The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Mark Eddison - One of the best experts on this subject based on the ideXlab platform.
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Segmental identity and cerebellar Granule Cell induction in rhombomere 1
BMC Biology, 2004Co-Authors: Mark Eddison, Leah Toole, Esther Bell, Richard Jt WingateAbstract:Background Cerebellar Granule Cell precursors are specifically generated within the hindbrain segment, rhombomere 1, which is bounded rostrally by the midbrain/hindbrain isthmus and caudally by the boundary of the Hoxa2 expression domain. While graded signals from the isthmus have a demonstrable patterning role within this region, the significance of segmental identity for neuronal specification within rhombomere 1 is unexplored. We examined the response of Granule Cell precursors to the overexpression of Hoxa2 , which normally determines patterns of development specific to the hindbrain. How much does the development of the cerebellum, a midbrain/hindbrain structure, reflect its neuromeric origin as a hindbrain segment? Results We show that a Gbx2 -positive, Otx2 -/ Hoxa2 -negative territory corresponding to rhombomere 1 forms prior to an identifiable isthmic organiser. Early global overexpression of Hoxa2 at embryonic day 0 has no effect on the expression of isthmic signalling molecules or the allocation of rhombomere 1 territory, but selectively results in the loss of Granule Cell markers at embryonic day 6 and the depletion of Cell bodies from the external Granule Cell layer. By comparison the trochlear nucleus and locus coeruleus form normally in ventral rhombomere 1 under these conditions. Microsurgery, coupled with electroporation, to target Hoxa2 overexpression to rhombic lip precursors, reveals a profound, autonomous respecification of migration. Rhombic lip derivatives, normally destined to occupy the external Granule Cell layer, violate the cerebellar boundary to form a ventrolateral nucleus in a position comparable to that occupied by rhombic lip derived neurons in rhombomere 2. Conclusions Different overexpression strategies reveal that the recognition of migration cues by Granule Cell precursors is dependent on their identity as rhombomere 1 derivatives. Segmental patterning cues operate autonomously within the rhombic lip precursor pool. By contrast, a subset of coextensive nuclei is refractory to ectopic Hoxa2 and is presumably induced solely by isthmic organiser activity. Thus, graded (isthmic) and segmental mechanisms may operate exclusively of one another in the specification of different neuronal populations within rhombomere 1. The early designation of an Otx2 -negative, Hoxa2 -negative region, prior to the appearance of the isthmic organiser, is a key initial step in the specification of the cerebellum.
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Segmental identity and cerebellar Granule Cell induction in rhombomere 1
BMC biology, 2004Co-Authors: Mark Eddison, Leah Toole, Esther Bell, Richard Jt T. WingateAbstract:Cerebellar Granule Cell precursors are specifically generated within the hindbrain segment, rhombomere 1, which is bounded rostrally by the midbrain/hindbrain isthmus and caudally by the boundary of the Hoxa2 expression domain. While graded signals from the isthmus have a demonstrable patterning role within this region, the significance of segmental identity for neuronal specification within rhombomere 1 is unexplored. We examined the response of Granule Cell precursors to the overexpression of Hoxa2, which normally determines patterns of development specific to the hindbrain. How much does the development of the cerebellum, a midbrain/hindbrain structure, reflect its neuromeric origin as a hindbrain segment? We show that a Gbx2-positive, Otx2-/Hoxa2-negative territory corresponding to rhombomere 1 forms prior to an identifiable isthmic organiser. Early global overexpression of Hoxa2 at embryonic day 0 has no effect on the expression of isthmic signalling molecules or the allocation of rhombomere 1 territory, but selectively results in the loss of Granule Cell markers at embryonic day 6 and the depletion of Cell bodies from the external Granule Cell layer. By comparison the trochlear nucleus and locus coeruleus form normally in ventral rhombomere 1 under these conditions. Microsurgery, coupled with electroporation, to target Hoxa2 overexpression to rhombic lip precursors, reveals a profound, autonomous respecification of migration. Rhombic lip derivatives, normally destined to occupy the external Granule Cell layer, violate the cerebellar boundary to form a ventrolateral nucleus in a position comparable to that occupied by rhombic lip derived neurons in rhombomere 2. Different overexpression strategies reveal that the recognition of migration cues by Granule Cell precursors is dependent on their identity as rhombomere 1 derivatives. Segmental patterning cues operate autonomously within the rhombic lip precursor pool. By contrast, a subset of coextensive nuclei is refractory to ectopic Hoxa2 and is presumably induced solely by isthmic organiser activity. Thus, graded (isthmic) and segmental mechanisms may operate exclusively of one another in the specification of different neuronal populations within rhombomere 1. The early designation of an Otx2-negative, Hoxa2-negative region, prior to the appearance of the isthmic organiser, is a key initial step in the specification of the cerebellum.
Alain Chédotal - One of the best experts on this subject based on the ideXlab platform.
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should i stay or should i go becoming a Granule Cell
Trends in Neurosciences, 2010Co-Authors: Alain ChédotalAbstract:Cerebellar Granule Cells undergo profound and rapid morphological modifications during development while they migrate from their birthplace at the surface of the cerebellar cortex to its deepest layer. Post-mitotic Granule Cells extend bipolar axons and sequentially use the two main modes of migration, tangential and radial, to reach their final destinations. Recent studies show that protein degradation involving key Cell-cycle regulators controls Granule Cell axon extension. The use of knockout mice deficient in different axon-guidance molecules combined with cutting-edge imaging methods has started to shed light on the molecular mechanisms that trigger Granule Cell migration. These studies suggest that a major reorganization of the cytoskeleton occurs as Granule Cells switch from tangential to radial migration.
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Should I stay or should I go? Becoming a Granule Cell
Trends in neurosciences, 2010Co-Authors: Alain ChédotalAbstract:Cerebellar Granule Cells undergo profound and rapid morphological modifications during development while they migrate from their birthplace at the surface of the cerebellar cortex to its deepest layer. Post-mitotic Granule Cells extend bipolar axons and sequentially use the two main modes of migration, tangential and radial, to reach their final destinations. Recent studies show that protein degradation involving key Cell-cycle regulators controls Granule Cell axon extension. The use of knockout mice deficient in different axon-guidance molecules combined with cutting-edge imaging methods has started to shed light on the molecular mechanisms that trigger Granule Cell migration. These studies suggest that a major reorganization of the cytoskeleton occurs as Granule Cells switch from tangential to radial migration.
Richard Jt T. Wingate - One of the best experts on this subject based on the ideXlab platform.
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Segmental identity and cerebellar Granule Cell induction in rhombomere 1
BMC biology, 2004Co-Authors: Mark Eddison, Leah Toole, Esther Bell, Richard Jt T. WingateAbstract:Cerebellar Granule Cell precursors are specifically generated within the hindbrain segment, rhombomere 1, which is bounded rostrally by the midbrain/hindbrain isthmus and caudally by the boundary of the Hoxa2 expression domain. While graded signals from the isthmus have a demonstrable patterning role within this region, the significance of segmental identity for neuronal specification within rhombomere 1 is unexplored. We examined the response of Granule Cell precursors to the overexpression of Hoxa2, which normally determines patterns of development specific to the hindbrain. How much does the development of the cerebellum, a midbrain/hindbrain structure, reflect its neuromeric origin as a hindbrain segment? We show that a Gbx2-positive, Otx2-/Hoxa2-negative territory corresponding to rhombomere 1 forms prior to an identifiable isthmic organiser. Early global overexpression of Hoxa2 at embryonic day 0 has no effect on the expression of isthmic signalling molecules or the allocation of rhombomere 1 territory, but selectively results in the loss of Granule Cell markers at embryonic day 6 and the depletion of Cell bodies from the external Granule Cell layer. By comparison the trochlear nucleus and locus coeruleus form normally in ventral rhombomere 1 under these conditions. Microsurgery, coupled with electroporation, to target Hoxa2 overexpression to rhombic lip precursors, reveals a profound, autonomous respecification of migration. Rhombic lip derivatives, normally destined to occupy the external Granule Cell layer, violate the cerebellar boundary to form a ventrolateral nucleus in a position comparable to that occupied by rhombic lip derived neurons in rhombomere 2. Different overexpression strategies reveal that the recognition of migration cues by Granule Cell precursors is dependent on their identity as rhombomere 1 derivatives. Segmental patterning cues operate autonomously within the rhombic lip precursor pool. By contrast, a subset of coextensive nuclei is refractory to ectopic Hoxa2 and is presumably induced solely by isthmic organiser activity. Thus, graded (isthmic) and segmental mechanisms may operate exclusively of one another in the specification of different neuronal populations within rhombomere 1. The early designation of an Otx2-negative, Hoxa2-negative region, prior to the appearance of the isthmic organiser, is a key initial step in the specification of the cerebellum.
Richard Jt Wingate - One of the best experts on this subject based on the ideXlab platform.
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Segmental identity and cerebellar Granule Cell induction in rhombomere 1
BMC Biology, 2004Co-Authors: Mark Eddison, Leah Toole, Esther Bell, Richard Jt WingateAbstract:Background Cerebellar Granule Cell precursors are specifically generated within the hindbrain segment, rhombomere 1, which is bounded rostrally by the midbrain/hindbrain isthmus and caudally by the boundary of the Hoxa2 expression domain. While graded signals from the isthmus have a demonstrable patterning role within this region, the significance of segmental identity for neuronal specification within rhombomere 1 is unexplored. We examined the response of Granule Cell precursors to the overexpression of Hoxa2 , which normally determines patterns of development specific to the hindbrain. How much does the development of the cerebellum, a midbrain/hindbrain structure, reflect its neuromeric origin as a hindbrain segment? Results We show that a Gbx2 -positive, Otx2 -/ Hoxa2 -negative territory corresponding to rhombomere 1 forms prior to an identifiable isthmic organiser. Early global overexpression of Hoxa2 at embryonic day 0 has no effect on the expression of isthmic signalling molecules or the allocation of rhombomere 1 territory, but selectively results in the loss of Granule Cell markers at embryonic day 6 and the depletion of Cell bodies from the external Granule Cell layer. By comparison the trochlear nucleus and locus coeruleus form normally in ventral rhombomere 1 under these conditions. Microsurgery, coupled with electroporation, to target Hoxa2 overexpression to rhombic lip precursors, reveals a profound, autonomous respecification of migration. Rhombic lip derivatives, normally destined to occupy the external Granule Cell layer, violate the cerebellar boundary to form a ventrolateral nucleus in a position comparable to that occupied by rhombic lip derived neurons in rhombomere 2. Conclusions Different overexpression strategies reveal that the recognition of migration cues by Granule Cell precursors is dependent on their identity as rhombomere 1 derivatives. Segmental patterning cues operate autonomously within the rhombic lip precursor pool. By contrast, a subset of coextensive nuclei is refractory to ectopic Hoxa2 and is presumably induced solely by isthmic organiser activity. Thus, graded (isthmic) and segmental mechanisms may operate exclusively of one another in the specification of different neuronal populations within rhombomere 1. The early designation of an Otx2 -negative, Hoxa2 -negative region, prior to the appearance of the isthmic organiser, is a key initial step in the specification of the cerebellum.
Esther Bell - One of the best experts on this subject based on the ideXlab platform.
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Segmental identity and cerebellar Granule Cell induction in rhombomere 1
BMC Biology, 2004Co-Authors: Mark Eddison, Leah Toole, Esther Bell, Richard Jt WingateAbstract:Background Cerebellar Granule Cell precursors are specifically generated within the hindbrain segment, rhombomere 1, which is bounded rostrally by the midbrain/hindbrain isthmus and caudally by the boundary of the Hoxa2 expression domain. While graded signals from the isthmus have a demonstrable patterning role within this region, the significance of segmental identity for neuronal specification within rhombomere 1 is unexplored. We examined the response of Granule Cell precursors to the overexpression of Hoxa2 , which normally determines patterns of development specific to the hindbrain. How much does the development of the cerebellum, a midbrain/hindbrain structure, reflect its neuromeric origin as a hindbrain segment? Results We show that a Gbx2 -positive, Otx2 -/ Hoxa2 -negative territory corresponding to rhombomere 1 forms prior to an identifiable isthmic organiser. Early global overexpression of Hoxa2 at embryonic day 0 has no effect on the expression of isthmic signalling molecules or the allocation of rhombomere 1 territory, but selectively results in the loss of Granule Cell markers at embryonic day 6 and the depletion of Cell bodies from the external Granule Cell layer. By comparison the trochlear nucleus and locus coeruleus form normally in ventral rhombomere 1 under these conditions. Microsurgery, coupled with electroporation, to target Hoxa2 overexpression to rhombic lip precursors, reveals a profound, autonomous respecification of migration. Rhombic lip derivatives, normally destined to occupy the external Granule Cell layer, violate the cerebellar boundary to form a ventrolateral nucleus in a position comparable to that occupied by rhombic lip derived neurons in rhombomere 2. Conclusions Different overexpression strategies reveal that the recognition of migration cues by Granule Cell precursors is dependent on their identity as rhombomere 1 derivatives. Segmental patterning cues operate autonomously within the rhombic lip precursor pool. By contrast, a subset of coextensive nuclei is refractory to ectopic Hoxa2 and is presumably induced solely by isthmic organiser activity. Thus, graded (isthmic) and segmental mechanisms may operate exclusively of one another in the specification of different neuronal populations within rhombomere 1. The early designation of an Otx2 -negative, Hoxa2 -negative region, prior to the appearance of the isthmic organiser, is a key initial step in the specification of the cerebellum.
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Segmental identity and cerebellar Granule Cell induction in rhombomere 1
BMC biology, 2004Co-Authors: Mark Eddison, Leah Toole, Esther Bell, Richard Jt T. WingateAbstract:Cerebellar Granule Cell precursors are specifically generated within the hindbrain segment, rhombomere 1, which is bounded rostrally by the midbrain/hindbrain isthmus and caudally by the boundary of the Hoxa2 expression domain. While graded signals from the isthmus have a demonstrable patterning role within this region, the significance of segmental identity for neuronal specification within rhombomere 1 is unexplored. We examined the response of Granule Cell precursors to the overexpression of Hoxa2, which normally determines patterns of development specific to the hindbrain. How much does the development of the cerebellum, a midbrain/hindbrain structure, reflect its neuromeric origin as a hindbrain segment? We show that a Gbx2-positive, Otx2-/Hoxa2-negative territory corresponding to rhombomere 1 forms prior to an identifiable isthmic organiser. Early global overexpression of Hoxa2 at embryonic day 0 has no effect on the expression of isthmic signalling molecules or the allocation of rhombomere 1 territory, but selectively results in the loss of Granule Cell markers at embryonic day 6 and the depletion of Cell bodies from the external Granule Cell layer. By comparison the trochlear nucleus and locus coeruleus form normally in ventral rhombomere 1 under these conditions. Microsurgery, coupled with electroporation, to target Hoxa2 overexpression to rhombic lip precursors, reveals a profound, autonomous respecification of migration. Rhombic lip derivatives, normally destined to occupy the external Granule Cell layer, violate the cerebellar boundary to form a ventrolateral nucleus in a position comparable to that occupied by rhombic lip derived neurons in rhombomere 2. Different overexpression strategies reveal that the recognition of migration cues by Granule Cell precursors is dependent on their identity as rhombomere 1 derivatives. Segmental patterning cues operate autonomously within the rhombic lip precursor pool. By contrast, a subset of coextensive nuclei is refractory to ectopic Hoxa2 and is presumably induced solely by isthmic organiser activity. Thus, graded (isthmic) and segmental mechanisms may operate exclusively of one another in the specification of different neuronal populations within rhombomere 1. The early designation of an Otx2-negative, Hoxa2-negative region, prior to the appearance of the isthmic organiser, is a key initial step in the specification of the cerebellum.
