The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Mélanie Debiais-thibaud - One of the best experts on this subject based on the ideXlab platform.
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Formation of oral and Pharyngeal dentition in teleosts depends on differential recruitment of retinoic acid signaling.
FASEB Journal, 2010Co-Authors: Yann Gibert, Laure Bernard, Mélanie Debiais-thibaud, Frank Bourrat, Jean-stéphane Joly, Karen Pottin, Axel Meyer, Sylvie Rétaux, David W Stock, William R JackmanAbstract:One of the goals of evolutionary developmental biology is to link specific adaptations to changes in developmental pathways. The dentition of cypriniform fishes, which in contrast to many other teleost fish species possess Pharyngeal Teeth but lack oral Teeth, provides a suitable model to study the development of feeding adaptations. Here, we have examined the involvement of retinoic acid (RA) in tooth development and show that RA is specifically required to induce the Pharyngeal tooth developmental program in zebrafish. Perturbation of RA signaling at this stage abolished tooth induction without affecting the development of tooth-associated ceratobranchial bones. We show that this inductive event is dependent on RA synthesis from aldh1a2 in the ventral posterior pharynx. Fibroblast growth factor (FGF) signaling has been shown to be critical for tooth induction in zebrafish, and its loss has been associated with oral tooth loss in cypriniform fishes. Pharmacological treatments targeting the RA and FGF pathways revealed that both pathways act independently during tooth induction. In contrast, we find that in Mexican tetra and medaka, species that also possess oral Teeth, both oral and Pharyngeal Teeth are induced independently of RA. Our analyses suggest an evolutionary scenario in which the gene network controlling tooth development obtained RA dependency in the lineage leading to the cypriniforms. The loss of Pharyngeal Teeth in this group was cancelled out through a shift in aldh1a2 expression, while oral Teeth might have been lost ultimately due to deficient RA signaling in the oral cavity.-Gibert, Y., Bernard, L., Debiais-Thibaud, M., Bourrat, F., Joly, J.-S., Pottin, K., Meyer, A., Retaux, S., Stock, D. W., Jackman, W. R., Seritrakul, P., Begemann, G., Laudet, V. Formation of oral and Pharyngeal dentition in teleosts depends on differential recruitment of retinoic acid signaling.
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Low divergence in Dlx gene expression between dentitions of the medaka (Oryzias latipes) versus high level of expression shuffling in osteichtyans.
Evolution & development, 2008Co-Authors: Mélanie Debiais-thibaud, Isabelle Germon, Didier Casane, Patrick Laurenti, Véronique Borday-birrauxAbstract:SUMMARY Serially homologous structures are believed to originate from the redeployment of a genetic cascade in different locations of the body. Serial homologs may diverge at the genetic and morphological level and acquire developmental independency (individualization). Teeth are repeated units that form dentitions found on different bones of the oral–Pharyngeal cavity in gnathostomes and provide a good model to study such processes. Previous comparisons of dlx gene expression patterns between mouse oral Teeth and zebrafish Pharyngeal Teeth showed a high level of divergence. Furthermore, these genes are differentially expressed in different Teeth of the zebrafish, and in the mouse they are responsible for tooth identity (incisors vs. molars). We examined the potential divergence of dlx gene expression between oral and Pharyngeal Teeth by examining the expression pattern in the development of the first generation Teeth of the medaka and comparing it with data from the zebrafish and the mouse. Out of the seven medaka dlx genes, five are expressed during odontogenesis compared with six in both the zebrafish and the mouse. The only difference observed between oral and Pharyngeal Teeth in the medaka is an earlier expression of dlx5a in the oral dental epithelium. The subset of dlx genes expressed in the medaka, zebrafish, and mouse is slightly different but their detailed expression patterns are highly divergent. Our results demonstrate a low constraint on dlx gene expression shuffling in the odontogenic cascade within osteichtyans but the non-individualization of oral and Pharyngeal dentitions in the medaka.
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Development of oral and Pharyngeal Teeth in the medaka (Oryzias latipes): comparison of morphology and expression ofeve1 gene
Journal of Experimental Zoology Part B: Molecular and Developmental Evolution, 2007Co-Authors: Mélanie Debiais-thibaud, Véronique Borday-birraux, Isabelle Germon, Frank Bourrat, Cushla Jane Metcalfe, Didier Casane, Patrick LaurentiAbstract:Gnathostome Teeth are one of the most promising models for developmental evolutionary studies, they are the most abundant organ in the fossil record and an excellent example of organogenesis. Teeth have a complex morphology and are restricted to the mouth in mammals, whereas actinopterygian Teeth have a simple morphology and are found in several locations, notably on Pharyngeal bones. Morphological and developmental similarities support the hypothesis that oral and Pharyngeal Teeth are serially homologous. Gene expression data from the mouse and some teleosts have shown that the gene families involved in Pharyngeal odontogenesis are also involved in oral tooth formation, with the notable exception of the evx gene family. Here, we present a complete description of early odontogenesis in the medaka (Oryzias latipes), which has both oral and Pharyngeal dentition. We show that oral and Pharyngeal Teeth share deep developmental similarities. In the medaka, like in the zebrafish, eve1 is the only evx gene expressed during odontogenesis. In each forming tooth, regardless of its location, eve1 transcription is activated in the placode, then becomes restricted to the inner dental epithelium and is activated in the dental mesenchyme during early differentiation, and finally ceases at late differentiation. Thus eve1 expression is not specific to Pharyngeal Teeth development as was previously suggested. Because it permits direct comparisons between oral and Pharyngeal Teeth by molecular, development and functional studies, the medaka is an excellent model to develop further insights into the evolution of odontogenesis in gnathostomes. J. Exp. Zool. (Mol. Dev. Evol.) 308B, 2007. (c) 2007 Wiley-Liss, Inc
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Development of oral and Pharyngeal Teeth in the medaka (Oryzias latipes): comparison of morphology and expression of eve1 gene.
Journal of Experimental Zoology Part B: Molecular and Developmental Evolution, 2007Co-Authors: Mélanie Debiais-thibaud, Véronique Borday-birraux, Isabelle Germon, Frank Bourrat, Cushla Jane Metcalfe, Didier Casane, Patrick LaurentiAbstract:Gnathostome Teeth are one of the most promising models for developmental evolutionary studies, they are the most abundant organ in the fossil record and an excellent example of organogenesis. Teeth have a complex morphology and are restricted to the mouth in mammals, whereas actinopterygian Teeth have a simple morphology and are found in several locations, notably on Pharyngeal bones. Morphological and developmental similarities support the hypothesis that oral and Pharyngeal Teeth are serially homologous. Gene expression data from the mouse and some teleosts have shown that the gene families involved in Pharyngeal odontogenesis are also involved in oral tooth formation, with the notable exception of the evx gene family. Here, we present a complete description of early odontogenesis in the medaka (Oryzias latipes), which has both oral and Pharyngeal dentition. We show that oral and Pharyngeal Teeth share deep developmental similarities. In the medaka, like in the zebrafish, eve1 is the only evx gene expressed during odontogenesis. In each forming tooth, regardless of its location, eve1 transcription is activated in the placode, then becomes restricted to the inner dental epithelium and is activated in the dental mesenchyme during early differentiation, and finally ceases at late differentiation. Thus eve1 expression is not specific to Pharyngeal Teeth development as was previously suggested. Because it permits direct comparisons between oral and Pharyngeal Teeth by molecular, development and functional studies, the medaka is an excellent model to develop further insights into the evolution of odontogenesis in gnathostomes. J. Exp. Zool. (Mol. Dev. Evol.) 308B, 2007. (c) 2007 Wiley-Liss, Inc.
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Development of Oral and Pharyngeal Teeth in the Medaka (Oryzias latipes): Comparison of Morphology and Expression of eve1 Gene
JOURNAL OF EXPERIMENTAL ZOOLOGY (MOL DEV EVOL), 2007Co-Authors: Mélanie Debiais-thibaud, Véronique Borday-birraux, Isabelle Germon, Frank Bourrat, Cushla Jane Metcalfe, Didier Casane, Patrick LaurentiAbstract:Gnathostome Teeth are one of the most promising models for developmental evolutionary studies, they are the most abundant organ in the fossil record and an excellent example of organogenesis. Teeth have a complex morphology and are restricted to the mouth in mammals, whereas actinopterygian Teeth have a simple morphology and are found in several locations, notably on Pharyngeal bones. Morphological and developmental similarities support the hypothesis that oral and Pharyngeal Teeth are serially homologous. Gene expression data from the mouse and some teleosts have shown that the gene families involved in Pharyngeal odontogenesis are also involved in oral tooth formation, with the notable exception of the evx gene family. Here, we present a complete description of early odontogenesis in the medaka (Oryzias latipes), which has both oral and Pharyngeal dentition. We show that oral and Pharyngeal Teeth share deep developmental similarities. In the medaka, like in the zebrafish, eve1 is the only evx gene expressed during odontogenesis. In each forming tooth, regardless of its location, eve1 transcription is activated in the placode, then becomes restricted to the inner dental epithelium and is activated in the dental mesenchyme during early differentiation, and finally ceases at late differentiation. Thus eve1 expression is not specific to Pharyngeal Teeth development as was previously suggested. Because it permits direct comparisons between oral and Pharyngeal Teeth by molecular, development and functional studies, the medaka is an excellent model to develop further insights into the evolution of odontogenesis in gnathostomes.. 2007. Development of oral and Pharyngeal Teeth in the medaka (Oryzias latipes): comparison of morphology and expression of eve1 gene. J. Exp. Zool. (Mol. Dev. Evol.) 308B:693-708. Teeth are regarded by both palaeontologists and developmental geneticists as an excellent model for studying evolutionary mechanisms for several reasons. They are the most abundant organ in the vertebrate fossil record, chiefly because they are mainly composed of hard tissues and are partially hyper mineralised. They have undergone extensive morphological variation during the course of evolution, are therefore a very informative character, and have been used in a wide range of palaeontological studies. Finally, although the tooth is one of the simplest organs that form during gnathostomes development, it represents a model of organ ontogeny.
Patrick Laurenti - One of the best experts on this subject based on the ideXlab platform.
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Low divergence in Dlx gene expression between dentitions of the medaka (Oryzias latipes) versus high level of expression shuffling in osteichtyans.
Evolution & development, 2008Co-Authors: Mélanie Debiais-thibaud, Isabelle Germon, Didier Casane, Patrick Laurenti, Véronique Borday-birrauxAbstract:SUMMARY Serially homologous structures are believed to originate from the redeployment of a genetic cascade in different locations of the body. Serial homologs may diverge at the genetic and morphological level and acquire developmental independency (individualization). Teeth are repeated units that form dentitions found on different bones of the oral–Pharyngeal cavity in gnathostomes and provide a good model to study such processes. Previous comparisons of dlx gene expression patterns between mouse oral Teeth and zebrafish Pharyngeal Teeth showed a high level of divergence. Furthermore, these genes are differentially expressed in different Teeth of the zebrafish, and in the mouse they are responsible for tooth identity (incisors vs. molars). We examined the potential divergence of dlx gene expression between oral and Pharyngeal Teeth by examining the expression pattern in the development of the first generation Teeth of the medaka and comparing it with data from the zebrafish and the mouse. Out of the seven medaka dlx genes, five are expressed during odontogenesis compared with six in both the zebrafish and the mouse. The only difference observed between oral and Pharyngeal Teeth in the medaka is an earlier expression of dlx5a in the oral dental epithelium. The subset of dlx genes expressed in the medaka, zebrafish, and mouse is slightly different but their detailed expression patterns are highly divergent. Our results demonstrate a low constraint on dlx gene expression shuffling in the odontogenic cascade within osteichtyans but the non-individualization of oral and Pharyngeal dentitions in the medaka.
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Development of oral and Pharyngeal Teeth in the medaka (Oryzias latipes): comparison of morphology and expression ofeve1 gene
Journal of Experimental Zoology Part B: Molecular and Developmental Evolution, 2007Co-Authors: Mélanie Debiais-thibaud, Véronique Borday-birraux, Isabelle Germon, Frank Bourrat, Cushla Jane Metcalfe, Didier Casane, Patrick LaurentiAbstract:Gnathostome Teeth are one of the most promising models for developmental evolutionary studies, they are the most abundant organ in the fossil record and an excellent example of organogenesis. Teeth have a complex morphology and are restricted to the mouth in mammals, whereas actinopterygian Teeth have a simple morphology and are found in several locations, notably on Pharyngeal bones. Morphological and developmental similarities support the hypothesis that oral and Pharyngeal Teeth are serially homologous. Gene expression data from the mouse and some teleosts have shown that the gene families involved in Pharyngeal odontogenesis are also involved in oral tooth formation, with the notable exception of the evx gene family. Here, we present a complete description of early odontogenesis in the medaka (Oryzias latipes), which has both oral and Pharyngeal dentition. We show that oral and Pharyngeal Teeth share deep developmental similarities. In the medaka, like in the zebrafish, eve1 is the only evx gene expressed during odontogenesis. In each forming tooth, regardless of its location, eve1 transcription is activated in the placode, then becomes restricted to the inner dental epithelium and is activated in the dental mesenchyme during early differentiation, and finally ceases at late differentiation. Thus eve1 expression is not specific to Pharyngeal Teeth development as was previously suggested. Because it permits direct comparisons between oral and Pharyngeal Teeth by molecular, development and functional studies, the medaka is an excellent model to develop further insights into the evolution of odontogenesis in gnathostomes. J. Exp. Zool. (Mol. Dev. Evol.) 308B, 2007. (c) 2007 Wiley-Liss, Inc
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Development of oral and Pharyngeal Teeth in the medaka (Oryzias latipes): comparison of morphology and expression of eve1 gene.
Journal of Experimental Zoology Part B: Molecular and Developmental Evolution, 2007Co-Authors: Mélanie Debiais-thibaud, Véronique Borday-birraux, Isabelle Germon, Frank Bourrat, Cushla Jane Metcalfe, Didier Casane, Patrick LaurentiAbstract:Gnathostome Teeth are one of the most promising models for developmental evolutionary studies, they are the most abundant organ in the fossil record and an excellent example of organogenesis. Teeth have a complex morphology and are restricted to the mouth in mammals, whereas actinopterygian Teeth have a simple morphology and are found in several locations, notably on Pharyngeal bones. Morphological and developmental similarities support the hypothesis that oral and Pharyngeal Teeth are serially homologous. Gene expression data from the mouse and some teleosts have shown that the gene families involved in Pharyngeal odontogenesis are also involved in oral tooth formation, with the notable exception of the evx gene family. Here, we present a complete description of early odontogenesis in the medaka (Oryzias latipes), which has both oral and Pharyngeal dentition. We show that oral and Pharyngeal Teeth share deep developmental similarities. In the medaka, like in the zebrafish, eve1 is the only evx gene expressed during odontogenesis. In each forming tooth, regardless of its location, eve1 transcription is activated in the placode, then becomes restricted to the inner dental epithelium and is activated in the dental mesenchyme during early differentiation, and finally ceases at late differentiation. Thus eve1 expression is not specific to Pharyngeal Teeth development as was previously suggested. Because it permits direct comparisons between oral and Pharyngeal Teeth by molecular, development and functional studies, the medaka is an excellent model to develop further insights into the evolution of odontogenesis in gnathostomes. J. Exp. Zool. (Mol. Dev. Evol.) 308B, 2007. (c) 2007 Wiley-Liss, Inc.
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Development of Oral and Pharyngeal Teeth in the Medaka (Oryzias latipes): Comparison of Morphology and Expression of eve1 Gene
JOURNAL OF EXPERIMENTAL ZOOLOGY (MOL DEV EVOL), 2007Co-Authors: Mélanie Debiais-thibaud, Véronique Borday-birraux, Isabelle Germon, Frank Bourrat, Cushla Jane Metcalfe, Didier Casane, Patrick LaurentiAbstract:Gnathostome Teeth are one of the most promising models for developmental evolutionary studies, they are the most abundant organ in the fossil record and an excellent example of organogenesis. Teeth have a complex morphology and are restricted to the mouth in mammals, whereas actinopterygian Teeth have a simple morphology and are found in several locations, notably on Pharyngeal bones. Morphological and developmental similarities support the hypothesis that oral and Pharyngeal Teeth are serially homologous. Gene expression data from the mouse and some teleosts have shown that the gene families involved in Pharyngeal odontogenesis are also involved in oral tooth formation, with the notable exception of the evx gene family. Here, we present a complete description of early odontogenesis in the medaka (Oryzias latipes), which has both oral and Pharyngeal dentition. We show that oral and Pharyngeal Teeth share deep developmental similarities. In the medaka, like in the zebrafish, eve1 is the only evx gene expressed during odontogenesis. In each forming tooth, regardless of its location, eve1 transcription is activated in the placode, then becomes restricted to the inner dental epithelium and is activated in the dental mesenchyme during early differentiation, and finally ceases at late differentiation. Thus eve1 expression is not specific to Pharyngeal Teeth development as was previously suggested. Because it permits direct comparisons between oral and Pharyngeal Teeth by molecular, development and functional studies, the medaka is an excellent model to develop further insights into the evolution of odontogenesis in gnathostomes.. 2007. Development of oral and Pharyngeal Teeth in the medaka (Oryzias latipes): comparison of morphology and expression of eve1 gene. J. Exp. Zool. (Mol. Dev. Evol.) 308B:693-708. Teeth are regarded by both palaeontologists and developmental geneticists as an excellent model for studying evolutionary mechanisms for several reasons. They are the most abundant organ in the vertebrate fossil record, chiefly because they are mainly composed of hard tissues and are partially hyper mineralised. They have undergone extensive morphological variation during the course of evolution, are therefore a very informative character, and have been used in a wide range of palaeontological studies. Finally, although the tooth is one of the simplest organs that form during gnathostomes development, it represents a model of organ ontogeny.
Véronique Borday-birraux - One of the best experts on this subject based on the ideXlab platform.
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Low divergence in Dlx gene expression between dentitions of the medaka (Oryzias latipes) versus high level of expression shuffling in osteichtyans.
Evolution & development, 2008Co-Authors: Mélanie Debiais-thibaud, Isabelle Germon, Didier Casane, Patrick Laurenti, Véronique Borday-birrauxAbstract:SUMMARY Serially homologous structures are believed to originate from the redeployment of a genetic cascade in different locations of the body. Serial homologs may diverge at the genetic and morphological level and acquire developmental independency (individualization). Teeth are repeated units that form dentitions found on different bones of the oral–Pharyngeal cavity in gnathostomes and provide a good model to study such processes. Previous comparisons of dlx gene expression patterns between mouse oral Teeth and zebrafish Pharyngeal Teeth showed a high level of divergence. Furthermore, these genes are differentially expressed in different Teeth of the zebrafish, and in the mouse they are responsible for tooth identity (incisors vs. molars). We examined the potential divergence of dlx gene expression between oral and Pharyngeal Teeth by examining the expression pattern in the development of the first generation Teeth of the medaka and comparing it with data from the zebrafish and the mouse. Out of the seven medaka dlx genes, five are expressed during odontogenesis compared with six in both the zebrafish and the mouse. The only difference observed between oral and Pharyngeal Teeth in the medaka is an earlier expression of dlx5a in the oral dental epithelium. The subset of dlx genes expressed in the medaka, zebrafish, and mouse is slightly different but their detailed expression patterns are highly divergent. Our results demonstrate a low constraint on dlx gene expression shuffling in the odontogenic cascade within osteichtyans but the non-individualization of oral and Pharyngeal dentitions in the medaka.
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Development of oral and Pharyngeal Teeth in the medaka (Oryzias latipes): comparison of morphology and expression ofeve1 gene
Journal of Experimental Zoology Part B: Molecular and Developmental Evolution, 2007Co-Authors: Mélanie Debiais-thibaud, Véronique Borday-birraux, Isabelle Germon, Frank Bourrat, Cushla Jane Metcalfe, Didier Casane, Patrick LaurentiAbstract:Gnathostome Teeth are one of the most promising models for developmental evolutionary studies, they are the most abundant organ in the fossil record and an excellent example of organogenesis. Teeth have a complex morphology and are restricted to the mouth in mammals, whereas actinopterygian Teeth have a simple morphology and are found in several locations, notably on Pharyngeal bones. Morphological and developmental similarities support the hypothesis that oral and Pharyngeal Teeth are serially homologous. Gene expression data from the mouse and some teleosts have shown that the gene families involved in Pharyngeal odontogenesis are also involved in oral tooth formation, with the notable exception of the evx gene family. Here, we present a complete description of early odontogenesis in the medaka (Oryzias latipes), which has both oral and Pharyngeal dentition. We show that oral and Pharyngeal Teeth share deep developmental similarities. In the medaka, like in the zebrafish, eve1 is the only evx gene expressed during odontogenesis. In each forming tooth, regardless of its location, eve1 transcription is activated in the placode, then becomes restricted to the inner dental epithelium and is activated in the dental mesenchyme during early differentiation, and finally ceases at late differentiation. Thus eve1 expression is not specific to Pharyngeal Teeth development as was previously suggested. Because it permits direct comparisons between oral and Pharyngeal Teeth by molecular, development and functional studies, the medaka is an excellent model to develop further insights into the evolution of odontogenesis in gnathostomes. J. Exp. Zool. (Mol. Dev. Evol.) 308B, 2007. (c) 2007 Wiley-Liss, Inc
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Development of oral and Pharyngeal Teeth in the medaka (Oryzias latipes): comparison of morphology and expression of eve1 gene.
Journal of Experimental Zoology Part B: Molecular and Developmental Evolution, 2007Co-Authors: Mélanie Debiais-thibaud, Véronique Borday-birraux, Isabelle Germon, Frank Bourrat, Cushla Jane Metcalfe, Didier Casane, Patrick LaurentiAbstract:Gnathostome Teeth are one of the most promising models for developmental evolutionary studies, they are the most abundant organ in the fossil record and an excellent example of organogenesis. Teeth have a complex morphology and are restricted to the mouth in mammals, whereas actinopterygian Teeth have a simple morphology and are found in several locations, notably on Pharyngeal bones. Morphological and developmental similarities support the hypothesis that oral and Pharyngeal Teeth are serially homologous. Gene expression data from the mouse and some teleosts have shown that the gene families involved in Pharyngeal odontogenesis are also involved in oral tooth formation, with the notable exception of the evx gene family. Here, we present a complete description of early odontogenesis in the medaka (Oryzias latipes), which has both oral and Pharyngeal dentition. We show that oral and Pharyngeal Teeth share deep developmental similarities. In the medaka, like in the zebrafish, eve1 is the only evx gene expressed during odontogenesis. In each forming tooth, regardless of its location, eve1 transcription is activated in the placode, then becomes restricted to the inner dental epithelium and is activated in the dental mesenchyme during early differentiation, and finally ceases at late differentiation. Thus eve1 expression is not specific to Pharyngeal Teeth development as was previously suggested. Because it permits direct comparisons between oral and Pharyngeal Teeth by molecular, development and functional studies, the medaka is an excellent model to develop further insights into the evolution of odontogenesis in gnathostomes. J. Exp. Zool. (Mol. Dev. Evol.) 308B, 2007. (c) 2007 Wiley-Liss, Inc.
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Development of Oral and Pharyngeal Teeth in the Medaka (Oryzias latipes): Comparison of Morphology and Expression of eve1 Gene
JOURNAL OF EXPERIMENTAL ZOOLOGY (MOL DEV EVOL), 2007Co-Authors: Mélanie Debiais-thibaud, Véronique Borday-birraux, Isabelle Germon, Frank Bourrat, Cushla Jane Metcalfe, Didier Casane, Patrick LaurentiAbstract:Gnathostome Teeth are one of the most promising models for developmental evolutionary studies, they are the most abundant organ in the fossil record and an excellent example of organogenesis. Teeth have a complex morphology and are restricted to the mouth in mammals, whereas actinopterygian Teeth have a simple morphology and are found in several locations, notably on Pharyngeal bones. Morphological and developmental similarities support the hypothesis that oral and Pharyngeal Teeth are serially homologous. Gene expression data from the mouse and some teleosts have shown that the gene families involved in Pharyngeal odontogenesis are also involved in oral tooth formation, with the notable exception of the evx gene family. Here, we present a complete description of early odontogenesis in the medaka (Oryzias latipes), which has both oral and Pharyngeal dentition. We show that oral and Pharyngeal Teeth share deep developmental similarities. In the medaka, like in the zebrafish, eve1 is the only evx gene expressed during odontogenesis. In each forming tooth, regardless of its location, eve1 transcription is activated in the placode, then becomes restricted to the inner dental epithelium and is activated in the dental mesenchyme during early differentiation, and finally ceases at late differentiation. Thus eve1 expression is not specific to Pharyngeal Teeth development as was previously suggested. Because it permits direct comparisons between oral and Pharyngeal Teeth by molecular, development and functional studies, the medaka is an excellent model to develop further insights into the evolution of odontogenesis in gnathostomes.. 2007. Development of oral and Pharyngeal Teeth in the medaka (Oryzias latipes): comparison of morphology and expression of eve1 gene. J. Exp. Zool. (Mol. Dev. Evol.) 308B:693-708. Teeth are regarded by both palaeontologists and developmental geneticists as an excellent model for studying evolutionary mechanisms for several reasons. They are the most abundant organ in the vertebrate fossil record, chiefly because they are mainly composed of hard tissues and are partially hyper mineralised. They have undergone extensive morphological variation during the course of evolution, are therefore a very informative character, and have been used in a wide range of palaeontological studies. Finally, although the tooth is one of the simplest organs that form during gnathostomes development, it represents a model of organ ontogeny.
Ann Huysseune - One of the best experts on this subject based on the ideXlab platform.
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multiple epithelia are required to develop Teeth deep inside the pharynx
Proceedings of the National Academy of Sciences of the United States of America, 2020Co-Authors: Veronika Oralova, Joana Rosa, Daria Larionova, Eckhard P Witten, Ann HuysseuneAbstract:To explain the evolutionary origin of vertebrate Teeth from odontodes, it has been proposed that competent epithelium spread into the oroPharyngeal cavity via the mouth and other possible channels such as the gill slits [Huysseune et al., 2009, J. Anat. 214, 465–476]. Whether tooth formation deep inside the pharynx in extant vertebrates continues to require external epithelia has not been addressed so far. Using zebrafish we have previously demonstrated that cells derived from the periderm penetrate the oroPharyngeal cavity via the mouth and via the endodermal pouches and connect to periderm-like cells that subsequently cover the entire endoderm-derived Pharyngeal epithelium [Rosa et al., 2019, Sci. Rep. 9, 10082]. We now provide conclusive evidence that the epithelial component of Pharyngeal Teeth in zebrafish (the enamel organ) is derived from medial endoderm, as hitherto assumed based on position deep in the pharynx. Yet, dental morphogenesis starts only after the corresponding endodermal pouch (pouch 6) has made contact with the skin ectoderm, and only after periderm-like cells have covered the prospective tooth-forming endodermal epithelium. Manipulation of signaling pathways shown to adversely affect tooth development indicates they act downstream of these events. We demonstrate that pouch–ectoderm contact and the presence of a periderm-like layer are both required, but not sufficient, for tooth initiation in the pharynx. We conclude that the earliest interactions to generate Pharyngeal Teeth encompass those between different epithelial populations (skin ectoderm, endoderm, and periderm-like cells in zebrafish), in addition to the epithelial–mesenchymal interactions that govern the formation of all vertebrate Teeth.
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Telomerase Expression in Medaka ( Oryzias melastigma) Pharyngeal Teeth.
Journal of Dental Research, 2017Co-Authors: Paul Witten, Dwt Au, Christoph Winkler, Ann HuysseuneAbstract:Nonmammalian vertebrates have the capacity of lifelong tooth replacement. In all vertebrates, tooth formation requires contact and interaction between the oral or Pharyngeal epithelium and the underlying mesenchyme. To secure lifelong replacement, the presence of odontogenic stem cells has been postulated, particularly in the epithelial compartment. This study uses an advanced teleost fish species, the marine medaka Oryzias melastigma, a close relative to Oryzias latipes, to examine the expression and distribution of telomerase reverse transcriptase (Tert), the catalytic unit of telomerase, in developing Pharyngeal Teeth and to relate these data to the proliferative activity of the cells. The data are complemented by expression analysis of the pluripotency marker oct4 and bona fide stem cell marker lgr5. Tert distribution and tert expression in developing tooth germs show a dynamic spatiotemporal pattern. Tert is present first in the mesenchyme but is downregulated as the odontoblasts differentiate. In co...
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Telomerase Expression in Medaka ( Oryzias melastigma) Pharyngeal Teeth.
Journal of dental research, 2017Co-Authors: Wh Tan, Paul Witten, Christoph Winkler, Ann HuysseuneAbstract:Nonmammalian vertebrates have the capacity of lifelong tooth replacement. In all vertebrates, tooth formation requires contact and interaction between the oral or Pharyngeal epithelium and the underlying mesenchyme. To secure lifelong replacement, the presence of odontogenic stem cells has been postulated, particularly in the epithelial compartment. This study uses an advanced teleost fish species, the marine medaka Oryzias melastigma, a close relative to Oryzias latipes, to examine the expression and distribution of telomerase reverse transcriptase (Tert), the catalytic unit of telomerase, in developing Pharyngeal Teeth and to relate these data to the proliferative activity of the cells. The data are complemented by expression analysis of the pluripotency marker oct4 and bona fide stem cell marker lgr5. Tert distribution and tert expression in developing tooth germs show a dynamic spatiotemporal pattern. Tert is present first in the mesenchyme but is downregulated as the odontoblasts differentiate. In contrast, in the epithelial enamel organ, Tert is absent during early stages of tooth formation and upregulated first in ameloblasts. Later, Tert is expressed and immunolocalized throughout the entire inner enamel epithelium. The pattern of Tert distribution is largely mutually exclusive with that of proliferating cell nuclear antigen (PCNA) immunoreactivity: highly proliferative cells, as revealed by PCNA staining, are negative for Tert; conversely, PCNA-negative cells are Tert-positive. Only the early condensed mesenchyme is both Tert- and PCNA-positive. The absence of tert-positive cells in the epithelial compartment of early tooth germs is underscored by the absence of oct4- and lgr5-positive cells, suggesting ways other than stem cell involvement to secure continuous renewal.
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A revised hypothesis on the evolutionary origin of the vertebrate dentition
Journal of Applied Ichthyology, 2010Co-Authors: Ann Huysseune, J-y Sire, Paul WittenAbstract:Despite claims to the contrary, the evolutionary origin of Teeth has not been definitely established. The classical 'outside in' theory stating that Teeth derive from odontodes that invaded the oral cavity in conjunction with the origin of jaws has been challenged by an alternative, 'inside out', hypothesis suggesting that Teeth evolved from Pharyngeal denticles, as endodermal derivatives, prior to the origin of jaws. We propose a third scenario, a revised 'outside in' hypothesis (Huysseune et al., 2009). Our hypothesis is consistent with the current data and avoids speculations about convergent tooth evolution. We suggest that Teeth may indeed have arisen before the origin of jaws, a pillar of the 'inside out' hypothesis, but not from the endodermally lined posterior pharynx. Rather, Teeth would have been the result of competent, odontode-forming ectoderm invading the oroPharyngeal cavity through the mouth as well as through the gill slits, interacting with neural-crest derived mesenchyme. Arguments in support of this hypothesis are: (i) the observation that Pharyngeal Teeth are present only in species known to possess gill slits, and disappear from the Pharyngeal region in early tetrapods concomitant with the closure of gill slits; (ii) the assumption that endoderm alone, together with neural crest, cannot form Teeth; (iii) observations on Pharyngeal tooth and gill slit formation in extant species; (iv) the observation that the dental lamina (sensu Reif, 1982) is not a prerequisite for tooth formation; (v) evidence that patterning does not distinguish Pharyngeal from skin denticles, and (vi) the observation on zebrafish mutants affected in the dermal skeleton. This 'modified outside in' hypothesis can be tested both on paleontological data (it predicts a correlation of the presence of Pharyngeal Teeth and of gill slits), and on developmental data in extant species (it predicts the necessity of an ectodermal signal to make [Pharyngeal] Teeth).
Isabelle Germon - One of the best experts on this subject based on the ideXlab platform.
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Low divergence in Dlx gene expression between dentitions of the medaka (Oryzias latipes) versus high level of expression shuffling in osteichtyans.
Evolution & development, 2008Co-Authors: Mélanie Debiais-thibaud, Isabelle Germon, Didier Casane, Patrick Laurenti, Véronique Borday-birrauxAbstract:SUMMARY Serially homologous structures are believed to originate from the redeployment of a genetic cascade in different locations of the body. Serial homologs may diverge at the genetic and morphological level and acquire developmental independency (individualization). Teeth are repeated units that form dentitions found on different bones of the oral–Pharyngeal cavity in gnathostomes and provide a good model to study such processes. Previous comparisons of dlx gene expression patterns between mouse oral Teeth and zebrafish Pharyngeal Teeth showed a high level of divergence. Furthermore, these genes are differentially expressed in different Teeth of the zebrafish, and in the mouse they are responsible for tooth identity (incisors vs. molars). We examined the potential divergence of dlx gene expression between oral and Pharyngeal Teeth by examining the expression pattern in the development of the first generation Teeth of the medaka and comparing it with data from the zebrafish and the mouse. Out of the seven medaka dlx genes, five are expressed during odontogenesis compared with six in both the zebrafish and the mouse. The only difference observed between oral and Pharyngeal Teeth in the medaka is an earlier expression of dlx5a in the oral dental epithelium. The subset of dlx genes expressed in the medaka, zebrafish, and mouse is slightly different but their detailed expression patterns are highly divergent. Our results demonstrate a low constraint on dlx gene expression shuffling in the odontogenic cascade within osteichtyans but the non-individualization of oral and Pharyngeal dentitions in the medaka.
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Development of oral and Pharyngeal Teeth in the medaka (Oryzias latipes): comparison of morphology and expression ofeve1 gene
Journal of Experimental Zoology Part B: Molecular and Developmental Evolution, 2007Co-Authors: Mélanie Debiais-thibaud, Véronique Borday-birraux, Isabelle Germon, Frank Bourrat, Cushla Jane Metcalfe, Didier Casane, Patrick LaurentiAbstract:Gnathostome Teeth are one of the most promising models for developmental evolutionary studies, they are the most abundant organ in the fossil record and an excellent example of organogenesis. Teeth have a complex morphology and are restricted to the mouth in mammals, whereas actinopterygian Teeth have a simple morphology and are found in several locations, notably on Pharyngeal bones. Morphological and developmental similarities support the hypothesis that oral and Pharyngeal Teeth are serially homologous. Gene expression data from the mouse and some teleosts have shown that the gene families involved in Pharyngeal odontogenesis are also involved in oral tooth formation, with the notable exception of the evx gene family. Here, we present a complete description of early odontogenesis in the medaka (Oryzias latipes), which has both oral and Pharyngeal dentition. We show that oral and Pharyngeal Teeth share deep developmental similarities. In the medaka, like in the zebrafish, eve1 is the only evx gene expressed during odontogenesis. In each forming tooth, regardless of its location, eve1 transcription is activated in the placode, then becomes restricted to the inner dental epithelium and is activated in the dental mesenchyme during early differentiation, and finally ceases at late differentiation. Thus eve1 expression is not specific to Pharyngeal Teeth development as was previously suggested. Because it permits direct comparisons between oral and Pharyngeal Teeth by molecular, development and functional studies, the medaka is an excellent model to develop further insights into the evolution of odontogenesis in gnathostomes. J. Exp. Zool. (Mol. Dev. Evol.) 308B, 2007. (c) 2007 Wiley-Liss, Inc
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Development of oral and Pharyngeal Teeth in the medaka (Oryzias latipes): comparison of morphology and expression of eve1 gene.
Journal of Experimental Zoology Part B: Molecular and Developmental Evolution, 2007Co-Authors: Mélanie Debiais-thibaud, Véronique Borday-birraux, Isabelle Germon, Frank Bourrat, Cushla Jane Metcalfe, Didier Casane, Patrick LaurentiAbstract:Gnathostome Teeth are one of the most promising models for developmental evolutionary studies, they are the most abundant organ in the fossil record and an excellent example of organogenesis. Teeth have a complex morphology and are restricted to the mouth in mammals, whereas actinopterygian Teeth have a simple morphology and are found in several locations, notably on Pharyngeal bones. Morphological and developmental similarities support the hypothesis that oral and Pharyngeal Teeth are serially homologous. Gene expression data from the mouse and some teleosts have shown that the gene families involved in Pharyngeal odontogenesis are also involved in oral tooth formation, with the notable exception of the evx gene family. Here, we present a complete description of early odontogenesis in the medaka (Oryzias latipes), which has both oral and Pharyngeal dentition. We show that oral and Pharyngeal Teeth share deep developmental similarities. In the medaka, like in the zebrafish, eve1 is the only evx gene expressed during odontogenesis. In each forming tooth, regardless of its location, eve1 transcription is activated in the placode, then becomes restricted to the inner dental epithelium and is activated in the dental mesenchyme during early differentiation, and finally ceases at late differentiation. Thus eve1 expression is not specific to Pharyngeal Teeth development as was previously suggested. Because it permits direct comparisons between oral and Pharyngeal Teeth by molecular, development and functional studies, the medaka is an excellent model to develop further insights into the evolution of odontogenesis in gnathostomes. J. Exp. Zool. (Mol. Dev. Evol.) 308B, 2007. (c) 2007 Wiley-Liss, Inc.
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Development of Oral and Pharyngeal Teeth in the Medaka (Oryzias latipes): Comparison of Morphology and Expression of eve1 Gene
JOURNAL OF EXPERIMENTAL ZOOLOGY (MOL DEV EVOL), 2007Co-Authors: Mélanie Debiais-thibaud, Véronique Borday-birraux, Isabelle Germon, Frank Bourrat, Cushla Jane Metcalfe, Didier Casane, Patrick LaurentiAbstract:Gnathostome Teeth are one of the most promising models for developmental evolutionary studies, they are the most abundant organ in the fossil record and an excellent example of organogenesis. Teeth have a complex morphology and are restricted to the mouth in mammals, whereas actinopterygian Teeth have a simple morphology and are found in several locations, notably on Pharyngeal bones. Morphological and developmental similarities support the hypothesis that oral and Pharyngeal Teeth are serially homologous. Gene expression data from the mouse and some teleosts have shown that the gene families involved in Pharyngeal odontogenesis are also involved in oral tooth formation, with the notable exception of the evx gene family. Here, we present a complete description of early odontogenesis in the medaka (Oryzias latipes), which has both oral and Pharyngeal dentition. We show that oral and Pharyngeal Teeth share deep developmental similarities. In the medaka, like in the zebrafish, eve1 is the only evx gene expressed during odontogenesis. In each forming tooth, regardless of its location, eve1 transcription is activated in the placode, then becomes restricted to the inner dental epithelium and is activated in the dental mesenchyme during early differentiation, and finally ceases at late differentiation. Thus eve1 expression is not specific to Pharyngeal Teeth development as was previously suggested. Because it permits direct comparisons between oral and Pharyngeal Teeth by molecular, development and functional studies, the medaka is an excellent model to develop further insights into the evolution of odontogenesis in gnathostomes.. 2007. Development of oral and Pharyngeal Teeth in the medaka (Oryzias latipes): comparison of morphology and expression of eve1 gene. J. Exp. Zool. (Mol. Dev. Evol.) 308B:693-708. Teeth are regarded by both palaeontologists and developmental geneticists as an excellent model for studying evolutionary mechanisms for several reasons. They are the most abundant organ in the vertebrate fossil record, chiefly because they are mainly composed of hard tissues and are partially hyper mineralised. They have undergone extensive morphological variation during the course of evolution, are therefore a very informative character, and have been used in a wide range of palaeontological studies. Finally, although the tooth is one of the simplest organs that form during gnathostomes development, it represents a model of organ ontogeny.