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Machacova S, Kozmik Z, Kozmikova I. Identification of Nodal-dependent enhancer of amphioxus Chordin sufficient to drive gene expression into the chordate dorsal organizer. Dev Genes Evol 2022; 232:137-145. [PMID: 36372862 DOI: 10.1007/s00427-022-00698-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 10/12/2022] [Indexed: 11/15/2022]
Abstract
The core molecular mechanisms of dorsal organizer formation during gastrulation are highly conserved within the chordate lineage. One of the key characteristics is that Nodal signaling is required for the organizer-specific gene expression. This feature appears to be ancestral, as evidenced by the presence in the most basally divergent chordate amphioxus. To provide a better understanding of the evolution of organizer-specific gene regulation in chordates, we analyzed the cis-regulatory sequence of amphioxus Chordin in the context of the vertebrate embryo. First, we generated stable zebrafish transgenic lines, and by using light-sheet fluorescent microscopy, characterized in detail the expression pattern of GFP driven by the cis-regulatory sequences of amphioxus Chordin. Next, we performed a 5'deletion analysis and identified an enhancer sufficient to drive the expression of the reporter gene into a chordate dorsal organizer. Finally, we found that the identified enhancer element strongly depends on Nodal signaling, which is consistent with the well-established role of this pathway in the regulation of the expression of dorsal organizer-specific genes across chordates. The enhancer identified in our study may represent a suitable simple system to study the interplay of the evolutionarily conserved regulatory mechanisms operating during early chordate development.
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Affiliation(s)
- Simona Machacova
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague 4, Videnska, 1083, Czech Republic
| | - Zbynek Kozmik
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague 4, Videnska, 1083, Czech Republic
| | - Iryna Kozmikova
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague 4, Videnska, 1083, Czech Republic.
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Yasuoka Y. Enhancer evolution in chordates: Lessons from functional analyses of cephalochordate cis‐regulatory modules. Dev Growth Differ 2020; 62:279-300. [DOI: 10.1111/dgd.12684] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/25/2020] [Accepted: 05/27/2020] [Indexed: 12/20/2022]
Affiliation(s)
- Yuuri Yasuoka
- Laboratory for Comprehensive Genomic Analysis RIKEN Center for Integrative Medical Sciences Tsurumi‐ku Japan
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Kozmikova I, Kozmik Z. Wnt/β-catenin signaling is an evolutionarily conserved determinant of chordate dorsal organizer. eLife 2020; 9:56817. [PMID: 32452768 PMCID: PMC7292647 DOI: 10.7554/elife.56817] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 05/25/2020] [Indexed: 12/11/2022] Open
Abstract
Deciphering the mechanisms of axis formation in amphioxus is a key step to understanding the evolution of chordate body plan. The current view is that Nodal signaling is the only factor promoting the dorsal axis specification in the amphioxus, whereas Wnt/β-catenin signaling plays no role in this process. Here, we re-examined the role of Wnt/βcatenin signaling in the dorsal/ventral patterning of amphioxus embryo. We demonstrated that the spatial activity of Wnt/β-catenin signaling is located in presumptive dorsal cells from cleavage to gastrula stage, and provided functional evidence that Wnt/β-catenin signaling is necessary for the specification of dorsal cell fate in a stage-dependent manner. Microinjection of Wnt8 and Wnt11 mRNA induced ectopic dorsal axis in neurulae and larvae. Finally, we demonstrated that Nodal and Wnt/β-catenin signaling cooperate to promote the dorsal-specific gene expression in amphioxus gastrula. Our study reveals high evolutionary conservation of dorsal organizer formation in the chordate lineage.
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Affiliation(s)
- Iryna Kozmikova
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Zbynek Kozmik
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
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Scerbo P, Monsoro-Burq AH. The vertebrate-specific VENTX/NANOG gene empowers neural crest with ectomesenchyme potential. Sci Adv 2020; 6:eaaz1469. [PMID: 32494672 PMCID: PMC7190326 DOI: 10.1126/sciadv.aaz1469] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 02/27/2020] [Indexed: 05/10/2023]
Abstract
During Cambrian, unipotent progenitors located at the neural (plate) border (NB) of an Olfactoria chordate embryo acquired the competence to form ectomesenchyme, pigment cells and neurons, initiating the rise of the multipotent neural crest cells (NC) specific to vertebrates. Surprisingly, the known vertebrate NB/NC transcriptional circuitry is a constrained feature also found in invertebrates. Therefore, evidence for vertebrate-specific innovations endowing vertebrate NC with multipotency is still missing. Here, we identified VENTX/NANOG and POU5/OCT4 as vertebrate-specific innovations. When VENTX was depleted in vivo and in directly-induced NC, the NC lost its early multipotent state and its skeletogenic potential, but kept sensory neuron and pigment identity, thus reminiscent of invertebrate NB precursors. In vivo, VENTX gain-of-function enabled NB specifiers to reprogram embryonic non-neural ectoderm towards early NC identity. We propose that skeletogenic NC evolved by acquiring VENTX/NANOG activity, promoting a novel multipotent progenitor regulatory state into the pre-existing sensory neuron/pigment NB program.
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Affiliation(s)
- Pierluigi Scerbo
- Univ. Paris Sud, Université Paris Saclay, Centre Universitaire, 15, rue Georges Clémenceau, F-91405 Orsay, France
- Institut Curie Research Division, PSL Research University, CNRS UMR 3347, INSERM U1021, F-91405 Orsay, France
| | - Anne H. Monsoro-Burq
- Univ. Paris Sud, Université Paris Saclay, Centre Universitaire, 15, rue Georges Clémenceau, F-91405 Orsay, France
- Institut Curie Research Division, PSL Research University, CNRS UMR 3347, INSERM U1021, F-91405 Orsay, France
- Institut Universitaire de France, F-75005 Paris, France
- Corresponding author.
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Yasuoka Y, Taira M. Microinjection of DNA Constructs into Xenopus Embryos for Gene Misexpression and cis-Regulatory Module Analysis. Cold Spring Harb Protoc 2019; 2019:pdb.prot097279. [PMID: 30131366 DOI: 10.1101/pdb.prot097279] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Introducing exogenous DNA into an embryo can promote misexpression of a gene of interest via transcription regulated by an attached enhancer-promoter. This protocol describes plasmid DNA microinjection into Xenopus embryos for misexpression of genes after zygotic gene expression begins. It also describes a method for coinjecting a reporter plasmid with mRNA or antisense morpholinos to perform luciferase reporter assays, which are useful for quantitative analysis of cis-regulatory sequences responding to endogenous or exogenous stimuli in embryos.
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Affiliation(s)
- Yuuri Yasuoka
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Masanori Taira
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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Yasuoka Y, Tando Y, Kubokawa K, Taira M. Evolution of cis-regulatory modules for the head organizer gene goosecoid in chordates: comparisons between Branchiostoma and Xenopus. Zoological Lett 2019; 5:27. [PMID: 31388442 PMCID: PMC6679436 DOI: 10.1186/s40851-019-0143-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Accepted: 07/12/2019] [Indexed: 05/03/2023]
Abstract
BACKGROUND In cephalochordates (amphioxus), the notochord runs along the dorsal to the anterior tip of the body. In contrast, the vertebrate head is formed anterior to the notochord, as a result of head organizer formation in anterior mesoderm during early development. A key gene for the vertebrate head organizer, goosecoid (gsc), is broadly expressed in the dorsal mesoderm of amphioxus gastrula. Amphioxus gsc expression subsequently becomes restricted to the posterior notochord from the early neurula. This has prompted the hypothesis that a change in expression patterns of gsc led to development of the vertebrate head during chordate evolution. However, molecular mechanisms of head organizer evolution involving gsc have never been elucidated. RESULTS To address this question, we compared cis-regulatory modules of vertebrate organizer genes between amphioxus, Branchiostoma japonicum, and frogs, Xenopus laevis and Xenopus tropicalis. Here we show conservation and diversification of gene regulatory mechanisms through cis-regulatory modules for gsc, lim1/lhx1, and chordin in Branchiostoma and Xenopus. Reporter analysis using Xenopus embryos demonstrates that activation of gsc by Nodal/FoxH1 signal through the 5' upstream region, that of lim1 by Nodal/FoxH1 signal through the first intron, and that of chordin by Lim1 through the second intron, are conserved between amphioxus and Xenopus. However, activation of gsc by Lim1 and Otx through the 5' upstream region in Xenopus are not conserved in amphioxus. Furthermore, the 5' region of amphioxus gsc recapitulated the amphioxus-like posterior mesoderm expression of the reporter gene in transgenic Xenopus embryos. CONCLUSIONS On the basis of this study, we propose a model, in which the gsc gene acquired the cis-regulatory module bound with Lim1 and Otx at its 5' upstream region to be activated persistently in anterior mesoderm, in the vertebrate lineage. Because Gsc globally represses trunk (notochord) genes in the vertebrate head organizer, this cooption of gsc in vertebrates appears to have resulted in inhibition of trunk genes and acquisition of the head organizer and its derivative prechordal plate.
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Affiliation(s)
- Yuuri Yasuoka
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa, 904-0495 Japan
- Laboratory for Comprehensive Genomic Analysis, RIKEN Center for Integrative Medical Sciences, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045 Japan
| | - Yukiko Tando
- Center for Advance Marine Research, Ocean Research Institute, The University of Tokyo, 1-15-1, Minamidai, Nakano-ku, Tokyo, 164-8639 Japan
- Present address: Cell Resource Center for Biomedical Research, Institute of Development, Aging and Cancer (IDAC), Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575 Japan
| | - Kaoru Kubokawa
- Center for Advance Marine Research, Ocean Research Institute, The University of Tokyo, 1-15-1, Minamidai, Nakano-ku, Tokyo, 164-8639 Japan
- Present address: SIRC, Teikyo University, 2-11-1, Itabashi-ku, Tokyo, 173-8605 Japan
| | - Masanori Taira
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
- Present address: Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551 Japan
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Shi C, Huang J, Chen S, Li G, Wang Y. Generation of two transgenic amphioxus lines using the Tol2 transposon system. J Genet Genomics 2018; 45:513-516. [PMID: 30268359 DOI: 10.1016/j.jgg.2018.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 05/06/2018] [Accepted: 06/12/2018] [Indexed: 12/26/2022]
Affiliation(s)
- Chenggang Shi
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Jing Huang
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
| | - Shixi Chen
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China; State-Province Joint Engineering Laboratory of Marine Bioproducts and Technology, Xiamen University, Xiamen 361102, China
| | - Guang Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China.
| | - Yiquan Wang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China.
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Barton-Owen TB, Ferrier DEK, Somorjai IML. Pax3/7 duplicated and diverged independently in amphioxus, the basal chordate lineage. Sci Rep 2018; 8:9414. [PMID: 29925900 PMCID: PMC6010424 DOI: 10.1038/s41598-018-27700-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 06/06/2018] [Indexed: 01/06/2023] Open
Abstract
The Pax3/7 transcription factor family is integral to developmental gene networks contributing to important innovations in vertebrate evolution, including the neural crest. The basal chordate lineage of amphioxus is ideally placed to understand the dynamics of the gene regulatory network evolution that produced these novelties. We report here the discovery that the cephalochordate lineage possesses two Pax3/7 genes, Pax3/7a and Pax3/7b. The tandem duplication is ancestral to all extant amphioxus, occurring in both Asymmetron and Branchiostoma, but originated after the split from the lineage leading to vertebrates. The two paralogues are differentially expressed during embryonic development, particularly in neural and somitic tissues, suggesting distinct regulation. Our results have implications for the study of amphioxus regeneration, neural plate and crest evolution, and differential tandem paralogue evolution.
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Affiliation(s)
- Thomas B Barton-Owen
- University of St Andrews, Gatty Marine Laboratory, Scottish Oceans Institute, East Sands, St Andrews, Fife, KY16 8LB, UK.,University of St Andrews, Biomedical Sciences Research Complex, North Haugh, St Andrews, Fife, KY16 9ST, UK
| | - David E K Ferrier
- University of St Andrews, Gatty Marine Laboratory, Scottish Oceans Institute, East Sands, St Andrews, Fife, KY16 8LB, UK
| | - Ildikó M L Somorjai
- University of St Andrews, Gatty Marine Laboratory, Scottish Oceans Institute, East Sands, St Andrews, Fife, KY16 8LB, UK. .,University of St Andrews, Biomedical Sciences Research Complex, North Haugh, St Andrews, Fife, KY16 9ST, UK.
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Kozmikova I, Kozmik Z. Gene regulation in amphioxus: An insight from transgenic studies in amphioxus and vertebrates. Mar Genomics 2015; 24 Pt 2:159-66. [PMID: 26094865 DOI: 10.1016/j.margen.2015.06.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 06/10/2015] [Accepted: 06/10/2015] [Indexed: 01/07/2023]
Abstract
Cephalochordates, commonly known as amphioxus or lancelets, are the most basal subphylum of chordates. Cephalochordates are thus key to understanding the origin of vertebrates and molecular mechanisms underlying vertebrate evolution. The evolution of developmental control mechanisms during invertebrate-to-vertebrate transition involved not only gene duplication events, but also specific changes in spatial and temporal expression of many genes. To get insight into the spatiotemporal regulation of gene expression during invertebrate-to-vertebrate transition, functional studies of amphioxus gene regulatory elements are highly warranted. Here, we review transgenic studies performed in amphioxus and vertebrates using promoters and enhancers derived from the genome of Branchiostoma floridae. We describe the current methods of transgenesis in amphioxus, provide evidence of Tol2 transposon-generated transgenic embryos of Branchiostoma lanceolatum and discuss possible future directions. We envision that comparative transgenic analysis of gene regulatory sequences in the context of amphioxus and vertebrate embryos will likely provide an important mechanistic insight into the evolution of vertebrate body plan.
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Affiliation(s)
- Iryna Kozmikova
- Institute of Molecular Genetics of the Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic
| | - Zbynek Kozmik
- Institute of Molecular Genetics of the Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic.
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10
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Abstract
Evolutionary innovations often arise by tinkering with preexisting components building new regulatory networks by the rewiring of old parts. The cranial placodes of vertebrates, ectodermal thickenings that give rise to many of the cranial sense organs (ear, nose, lateral line) and ganglia, originated as such novel structures, when vertebrate ancestors elaborated their head in support of a more active and exploratory life style. This review addresses the question of how cranial placodes evolved by tinkering with ectodermal patterning mechanisms and sensory and neurosecretory cell types that have their own evolutionary history. With phylogenetic relationships among the major branches of metazoans now relatively well established, a comparative approach is used to infer, which structures evolved in which lineages and allows us to trace the origin of placodes and their components back from ancestor to ancestor. Some of the core networks of ectodermal patterning and sensory and neurosecretory differentiation were already established in the common ancestor of cnidarians and bilaterians and were greatly elaborated in the bilaterian ancestor (with BMP- and Wnt-dependent patterning of dorsoventral and anteroposterior ectoderm and multiple neurosecretory and sensory cell types). Rostral and caudal protoplacodal domains, giving rise to some neurosecretory and sensory cells, were then established in the ectoderm of the chordate and tunicate-vertebrate ancestor, respectively. However, proper cranial placodes as clusters of proliferating progenitors producing high-density arrays of neurosecretory and sensory cells only evolved and diversified in the ancestors of vertebrates.
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Affiliation(s)
- Gerhard Schlosser
- School of Natural Sciences & Regenerative Medicine Institute (REMEDI), National University of Ireland, Galway, Ireland.
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Fritzenwanker JH, Gerhart J, Freeman RM, Lowe CJ. The Fox/Forkhead transcription factor family of the hemichordate Saccoglossus kowalevskii. EvoDevo 2014; 5:17. [PMID: 24987514 PMCID: PMC4077281 DOI: 10.1186/2041-9139-5-17] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 04/03/2014] [Indexed: 12/31/2022] Open
Abstract
Background The Fox gene family is a large family of transcription factors that arose early in organismal evolution dating back to at least the common ancestor of metazoans and fungi. They are key components of many gene regulatory networks essential for embryonic development. Although much is known about the role of Fox genes during vertebrate development, comprehensive comparative studies outside vertebrates are sparse. We have characterized the Fox transcription factor gene family from the genome of the enteropneust hemichordate Saccoglossus kowalevskii, including phylogenetic analysis, genomic organization, and expression analysis during early development. Hemichordates are a sister group to echinoderms, closely related to chordates and are a key group for tracing the evolution of gene regulatory mechanisms likely to have been important in the diversification of the deuterostome phyla. Results Of the 22 Fox gene families that were likely present in the last common ancestor of all deuterostomes, S. kowalevskii has a single ortholog of each group except FoxH, which we were unable to detect, and FoxQ2, which has three paralogs. A phylogenetic analysis of the FoxQ2 family identified an ancestral duplication in the FoxQ2 lineage at the base of the bilaterians. The expression analyses of all 23 Fox genes of S. kowalevskii provide insights into the evolution of components of the regulatory networks for the development of pharyngeal gill slits (foxC, foxL1, and foxI), mesoderm patterning (foxD, foxF, foxG), hindgut development (foxD, foxI), cilia formation (foxJ1), and patterning of the embryonic apical territory (foxQ2). Conclusions Comparisons of our results with data from echinoderms, chordates, and other bilaterians help to develop hypotheses about the developmental roles of Fox genes that likely characterized ancestral deuterostomes and bilaterians, and more recent clade-specific innovations.
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Affiliation(s)
- Jens H Fritzenwanker
- Hopkins Marine Station of Stanford University, 120 Oceanview Boulevard, Pacific Grove, CA 93950, USA
| | - John Gerhart
- Department of Molecular and Cell Biology, University of California, 142 Life Sciences Addition #3200, Berkeley, CA 94720, USA
| | - Robert M Freeman
- Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Warren Alpert 536, Boston, MA 02115, USA
| | - Christopher J Lowe
- Hopkins Marine Station of Stanford University, 120 Oceanview Boulevard, Pacific Grove, CA 93950, USA
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Kozmikova I, Candiani S, Fabian P, Gurska D, Kozmik Z. Essential role of Bmp signaling and its positive feedback loop in the early cell fate evolution of chordates. Dev Biol 2013; 382:538-54. [DOI: 10.1016/j.ydbio.2013.07.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 07/18/2013] [Accepted: 07/19/2013] [Indexed: 11/25/2022]
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Terada K, Misao S, Katase N, Nishimatsu S, Nohno T. Interaction of Wnt Signaling with BMP/Smad Signaling during the Transition from Cell Proliferation to Myogenic Differentiation in Mouse Myoblast-Derived Cells. Int J Cell Biol 2013; 2013:616294. [PMID: 23864860 DOI: 10.1155/2013/616294] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Accepted: 06/03/2013] [Indexed: 11/17/2022] Open
Abstract
Background. Wnt signaling is involved in muscle formation through β-catenin-dependent or -independent pathways, but interactions with other signaling pathways including transforming growth factor β/Smad have not been precisely elucidated. Results. As Wnt4 stimulates myogenic differentiation by antagonizing myostatin (GDF8) activity, we examined the role of Wnt4 signaling during muscle differentiation in the C2C12 myoblast cell line. Among several extrinsic signaling molecules examined in a microarray analysis of C2C12 cells during the transition from cell proliferation to differentiation after mitogen deprivation, bone morphogenetic protein 4 (BMP4) expression was prominently increased. Wnt4 overexpression had similar effects on BMP4 expression. BMP4 was able to inhibit muscle differentiation when added to the culture medium. BMP4 and noggin had no effects on the cellular localization of β-catenin induced by Wnt3a; however, the BMP4-induced phosphorylation of Smad1/5/8 was enhanced by Wnt4, but not by Wnt3a. The BMP antagonist noggin effectively stimulated muscle differentiation through binding to endogenous BMPs, and the effect of noggin was enhanced by the presence of Wnt3a and Wnt4. Conclusion. These results suggest that BMP/Smad pathways are modified through Wnt signaling during the transition from progenitor cell proliferation to myogenic differentiation, although Wnt/β-catenin signaling is not modified with BMP/Smad signaling.
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14
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Kong W, Yang Y, Zhang T, Shi DL, Zhang Y. Characterization of sFRP2-like in amphioxus: insights into the evolutionary conservation of Wnt antagonizing function. Evol Dev 2013; 14:168-77. [PMID: 23017025 DOI: 10.1111/j.1525-142x.2012.00533.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Wnt signaling plays a key role in embryonic patterning and morphogenetic movements. The secreted Frizzled-related proteins (sFRPs) antagonize Wnt signaling, but their roles in development are poorly understood. To determine whether function of sFRPs is conserved between amphioxus and vertebrates, we characterized sFRP2-like function in the amphioxus, Branchiostoma belcheri tsingtauense (B. belcheri). As in other species of Branchiostome, in B. belcheri, expression of sFRP2-like is restricted to the mesendoderm during gastrulation and to the anterior mesoderm and endoderm during neurulation. Functional analyses in frog (Xenopus laevis) indicate that amphioxus sFRP2-like potently inhibits both canonical and non-canonical Wnts. Thus, sFRP-2 probably functions in amphioxus embryos to inhibit Wnt signaling anteriorly. Moreover, dorsal overexpression of amphioxus sFRP2-like in Xenopus embryos, like inhibition of Wnt11, blocks gastrulation movements. This implies that sFRP2-like may also modulate Wnt signaling during gastrulation movements in amphioxus.
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Affiliation(s)
- Weihua Kong
- Institute of Developmental Biology, School of Life Sciences, Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, Shandong University, Jinan, 250100, China
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15
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Abstract
The phylogenetic position of amphioxus, together with its relatively simple and evolutionarily conserved morphology and genome structure, has led to its use as a model for studies of vertebrate evolution. In particular, the recent development of technical approaches, as well as access to the complete amphioxus genome sequence, has provided the community with tools with which to study the invertebrate-chordate to vertebrate transition. Here, we present this animal model, discussing its life cycle, the model species studied and the experimental techniques that it is amenable to. We also summarize the major findings made using amphioxus that have informed us about the evolution of vertebrate traits.
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Affiliation(s)
- Stephanie Bertrand
- CNRS UMR7232, UPMC Université Paris 06, Observatoire océanologique, F-66651 Banyuls-sur-Mer, France
| | - Hector Escriva
- CNRS UMR7232, UPMC Université Paris 06, Observatoire océanologique, F-66651 Banyuls-sur-Mer, France
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16
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Abstract
Tissue morphogenesis requires intricate temporal and spatial control of gene expression that is executed through specific gene regulatory networks (GRNs). GRNs are comprised from individual subcircuits of different levels of complexity. An important question is to elucidate the mutual relationship between those genes encoding DNA-binding factors that trigger the subcircuit with those that play major "later" roles during terminal differentiation via expression of specific genes that constitute the phenotype of individual tissues. The ocular lens is a classical model system to study tissue morphogenesis. Pax6 is essential for both lens placode formation and subsequent stages of lens morphogenesis, whereas c-Maf controls terminal differentiation of lens fibers, including regulation of crystallins, key lens structural proteins required for its transparency and refraction. Here, we show that Pax6 directly regulates c-Maf expression during lens development. A 1.3-kb c-Maf promoter with a 1.6-kb upstream enhancer (CR1) recapitulated the endogenous c-Maf expression pattern in lens and retinal pigmented epithelium. ChIP assays revealed binding of Pax6 and c-Maf to multiple regions of the c-Maf locus in lens chromatin. To predict functional Pax6-binding sites, nine novel variants of Pax6 DNA-binding motifs were identified and characterized. Two of these motifs predicted a pair of Pax6-binding sites in the CR1. Mutagenesis of these Pax6-binding sites inactivated transgenic expression in the lens but not in retinal pigmented epithelium. These data establish a novel regulatory role for Pax6 during lens development, link together the Pax6/c-Maf/crystallin regulatory network, and suggest a novel type of GRN subcircuit that controls a major part of embryonic lens development.
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Affiliation(s)
- Qing Xie
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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