1
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Jia X, Lin W, Wang W. Regulation of chromatin organization during animal regeneration. CELL REGENERATION (LONDON, ENGLAND) 2023; 12:19. [PMID: 37259007 DOI: 10.1186/s13619-023-00162-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 03/21/2023] [Indexed: 06/02/2023]
Abstract
Activation of regeneration upon tissue damages requires the activation of many developmental genes responsible for cell proliferation, migration, differentiation, and tissue patterning. Ample evidence revealed that the regulation of chromatin organization functions as a crucial mechanism for establishing and maintaining cellular identity through precise control of gene transcription. The alteration of chromatin organization can lead to changes in chromatin accessibility and/or enhancer-promoter interactions. Like embryogenesis, each stage of tissue regeneration is accompanied by dynamic changes of chromatin organization in regeneration-responsive cells. In the past decade, many studies have been conducted to investigate the contribution of chromatin organization during regeneration in various tissues, organs, and organisms. A collection of chromatin regulators were demonstrated to play critical roles in regeneration. In this review, we will summarize the progress in the understanding of chromatin organization during regeneration in different research organisms and discuss potential common mechanisms responsible for the activation of regeneration response program.
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Affiliation(s)
- Xiaohui Jia
- National Institute of Biological Sciences, Beijing, 102206, China
- China Agricultural University, Beijing, 100083, China
| | - Weifeng Lin
- National Institute of Biological Sciences, Beijing, 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, 100084, China
| | - Wei Wang
- National Institute of Biological Sciences, Beijing, 102206, China.
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, 100084, China.
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2
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Adil MT, Henry JJ. Understanding cornea epithelial stem cells and stem cell deficiency: Lessons learned using vertebrate model systems. Genesis 2021; 59:e23411. [PMID: 33576188 DOI: 10.1002/dvg.23411] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 01/08/2021] [Accepted: 01/09/2021] [Indexed: 12/13/2022]
Abstract
Animal models have contributed greatly to our understanding of human diseases. Here, we focus on cornea epithelial stem cell (CESC) deficiency (commonly called limbal stem cell deficiency, LSCD). Corneal development, homeostasis and wound healing are supported by specific stem cells, that include the CESCs. Damage to or loss of these cells results in blindness and other debilitating ocular conditions. Here we describe the contributions from several vertebrate models toward understanding CESCs and LSCD treatments. These include both mammalian models, as well as two aquatic models, Zebrafish and the amphibian, Xenopus. Pioneering developments have been made using stem cell transplants to restore normal vision in patients with LSCD, but questions still remain about the basic biology of CESCs, including their precise cell lineages and behavior in the cornea. We describe various cell lineage tracing studies to follow their patterns of division, and the fates of their progeny during development, homeostasis, and wound healing. In addition, we present some preliminary results using the Xenopus model system. Ultimately, a more thorough understanding of these cornea cells will advance our knowledge of stem cell biology and lead to better cornea disease therapeutics.
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Affiliation(s)
- Mohd Tayyab Adil
- Department of Cell & Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Jonathan J Henry
- Department of Cell & Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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3
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Viet J, Reboutier D, Hardy S, Lachke SA, Paillard L, Gautier-Courteille C. Modeling ocular lens disease in Xenopus. Dev Dyn 2020; 249:610-621. [PMID: 31872467 PMCID: PMC7759097 DOI: 10.1002/dvdy.147] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 12/18/2019] [Accepted: 12/20/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Ocular lens clouding is termed as cataract, which depending on the onset, is classified as congenital or age-related. Developing new cataract treatments requires new models. Thus far, Xenopus embryos have not been evaluated as a system for studying cataract. RESULTS We characterized the developmental process of lens formation in Xenopus laevis tailbuds and tadpoles, and we disrupted the orthologues of three mammalian cataract-linked genes in F0 by CRISPR/Cas9. We assessed the consequences of gene inactivation by combining external examination with histochemical analyses and functional vision assays. Inactivating the key metazoan eye development transcription factor gene pax6 produces a strong eye phenotype including an absence of eye tissue. Inactivating the genes for gap-junction protein and a nuclease, gja8 and dnase2b, produces lens defects that share several features of human cataracts, including impaired vision acuity, nuclei retention in lens fiber cells, and actin fibers disorganization. We tested the potential improvement of the visual acuity of gja8 crispant tadpoles upon treatment with the molecular chaperone 4-phenylbutyrate. CONCLUSION Xenopus is a valuable model organism to understand the molecular pathology of congenital eye defects, including cataracts, and to screen molecules with a potential to prevent or reverse cataracts.
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Affiliation(s)
- Justine Viet
- Univ Rennes, CNRS, IGDR-UMR 6290, F-35000 Rennes, France
| | | | - Serge Hardy
- Univ Rennes, CNRS, IGDR-UMR 6290, F-35000 Rennes, France
| | - Salil A. Lachke
- Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | - Luc Paillard
- Univ Rennes, CNRS, IGDR-UMR 6290, F-35000 Rennes, France
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Kha CX, Guerin DJ, Tseng KAS. Studying In Vivo Retinal Progenitor Cell Proliferation in Xenopus laevis. Methods Mol Biol 2019; 2092:19-33. [PMID: 31786778 DOI: 10.1007/978-1-0716-0175-4_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
The efficient generation and maintenance of retinal progenitor cells (RPCs) are key goals needed for developing strategies for productive eye repair. Although vertebrate eye development and retinogenesis are well characterized, the mechanisms that can initiate RPC proliferation following injury-induced regrowth and repair remain unknown. This is partly because endogenous RPC proliferation typically occurs during embryogenesis while studies of retinal regeneration have largely utilized adult (or mature) models. We found that embryos of the African clawed frog, Xenopus laevis, successfully regrew functional eyes after ablation. The initiation of regrowth induced a robust RPC proliferative response with a concomitant delay of the endogenous RPC differentiation program. During eye regrowth, overall embryonic development proceeded normally. Here, we provide a protocol to study regrowth-dependent RPC proliferation in vivo. This system represents a robust and low-cost strategy to rapidly define fundamental mechanisms that regulate regrowth-initiated RPC proliferation, which will facilitate progress in identifying promising strategies for productive eye repair.
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Affiliation(s)
- Cindy X Kha
- School of Life Sciences and Nevada Institute of Personalized Medicine, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Dylan J Guerin
- School of Life Sciences and Nevada Institute of Personalized Medicine, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Kelly Ai-Sun Tseng
- School of Life Sciences and Nevada Institute of Personalized Medicine, University of Nevada, Las Vegas, Las Vegas, NV, USA.
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5
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Kha CX, Guerin DJ, Tseng KAS. Using the Xenopus Developmental Eye Regrowth System to Distinguish the Role of Developmental Versus Regenerative Mechanisms. Front Physiol 2019; 10:502. [PMID: 31139088 PMCID: PMC6518849 DOI: 10.3389/fphys.2019.00502] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 04/08/2019] [Indexed: 12/13/2022] Open
Abstract
A longstanding challenge in regeneration biology is to understand the role of developmental mechanisms in restoring lost or damaged tissues and organs. As these body structures were built during embryogenesis, it is not surprising that a number of developmental mechanisms are also active during regeneration. However, it remains unclear whether developmental mechanisms act similarly or differently during regeneration as compared to development. Since regeneration is studied in the context of mature, differentiated tissues, it is difficult to evaluate comparative studies with developmental processes due to the latter's highly proliferative environment. We have taken a more direct approach to study regeneration in a developmental context (regrowth). Xenopus laevis, the African clawed frog, is a well-established model for both embryology and regeneration studies, especially for the eye. Xenopus eye development is well-defined. Xenopus is also an established model for retinal and lens regeneration studies. Previously, we demonstrated that Xenopus tailbud embryo can successfully regrow a functional eye that is morphologically indistinguishable from an age-matched control eye. In this study, we assessed the temporal regulation of retinal differentiation and patterning restoration during eye regrowth. Our findings showed that during regrowth, cellular patterning and retinal layer formation was delayed by approximately 1 day but was restored by 3 days when compared to eye development. An assessment of the differentiation of ganglion cells, photoreceptor cells, and Müller glia indicated that the retinal birth order generated during regrowth was consistent with that observed for eye development. Thus, retina differentiation and patterning during regrowth is similar to endogenous eye development. We used this eye regrowth model to assess the role of known mechanisms in development versus regrowth. Loss-of-function studies showed that Pax6 was required for both eye development and regrowth whereas apoptosis was only required for regrowth. Together, these results revealed that the mechanisms required for both development and regrowth can be distinguished from regrowth-specific ones. Our study highlights this developmental model of eye regrowth as a robust platform to systematically and efficiently define the molecular mechanisms that are required for regeneration versus development.
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Affiliation(s)
- Cindy X Kha
- School of Life Sciences and Nevada Institute of Personalized Medicine, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Dylan J Guerin
- School of Life Sciences and Nevada Institute of Personalized Medicine, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Kelly Ai-Sun Tseng
- School of Life Sciences and Nevada Institute of Personalized Medicine, University of Nevada, Las Vegas, Las Vegas, NV, United States
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6
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Vergara MN, Tsissios G, Del Rio-Tsonis K. Lens regeneration: a historical perspective. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2019; 62:351-361. [PMID: 29877565 PMCID: PMC6378223 DOI: 10.1387/ijdb.180084nv] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The idea of regenerating injured body parts has captivated human imagination for centuries, and the topic still remains an area of extensive scientific research. This review focuses on the process of lens regeneration: its history, our current knowledge, and the questions that remain unanswered. By highlighting some of the milestones that have shaped our understanding of this phenomenon and the contributions of scientists who have dedicated their lives to investigating these questions, we explore how regeneration enquiry evolved into the science it is today, and how technological advances accelerated our understanding of these remarkable processes.
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Affiliation(s)
- M Natalia Vergara
- Department of Ophthalmology, University of Colorado Denver School of Medicine, Aurora, CO, USA
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7
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Physiological effects of KDM5C on neural crest migration and eye formation during vertebrate development. Epigenetics Chromatin 2018; 11:72. [PMID: 30522514 PMCID: PMC6282277 DOI: 10.1186/s13072-018-0241-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 11/22/2018] [Indexed: 02/07/2023] Open
Abstract
Background Lysine-specific histone demethylase 5C (KDM5C) belongs to the jumonji family of demethylases and is specific for the di- and tri-demethylation of lysine 4 residues on histone 3 (H3K4 me2/3). KDM5C is expressed in the brain and skeletal muscles of humans and is associated with various biologically significant processes. KDM5C is known to be associated with X-linked mental retardation and is also involved in the development of cancer. However, the developmental significance of KDM5C has not been explored yet. In the present study, we investigated the physiological roles of KDM5C during Xenopus laevis embryonic development. Results Loss-of-function analysis using kdm5c antisense morpholino oligonucleotides indicated that kdm5c knockdown led to small-sized heads, reduced cartilage size, and malformed eyes (i.e., small-sized and deformed eyes). Molecular analyses of KDM5C functional roles using whole-mount in situ hybridization, β-galactosidase staining, and reverse transcription-polymerase chain reaction revealed that loss of kdm5c resulted in reduced expression levels of neural crest specifiers and genes involved in eye development. Furthermore, transcriptome analysis indicated the significance of KDM5C in morphogenesis and organogenesis. Conclusion Our findings indicated that KDM5C is associated with embryonic development and provided additional information regarding the complex and dynamic gene network that regulates neural crest formation and eye development. This study emphasizes the functional significance of KDM5C in Xenopus embryogenesis; however, further analysis is needed to explore the interactions of KDM5C with specific developmental genes. Electronic supplementary material The online version of this article (10.1186/s13072-018-0241-x) contains supplementary material, which is available to authorized users.
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8
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Abstract
In this review, we compare and contrast the three different forms of vertebrate lens regeneration: Wolffian lens regeneration, cornea-lens regeneration, and lens regeneration from lens epithelial cells. An examination of the diverse cellular origins of these lenses, their unique phylogenetic distribution, and the underlying molecular mechanisms, suggests that these different forms of lens regeneration evolved independently and utilize neither conserved nor convergent mechanisms to regulate these processes.
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Affiliation(s)
- Jonathan J Henry
- Department of Cell and Developmental Biology, University of Illinois, Urbana, IL
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9
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Marjan P, Bragg LM, MacLatchy DL, Servos MR, Martyniuk CJ. How Does Reference Site Selection Influence Interpretation of Omics Data?: Evaluating Liver Transcriptome Responses in Male Rainbow Darter (Etheostoma caeruleum) across an Urban Environment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:6470-6479. [PMID: 28489360 DOI: 10.1021/acs.est.7b00894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Studies quantifying the influence of reference site selection on transcriptomic profiles in aquatic organisms exposed to complex mixtures are lacking in the literature, despite the significant implications of such research for the interpretation of omics data sets. We measured hepatic transcriptomic responses in fish across an urban environment in the central Grand River watershed (Ontario, Canada). Adult male rainbow darter (RBD) (Etheostoma caeruleum) were collected from nine sites at varying distances from two major municipal wastewater treatment plants (MWWTPs) (Waterloo, Kitchener), including three upstream reference sites. The transcriptomic response in RBD was independently compared with that of fish from each of the three reference sites. Data collected in fish downstream of the Waterloo MWWTP (poorest effluent quality) suggested that ∼15.5% of the transcriptome response was influenced by reference site selection. In contrast, at sites where the impact of MWWTPs was less-pronounced and fish showed less of a transcriptome response, reference site selection had a greater influence (i.e., ∼56.9% of transcripts were different depending on the site used). This study highlights the importance of conducting transcriptomics studies that leverage more than one reference site, and it broadens our understanding of the molecular responses in fish in dynamic natural environments.
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Affiliation(s)
- Patricija Marjan
- Department of Biology, University of Waterloo , 200 University Avenue West, N2L 3G1 Waterloo, Ontario, Canada
| | - Leslie M Bragg
- Department of Biology, University of Waterloo , 200 University Avenue West, N2L 3G1 Waterloo, Ontario, Canada
| | - Deborah L MacLatchy
- Department of Biology, Wilfrid Laurier University , 75 University Avenue West, N2L 3C5 Waterloo, Ontario, Canada
| | - Mark R Servos
- Department of Biology, University of Waterloo , 200 University Avenue West, N2L 3G1 Waterloo, Ontario, Canada
| | - Cristopher J Martyniuk
- Center for Environmental and Human Toxicology & Department of Physiological Sciences, University of Florida , 2187 Mowry Road, Building 471, PO Box 110885, Gainesville, Florida 32611, United States
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10
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Abstract
The Xenopus genus includes several members of aquatic frogs native to Africa but is perhaps best known for the species Xenopus laevis and Xenopus tropicalis. These species were popularized as model organisms from as early as the 1800s and have been instrumental in expanding several biological fields including cell biology, environmental toxicology, regenerative biology, and developmental biology. In fact, much of what we know about the formation and maturation of the vertebrate renal system has been acquired by examining the intricate genetic and morphological patterns that epitomize nephrogenesis in Xenopus. From these numerous reports, we have learned that the process of kidney development is as unique among organs as it is conserved among vertebrates. While development of most organs involves increases in size at a single location, development of the kidney occurs through a series of three increasingly complex nephric structures that are temporally distinct from one another and which occupy discrete spatial locales within the body. These three renal systems all serve to provide homeostatic, osmoregulatory, and excretory functions in animals. Importantly, the kidneys in amphibians, such as Xenopus, are less complex and more easily accessed than those in mammals, and thus tadpoles and frogs provide useful models for understanding our own kidney development. Several descriptive and mechanistic studies conducted with the Xenopus model system have allowed us to elucidate the cellular and molecular mediators of renal patterning and have also laid the foundation for our current understanding of kidney repair mechanisms in vertebrates. While some species-specific responses to renal injury have been observed, we still recognize the advantage of the Xenopus system due to its distinctive similarity to mammalian wound healing, reparative, and regenerative responses. In addition, the first evidence of renal regeneration in an amphibian system was recently demonstrated in Xenopus laevis. As genetic and molecular tools continue to advance, our appreciation for and utilization of this amphibian model organism can only intensify and will certainly provide ample opportunities to further our understanding of renal development and repair.
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11
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Hamilton PW, Sun Y, Henry JJ. Lens regeneration from the cornea requires suppression of Wnt/β-catenin signaling. Exp Eye Res 2016; 145:206-215. [PMID: 26778749 DOI: 10.1016/j.exer.2016.01.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 12/18/2015] [Accepted: 01/05/2016] [Indexed: 10/22/2022]
Abstract
The frog, Xenopus laevis, possesses a high capacity to regenerate various larval tissues, including the lens, which is capable of complete regeneration from the cornea epithelium. However, the molecular signaling mechanisms of cornea-lens regeneration are not fully understood. Previous work has implicated the involvement of the Wnt signaling pathway, but molecular studies have been very limited. Iris-derived lens regeneration in the newt (Wolffian lens regeneration) has shown a necessity for active Wnt signaling in order to regenerate a new lens. Here we provide evidence that the Wnt signaling pathway plays a different role in the context of cornea-lens regeneration in Xenopus. We examined the expression of frizzled receptors and wnt ligands in the frog cornea epithelium. Numerous frizzled receptors (fzd1, fzd2, fzd3, fzd4, fzd6, fzd7, fzd8, and fzd10) and wnt ligands (wnt2b.a, wnt3a, wnt4, wnt5a, wnt5b, wnt6, wnt7b, wnt10a, wnt11, and wnt11b) are expressed in the cornea epithelium, demonstrating that this tissue is transcribing many of the ligands and receptors of the Wnt signaling pathway. When compared to flank epithelium, which is lens regeneration incompetent, only wnt11 and wnt11b are different (present only in the cornea epithelium), identifying them as potential regulators of cornea-lens regeneration. To detect changes in canonical Wnt/β-catenin signaling occurring within the cornea epithelium, axin2 expression was measured over the course of regeneration. axin2 is a well-established reporter of active Wnt/β-catenin signaling, and its expression shows a significant decrease at 24 h post-lentectomy. This decrease recovers to normal endogenous levels by 48 h. To test whether this signaling decrease was necessary for lens regeneration to occur, regenerating eyes were treated with either 6-bromoindirubin-3'-oxime (BIO) or 1-azakenpaullone - both activators of Wnt signaling - resulting in a significant reduction in the percentage of cases with successful regeneration. In contrast, inhibition of Wnt signaling using either the small molecule IWR-1, treatment with recombinant human Dickkopf-1 (rhDKK1) protein, or transgenic expression of Xenopus DKK1, did not significantly affect the percentage of successful regeneration. Together, these results suggest a model where Wnt/β-catenin signaling is active in the cornea epithelium and needs to be suppressed during early lens regeneration in order for these cornea cells to give rise to a new lentoid. While this finding differs from what has been described in the newt, it closely resembles the role of Wnt signaling during the initial formation of the lens placode from the surface ectoderm during early embryogenesis.
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Affiliation(s)
- Paul W Hamilton
- Department of Cell & Developmental Biology, University of Illinois, 601 S. Goodwin Ave. Urbana, IL 61801, USA
| | - Yu Sun
- Department of Cell & Developmental Biology, University of Illinois, 601 S. Goodwin Ave. Urbana, IL 61801, USA
| | - Jonathan J Henry
- Department of Cell & Developmental Biology, University of Illinois, 601 S. Goodwin Ave. Urbana, IL 61801, USA.
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12
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Thomas AG, Henry JJ. Retinoic acid regulation by CYP26 in vertebrate lens regeneration. Dev Biol 2013; 386:291-301. [PMID: 24384390 DOI: 10.1016/j.ydbio.2013.12.036] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 12/18/2013] [Accepted: 12/23/2013] [Indexed: 12/20/2022]
Abstract
Xenopus laevis is among the few species that are capable of fully regenerating a lost lens de novo. This occurs upon removal of the lens, when secreted factors from the retina are permitted to reach the cornea epithelium and trigger it to form a new lens. Although many studies have investigated the retinal factors that initiate lens regeneration, relatively little is known about what factors support this process and make the cornea competent to form a lens. We presently investigate the role of Retinoic acid (RA) signaling in lens regeneration in Xenopus. RA is a highly important morphogen during vertebrate development, including the development of various eye tissues, and has been previously implicated in several regenerative processes as well. For instance, Wolffian lens regeneration in the newt requires active RA signaling. In contrast, we provide evidence here that lens regeneration in Xenopus actually depends on the attenuation of RA signaling, which is regulated by the RA-degrading enzyme CYP26. Using RT-PCR we examined the expression of RA synthesis and metabolism related genes within ocular tissues. We found expression of aldh1a1, aldh1a2, and aldh1a3, as well as cyp26a1 and cyp26b1 in both normal and regenerating corneal tissue. On the other hand, cyp26c1 does not appear to be expressed in either control or regenerating corneas, but it is expressed in the lens. Additionally in the lens, we found expression of aldh1a1 and aldh1a2, but not aldh1a3. Using an inhibitor of CYP26, and separately using exogenous retinoids, as well as RA signaling inhibitors, we demonstrate that CYP26 activity is necessary for lens regeneration to occur. We also find using phosphorylated Histone H3 labeling that CYP26 antagonism reduces cell proliferation in the cornea, and using qPCR we find that exogenous retinoids alter the expression of putative corneal stem cell markers. Furthermore, the Xenopus cornea is composed of an outer layer and inner basal epithelium, as well as a deeper fibrillar layer sparsely populated with cells. We employed antibody staining to visualize the localization of CYP26A, CYP26B, and RALDH1 within these corneal layers. Immunohistochemical staining of these enzymes revealed that all 3 proteins are expressed in both the outer and basal layers. CYP26A appears to be unique in also being present in the deeper fibrillar layer, which may contain cornea stem cells. This study reveals a clear molecular difference between newt and Xenopus lens regeneration, and it implicates CYP26 in the latter regenerative process.
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Affiliation(s)
- Alvin G Thomas
- Department of Cell & Developmental Biology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Ave. Urbana, IL 61801, United States.
| | - Jonathan J Henry
- Department of Cell & Developmental Biology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Ave. Urbana, IL 61801, United States.
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13
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Blum N, Begemann G. The roles of endogenous retinoid signaling in organ and appendage regeneration. Cell Mol Life Sci 2013; 70:3907-27. [PMID: 23479131 PMCID: PMC11113817 DOI: 10.1007/s00018-013-1303-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 01/29/2013] [Accepted: 02/14/2013] [Indexed: 12/20/2022]
Abstract
The ability to regenerate injured or lost body parts has been an age-old ambition of medical science. In contrast to humans, teleost fish and urodele amphibians can regrow almost any part of the body with seeming effortlessness. Retinoic acid is a molecule that has long been associated with these impressive regenerative capacities. The discovery 30 years ago that addition of retinoic acid to regenerating amphibian limbs causes "super-regeneration" initiated investigations into the presumptive roles of retinoic acid in regeneration of appendages and other organs. However, the evidence favoring or dismissing a role for endogenous retinoids in regeneration processes remained sparse and ambiguous. Now, the availability of genetic tools to manipulate and visualize the retinoic acid signaling pathway has opened up new routes to dissect its roles in regeneration. Here, we review the current understanding on endogenous functions of retinoic acid in regeneration and discuss key questions to be addressed in future research.
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Affiliation(s)
- Nicola Blum
- Developmental Biology, University of Bayreuth, 95440 Bayreuth, Germany
| | - Gerrit Begemann
- Developmental Biology, University of Bayreuth, 95440 Bayreuth, Germany
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14
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Henry JJ, Thomas AG, Hamilton PW, Moore L, Perry KJ. Cell signaling pathways in vertebrate lens regeneration. Curr Top Microbiol Immunol 2013; 367:75-98. [PMID: 23224710 DOI: 10.1007/82_2012_289] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Abstract
Certain vertebrates are capable of regenerating parts of the eye, including the lens. Depending on the species, two principal forms of in vivo lens regeneration have been described wherein the new lens arises from either the pigmented epithelium of the dorsal iris or the cornea epithelium. These forms of lens regeneration are triggered by retinal factors present in the eye. Studies have begun to illuminate the nature of the signals that support lens regeneration. This review describes evidence for the involvement of specific signaling pathways in lens regeneration, including the FGF, retinoic acid, TGF-beta, Wnt, and Hedgehog pathways.
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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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15
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Abstract
Comparative studies of lens and retina regeneration have been conducted within a wide variety of animals over the last 100 years. Although amphibians, fish, birds and mammals have all been noted to possess lens- or retina-regenerative properties at specific developmental stages, lens or retina regeneration in adult animals is limited to lower vertebrates. The present review covers the newest perspectives on lens and retina regeneration from these different model organisms with a focus on future trends in regeneration research.
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Sousounis K, Tsonis PA. Patterns of gene expression in microarrays and expressed sequence tags from normal and cataractous lenses. Hum Genomics 2012; 6:14. [PMID: 23244575 PMCID: PMC3563465 DOI: 10.1186/1479-7364-6-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 05/14/2012] [Indexed: 11/30/2022] Open
Abstract
In this contribution, we have examined the patterns of gene expression in normal and cataractous lenses as presented in five different papers using microarrays and expressed sequence tags. The purpose was to evaluate unique and common patterns of gene expression during development, aging and cataracts.
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Affiliation(s)
- Konstantinos Sousounis
- Department of Biology and Center for Tissue Regeneration and Engineering, University of Dayton, Dayton, OH 45469-2320, USA
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17
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Histone deacetylases are required for amphibian tail and limb regeneration but not development. Mech Dev 2012; 129:208-18. [DOI: 10.1016/j.mod.2012.08.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 08/08/2012] [Accepted: 08/15/2012] [Indexed: 01/09/2023]
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18
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Pasten C, Ortiz-Pineda PA, García-Arrarás JE. Ubiquitin-proteasome system components are upregulated during intestinal regeneration. Genesis 2012; 50:350-65. [PMID: 21913312 DOI: 10.1002/dvg.20803] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 08/12/2011] [Accepted: 09/06/2011] [Indexed: 11/06/2022]
Abstract
The ubiquitin proteasome system (UPS) is the main proteolytic system of cells. Recent evidence suggests that the UPS plays a regulatory role in regeneration processes. Here, we explore the possibility that the UPS is involved during intestinal regeneration of the sea cucumber Holothuria glaberrima. These organisms can regenerate most of their digestive tract following a process of evisceration. Initially, we identified components of H. glaberrima UPS, including sequences for Rpn10, β3, and ubiquitin-RPL40. Predicted proteins from the mRNA sequences showed high degree of conservation that ranged from 60% (Rpn10) to 98% (Ub-RPL40). Microarrays and RT-PCR experiments showed that these genes were upregulated during intestinal regeneration. In addition, we demonstrated expression of alpha 20S proteasome subunits and ubiquitinated proteins during intestinal regeneration and detected them in the epithelium and connective tissue of the regenerating intestine. Finally, the intestinal regeneration was altered in animals treated with MG132, a proteasome inhibitor. These findings support our contention that proteasomes are playing an important role during intestinal regeneration.
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Affiliation(s)
- Consuelo Pasten
- Department of Biology, University of Puerto Rico, Rio Piedras Campus, San Juan, Puerto Rico 00931
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Day RC, Beck CW. Transdifferentiation from cornea to lens in Xenopus laevis depends on BMP signalling and involves upregulation of Wnt signalling. BMC DEVELOPMENTAL BIOLOGY 2011; 11:54. [PMID: 21896182 PMCID: PMC3184090 DOI: 10.1186/1471-213x-11-54] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 09/06/2011] [Indexed: 11/30/2022]
Abstract
Background Surgical removal of the lens from larval Xenopus laevis results in a rapid transdifferention of central corneal cells to form a new lens. The trigger for this process is understood to be an induction event arising from the unprecedented exposure of the cornea to the vitreous humour that occurs following lens removal. The molecular identity of this trigger is unknown. Results Here, we have used a functional transgenic approach to show that BMP signalling is required for lens regeneration and a microarray approach to identify genes that are upregulated specifically during this process. Analysis of the array data strongly implicates Wnt signalling and the Pitx family of transcription factors in the process of cornea to lens transdifferentiation. Our analysis also captured several genes associated with congenital cataract in humans. Pluripotency genes, in contrast, were not upregulated, supporting the idea that corneal cells transdifferentiate without returning to a stem cell state. Several genes from the array were expressed in the forming lens during embryogenesis. One of these, Nipsnap1, is a known direct target of BMP signalling. Conclusions Our results strongly implicate the developmental Wnt and BMP signalling pathways in the process of cornea to lens transdifferentiation (CLT) in Xenopus, and suggest direct transdifferentiation between these two anterior eye tissues.
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Affiliation(s)
- Robert C Day
- Genetics Otago, University of Otago, PO Box 56, Dunedin 9054, New Zealand
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Zhao Y, Ju F, Zhao Y, Wang L, Sun Z, Liu M, Gao L. The expression of αA- and βB1-crystallin during normal development and regeneration, and proteomic analysis for the regenerating lens in Xenopus laevis. Mol Vis 2011; 17:768-78. [PMID: 21527991 PMCID: PMC3081792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 03/15/2011] [Indexed: 12/02/2022] Open
Abstract
PURPOSE To explore the expression of the lens crystallins (αA- and βB1-crystallin) in Xenopus laevis embryonic lens development and regeneration and to analyze the order of different crystallins generated in the regenerating lens. METHODS Real Time-PCR, Immunofluorescence, and 2D-PAGE were used to analyze the expressions of αA-crystallin and βB1-crystallin, and related factors during embryonic lens development and regeneration in Xenopus laevis. RESULTS αA-crystallin and βB1-crystallin were first detected at stage 29/30 during normal development, and the two crystallins were simultaneously detected in regeneration. During embryonic lens development, the relative expression level of the βB1-crystallin gene was higher than that of the αA-crystallin gene. In the process of the lens regeneration, however, the relative expression level of the βB1-crystallin gene was lower than that of the αA-crystallin gene. Throughout embryonic lens development, the two crystallin transcripts showed the same variation trends, and similar occurrence did in the regeneration process. Crystallins showed different localization and distribution during the ontogeny and regeneration, especially in the lens fiber region. 2D-electrophores revealed the patterns of the sequential synthesis of crystallins, with regard to the different classes and apparent variations of some auxiliary regulatory factors. CONCLUSIONS The ontogeny and localization of the crystallins during embryonic lens development and regeneration indicated a different development program, although they have identical origins, the ectoderm. The expression level of crystallin transcripts displayed a consistent variation tendency, but the presence of appreciable differences was still exposed. In addition to stably producing the crystallins of different classes in accordance with established procedure, these auxiliary factors may perform the function, to some extent, because of significant changes in their expression throughout the process of lens regeneration.
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Affiliation(s)
- Yongqing Zhao
- School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Furong Ju
- School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Yuanlin Zhao
- School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Lei Wang
- School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Zhenglong Sun
- School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Mingxin Liu
- Department of Chemistry, Tsinghua University, Bejing, China
| | - Lan Gao
- School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
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Perry KJ, Johnson VR, Malloch EL, Fukui L, Wever J, Thomas AG, Hamilton PW, Henry JJ. The G-protein-coupled receptor, GPR84, is important for eye development in Xenopus laevis. Dev Dyn 2011; 239:3024-37. [PMID: 20925114 DOI: 10.1002/dvdy.22446] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) represent diverse, multifamily groups of cell signaling receptors involved in many cellular processes. We identified Xenopus laevis GPR84 as a member of the A18 subfamily of GPCRs. During development, GPR84 is detected in the embryonic lens placode, differentiating lens fiber cells, retina, and cornea. Anti-sense morpholino oligonucleotide-mediated knockdown and RNA rescue experiments demonstrate GPR84's importance in lens, cornea, and retinal development. Examination of cell proliferation using an antibody against histone H3 S10P reveals significant increases in the lens and retina following GPR84 knockdown. Additionally, there was also an increase in apoptosis in the retina and lens, as revealed by TUNEL assay. Reciprocal transplantation of the presumptive lens ectoderm between uninjected controls and morpholino-injected embryos demonstrates that GPR84 is necessary in the retina for proper development of the retina, as well as other eye tissues including the lens and cornea.
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Affiliation(s)
- Kimberly J Perry
- University of Illinois, Department of Cell and Developmental Biology, Urbana, Illionis 61801, USA
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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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Lynch J, McEwan J, Beck CW. Analysis of the expression of retinoic acid metabolising genes during Xenopus laevis organogenesis. Gene Expr Patterns 2010; 11:112-7. [PMID: 20969978 DOI: 10.1016/j.gep.2010.10.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Revised: 10/12/2010] [Accepted: 10/15/2010] [Indexed: 11/17/2022]
Abstract
Retinoic acid (RA) is a known teratogen that is also required endogenously for normal development of the embryo. RA can act as a morphogen, through direct binding to receptors and RA response elements in the genome, and classical studies of limb development and regeneration in amphibians have shown that it is likely to provide positional information. Availability of RA depends on both metabolic synthesis and catabolic degradation, and specific binding proteins act to further modulate the binding of RA to response elements. Here, we describe the expression of seven genes involved in metabolism (Raldh1-3), catabolism (Cyp26a and b) and binding of RA (Crabp1 and 2) during organogenesis in the clawed frog Xenopus laevis. Taken together, this data indicates regions of the embryo that could be affected by RA mediated patterning, and identifies some differences with other vertebrates.
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Affiliation(s)
- Joshua Lynch
- Department of Zoology, University of Otago, 340 Great King Street, Dunedin, New Zealand
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Henry JJ, Perry KJ, Fukui L, Alvi N. Differential localization of mRNAs during early development in the mollusc, Crepidula fornicata. Integr Comp Biol 2010; 50:720-33. [PMID: 21558235 DOI: 10.1093/icb/icq088] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Certain mRNAs have been shown to be segregated in different cells in various metazoan embryos. These events represent aspects of autonomous mechanisms that establish particular embryonic cell fates and axial properties associated with asymmetric cell divisions. The spiralian lophotrochozoans (which include molluscs, annelids, nemerteans, gnathostomulids, dicyemid mesozoans, entoprocts, and platyhelminthes) exhibit a highly conserved pattern of early development that involves stereotypical, asymmetric cell divisions (termed "spiral cleavage"). Recently, it was demonstrated that various mRNAs are dynamically localized to the centrosomes in specific cells during early development in the gastropod mollusc, Ilyanassa obsoleta. During subsequent cell divisions, these messages become segregated in particular daughter cells, and it has been proposed that these events distinguish the developmental potential of these cells within the early embryo of I. obsoleta. The molecular mechanisms underlying these events, however, are still unknown. Here we show for the first time in another spiralian lophotrochozoan (the gastropod Crepidula fornicata) that similar patterns of mRNA localization take place during early development. To characterize the transcriptome of early development, and identify candidate genes for the expression analyses, high-throughput sequencing was carried out, via GS FLX Titanium 454 pyrosequencing. The annotated sequences have been made available as a resource for the scientific community (www.life.illinoi.edu/henry/crepidula_databases.html). Presumably, specific proteins associated with centrosomes may be important for these mRNA localization events. In silico sequence comparisons with known centriolar/centrosomal, ciliary/basal body proteomes shows that a large number of those proteins are represented in the collection of expressed sequence tags of C. fornicata annotated in this study. These data should be useful for future studies of the role of specific mRNAs in controlling cell fate and axial specification in the spiralian Lophotrochozoa, and for dissecting the underlying molecular mechanisms that accomplish these events.
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Affiliation(s)
- Jonathan J Henry
- Department of Cell and Developmental Biology, University of Illinois, 601 S. Goodwin Ave., Urbana IL 61801, USA.
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Galliot B, Chera S. The Hydra model: disclosing an apoptosis-driven generator of Wnt-based regeneration. Trends Cell Biol 2010; 20:514-23. [PMID: 20691596 DOI: 10.1016/j.tcb.2010.05.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 05/19/2010] [Accepted: 05/20/2010] [Indexed: 12/11/2022]
Abstract
The Hydra model system is well suited for the eludication of the mechanisms underlying regeneration in the adult, and an understanding of the core mechanisms is likely to cast light on pathways conserved in other species. Recent detailed analyses of the activation of the Wnt-beta-catenin pathway in bisected Hydra shows that the route taken to regenerate a structure as complex as the head varies dramatically according to the level of the amputation. When decapitation induces direct re-development due to Wnt3 signaling from epithelial cells, head regeneration after mid-gastric section relies first on Wnt3 signaling from interstitial cells, that undergo apoptosis-induced compensatory proliferation, and subsequently on activation of Wnt3 signaling in the epithelial cells. The relative distribution between stem cells and head progenitor cells is strikingly different in these two contexts, indicating that the pre-amputation homeostatic conditions define and constrain the route that bridges wound-healing to the re-development program of the missing structure.
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Affiliation(s)
- Brigitte Galliot
- Department of Zoology and Animal Biology, Faculty of Sciences, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland.
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Henry JQ, Perry KJ, Martindale MQ. -catenin and Early Development in the Gastropod, Crepidula fornicata. Integr Comp Biol 2010; 50:707-19. [DOI: 10.1093/icb/icq076] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Maki N, Martinson J, Nishimura O, Tarui H, Meller J, Tsonis PA, Agata K. Expression profiles during dedifferentiation in newt lens regeneration revealed by expressed sequence tags. Mol Vis 2010; 16:72-8. [PMID: 20090923 PMCID: PMC2807617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2009] [Accepted: 01/13/2010] [Indexed: 10/26/2022] Open
Abstract
PURPOSE The adult newt can regenerate lens from pigmented epithelial cells (PECs) of the dorsal iris via dedifferentiation. The purpose of this research is to obtain sequence resources for a newt lens regeneration study and to obtain insights of dedifferentiation at the molecular level. METHODS mRNA was purified from iris during dedifferentiation and its cDNA library was constructed. From the cDNA library 10,449 clones were sequenced and analyzed. RESULTS From 10,449 reads, 780 contigs and 1,666 singlets were annotated. The presence of several cancer- and apoptosis-related genes during newt dedifferentiation was revealed. Moreover, several candidate genes, which might participate in reprogramming during dedifferentiation, were also found. CONCLUSIONS The expression of cancer- and apoptosis-related genes could be hallmarks during dedifferentiation. The expression sequence tag (EST) resource is useful for the future study of newt dedifferentiation, and the sequence information is available in GenBank (accession numbers; FS290155-FS300559).
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Affiliation(s)
- Nobuyasu Maki
- Center for Developmental Biology, RIKEN Kobe, Kobe, Japan
- Department of Biology and Center for Tissue Regeneration and Engineering, University of Dayton, Dayton, OH
| | - John Martinson
- Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH
- Ecological Exposure Research Division, Cincinnati, OH
| | | | - Hiroshi Tarui
- Center for Developmental Biology, RIKEN Kobe, Kobe, Japan
| | - Jaroslaw Meller
- Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH
| | - Panagiotis A. Tsonis
- Department of Biology and Center for Tissue Regeneration and Engineering, University of Dayton, Dayton, OH
| | - Kiyokazu Agata
- Center for Developmental Biology, RIKEN Kobe, Kobe, Japan
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
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