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Gupta K, Pilli VSS, Aradhyam GK. Left-right axis asymmetry determining human Cryptic gene is transcriptionally repressed by Snail. BMC DEVELOPMENTAL BIOLOGY 2016; 16:39. [PMID: 27793090 PMCID: PMC5084438 DOI: 10.1186/s12861-016-0141-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 10/24/2016] [Indexed: 11/10/2022]
Abstract
BACKGROUND Establishment of the left-right axis is important for positioning organs asymmetrically in the developing vertebrate-embryo. A number of factors like maternally deposited molecules have emerged essential in initiating the specification of the axis; the downstream events, however, are regulated by signal-transduction and gene-expression changes identifying which remains a crucial challenge. The EGF-CFC family member Cryptic, that functions as a co-receptor for some TGF-beta ligands, is developmentally expressed in higher mammals and mutations in the gene cause loss or change in left-right axis asymmetry. Despite the strong phenotype, no transcriptional-regulator of this gene is known till date. RESULTS Using promoter-analyses tools, we found strong evidence that the developmentally essential transcription factor Snail binds to the human Cryptic-promoter. We cloned the promoter-region of human Cryptic in a reporter gene and observed decreased Cryptic-promoter activation upon increasing Snail expression. Further, the expression of Cryptic is down-regulated upon exogenous Snail expression, validating the reporter assays and the previously identified role of Snail as a transcriptional repressor. Finally, we demonstrate using gel-shift assay that Snail in nuclear extract of PANC1 cells interacts with the promoter-construct bearing putative Snail binding sites and confirm this finding using chromatin immunoprecipitation assay. CONCLUSIONS Snail represses the expression of human Cryptic and therefore, might affect the signaling via Nodal that has previously been demonstrated to specify the left-right axis using the EGF-CFC co-receptors.
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Affiliation(s)
- Kartik Gupta
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Vijaya Satish Sekhar Pilli
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Gopala Krishna Aradhyam
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600036, India.
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Katow H. Mechanisms of the epithelial-to-mesenchymal transition in sea urchin embryos. Tissue Barriers 2015; 3:e1059004. [PMID: 26716069 PMCID: PMC4681286 DOI: 10.1080/21688370.2015.1059004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 05/25/2015] [Accepted: 05/29/2015] [Indexed: 12/30/2022] Open
Abstract
Sea urchin mesenchyme is composed of the large micromere-derived spiculogenetic primary mesenchyme cells (PMC), veg2-tier macromere-derived non-spiculogenetic mesenchyme cells, the small micromere-derived germ cells, and the macro- and mesomere-derived neuronal mesenchyme cells. They are formed through the epithelial-to-mesenchymal transition (EMT) and possess multipotency, except PMCs that solely differentiate larval spicules. The process of EMT is associated with modification of epithelial cell surface property that includes loss of affinity to the apical and basal extracellular matrices, inter-epithelial cell adherens junctions and epithelial cell surface-specific proteins. These cell surface structures and molecules are endocytosed during EMT and utilized as initiators of cytoplasmic signaling pathways that often initiate protein phosphorylation to activate the gene regulatory networks. Acquisition of cell motility after EMT in these mesenchyme cells is associated with the expression of proteins such as Lefty, Snail and Seawi. Structural simplicity and genomic database of this model will further promote detailed EMT research.
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Affiliation(s)
- Hideki Katow
- Research Center for Marine Biology; Tohoku University; Asamushi, Aomori, Japan
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Medeiros DM. The evolution of the neural crest: new perspectives from lamprey and invertebrate neural crest-like cells. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2012; 2:1-15. [PMID: 23799627 DOI: 10.1002/wdev.85] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The neural crest is an embryonic cell population that gives rise to an array of tissues and structures in adult vertebrates including most of the head skeleton. Because neural crest cells (NCCs), and many of their derivatives, are unique to vertebrates, the evolution of the neural crest is thought to have potentiated vertebrate origins and diversification. However, the lack of clear NCC homologs in invertebrate chordates has made it difficult to reconstruct the evolutionary history of modern NCCs. In this review, the development of NCCs in the basal jawless vertebrate, lamprey, is compared with the development of neural crest-like cells in a range of invertebrates to deduce features of the first NCCs and their evolutionary precursors. These comparisons demonstrate that most of the defining attributes of NCCs are widespread features of invertebrate embryonic ectoderm. In addition, they suggest ancient origins for the neural border domain and chondroid skeletal tissue in the first bilaterian, and show that NCCs must have evolved in a chordate with an unduplicated invertebrate-type genome. On the basis of these observations, a stepwise model for the evolution of NCCs involving heterotopic and heterochronic activation of ancient ectodermal gene programs and new responsiveness to preexisting inducing signals is proposed. In light of the phylogenetic distribution of neural crest-like cells, the deep homology of developmental gene networks, and the central role of evolutionary loss in deuterostome evolution, this article concludes with suggestions for future studies in a broad range of bilaterians to test key aspects of this model. WIREs Dev Biol 2013, 2:1-15. doi: 10.1002/wdev.85 For further resources related to this article, please visit the WIREs website.
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Kerner P, Hung J, Béhague J, Le Gouar M, Balavoine G, Vervoort M. Insights into the evolution of the snail superfamily from metazoan wide molecular phylogenies and expression data in annelids. BMC Evol Biol 2009; 9:94. [PMID: 19426549 PMCID: PMC2688512 DOI: 10.1186/1471-2148-9-94] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 05/09/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND An important issue concerning the evolution of duplicated genes is to understand why paralogous genes are retained in a genome even though the most likely fate for a redundant duplicated gene is nonfunctionalization and thereby its elimination. Here we study a complex superfamily generated by gene duplications, the snail related genes that play key roles during animal development. We investigate the evolutionary history of these genes by genomic, phylogenetic, and expression data studies. RESULTS We systematically retrieved the full complement of snail related genes in several sequenced genomes. Through phylogenetic analysis, we found that the snail superfamily is composed of three ancestral families, snail, scratchA and scratchB. Analyses of the organization of the encoded proteins point out specific molecular signatures, indicative of functional specificities for Snail, ScratchA and ScratchB proteins. We also report the presence of two snail genes in the annelid Platynereis dumerilii, which have distinct expression patterns in the developing mesoderm, nervous system, and foregut. The combined expression of these two genes is identical to that of two independently duplicated snail genes in another annelid, Capitella spI, but different aspects of the expression patterns are differentially shared among paralogs of Platynereis and Capitella. CONCLUSION Our study indicates that the snail and scratchB families have expanded through multiple independent gene duplications in the different bilaterian lineages, and highlights potential functional diversifications of Snail and ScratchB proteins following duplications, as, in several instances, paralogous proteins in a given species show different domain organizations. Comparisons of the expression pattern domains of the two Platynereis and Capitella snail paralogs provide evidence for independent subfunctionalization events which have occurred in these two species. We propose that the snail related genes may be especially prone to subfunctionalization, and this would explain why the snail superfamily underwent so many independent duplications leading to maintenance of functional paralogs.
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Affiliation(s)
- Pierre Kerner
- Programme Development and Neurobiology, Institut Jacques Monod, UMR 7592 CNRS/Université Paris Diderot – Paris 7, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
- Evolution et Développement des Métazoaires, Centre de Génétique Moléculaire- FRE 3144 CNRS, 1, av. de la terrasse, 91198 Gif-sur-Yvette, France
- UFR des Sciences du Vivant, Université Paris Diderot – Paris 7, 5, rue Marie-Andrée Lagroua Weill-Hallé, 75205 Paris Cedex 13, France
| | - Johanne Hung
- Evolution et Développement des Métazoaires, Centre de Génétique Moléculaire- FRE 3144 CNRS, 1, av. de la terrasse, 91198 Gif-sur-Yvette, France
| | - Julien Béhague
- Programme Development and Neurobiology, Institut Jacques Monod, UMR 7592 CNRS/Université Paris Diderot – Paris 7, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
- Evolution et Développement des Métazoaires, Centre de Génétique Moléculaire- FRE 3144 CNRS, 1, av. de la terrasse, 91198 Gif-sur-Yvette, France
| | - Martine Le Gouar
- Evolution et Développement des Métazoaires, Centre de Génétique Moléculaire- FRE 3144 CNRS, 1, av. de la terrasse, 91198 Gif-sur-Yvette, France
| | - Guillaume Balavoine
- Programme Development and Neurobiology, Institut Jacques Monod, UMR 7592 CNRS/Université Paris Diderot – Paris 7, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
- Evolution et Développement des Métazoaires, Centre de Génétique Moléculaire- FRE 3144 CNRS, 1, av. de la terrasse, 91198 Gif-sur-Yvette, France
| | - Michel Vervoort
- Programme Development and Neurobiology, Institut Jacques Monod, UMR 7592 CNRS/Université Paris Diderot – Paris 7, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
- Evolution et Développement des Métazoaires, Centre de Génétique Moléculaire- FRE 3144 CNRS, 1, av. de la terrasse, 91198 Gif-sur-Yvette, France
- UFR des Sciences du Vivant, Université Paris Diderot – Paris 7, 5, rue Marie-Andrée Lagroua Weill-Hallé, 75205 Paris Cedex 13, France
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Wu SY, McClay DR. The Snail repressor is required for PMC ingression in the sea urchin embryo. Development 2007; 134:1061-70. [PMID: 17287249 PMCID: PMC3045531 DOI: 10.1242/dev.02805] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In metazoans, the epithelial-mesenchymal transition (EMT) is a crucial process for placing the mesoderm beneath the ectoderm. Primary mesenchyme cells (PMCs) at the vegetal pole of the sea urchin embryo ingress into the floor of the blastocoele from the blastula epithelium and later become the skeletogenic mesenchyme. This ingression movement is a classic EMT during which the PMCs penetrate the basal lamina, lose adherens junctions and migrate into the blastocoele. Later, secondary mesenchyme cells (SMCs) also enter the blastocoele via an EMT, but they accompany the invagination of the archenteron initially, in much the same way vertebrate mesenchyme enters the embryo along with endoderm. Here we identify a sea urchin ortholog of the Snail transcription factor, and focus on its roles regulating EMT during PMC ingression. Functional knockdown analyses of Snail in whole embryos and chimeras demonstrate that Snail is required in micromeres for PMC ingression. Snail represses the transcription of cadherin, a repression that appears evolutionarily conserved throughout the animal kingdom. Furthermore, Snail expression is required for endocytosis of cadherin, a cellular activity that accompanies PMC ingression. Perturbation studies position Snail in the sea urchin micromere-PMC gene regulatory network (GRN), downstream of Pmar1 and Alx1, and upstream of several PMC-expressed proteins. Taken together, our findings indicate that Snail plays an essential role in PMCs to control the EMT process, in part through its repression of cadherin expression during PMC ingression, and in part through its role in the endocytosis that helps convert an epithelial cell to a mesenchyme cell.
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