert Manak
- Department of Pediatrics,
- Department of Biology
- Interdisciplinary Graduate Program in Genetics
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16
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Kennedy AE, Kandalam S, Olivares-Navarrete R, Dickinson AJG. E-cigarette aerosol exposure can cause craniofacial defects in Xenopus laevis embryos and mammalian neural crest cells. PLoS One 2017; 12:e0185729. [PMID: 28957438 PMCID: PMC5619826 DOI: 10.1371/journal.pone.0185729] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 09/18/2017] [Indexed: 12/28/2022] Open
Abstract
Since electronic cigarette (ECIG) introduction to American markets in 2007, vaping has surged in popularity. Many, including women of reproductive age, also believe that ECIG use is safer than traditional tobacco cigarettes and is not hazardous when pregnant. However, there are few studies investigating the effects of ECIG exposure on the developing embryo and nothing is known about potential effects on craniofacial development. Therefore, we have tested the effects of several aerosolized e-cigarette liquids (e-cigAM) in an in vivo craniofacial model, Xenopus laevis, as well as a mammalian neural crest cell line. Results demonstrate that e-cigAM exposure during embryonic development induces a variety of defects, including median facial clefts and midface hypoplasia in two of e-cigAMs tested e-cigAMs. Detailed quantitative analyses of the facial morphology revealed that nicotine is not the main factor in inducing craniofacial defects, but can exacerbate the effects of the other e-liquid components. Additionally, while two different e-cigAMs can have very similar consequences on facial appearances, there are subtle differences that could be due to the differences in e-cigAM components. Further assessment of embryos exposed to these particular e-cigAMs revealed cranial cartilage and muscle defects and a reduction in the blood supply to the face. Finally, the expression of markers for vascular and cartilage differentiation was reduced in a mammalian neural crest cell line corroborating the in vivo effects. Our work is the first to show that ECIG use could pose a potential hazard to the developing embryo and cause craniofacial birth defects. This emphasizes the need for more testing and regulation of this new popular product.
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Affiliation(s)
- Allyson E. Kennedy
- Virginia Commonwealth University, Department of Biology, Richmond, VA, United States of America
| | - Suraj Kandalam
- Virginia Commonwealth University, Department of Biomedical Engineering, Richmond, VA, United States of America
| | - Rene Olivares-Navarrete
- Virginia Commonwealth University, Department of Biomedical Engineering, Richmond, VA, United States of America
| | - Amanda J. G. Dickinson
- Virginia Commonwealth University, Department of Biology, Richmond, VA, United States of America
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17
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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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18
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Sater AK, Moody SA. Using Xenopus to understand human disease and developmental disorders. Genesis 2017; 55. [PMID: 28095616 DOI: 10.1002/dvg.22997] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 11/14/2016] [Indexed: 02/03/2023]
Abstract
Model animals are crucial to biomedical research. Among the commonly used model animals, the amphibian, Xenopus, has had tremendous impact because of its unique experimental advantages, cost effectiveness, and close evolutionary relationship with mammals as a tetrapod. Over the past 50 years, the use of Xenopus has made possible many fundamental contributions to biomedicine, and it is a cornerstone of research in cell biology, developmental biology, evolutionary biology, immunology, molecular biology, neurobiology, and physiology. The prospects for Xenopus as an experimental system are excellent: Xenopus is uniquely well-suited for many contemporary approaches used to study fundamental biological and disease mechanisms. Moreover, recent advances in high throughput DNA sequencing, genome editing, proteomics, and pharmacological screening are easily applicable in Xenopus, enabling rapid functional genomics and human disease modeling at a systems level.
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Affiliation(s)
- Amy K Sater
- Department of Biology and Biochemistry, University of Houston, Houston, Texas
| | - Sally A Moody
- Department of Anatomy and Regenerative Biology, George Washington University School of Medicine and Health Sciences, Washington, District of Columbia
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19
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Abstract
PURPOSE OF REVIEW Craniofacial disorders are among the most common human birth defects and present an enormous health care and social burden. The development of animal models has been instrumental to investigate fundamental questions in craniofacial biology and this knowledge is critical to understand the etiology and pathogenesis of these disorders. RECENT FINDINGS The vast majority of craniofacial disorders arise from abnormal development of the neural crest, a multipotent and migratory cell population. Therefore, defining the pathogenesis of these conditions starts with a deep understanding of the mechanisms that preside over neural crest formation and its role in craniofacial development. SUMMARY This review discusses several studies using Xenopus embryos to model human craniofacial conditions, and emphasizes the strength of this system to inform important biological processes as they relate to human craniofacial development and disease.
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20
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Houssin NS, Bharathan NK, Turner SD, Dickinson AJG. Role of JNK during buccopharyngeal membrane perforation, the last step of embryonic mouth formation. Dev Dyn 2016; 246:100-115. [PMID: 28032936 DOI: 10.1002/dvdy.24470] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 09/23/2016] [Accepted: 10/31/2016] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The buccopharyngeal membrane is a thin layer of cells covering the embryonic mouth. The perforation of this structure creates an opening connecting the external and the digestive tube which is essential for oral cavity formation. In humans, persistence of the buccopharyngeal membrane can lead to orofacial defects such as choanal atresia, oral synechiaes, and cleft palate. Little is known about the causes of a persistent buccopharyngeal membrane and, importantly, how this structure ruptures. RESULTS We have determined, using antisense and pharmacological approaches, that Xenopus embryos deficient c-Jun N-terminal kinase (JNK) signaling have a persistent buccopharyngeal membrane. JNK deficient embryos have decreased cell division and increased cellular stress and apoptosis. However, altering these processes independently of JNK did not affect buccopharyngeal membrane perforation. JNK deficient embryos also have increased intercellular adhesion and defects in e-cadherin localization. Conversely, embryos with overactive JNK have epidermal fragility, increased E-cadherin internalization, and increased membrane localized clathrin. In the buccopharyngeal membrane, clathrin is colocalized with active JNK. Furthermore, inhibition of endocytosis results in a persistent buccopharyngeal membrane, mimicking the JNK deficient phenotype. CONCLUSIONS The results of this study suggest that JNK has a role in the disassembly adherens junctions by means of endocytosis that is required during buccopharyngeal membrane perforation. Developmental Dynamics 246:100-115, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Nathalie S Houssin
- Department of Biology, Virginia Commonwealth University, Richmond, Virginia
| | | | - Stephen D Turner
- Department of Public Health Sciences, University of Virginia School of Medicine, Charlottesville, Virginia
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