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Dennis R. Warner - One of the best experts on this subject based on the ideXlab platform.
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Deciphering TGF-β3 function in medial edge epithelium specification and fusion during mouse Secondary Palate development.
Developmental Dynamics, 2014Co-Authors: Jiu-zhen Jin, Robert M. Greene, Dennis R. Warner, M. Michele Pisano, Jixiang DingAbstract:Background: Transforming growth factor-β3 (TGF-β3) plays a central role in mediating Secondary Palate fusion along the facial midline. However, the mechanisms by which TGF-β3 functions during Secondary Palate fusion are still poorly understood. Results: We found that mouse cytokeratin 6α and 17 mRNAs were expressed exclusively in the Palate medial edge epithelium on embryonic day 14.5, and this expression was completely abolished in Tgf-β3 mutant embryos. In contrast, we found that Jagged2 was initially expressed throughout the Palate epithelium, but was specifically down-regulated in the medial edge epithelium during palatal fusion. Jagged2 down-regulation was regulated by TGF-β3, since Jagged2 was persistently expressed in palatal medial edge epithelium in Tgf-β3 null mutant embryos. Moreover, addition of DAPT, a specific inhibitor of Notch signaling, partially rescued the fusion defects in Tgf-β3 null mutant palatal shelves. Conclusions: Based on these results, together with the previous study indicating that the loss of Jagged2 function promotes embryonic oral epithelial fusion, we concluded that TGF-β3 mediates Palate fusion in part by down-regulating Jagged2 expression in palatal medial edge epithelium. In addition, cytokeratin 6α and 17 are two TGF-β3 downstream target genes in Palate medial edge epithelium differentiation. Developmental Dynamics 243:1536–1543, 2014. © 2014 Wiley Periodicals, Inc.
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gene expression changes in the Secondary Palate and mandible of prdm16 mice
Cell and Tissue Research, 2013Co-Authors: Dennis R. Warner, Robert M. Greene, Justin P. Wells, Michele M PisanoAbstract:Loss of Prdm16 expression in the mouse leads to a complete cleft of the Secondary Palate. We have now determined changes in gene expression in the Secondary Palates of Prdm16 −/− fetuses in an attempt to reveal the mechanism(s) leading to the failure of Palate closure in these mice. Defined pathway-based polymerase chain reaction arrays were used to analyze the expression of genes associated with the extracellular matrix and the transforming growth factor-β and bone morphogenetic protein signaling networks, perturbations of which can lead to palatal clefting. Loss of Prdm16 expression in the Secondary Palate leads to alterations in numerous genes within these groups, many of which have been linked to chondrogenesis and osteogenesis. The expression of several genes linked to bone development was significantly changed in the developing Secondary Palate. Analysis of gene expression in the mandibles of Prdm16 −/− fetuses revealed similar alterations in the same gene set. These data suggest that one function of Prdm16 is the regulation of genes that play a role in the differentiation of mesenchymal cells into chondro-/osteocytes.
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Gene expression changes in the Secondary Palate and mandible of Prdm16(-/-) mice.
Cell and Tissue Research, 2012Co-Authors: Dennis R. Warner, Robert M. Greene, Justin P. Wells, M. Michele PisanoAbstract:Loss of Prdm16 expression in the mouse leads to a complete cleft of the Secondary Palate. We have now determined changes in gene expression in the Secondary Palates of Prdm16 −/− fetuses in an attempt to reveal the mechanism(s) leading to the failure of Palate closure in these mice. Defined pathway-based polymerase chain reaction arrays were used to analyze the expression of genes associated with the extracellular matrix and the transforming growth factor-β and bone morphogenetic protein signaling networks, perturbations of which can lead to palatal clefting. Loss of Prdm16 expression in the Secondary Palate leads to alterations in numerous genes within these groups, many of which have been linked to chondrogenesis and osteogenesis. The expression of several genes linked to bone development was significantly changed in the developing Secondary Palate. Analysis of gene expression in the mandibles of Prdm16 −/− fetuses revealed similar alterations in the same gene set. These data suggest that one function of Prdm16 is the regulation of genes that play a role in the differentiation of mesenchymal cells into chondro-/osteocytes.
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Mesenchymal cell remodeling during mouse Secondary Palate reorientation.
Developmental Dynamics, 2010Co-Authors: Jiu-zhen Jin, Dennis R. Warner, Min Tan, Douglas S. Darling, Yujiro Higashi, Thomas Gridley, Jixiang DingAbstract:The formation of mammalian Secondary Palate requires a series of developmental events such as growth, elevation, and fusion. Despite recent advances in the field of Palate development, the process of Palate elevation remains poorly understood. The current consensus on Palate elevation is that the distal end of the vertical palatal shelf corresponds to the medial edge of the elevated horizontal palatal shelf. We provide evidence suggesting that the prospective medial edge of the vertical Palate is located toward the interior side (the side adjacent to the tongue), instead of the distal end, of the vertical palatal shelf and that the horizontal palatal axis is generated through palatal outgrowth from the side of the vertical palatal shelf rather than rotating the pre-existing vertical axis orthogonally. Because Palate elevation represents a classic example of embryonic tissue re-orientation, our findings here may also shed light on the process of tissue re-orientation in general. Developmental Dynamics 239:2110–2117, 2010. © 2010 Wiley-Liss, Inc.
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Expression of Wnts in the developing murine Secondary Palate
The International Journal of Developmental Biology, 2009Co-Authors: Dennis R. Warner, Robert M. Greene, Henry John Stephen Smith, Cynthia L. Webb, M. Michele PisanoAbstract:Morphogenesis of the mammalian Secondary Palate requires coordination of cell migration, proliferation, differentiation, apoptosis and synthesis of extracellular matrix molecules by numerous signal transduction pathways. Recent evidence suggests a role for members of the Wnt family of secreted cytokines in orofacial development. However, no study has systematically or comprehensively examined the expression of Wnts in embryonic orofacial tissue. We thus conducted a survey of the expression of all known Wnt genes in the developing murine Secondary Palate. Using an RT-PCR strategy to assay gene expression, 12 of the 19 known members of the Wnt family were found to be expressed in embryonic palatal tissue during key phases of its development. The expression of 5 Wnt family members was found to be temporally regulated. Moreover, these Wnts had unique spatio-temporal patterns of expression which suggested possible roles in palatal ontogeny.
M. Michele Pisano - One of the best experts on this subject based on the ideXlab platform.
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Deciphering TGF-β3 function in medial edge epithelium specification and fusion during mouse Secondary Palate development.
Developmental Dynamics, 2014Co-Authors: Jiu-zhen Jin, Robert M. Greene, Dennis R. Warner, M. Michele Pisano, Jixiang DingAbstract:Background: Transforming growth factor-β3 (TGF-β3) plays a central role in mediating Secondary Palate fusion along the facial midline. However, the mechanisms by which TGF-β3 functions during Secondary Palate fusion are still poorly understood. Results: We found that mouse cytokeratin 6α and 17 mRNAs were expressed exclusively in the Palate medial edge epithelium on embryonic day 14.5, and this expression was completely abolished in Tgf-β3 mutant embryos. In contrast, we found that Jagged2 was initially expressed throughout the Palate epithelium, but was specifically down-regulated in the medial edge epithelium during palatal fusion. Jagged2 down-regulation was regulated by TGF-β3, since Jagged2 was persistently expressed in palatal medial edge epithelium in Tgf-β3 null mutant embryos. Moreover, addition of DAPT, a specific inhibitor of Notch signaling, partially rescued the fusion defects in Tgf-β3 null mutant palatal shelves. Conclusions: Based on these results, together with the previous study indicating that the loss of Jagged2 function promotes embryonic oral epithelial fusion, we concluded that TGF-β3 mediates Palate fusion in part by down-regulating Jagged2 expression in palatal medial edge epithelium. In addition, cytokeratin 6α and 17 are two TGF-β3 downstream target genes in Palate medial edge epithelium differentiation. Developmental Dynamics 243:1536–1543, 2014. © 2014 Wiley Periodicals, Inc.
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Developmental epigenetics of the murine Secondary Palate.
ILAR Journal, 2012Co-Authors: Ratnam S. Seelan, M. Michele Pisano, Partha Mukhopadhyay, Robert M. GreeneAbstract:Orofacial clefts occur with a frequency of 1 to 2 per 1000 live births. Cleft Palate, which accounts for 30% of orofacial clefts, is caused by the failure of the Secondary palatal processes—medially directed, oral projections of the paired embryonic maxillary processes—to fuse. Both gene mutations and environmental effects contribute to the complex etiology of this disorder. Although much progress has been made in identifying genes whose mutations are associated with cleft Palate, little is known about the mechanisms by which the environment adversely influences gene expression during Secondary Palate development. An increasing body of evidence, however, implicates epigenetic processes as playing a role in adversely influencing orofacial development. Epigenetics refers to inherited changes in phenotype or gene expression caused by processes other than changes in the underlying DNA sequence. Such processes include, but are not limited to, DNA methylation, microRNA effects, and histone modifications that alter chromatin conformation. In this review, we describe our current understanding of the possible role epigenetics may play during development of the Secondary Palate. Specifically, we present the salient features of the embryonic palatal methylome and profile the expression of numerous microRNAs that regulate protein-encoding genes crucial to normal orofacial ontogeny.
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Gene expression changes in the Secondary Palate and mandible of Prdm16(-/-) mice.
Cell and Tissue Research, 2012Co-Authors: Dennis R. Warner, Robert M. Greene, Justin P. Wells, M. Michele PisanoAbstract:Loss of Prdm16 expression in the mouse leads to a complete cleft of the Secondary Palate. We have now determined changes in gene expression in the Secondary Palates of Prdm16 −/− fetuses in an attempt to reveal the mechanism(s) leading to the failure of Palate closure in these mice. Defined pathway-based polymerase chain reaction arrays were used to analyze the expression of genes associated with the extracellular matrix and the transforming growth factor-β and bone morphogenetic protein signaling networks, perturbations of which can lead to palatal clefting. Loss of Prdm16 expression in the Secondary Palate leads to alterations in numerous genes within these groups, many of which have been linked to chondrogenesis and osteogenesis. The expression of several genes linked to bone development was significantly changed in the developing Secondary Palate. Analysis of gene expression in the mandibles of Prdm16 −/− fetuses revealed similar alterations in the same gene set. These data suggest that one function of Prdm16 is the regulation of genes that play a role in the differentiation of mesenchymal cells into chondro-/osteocytes.
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Expression of Wnts in the developing murine Secondary Palate
The International Journal of Developmental Biology, 2009Co-Authors: Dennis R. Warner, Robert M. Greene, Henry John Stephen Smith, Cynthia L. Webb, M. Michele PisanoAbstract:Morphogenesis of the mammalian Secondary Palate requires coordination of cell migration, proliferation, differentiation, apoptosis and synthesis of extracellular matrix molecules by numerous signal transduction pathways. Recent evidence suggests a role for members of the Wnt family of secreted cytokines in orofacial development. However, no study has systematically or comprehensively examined the expression of Wnts in embryonic orofacial tissue. We thus conducted a survey of the expression of all known Wnt genes in the developing murine Secondary Palate. Using an RT-PCR strategy to assay gene expression, 12 of the 19 known members of the Wnt family were found to be expressed in embryonic palatal tissue during key phases of its development. The expression of 5 Wnt family members was found to be temporally regulated. Moreover, these Wnts had unique spatio-temporal patterns of expression which suggested possible roles in palatal ontogeny.
Jixiang Ding - One of the best experts on this subject based on the ideXlab platform.
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Inactivation of Fgfr2 gene in mouse Secondary Palate mesenchymal cells leads to cleft Palate.
Reproductive Toxicology, 2018Co-Authors: Jiu-zhen Jin, Partha Mukhopadhyay, Zhenmin Lei, Zi-jian Lan, Jixiang DingAbstract:Abstract Numerous studies have been conducted to understand the molecular mechanisms controlling mammalian Secondary Palate development such as growth, reorientation and fusion. However, little is known about the signaling factors regulating Palate initiation. Mouse fibroblast growth factor (FGF) receptor 2 gene (Fgfr2) is expressed on E11.5 in the Palate outgrowth within the maxillary process, in a region that is responsible for Palate cell specification and shelf initiation. Fgfr2 continues to express in Palate on E12.5 and E13.5 in both epithelial and mesenchymal cells, and inactivation of Fgfr2 expression in mesenchymal cells using floxed Fgfr2 allele and Osr2-Cre leads to cleft Palate at various stages including reorientation, horizontal growth and fusion. Notably, some mutant embryos displayed no sign of Palate shelf formation suggesting that FGF receptor 2 mediated FGF signaling may play an important role in Palate initiation.
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Deciphering TGF-β3 function in medial edge epithelium specification and fusion during mouse Secondary Palate development.
Developmental Dynamics, 2014Co-Authors: Jiu-zhen Jin, Robert M. Greene, Dennis R. Warner, M. Michele Pisano, Jixiang DingAbstract:Background: Transforming growth factor-β3 (TGF-β3) plays a central role in mediating Secondary Palate fusion along the facial midline. However, the mechanisms by which TGF-β3 functions during Secondary Palate fusion are still poorly understood. Results: We found that mouse cytokeratin 6α and 17 mRNAs were expressed exclusively in the Palate medial edge epithelium on embryonic day 14.5, and this expression was completely abolished in Tgf-β3 mutant embryos. In contrast, we found that Jagged2 was initially expressed throughout the Palate epithelium, but was specifically down-regulated in the medial edge epithelium during palatal fusion. Jagged2 down-regulation was regulated by TGF-β3, since Jagged2 was persistently expressed in palatal medial edge epithelium in Tgf-β3 null mutant embryos. Moreover, addition of DAPT, a specific inhibitor of Notch signaling, partially rescued the fusion defects in Tgf-β3 null mutant palatal shelves. Conclusions: Based on these results, together with the previous study indicating that the loss of Jagged2 function promotes embryonic oral epithelial fusion, we concluded that TGF-β3 mediates Palate fusion in part by down-regulating Jagged2 expression in palatal medial edge epithelium. In addition, cytokeratin 6α and 17 are two TGF-β3 downstream target genes in Palate medial edge epithelium differentiation. Developmental Dynamics 243:1536–1543, 2014. © 2014 Wiley Periodicals, Inc.
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Mesenchymal cell remodeling during mouse Secondary Palate reorientation.
Developmental Dynamics, 2010Co-Authors: Jiu-zhen Jin, Dennis R. Warner, Min Tan, Douglas S. Darling, Yujiro Higashi, Thomas Gridley, Jixiang DingAbstract:The formation of mammalian Secondary Palate requires a series of developmental events such as growth, elevation, and fusion. Despite recent advances in the field of Palate development, the process of Palate elevation remains poorly understood. The current consensus on Palate elevation is that the distal end of the vertical palatal shelf corresponds to the medial edge of the elevated horizontal palatal shelf. We provide evidence suggesting that the prospective medial edge of the vertical Palate is located toward the interior side (the side adjacent to the tongue), instead of the distal end, of the vertical palatal shelf and that the horizontal palatal axis is generated through palatal outgrowth from the side of the vertical palatal shelf rather than rotating the pre-existing vertical axis orthogonally. Because Palate elevation represents a classic example of embryonic tissue re-orientation, our findings here may also shed light on the process of tissue re-orientation in general. Developmental Dynamics 239:2110–2117, 2010. © 2010 Wiley-Liss, Inc.
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analysis of cell migration transdifferentiation and apoptosis during mouse Secondary Palate fusion
Development, 2006Co-Authors: Jiu-zhen Jin, Jixiang DingAbstract:Malformations in Secondary Palate fusion will lead to cleft Palate, a common human birth defect. Palate fusion involves the formation and subsequent degeneration of the medial edge epithelial seam. The cellular mechanisms underlying seam degeneration have been a major focus in the study of palatogenesis. Three mechanisms have been proposed for seam degeneration: lateral migration of medial edge epithelial cells; epithelial-mesenchymal trans-differentiation; and apoptosis of medial edge epithelial cells. However, there is still a great deal of controversy over these proposed mechanisms. In this study, we established a [ Rosa26 ↔C57BL/6] chimeric culture system, in which a Rosa26 -originated `blue9 palatal shelf was paired with a C57BL/6-derived `white9 palatal shelf. Using this organ culture system, we observed the migration of medial edge epithelial cells to the nasal side, but not to the oral side. We also observed an anteroposterior migration of medial edge epithelial cells, which may play an important role in posterior Palate fusion. To examine epithelial-mesenchymal transdifferentiation during Palate fusion, we bred a cytokeratin 14- Cre transgenic line into the R26R background. In situ hybridization showed that the Cre transgene is expressed exclusively in the epithelium. However,β -galactosidase staining gave extensive signals in the palatal mesenchymal region during and after Palate fusion, demonstrating the occurrence of an epithelial-mesenchymal transdifferentiation mechanism during Palate fusion. Finally, we showed that Apaf1 mutant mouse embryos are able to complete Palate fusion without DNA fragmentation-mediated programmed cell death, indicating that this is not essential for Palate fusion in vivo.
Robert M. Greene - One of the best experts on this subject based on the ideXlab platform.
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Deciphering TGF-β3 function in medial edge epithelium specification and fusion during mouse Secondary Palate development.
Developmental Dynamics, 2014Co-Authors: Jiu-zhen Jin, Robert M. Greene, Dennis R. Warner, M. Michele Pisano, Jixiang DingAbstract:Background: Transforming growth factor-β3 (TGF-β3) plays a central role in mediating Secondary Palate fusion along the facial midline. However, the mechanisms by which TGF-β3 functions during Secondary Palate fusion are still poorly understood. Results: We found that mouse cytokeratin 6α and 17 mRNAs were expressed exclusively in the Palate medial edge epithelium on embryonic day 14.5, and this expression was completely abolished in Tgf-β3 mutant embryos. In contrast, we found that Jagged2 was initially expressed throughout the Palate epithelium, but was specifically down-regulated in the medial edge epithelium during palatal fusion. Jagged2 down-regulation was regulated by TGF-β3, since Jagged2 was persistently expressed in palatal medial edge epithelium in Tgf-β3 null mutant embryos. Moreover, addition of DAPT, a specific inhibitor of Notch signaling, partially rescued the fusion defects in Tgf-β3 null mutant palatal shelves. Conclusions: Based on these results, together with the previous study indicating that the loss of Jagged2 function promotes embryonic oral epithelial fusion, we concluded that TGF-β3 mediates Palate fusion in part by down-regulating Jagged2 expression in palatal medial edge epithelium. In addition, cytokeratin 6α and 17 are two TGF-β3 downstream target genes in Palate medial edge epithelium differentiation. Developmental Dynamics 243:1536–1543, 2014. © 2014 Wiley Periodicals, Inc.
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gene expression changes in the Secondary Palate and mandible of prdm16 mice
Cell and Tissue Research, 2013Co-Authors: Dennis R. Warner, Robert M. Greene, Justin P. Wells, Michele M PisanoAbstract:Loss of Prdm16 expression in the mouse leads to a complete cleft of the Secondary Palate. We have now determined changes in gene expression in the Secondary Palates of Prdm16 −/− fetuses in an attempt to reveal the mechanism(s) leading to the failure of Palate closure in these mice. Defined pathway-based polymerase chain reaction arrays were used to analyze the expression of genes associated with the extracellular matrix and the transforming growth factor-β and bone morphogenetic protein signaling networks, perturbations of which can lead to palatal clefting. Loss of Prdm16 expression in the Secondary Palate leads to alterations in numerous genes within these groups, many of which have been linked to chondrogenesis and osteogenesis. The expression of several genes linked to bone development was significantly changed in the developing Secondary Palate. Analysis of gene expression in the mandibles of Prdm16 −/− fetuses revealed similar alterations in the same gene set. These data suggest that one function of Prdm16 is the regulation of genes that play a role in the differentiation of mesenchymal cells into chondro-/osteocytes.
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Developmental epigenetics of the murine Secondary Palate.
ILAR Journal, 2012Co-Authors: Ratnam S. Seelan, M. Michele Pisano, Partha Mukhopadhyay, Robert M. GreeneAbstract:Orofacial clefts occur with a frequency of 1 to 2 per 1000 live births. Cleft Palate, which accounts for 30% of orofacial clefts, is caused by the failure of the Secondary palatal processes—medially directed, oral projections of the paired embryonic maxillary processes—to fuse. Both gene mutations and environmental effects contribute to the complex etiology of this disorder. Although much progress has been made in identifying genes whose mutations are associated with cleft Palate, little is known about the mechanisms by which the environment adversely influences gene expression during Secondary Palate development. An increasing body of evidence, however, implicates epigenetic processes as playing a role in adversely influencing orofacial development. Epigenetics refers to inherited changes in phenotype or gene expression caused by processes other than changes in the underlying DNA sequence. Such processes include, but are not limited to, DNA methylation, microRNA effects, and histone modifications that alter chromatin conformation. In this review, we describe our current understanding of the possible role epigenetics may play during development of the Secondary Palate. Specifically, we present the salient features of the embryonic palatal methylome and profile the expression of numerous microRNAs that regulate protein-encoding genes crucial to normal orofacial ontogeny.
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Gene expression changes in the Secondary Palate and mandible of Prdm16(-/-) mice.
Cell and Tissue Research, 2012Co-Authors: Dennis R. Warner, Robert M. Greene, Justin P. Wells, M. Michele PisanoAbstract:Loss of Prdm16 expression in the mouse leads to a complete cleft of the Secondary Palate. We have now determined changes in gene expression in the Secondary Palates of Prdm16 −/− fetuses in an attempt to reveal the mechanism(s) leading to the failure of Palate closure in these mice. Defined pathway-based polymerase chain reaction arrays were used to analyze the expression of genes associated with the extracellular matrix and the transforming growth factor-β and bone morphogenetic protein signaling networks, perturbations of which can lead to palatal clefting. Loss of Prdm16 expression in the Secondary Palate leads to alterations in numerous genes within these groups, many of which have been linked to chondrogenesis and osteogenesis. The expression of several genes linked to bone development was significantly changed in the developing Secondary Palate. Analysis of gene expression in the mandibles of Prdm16 −/− fetuses revealed similar alterations in the same gene set. These data suggest that one function of Prdm16 is the regulation of genes that play a role in the differentiation of mesenchymal cells into chondro-/osteocytes.
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Expression of Wnts in the developing murine Secondary Palate
The International Journal of Developmental Biology, 2009Co-Authors: Dennis R. Warner, Robert M. Greene, Henry John Stephen Smith, Cynthia L. Webb, M. Michele PisanoAbstract:Morphogenesis of the mammalian Secondary Palate requires coordination of cell migration, proliferation, differentiation, apoptosis and synthesis of extracellular matrix molecules by numerous signal transduction pathways. Recent evidence suggests a role for members of the Wnt family of secreted cytokines in orofacial development. However, no study has systematically or comprehensively examined the expression of Wnts in embryonic orofacial tissue. We thus conducted a survey of the expression of all known Wnt genes in the developing murine Secondary Palate. Using an RT-PCR strategy to assay gene expression, 12 of the 19 known members of the Wnt family were found to be expressed in embryonic palatal tissue during key phases of its development. The expression of 5 Wnt family members was found to be temporally regulated. Moreover, these Wnts had unique spatio-temporal patterns of expression which suggested possible roles in palatal ontogeny.
Ravindra M. Shah - One of the best experts on this subject based on the ideXlab platform.
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In vivo and in vitro assessment of mitogen activated protein kinase involvement during quail Secondary Palate formation
The Anatomical Record, 1998Co-Authors: B.m. Hehn, M.f. Izadnegahdar, A.v. Young, J.s. Sanghera, S.l. Pelech, Ravindra M. ShahAbstract:Spatiotemporally regulated cell proliferation and differentiation are crucial for the successful completion of morphogenesis of the vertebrate Secondary Palate. An understanding of the mechanisms by which these cellular phenomena are regulated during Palate development involves the identification of the various signal transduction pathways. In the present study, the presence and activation of mitogen-activated protein (MAP) kinases were investigated during the development of quail Secondary Palate. The palatal shelves were dissected on days 5–9 of incubation, homogenized, and centrifuged, after which the samples were separated by anion exchange fast protein liquid chromatography. The fractions were analyzed for myelin basic protein (MBP) phosphorylation. In addition, primary cultures of quail Palate mesenchymal cells (QPMCs) were treated with epidermal growth factor (EGF) and prepared for MBP phosphorylation assays. A temporally regulated pattern of phosphotransferase activity, characterized by a three-fold increase in phosphotransferase activity toward MBP between days 5 and 8 of incubation, was observed during quail Palate development. Western blotting, using MAP kinase antibodies, demonstrated the presence of a 42-kDa isoform between days 5 and 9 of incubation, during which the level of protein remained constant. Antityrosine immunoblotting with 4G10 also detected a 42-kDa protein. Phosphotransferase assays, using either a MAP kinase-specific substrate peptide (S5) or a protein kinase C inhibitor (R3), further confirmed the presence of a MAP kinase in the developing Palate of quail. Because diverse biological processes occur concurrently during in vivo Palate morphogenesis, the involvement of MAP kinase was explored further in primary cell culture. The data showed that EGF stimulated proliferation and activated 42-kDa MAP kinase in QPMCs. It is suggested that MAP kinase cascade may be involved in growth factor-regulated cell proliferation during morphogenesis of quail Secondary Palate. Anat. Rec. 252:194–204, 1998. © 1998 Wiley-Liss, Inc.
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Developmental alterations in casein kinase 2 activity during the morphogenesis of quail Secondary Palate.
The Anatomical Record, 1997Co-Authors: B.m. Hehn, A.v. Young, J.s. Sanghera, S.l. Pelech, Ravindra M. ShahAbstract:BACKGROUND During the progression of avian Secondary Palate morphogenesis, the rate of cell proliferation declines, whereas the production and accumulation of extracellular matrices increases. To investigate the regulation of these events, we examined the quail Secondary Palate for the activity of casein kinase 2 (CK 2), a pleiotropic serine/threonine second messenger independent enzyme implicated in cell growth and differentiation. METHODS Quail palatal shelves were dissected between days 5 and 9 of incubation, which is the period of Palate morphogenesis in quail, and prepared either for light microscopic observations or homogenized, cleared by ultracentrifugation, and then subjected to fractionation on a MonoQ column by fast protein liquid chromatography and Western immunoblotting. RESULTS Histological examination showed that the palatal shelves appeared on day 5 of incubation and approximated by day 8 of incubation. Fractionation of Palate extract using a Mono-Q column revealed the presence of a major peak of phosvitin phosphotransferase activity which eluted with 0.5 M NaCl. This activity peak coincided with the presence of a 42 kDa subunit of CK 2 as determined by Western blotting with a CK 2 specific antibody. The CK 2 activity towards phosvitin was elevated on days 5 and 6 and then rapidly declined by day 9. The decrease in CK 2 activity did not correlate with a decrease in CK 2 protein during Palate development indicating that the differential activity of the CK 2 enzyme observed during quail Palate development may be due to post-translational modifications of the enzyme. A high positive correlation was found between the CK 2 phosphotransferase activity and both the proliferation index and DNA synthesis during Palate development. CONCLUSION On the basis of literature analysis and the results of the present study, it was suggested that the activity of CK 2 may be regulated along with protein kinase A to coordinate cell proliferation and the synthesis of extracellular matrices during Palate development in quail.
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GROWTH AND DIFFERENTIATION OF THE Secondary Palate IN A TELEOSTEAN FISH, ONCORHYNCHUS KISUTCH
Journal of Experimental Zoology, 1995Co-Authors: Ravindra M. Shah, Elizabeth J. E. Feeley, Alan V. Young, Edward M. DonaldsonAbstract:A study was undertaken to examine the growth and differentiation of Secondary Palate in a teleostean fish, Oncorhynchus kisutch. The rate, pattern, and time of synthesis of various macromolecules, which play a crucial role during Palate development in higher vertebrates were examined in the developing Palate of fish. A spurt in DNA synthesis during midmorphogenesis of fish Palate appeared to be related to temporal regulation of Palate development. RNA synthesis was high during the time of primordial appearance and increased again from day 4 post hatching (PH) to correspond with differentiation of Palate. Protein synthesis remained low initially but its trend paralleled that of RNA synthesis after day 4 PH. Glycosaminoglycan synthesis increased initially with the cartilaginous growth and then with the appearance of mucous cells. An increase in collagen synthesis corresponded with the thickening of collagen layer in the basement membrance. Cyclic AMP activity increased initially prior to the increase in DNA synthesis and subsequently remained high indicating its involvement in both growth and differentiation of fish Palate. These profiles of synthesis of various macromolecules in teleostean fish differ considerably from that seen in higher vertebrates. On the basis of comparative analysis, it was suggested that the timing of mesenchymal differentiation may be one of the features in determining the characteristics of Palate development in different classes of vertebrates. © 1995 Wiley-Liss, Inc.
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Effects of 5-fluorouracil on macromolecular synthesis during Secondary Palate development in quail
Journal of Experimental Zoology, 1994Co-Authors: Ravindra M. Shah, Kimberly M. Cheng, Elizabeth J. E. FeeleyAbstract:A study was undertaken to examine the growth of normal and 5-fluorouraciltreated quail Secondary Palate during embryogenesis. The rates of DNA, RNA, and protein synthesis were measured in the developing quail Palate by liquid scintillation counting of radiolabelled thymidine, uridine, or leucine. In addition, shelf volume was determined morphometrically. The results showed that in control Palates the shelf volume increased rapidly between days 5 and 7 of incubation. Drug treatment on day 4 did not alter the shelf volume until day 9 of incubation, at which time the treated shelves were smaller than controls. In control Palates, the rate of DNA synthesis decreased steadily between days 5 and 9 of incubation. A burst in RNA synthesis on day 7 of incubation was followed by an increase in protein synthesis. Administration of FU seems to exert its effect via disturbing the synthesis of RNA and protein, instead of disruption of DNA synthesis, to ultimately affect the shelf area, and thus Palate morphogenesis in quail. Comparison of avian and mammalian data indicated that differences in their Palate morphogenesis are also reflected in the different temporal patterns of various macromolecular synthesis. © 1994 Wiley-Liss, Inc.
