The Experts below are selected from a list of 8904 Experts worldwide ranked by ideXlab platform
Lucie Jeannotte - One of the best experts on this subject based on the ideXlab platform.
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stomach Regional Specification requires hoxa5 driven mesenchymal epithelial signaling
Development, 2002Co-Authors: Josee Aubin, Ugo Dery, Margot Lemieux, Pierre Chailler, Lucie JeannotteAbstract:The genetic control of gut Regionalization relies on a hierarchy of molecular events in which the Hox gene family of transcription factors is suspected to be key participant. We have examined the role of Hox genes in gut patterning using the Hoxa5(-/-) mice as a model. Hoxa5 is expressed in a dynamic fashion in the mesenchymal component of the developing gut. Its loss of function results in gastric enzymatic anomalies in Hoxa5(-/-) surviving mutants that are due to perturbed cell Specification during stomach development. Histological, biochemical and molecular characterization of the mutant stomach phenotype may be compatible with a homeotic transformation of the gastric mucosa. As the loss of mesenchymal Hoxa5 function leads to gastric epithelial defects, Hoxa5 should exert its action by controlling molecules involved in mesenchymal-epithelial signaling. Indeed, in the absence of Hoxa5 function, the expression of genes encoding for signaling molecules such as sonic hedgehog, Indian hedgehog, transforming growth factor beta family members and fibroblast growth factor 10, is altered. These findings provide insight into the molecular controls of patterning events of the stomach, supporting the notion that Hoxa5 acts in Regionalization and Specification of the stomach by setting up the proper domains of expression of signaling molecules.
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Stomach Regional Specification requires Hoxa5-driven mesenchymal-epithelial signaling.
Development (Cambridge England), 2002Co-Authors: Josee Aubin, Ugo Dery, Margot Lemieux, Pierre Chailler, Lucie JeannotteAbstract:The genetic control of gut Regionalization relies on a hierarchy of molecular events in which the Hox gene family of transcription factors is suspected to be key participant. We have examined the role of Hox genes in gut patterning using the Hoxa5 –/– mice as a model. Hoxa5 is expressed in a dynamic fashion in the mesenchymal component of the developing gut. Its loss of function results in gastric enzymatic anomalies in Hoxa5 –/– surviving mutants that are due to perturbed cell Specification during stomach development. Histological, biochemical and molecular characterization of the mutant stomach phenotype may be compatible with a homeotic transformation of the gastric mucosa. As the loss of mesenchymal Hoxa5 function leads to gastric epithelial defects, Hoxa5 should exert its action by controlling molecules involved in mesenchymal-epithelial signaling. Indeed, in the absence of Hoxa5 function, the expression of genes encoding for signaling molecules such as sonic hedgehog, Indian hedgehog, transforming growth factor β family members and fibroblast growth factor 10, is altered. These findings provide insight into the molecular controls of patterning events of the stomach, supporting the notion that Hoxa5 acts in Regionalization and Specification of the stomach by setting up the proper domains of expression of signaling molecules.
Akio S Suzuki - One of the best experts on this subject based on the ideXlab platform.
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Regional Specification of the head and trunk tail organizers of a urodele cynops pyrrhogaster embryo is patterned during gastrulation
Developmental Biology, 2002Co-Authors: Teruo Kaneda, Keiko Miyazaki, Risa Kudo, Kazutoshi Goto, Koji Sakaguchi, Miwako Matsumoto, Syouen Todaka, Keisuke Yoshinaga, Akio S SuzukiAbstract:The dorsal marginal zone (DMZ) of an amphibian early gastrula is thought to consist of at least two distinct domains: the future head and trunk-tail organizers. We studied the mechanism by which the organizing activities of the lower half of the DMZ (LDMZ) of the urodelean (Cynops pyrrhogaster) embryo are changed. The uninvoluted LDMZ induces the notochord and then organizes the trunk-tail structures, whereas after cultivation in vitro or suramin treatment, the same LDMZ loses the notochord-inducing ability and organizes the head structures. A cell-lineage experiment indicated that the change in the organizing activity of the LDMZ was reflected in the transformation of the inductive ability: from notochord-inducing to neural-inducing activity. Using RT-PCR, we showed that the LDMZ expressed gsc, lim-1, chordin, and noggin, but not the mesoderm marker bra. In the sandwich assay, the LDMZ induced bra expression in the animal cap ectoderm, but the inductive activity was inhibited by cultivation or suramin treatment. The present study indicates that the change in the organizing activity of the LDMZ from trunk-tail to head is coupled with the loss of notochord-inducing activity. Based on these results, we suggest that this change is essential for the Specification of the head and trunk-tail organizers during gastrulation.
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Regional Specification of the Head and Trunk–Tail Organizers of a Urodele (Cynops pyrrhogaster) Embryo Is Patterned during Gastrulation
Developmental biology, 2002Co-Authors: Teruo Kaneda, Keiko Miyazaki, Risa Kudo, Kazutoshi Goto, Koji Sakaguchi, Miwako Matsumoto, Syouen Todaka, Keisuke Yoshinaga, Akio S SuzukiAbstract:The dorsal marginal zone (DMZ) of an amphibian early gastrula is thought to consist of at least two distinct domains: the future head and trunk-tail organizers. We studied the mechanism by which the organizing activities of the lower half of the DMZ (LDMZ) of the urodelean (Cynops pyrrhogaster) embryo are changed. The uninvoluted LDMZ induces the notochord and then organizes the trunk-tail structures, whereas after cultivation in vitro or suramin treatment, the same LDMZ loses the notochord-inducing ability and organizes the head structures. A cell-lineage experiment indicated that the change in the organizing activity of the LDMZ was reflected in the transformation of the inductive ability: from notochord-inducing to neural-inducing activity. Using RT-PCR, we showed that the LDMZ expressed gsc, lim-1, chordin, and noggin, but not the mesoderm marker bra. In the sandwich assay, the LDMZ induced bra expression in the animal cap ectoderm, but the inductive activity was inhibited by cultivation or suramin treatment. The present study indicates that the change in the organizing activity of the LDMZ from trunk-tail to head is coupled with the loss of notochord-inducing activity. Based on these results, we suggest that this change is essential for the Specification of the head and trunk-tail organizers during gastrulation.
Josee Aubin - One of the best experts on this subject based on the ideXlab platform.
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stomach Regional Specification requires hoxa5 driven mesenchymal epithelial signaling
Development, 2002Co-Authors: Josee Aubin, Ugo Dery, Margot Lemieux, Pierre Chailler, Lucie JeannotteAbstract:The genetic control of gut Regionalization relies on a hierarchy of molecular events in which the Hox gene family of transcription factors is suspected to be key participant. We have examined the role of Hox genes in gut patterning using the Hoxa5(-/-) mice as a model. Hoxa5 is expressed in a dynamic fashion in the mesenchymal component of the developing gut. Its loss of function results in gastric enzymatic anomalies in Hoxa5(-/-) surviving mutants that are due to perturbed cell Specification during stomach development. Histological, biochemical and molecular characterization of the mutant stomach phenotype may be compatible with a homeotic transformation of the gastric mucosa. As the loss of mesenchymal Hoxa5 function leads to gastric epithelial defects, Hoxa5 should exert its action by controlling molecules involved in mesenchymal-epithelial signaling. Indeed, in the absence of Hoxa5 function, the expression of genes encoding for signaling molecules such as sonic hedgehog, Indian hedgehog, transforming growth factor beta family members and fibroblast growth factor 10, is altered. These findings provide insight into the molecular controls of patterning events of the stomach, supporting the notion that Hoxa5 acts in Regionalization and Specification of the stomach by setting up the proper domains of expression of signaling molecules.
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Stomach Regional Specification requires Hoxa5-driven mesenchymal-epithelial signaling.
Development (Cambridge England), 2002Co-Authors: Josee Aubin, Ugo Dery, Margot Lemieux, Pierre Chailler, Lucie JeannotteAbstract:The genetic control of gut Regionalization relies on a hierarchy of molecular events in which the Hox gene family of transcription factors is suspected to be key participant. We have examined the role of Hox genes in gut patterning using the Hoxa5 –/– mice as a model. Hoxa5 is expressed in a dynamic fashion in the mesenchymal component of the developing gut. Its loss of function results in gastric enzymatic anomalies in Hoxa5 –/– surviving mutants that are due to perturbed cell Specification during stomach development. Histological, biochemical and molecular characterization of the mutant stomach phenotype may be compatible with a homeotic transformation of the gastric mucosa. As the loss of mesenchymal Hoxa5 function leads to gastric epithelial defects, Hoxa5 should exert its action by controlling molecules involved in mesenchymal-epithelial signaling. Indeed, in the absence of Hoxa5 function, the expression of genes encoding for signaling molecules such as sonic hedgehog, Indian hedgehog, transforming growth factor β family members and fibroblast growth factor 10, is altered. These findings provide insight into the molecular controls of patterning events of the stomach, supporting the notion that Hoxa5 acts in Regionalization and Specification of the stomach by setting up the proper domains of expression of signaling molecules.
Robin L Davis - One of the best experts on this subject based on the ideXlab platform.
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Regional Specification of threshold sensitivity and response time in cba caj mouse spiral ganglion neurons
Journal of Neurophysiology, 2007Co-Authors: Qing Liu, Robin L DavisAbstract:Previous studies of spiral ganglion neuron electrophysiology have shown that specific parameters differ according to cochlear location, with apical neurons being distinctly different from basal neurons. To align these features more precisely along the tonotopic axis of the cochlea, we developed a novel spiral ganglion culture system in which positional information is retained. Patch-clamp recordings made from neurons of known gangliotopic location revealed two basic firing pattern distributions. Membrane characteristics related to spike timing, such as accommodation, latency and onset tau, were distinctly heterogeneous, yet when averaged, they were distributed in a graded manner along the length of the cochlea. Action potential threshold levels also displayed a wide range, the averages of which were distributed nonmonotonically such that neurons with the greatest sensitivity were localized to the mid-regions of the ganglion. These studies shed new light on the complexity and sophistication of the intrinsic firing features of spiral ganglion neurons. Because timing-related elements are organized in an overall tonotopic manner, it is hypothesized that they contribute to aspects of frequency-dependent acoustic processing. On the other hand, the different distribution of threshold levels, with the greatest sensitivity in the middle region of the tonotopic map, suggests that this neuronal parameter is regulated differently and thus may contribute a distinct realm of auditory sensory processing.
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Regional Specification of Threshold Sensitivity and Response Time in CBA/CaJ Mouse Spiral Ganglion Neurons
Journal of neurophysiology, 2007Co-Authors: Qing Liu, Robin L DavisAbstract:Previous studies of spiral ganglion neuron electrophysiology have shown that specific parameters differ according to cochlear location, with apical neurons being distinctly different from basal neurons. To align these features more precisely along the tonotopic axis of the cochlea, we developed a novel spiral ganglion culture system in which positional information is retained. Patch-clamp recordings made from neurons of known gangliotopic location revealed two basic firing pattern distributions. Membrane characteristics related to spike timing, such as accommodation, latency and onset tau, were distinctly heterogeneous, yet when averaged, they were distributed in a graded manner along the length of the cochlea. Action potential threshold levels also displayed a wide range, the averages of which were distributed nonmonotonically such that neurons with the greatest sensitivity were localized to the mid-regions of the ganglion. These studies shed new light on the complexity and sophistication of the intrinsic firing features of spiral ganglion neurons. Because timing-related elements are organized in an overall tonotopic manner, it is hypothesized that they contribute to aspects of frequency-dependent acoustic processing. On the other hand, the different distribution of threshold levels, with the greatest sensitivity in the middle region of the tonotopic map, suggests that this neuronal parameter is regulated differently and thus may contribute a distinct realm of auditory sensory processing.
Erika A. Bach - One of the best experts on this subject based on the ideXlab platform.
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jak stat signaling promotes Regional Specification by negatively regulating wingless expression in drosophila
Development, 2006Co-Authors: Laura A. Ekas, Gyeong Hun Baeg, Maria Sol Flaherty, Aidee Ayalacamargo, Erika A. BachAbstract:During development, a small number of conserved signaling molecules regulate Regional Specification, in which uniform populations of cells acquire differences and ultimately give rise to distinct organs. In the Drosophila eye imaginal disc, Wingless (Wg) signaling defines the region that gives rise to head tissue. JAK/STAT signaling was thought to regulate growth of the eye disc but not pattern formation. However, we show that the JAK/STAT pathway plays an important role in patterning the eye disc: it promotes formation of the eye field through repression of the wg gene. Overexpression of the JAK/STAT activating ligand Unpaired in the eye leads to loss of wg expression and ectopic morphogenetic furrow initiation from the lateral margins. Conversely, tissue lacking stat92E, which cannot transduce JAK/STAT signals, is transformed from retinal tissue into head cuticle, a phenotype that is also observed with ectopic Wg signaling. Consistent with this, cells lacking stat92E exhibit ectopic wg expression. Conversely, wg is autonomously repressed in cells with hyperactivated Stat92E. Furthermore, we show that the JAK/STAT pathway regulates a small enhancer in the wg 3' cis genomic region. As this enhancer is devoid of Stat92E-binding elements, we conclude that Stat92E represses wg through another, as yet unidentified factor that is probably a direct target of Stat92E. Taken together, our study is the first to demonstrate a role for the JAK/STAT pathway in Regional Specification by acting antagonistically to wg.
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JAK/STAT signaling promotes Regional Specification by negatively regulating wingless expression in Drosophila.
Development (Cambridge England), 2006Co-Authors: Laura A. Ekas, Gyeong Hun Baeg, Maria Sol Flaherty, Aidee Ayala-camargo, Erika A. BachAbstract:During development, a small number of conserved signaling molecules regulate Regional Specification, in which uniform populations of cells acquire differences and ultimately give rise to distinct organs. In the Drosophila eye imaginal disc, Wingless (Wg) signaling defines the region that gives rise to head tissue. JAK/STAT signaling was thought to regulate growth of the eye disc but not pattern formation. However, we show that the JAK/STAT pathway plays an important role in patterning the eye disc: it promotes formation of the eye field through repression of the wg gene. Overexpression of the JAK/STAT activating ligand Unpaired in the eye leads to loss of wg expression and ectopic morphogenetic furrow initiation from the lateral margins. Conversely, tissue lacking stat92E, which cannot transduce JAK/STAT signals, is transformed from retinal tissue into head cuticle, a phenotype that is also observed with ectopic Wg signaling. Consistent with this, cells lacking stat92E exhibit ectopic wg expression. Conversely, wg is autonomously repressed in cells with hyperactivated Stat92E. Furthermore, we show that the JAK/STAT pathway regulates a small enhancer in the wg 3' cis genomic region. As this enhancer is devoid of Stat92E-binding elements, we conclude that Stat92E represses wg through another, as yet unidentified factor that is probably a direct target of Stat92E. Taken together, our study is the first to demonstrate a role for the JAK/STAT pathway in Regional Specification by acting antagonistically to wg.
