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Dalgin G, Prince VE. Midline morphogenesis of zebrafish foregut endoderm is dependent on Hoxb5b. Dev Biol 2020; 471:1-9. [PMID: 33290819 DOI: 10.1016/j.ydbio.2020.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 11/25/2020] [Accepted: 12/03/2020] [Indexed: 11/16/2022]
Abstract
During vertebrate embryonic development complex morphogenetic events drive the formation of internal organs associated with the developing digestive tract. The foregut organs derive from hepatopancreatic precursor cells that originate bilaterally within the endoderm monolayer, and subsequently converge toward the midline where they coalesce to produce the gut tube from which the liver and pancreas form. The progenitor cells of these internal organs are influenced by the lateral plate mesoderm (LPM), which helps direct them towards their specific fates. However, it is not completely understood how the bilateral organ precursors move toward the embryonic midline and ultimately coalesce to form functional organs. Here we demonstrate that the zebrafish homeobox gene hoxb5b regulates morphogenesis of the foregut endoderm at the midline. At early segmentation stages, hoxb5b is expressed in the LPM adjacent to the developing foregut endoderm. By 24 hpf hoxb5b is expressed directly in the endoderm cells of the developing gut tube. When Hoxb5b function is disrupted, either by morpholino knockdown or sgRNA/Cas9 somatic disruption, the process of foregut morphogenesis is disrupted, resulting in a bifurcated foregut. By contrast, knockdown of the paralogous hoxb5a gene does not alter gut morphology. Further analysis has indicated that Hoxb5b knockdown specimens produce endocrine pancreas cell types, but liver cells are absent. Finally, cell transplantation experiments revealed that Hoxb5b function in the endoderm is not needed for proper coalescence of the foregut at the midline. Together, our findings imply that midline morphogenesis of foregut endoderm is guided by a hoxb5b-mediated mechanism that functions extrinsically, likely within the LPM. Loss of hoxb5b function prevents normal coalescence of endoderm cells at the midline and thus disrupts gut morphogenesis.
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Affiliation(s)
- Gökhan Dalgin
- Department of Medicine, Section of Endocrinology, Diabetes and Metabolism, The University of Chicago, Chicago, IL, 60637, USA
| | - Victoria E Prince
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL, 60637, USA.
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Parker HJ, Krumlauf R. Segmental arithmetic: summing up the Hox gene regulatory network for hindbrain development in chordates. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2017; 6. [PMID: 28771970 DOI: 10.1002/wdev.286] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 06/13/2017] [Accepted: 06/15/2017] [Indexed: 11/10/2022]
Abstract
Organization and development of the early vertebrate hindbrain are controlled by a cascade of regulatory interactions that govern the process of segmentation and patterning along the anterior-posterior axis via Hox genes. These interactions can be assembled into a gene regulatory network that provides a framework to interpret experimental data, generate hypotheses, and identify gaps in our understanding of the progressive process of hindbrain segmentation. The network can be broadly separated into a series of interconnected programs that govern early signaling, segmental subdivision, secondary signaling, segmentation, and ultimately specification of segmental identity. Hox genes play crucial roles in multiple programs within this network. Furthermore, the network reveals properties and principles that are likely to be general to other complex developmental systems. Data from vertebrate and invertebrate chordate models are shedding light on the origin and diversification of the network. Comprehensive cis-regulatory analyses of vertebrate Hox gene regulation have enabled powerful cross-species gene regulatory comparisons. Such an approach in the sea lamprey has revealed that the network mediating segmental Hox expression was present in ancestral vertebrates and has been maintained across diverse vertebrate lineages. Invertebrate chordates lack hindbrain segmentation but exhibit conservation of some aspects of the network, such as a role for retinoic acid in establishing nested Hox expression domains. These comparisons lead to a model in which early vertebrates underwent an elaboration of the network between anterior-posterior patterning and Hox gene expression, leading to the gene-regulatory programs for segmental subdivision and rhombomeric segmentation. WIREs Dev Biol 2017, 6:e286. doi: 10.1002/wdev.286 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Hugo J Parker
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Robb Krumlauf
- Stowers Institute for Medical Research, Kansas City, MO, USA.,Department of Anatomy and Cell Biology, Kansas University Medical Center, Kansas City, Kansas 66160, USA
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Davis A, Reubens MC, Stellwag EJ. Functional and Comparative Genomics of Hoxa2 Gene cis-Regulatory Elements: Evidence for Evolutionary Modification of Ancestral Core Element Activity. J Dev Biol 2016; 4:jdb4020015. [PMID: 29615583 PMCID: PMC5831782 DOI: 10.3390/jdb4020015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 03/15/2016] [Accepted: 03/17/2016] [Indexed: 11/24/2022] Open
Abstract
Hoxa2 is an evolutionarily conserved developmental regulatory gene that functions to specify rhombomere (r) and pharyngeal arch (PA) identities throughout the Osteichthyes. Japanese medaka (Oryzias latipes) hoxa2a, like orthologous Hoxa2 genes from other osteichthyans, is expressed during embryogenesis in r2–7 and PA2-7, whereas the paralogous medaka pseudogene, ψhoxa2b, is expressed in noncanonical Hoxa2 domains, including the pectoral fin buds. To understand the evolution of cis-regulatory element (CRE) control of gene expression, we conducted eGFP reporter gene expression studies with extensive functional mapping of several conserved CREs upstream of medaka hoxa2a and ψhoxa2b in transient and stable-line transgenic medaka embryos. The CREs tested were previously shown to contribute to directing mouse Hoxa2 gene expression in r3, r5, and PA2-4. Our results reveal the presence of sequence elements embedded in the medaka hoxa2a and ψhoxa2b upstream enhancer regions (UERs) that mediate expression in r4 and the PAs (hoxa2a r4/CNCC element) or in r3–7 and the PAs ψhoxa2b r3–7/CNCC element), respectively. Further, these elements were shown to be highly conserved among osteichthyans, which suggests that the r4 specifying element embedded in the UER of Hoxa2 is a deeply rooted rhombomere specifying element and the activity of this element has been modified by the evolution of flanking sequences that redirect its activity to alternative developmental compartments.
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Affiliation(s)
- Adam Davis
- Department of Biology and Physical Sciences, Gordon State College, Barnesville, GA 30204, USA.
| | - Michael C Reubens
- The Scripps Research Institute, 10550 N, Torrey Pines Road, MB3, La Jolla, CA 92037, USA.
| | - Edmund J Stellwag
- Department of Biology, Howell Science Complex, East Carolina University, Greenville, NC 27858, USA.
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Suzuki H, Nikaido M, Hagino-Yamagishi K, Okada N. Distinct functions of two olfactory marker protein genes derived from teleost-specific whole genome duplication. BMC Evol Biol 2015; 15:245. [PMID: 26555542 PMCID: PMC4640105 DOI: 10.1186/s12862-015-0530-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 11/04/2015] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Whole genome duplications (WGDs) have been proposed to have made a significant impact on vertebrate evolution. Two rounds of WGD (1R and 2R) occurred in the common ancestor of Gnathostomata and Cyclostomata, followed by the third-round WGD (3R) in a common ancestor of all modern teleosts. The 3R-derived paralogs are good models for understanding the evolution of genes after WGD, which have the potential to facilitate phenotypic diversification. However, the recent studies of 3R-derived paralogs tend to be based on in silico analyses. Here we analyzed the paralogs encoding teleost olfactory marker protein (OMP), which was shown to be specifically expressed in mature olfactory sensory neurons and is expected to be involved in olfactory transduction. RESULTS Our genome database search identified two OMPs (OMP1 and OMP2) in teleosts, whereas only one was present in other vertebrates. Phylogenetic and synteny analyses suggested that OMP1 and 2 were derived from 3R. Both OMPs showed distinct expression patterns in zebrafish; OMP1 was expressed in the deep layer of the olfactory epithelium (OE), which is consistent with previous studies of mice and zebrafish, whereas OMP2 was sporadically expressed in the superficial layer. Interestingly, OMP2 was expressed in a very restricted region of the retina as well as in the OE. In addition, the analysis of transcriptome data of spotted gar, a non-teleost fish, revealed that single OMP gene was expressed in the eyes. CONCLUSION We found distinct expression patterns of zebrafish OMP1 and 2 at the tissue and cellular level. These differences in expression patterns may be explained by subfunctionalization as the model of molecular evolution. Namely, single OMP gene was speculated to be originally expressed in the OE and the eyes in the common ancestor of all Osteichthyes (bony fish including tetrapods). Then, two OMP gene paralogs derived from 3R-WGD reduced and specialized the expression patterns. This study provides a good example for analyzing a functional subdivision of the teleost OE and eyes as revealed by 3R-derived paralogs of OMPs.
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Affiliation(s)
- Hikoyu Suzuki
- Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, 226-8501, Japan.
| | - Masato Nikaido
- Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, 226-8501, Japan.
| | - Kimiko Hagino-Yamagishi
- Department of Dementia and Higher Brain Function, Integrated Neuroscience Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, 156-8506, Japan.
| | - Norihiro Okada
- Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, 226-8501, Japan.
- Foundation for Advancement of International Science, Tsukuba, 305-0821, Japan.
- Department of Life Sciences, National Cheng Kung University, Tainan, 701, Taiwan.
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Distinct phenotypes in zebrafish models of human startle disease. Neurobiol Dis 2013; 60:139-51. [PMID: 24029548 PMCID: PMC3972633 DOI: 10.1016/j.nbd.2013.09.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 08/13/2013] [Accepted: 09/01/2013] [Indexed: 11/21/2022] Open
Abstract
Startle disease is an inherited neurological disorder that causes affected individuals to suffer noise- or touch-induced non-epileptic seizures, excessive muscle stiffness and neonatal apnea episodes. Mutations known to cause startle disease have been identified in glycine receptor subunit (GLRA1 and GLRB) and glycine transporter (SLC6A5) genes, which serve essential functions at glycinergic synapses. Despite the significant successes in identifying startle disease mutations, many idiopathic cases remain unresolved. Exome sequencing in these individuals will identify new candidate genes. To validate these candidate disease genes, zebrafish is an ideal choice due to rapid knockdown strategies, accessible embryonic stages, and stereotyped behaviors. The only existing zebrafish model of startle disease, bandoneon (beo), harbors point mutations in glrbb (one of two zebrafish orthologs of human GLRB) that cause compromised glycinergic transmission and touch-induced bilateral muscle contractions. In order to further develop zebrafish as a model for startle disease, we sought to identify common phenotypic outcomes of knocking down zebrafish orthologs of two known startle disease genes, GLRA1 and GLRB, using splice site-targeted morpholinos. Although both morphants were expected to result in phenotypes similar to the zebrafish beo mutant, our direct comparison demonstrated that while both glra1 and glrbb morphants exhibited embryonic spasticity, only glrbb morphants exhibited bilateral contractions characteristic of beo mutants. Likewise, zebrafish over-expressing a dominant startle disease mutation (GlyR α1(R271Q)) exhibited spasticity but not bilateral contractions. Since GlyR βb can interact with GlyR α subunits 2-4 in addition to GlyR α1, loss of the GlyR βb subunit may produce more severe phenotypes by affecting multiple GlyR subtypes. Indeed, immunohistochemistry of glra1 morphants suggests that in zebrafish, alternate GlyR α subunits can compensate for the loss of the GlyR α1 subunit. To address the potential for interplay among GlyR subunits during development, we quantified the expression time-course for genes known to be critical to glycinergic synapse function. We found that GlyR α2, α3 and α4a are expressed in the correct temporal pattern and could compensate for the loss of the GlyR α1 subunit. Based on our findings, future studies that aim to model candidate startle disease genes in zebrafish should include measures of spasticity and synaptic development.
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Wong L, Weadick CJ, Kuo C, Chang BSW, Tropepe V. Duplicate dmbx1 genes regulate progenitor cell cycle and differentiation during zebrafish midbrain and retinal development. BMC DEVELOPMENTAL BIOLOGY 2010; 10:100. [PMID: 20860823 PMCID: PMC2954992 DOI: 10.1186/1471-213x-10-100] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 09/22/2010] [Indexed: 01/03/2023]
Abstract
Background The Dmbx1 gene is important for the development of the midbrain and hindbrain, and mouse gene targeting experiments reveal that this gene is required for mediating postnatal and adult feeding behaviours. A single Dmbx1 gene exists in terrestrial vertebrate genomes, while teleost genomes have at least two paralogs. We compared the loss of function of the zebrafish dmbx1a and dmbx1b genes in order to gain insight into the molecular mechanism by which dmbx1 regulates neurogenesis, and to begin to understand why these duplicate genes have been retained in the zebrafish genome. Results Using gene knockdown experiments we examined the function of the dmbx1 gene paralogs in zebrafish, dmbx1a and dmbx1b in regulating neurogenesis in the developing retina and midbrain. Dose-dependent loss of dmbx1a and dmbx1b function causes a significant reduction in growth of the midbrain and retina that is evident between 48-72 hpf. We show that this phenotype is not due to patterning defects or persistent cell death, but rather a deficit in progenitor cell cycle exit and differentiation. Analyses of the morphant retina or anterior hindbrain indicate that paralogous function is partially diverged since loss of dmbx1a is more severe than loss of dmbx1b. Molecular evolutionary analyses of the Dmbx1 genes suggest that while this gene family is conservative in its evolution, there was a dramatic change in selective constraint after the duplication event that gave rise to the dmbx1a and dmbx1b gene families in teleost fish, suggestive of positive selection. Interestingly, in contrast to zebrafish dmbx1a, over expression of the mouse Dmbx1 gene does not functionally compensate for the zebrafish dmbx1a knockdown phenotype, while over expression of the dmbx1b gene only partially compensates for the dmbx1a knockdown phenotype. Conclusion Our data suggest that both zebrafish dmbx1a and dmbx1b genes are retained in the fish genome due to their requirement during midbrain and retinal neurogenesis, although their function is partially diverged. At the cellular level, Dmbx1 regulates cell cycle exit and differentiation of progenitor cells. The unexpected observation of putative post-duplication positive selection of teleost Dmbx1 genes, especially dmbx1a, and the differences in functionality between the mouse and zebrafish genes suggests that the teleost Dmbx1 genes may have evolved a diverged function in the regulation of neurogenesis.
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Affiliation(s)
- Loksum Wong
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
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Spatio-temporal patterns of Hox paralog group 3–6 gene expression during Japanese medaka (Oryzias latipes) embryonic development. Gene Expr Patterns 2010; 10:244-50. [DOI: 10.1016/j.gep.2010.05.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 05/06/2010] [Accepted: 05/08/2010] [Indexed: 12/20/2022]
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Ma LH, Punnamoottil B, Rinkwitz S, Baker R. Mosaic hoxb4a neuronal pleiotropism in zebrafish caudal hindbrain. PLoS One 2009; 4:e5944. [PMID: 19536294 PMCID: PMC2693931 DOI: 10.1371/journal.pone.0005944] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Accepted: 05/12/2009] [Indexed: 12/26/2022] Open
Abstract
To better understand how individual genes and experience influence behavior, the role of a single homeotic unit, hoxb4a, was comprehensively analyzed in vivo by clonal and retrograde fluorescent labeling of caudal hindbrain neurons in a zebrafish enhancer-trap YFP line. A quantitative spatiotemporal neuronal atlas showed hoxb4a activity to be highly variable and mosaic in rhombomere 7–8 reticular, motoneuronal and precerebellar nuclei with expression decreasing differentially in all subgroups through juvenile stages. The extensive Hox mosaicism and widespread pleiotropism demonstrate that the same transcriptional protein plays a role in the development of circuits that drive behaviors from autonomic through motor function including cerebellar regulation. We propose that the continuous presence of hoxb4a positive neurons may provide a developmental plasticity for behavior-specific circuits to accommodate experience- and growth-related changes. Hence, the ubiquitous hoxb4a pleitropism and modularity likely offer an adaptable transcriptional element for circuit modification during both growth and evolution.
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Affiliation(s)
- Leung-Hang Ma
- Department of Physiology and Neuroscience, New York University Medical Center, New York, New York, United States of America
| | - Beena Punnamoottil
- Brain & Mind Research Institute, University of Sydney, Camperdown, New South Wales, Australia
| | - Silke Rinkwitz
- Brain & Mind Research Institute, University of Sydney, Camperdown, New South Wales, Australia
| | - Robert Baker
- Department of Physiology and Neuroscience, New York University Medical Center, New York, New York, United States of America
- * E-mail:
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Douard V, Brunet F, Boussau B, Ahrens-Fath I, Vlaeminck-Guillem V, Haendler B, Laudet V, Guiguen Y. The fate of the duplicated androgen receptor in fishes: a late neofunctionalization event? BMC Evol Biol 2008; 8:336. [PMID: 19094205 PMCID: PMC2637867 DOI: 10.1186/1471-2148-8-336] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2008] [Accepted: 12/18/2008] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Based on the observation of an increased number of paralogous genes in teleost fishes compared with other vertebrates and on the conserved synteny between duplicated copies, it has been shown that a whole genome duplication (WGD) occurred during the evolution of Actinopterygian fish. Comparative phylogenetic dating of this duplication event suggests that it occurred early on, specifically in teleosts. It has been proposed that this event might have facilitated the evolutionary radiation and the phenotypic diversification of the teleost fish, notably by allowing the sub- or neo-functionalization of many duplicated genes. RESULTS In this paper, we studied in a wide range of Actinopterygians the duplication and fate of the androgen receptor (AR, NR3C4), a nuclear receptor known to play a key role in sex-determination in vertebrates. The pattern of AR gene duplication is consistent with an early WGD event: it has been duplicated into two genes AR-A and AR-B after the split of the Acipenseriformes from the lineage leading to teleost fish but before the divergence of Osteoglossiformes. Genomic and syntenic analyses in addition to lack of PCR amplification show that one of the duplicated copies, AR-B, was lost in several basal Clupeocephala such as Cypriniformes (including the model species zebrafish), Siluriformes, Characiformes and Salmoniformes. Interestingly, we also found that, in basal teleost fish (Osteoglossiformes and Anguilliformes), the two copies remain very similar, whereas, specifically in Percomorphs, one of the copies, AR-B, has accumulated substitutions in both the ligand binding domain (LBD) and the DNA binding domain (DBD). CONCLUSION The comparison of the mutations present in these divergent AR-B with those known in human to be implicated in complete, partial or mild androgen insensitivity syndrome suggests that the existence of two distinct AR duplicates may be correlated to specific functional differences that may be connected to the well-known plasticity of sex determination in fish. This suggests that three specific events have shaped the present diversity of ARs in Actinopterygians: (i) early WGD, (ii) parallel loss of one duplicate in several lineages and (iii) putative neofunctionalization of the same duplicate in percomorphs, which occurred a long time after the WGD.
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Affiliation(s)
- Véronique Douard
- INRA-SCRIBE IFR 140, Campus de Beaulieu, 35042 Rennes Cedex, France
| | - Frédéric Brunet
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, UMR 5242 du CNRS, INRA, IFR128 BioSciences Lyon-Gerland, Ecole Normale Supérieure de Lyon, 46, Allée d'Italie, 69364 Lyon Cedex 07, France
| | - Bastien Boussau
- Biométrie et Biologie Évolutive UMR CNRS 5558 Université Claude Bernard-Lyon 1, 43, Boulevard du 11 novembre 1918, 69622 Villeurbanne Cedex, France
| | | | - Virginie Vlaeminck-Guillem
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, UMR 5242 du CNRS, INRA, IFR128 BioSciences Lyon-Gerland, Ecole Normale Supérieure de Lyon, 46, Allée d'Italie, 69364 Lyon Cedex 07, France
| | | | - Vincent Laudet
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, UMR 5242 du CNRS, INRA, IFR128 BioSciences Lyon-Gerland, Ecole Normale Supérieure de Lyon, 46, Allée d'Italie, 69364 Lyon Cedex 07, France
| | - Yann Guiguen
- INRA-SCRIBE IFR 140, Campus de Beaulieu, 35042 Rennes Cedex, France
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