The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Noriko Osumi - One of the best experts on this subject based on the ideXlab platform.
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Organizing activity of Fgf8 on the anterior Telencephalon
Development growth & differentiation, 2017Co-Authors: Tatsuya Sato, Takako Kikkawa, Tetsuichiro Saito, Keiichi Itoi, Noriko OsumiAbstract:The anterior part of the embryonic Telencephalon gives rise to several brain regions that are important for animal behavior, including the frontal cortex (FC) and the olfactory bulb. The FC plays an important role in decision-making behaviors, such as social and cognitive behavior, and the olfactory bulb is involved in olfaction. Here, we show the organizing activity of fibroblast growth factor 8 (Fgf8) in the regionalization of the anterior Telencephalon, specifically the FC and the olfactory bulb. Misexpression of Fgf8 in the most anterior part of the mouse Telencephalon at embryonic day 11.5 (E11.5) by ex utero electroporation resulted in a lateral shift of dorsal FC subdivision markers and a lateral expansion of the dorsomedial part of the FC, the future anterior cingulate and prelimbic cortex. Fgf8-transfected brains had lacked ventral FC, including the future orbital cortex, which was replaced by the expanded olfactory bulb. The olfactory region occupied a larger area of the FC when transfection efficiency of Fgf8 was higher. These results suggest that Fgf8 regulates the proportions of the FC and olfactory bulb in the anterior Telencephalon and has a medializing effect on the formation of FC subdivisions.
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Dmrta1 regulates proneural gene expression downstream of Pax6 in the mammalian Telencephalon.
Genes to cells : devoted to molecular & cellular mechanisms, 2013Co-Authors: Takako Kikkawa, Masanori Takahashi, Takeshi Obayashi, Urara Fukuzaki-dohi, Keiko Numayama-tsuruta, Noriko OsumiAbstract:The transcription factor Pax6 balances cell proliferation and neuronal differentiation in the mammalian developing neocortex by regulating the expression of target genes. Using microarray analysis, we observed the down-regulation of Dmrta1 (doublesex and mab-3-related transcription factor-like family A1) in the Telencephalon of Pax6 homozygous mutant rats (rSey2/rSey2). Dmrta1 expression was restricted to the neural stem/progenitor cells of the dorsal Telencephalon. Overexpression of Dmrta1 induced the expression of the proneural gene Neurogenin2 (Neurog2) and conversely repressed Ascl1 (Mash1), a proneural gene expressed in the ventral Telencephalon. We found that another Dmrt family molecule, Dmrt3, induced Neurog2 expression in the dorsal Telencephalon. Our novel findings suggest that dual regulation of proneural genes mediated by Pax6 and Dmrt family members is crucial for cortical neurogenesis.
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Penetration and differentiation of cephalic neural crest‐derived cells in the developing mouse Telencephalon
Development growth & differentiation, 2012Co-Authors: Emiko Yamanishi, Masanori Takahashi, Yumiko Saga, Noriko OsumiAbstract:Neural crest (NC) cells originate from the neural folds and migrate into the various embryonic regions where they differentiate into multiple cell types. A population of cephalic neural crest-derived cells (NCDCs) penetrates back into the developing forebrain to differentiate into microvascular pericytes, but little is known about when and how cephalic NCDCs invade the Telencephalon and differentiate into pericytes. Using a transgenic mouse line in which NCDCs are genetically labeled with enhanced green fluorescent protein (EGFP), we observed that NCDCs started to invade the Telencephalon together with endothelial cells from embryonic day (E) 9.5. A majority of NCDCs located in the Telencephalon expressed pericyte markers, that is, PDGFRβ and NG2, and differentiated into pericytes around E11.5. Surprisingly, many of the NC-derived pericytes express p75, an undifferentiated NCDC marker at E11.5, as well as NCDCs in the mesenchyme. At the same time, a minor population of NCDCs that located separately from blood vessels in the Telencephalon were NG2-negative and some of these NCDCs also expressed p75. Proliferation and differentiation of pericytes appeared to occur in a specific mesenchymal region where blood vessels penetrated into the Telencephalon. These results indicate that (i) NCDCs penetrate back into the Telencephalon in parallel with angiogenesis, (ii) many NC-derived pericytes may be still in pre-mature states even though after differentiation into pericytes in the early developing stages, (iii) a small minority of NCDCs may retain undifferentiated states in the developing Telencephalon, and (iv) a majority of NCDCs proliferate and differentiate into pericytes in the mesenchyme around the Telencephalon.
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Pax6-dependent boundary defines alignment of migrating olfactory cortex neurons via the repulsive activity of ephrin A5.
Development (Cambridge England), 2006Co-Authors: Tadashi Nomura, Johan Holmberg, Noriko OsumiAbstract:Neuronal migration is a prerequisite event for the establishment of highly ordered neuronal circuits in the developing brain. Here, we report Pax6-dependent alignment of the olfactory cortex neurons in the developing Telencephalon. These neurons were generated in the dorsal part of Telencephalon, migrated ventrally and stopped at the pallium-subpallium boundary (PSB). In Pax6 mutant rat embryos, however, these neurons invaded the ventral part of the Telencephalon by crossing the PSB. Ephrin A5, one of the ligands for EphA receptors, was specifically expressed in the ventral part of the Telencephalon, and its expression level was markedly reduced in the Pax6 mutant. Gain- and loss-of-function studies of ephrin A5 indicated that ephrin A5 plays an important role in the alignment of olfactory cortex neurons at the PSB. Our results suggest that Pax6-regulated ephrin A5 acts as a repulsive molecule for olfactory cortex neurons in the developing Telencephalon.
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Misrouting of mitral cell progenitors in the Pax6/small eye rat Telencephalon.
Development (Cambridge England), 2004Co-Authors: Tadashi Nomura, Noriko OsumiAbstract:The olfactory bulb is a protruding structure formed at the rostral end of the Telencephalon. Pax6-mutant mice and rats lack the olfactory bulb and, instead, develop an olfactory bulb-like structure at the lateral part of the Telencephalon. Here, we report that ectopic formation of the olfactory bulb-like structure in these mutants is caused by the abnormal migration of mitral cell progenitors, which first differentiate within the olfactory bulb. Cell-tracing experiments in whole embryos in culture indicate that, in the mutants, the mitral cell progenitors that originate from the rostral part of the Telencephalon migrate caudally toward the lateral part of the Telencephalon. Cell transplantation demonstrates that the abnormal cell migration is not autonomous to the mitral cell progenitors themselves. The mislocation of the olfactory bulb in the mutant is not caused by loss of olfactory nerve innervation. Furthermore, transfection of a Pax6-expression vector to the mutant Telencephalon restores the normal migration of mitral cell progenitors. These results provide evidence that Pax6 is required to position the mitral cell progenitors at the rostral end of the Telencephalon.
Michael A Bell - One of the best experts on this subject based on the ideXlab platform.
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phenotypic plasticity of the threespine stickleback gasterosteus aculeatus Telencephalon in response to experience in captivity
Current Zoology, 2012Co-Authors: Peter J Park, Ivan D Chase, Michael A BellAbstract:Threespine stickleback were used to examine phenotypic plasticity of telencephala in relation to inferred ecology. Fish from derived, allopatric, freshwater populations were sampled from three shallow, structurally complex lakes with ben- thic-foraging stickleback (benthics) and from three deep, structurally simple lakes with planktivores (limnetics). The telencepha- lon of specimens preserved immediately after capture (field-preserved), field-caught fish held in aquaria for 90 days (lab-held), and lab-bred fish from crosses and raised in aquaria were compared. Field-preserved sea-run (ancestral) stickleback were col- lected from two separate sites, and parents of lab-bred sea-run stickleback were collected from one of these sites. In field-preserved and lab-held fish, the telencephala of limnetics exhibited triangular dorsal shape, while those of benthics and sea-run fish had rounder shapes. No such pattern was detected in lab-bred fish. Within each treatment type, benthics had larger relative Telencephalon sizes, using overall brain size as the covariate, than limnetics. Among field-preserved samples, sea-run fish had smaller Telencephalon sizes than lake fish. Intra-population analyses of lake samples showed that field-preserved fish consis- tently had larger relative Telencephalon sizes than lab-bred fish. The opposite was true of the sea-run population. In a separate study using one benthic population and one limnetic population, samples were preserved in the field immediately or held in the lab for 30, 60, and 90 days before they were sacrificed. In both populations, the Telencephalon shapes of lab-held fish were similar to those of field-preserved fish but became progressively more like lab-bred ones over 90 days. In contrast, relative Telencephalon size decreased dramatically by 30 days after which there was little change. In freshwater threespine stickleback, the Telencephalon exhibits considerable phenotypic plasticity, which was probably present in the ancestor (Current Zoology 58 (1): 189-210, 2012).
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variation of Telencephalon morphology of the threespine stickleback gasterosteus aculeatus in relation to inferred ecology
Journal of Evolutionary Biology, 2010Co-Authors: Peter J Park, Michael A BellAbstract:We tested the hypothesis that increased Telencephalon size has evolved in threespine stickleback fish (Gasterosteus aculeatus) from structurally complex habitats using field-caught samples from one sea-run (ancestral) and 18 ecologically diverse freshwater (descendant) populations. Freshwater habitats ranged from shallow, structurally complex lakes with benthic-foraging stickleback (benthics), to deeper, structurally simple lakes in which stickleback depend more heavily on plankton for prey (generalists). Contrary to our expectations, benthics had smaller telencephala than generalists, but the shape of the Telencephalon of the sea-run and benthic populations were more convex laterally. Convex Telencephalon shape may indicate enlargement of the dorsolateral region, which is homologous with the tetrapod hippocampus. Telencephalon morphology is also sexually dimorphic, with larger, less convex telencephala in males. Freshwater stickleback from structurally complex habitats have retained the ancestral Telencephalon morphology, but populations that feed more in open habitats on plankton have evolved larger, laterally concave telencephala.
John L.r. Rubenstein - One of the best experts on this subject based on the ideXlab platform.
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Fgf signaling controls the telencephalic distribution of Fgf-expressing progenitors generated in the rostral patterning center
Neural Development, 2015Co-Authors: Renée V Hoch, Jeffrey A Clarke, John L.r. RubensteinAbstract:Background The rostral patterning center (RPC) secretes multiple fibroblast growth factors (Fgfs) essential for Telencephalon growth and patterning. Fgf expression patterns suggest that they mark functionally distinct RPC subdomains. We generated Fgf8 ^ CreER and Fgf17 ^ CreER mice and used them to analyze the lineages of Fgf8- versus Fgf17-expressing RPC cells. Results Both lineages contributed to medial structures of the rostroventral Telencephalon structures including the septum and medial prefrontral cortex. In addition, RPC-derived progenitors were observed in other regions of the early telencephalic neuroepithelium and generated neurons in the olfactory bulb, neocortex, and basal ganglia. Surprisingly, Fgf8^+ RPC progenitors generated the majority of basal ganglia cholinergic neurons. Compared to the Fgf8 lineage, the Fgf17 lineage was more restricted in its early dispersion and its contributions to the Telencephalon. Mutant studies suggested that Fgf8 and Fgf17 restrict spread of RPC progenitor subpopulations. Conclusions We identified the RPC as an important source of progenitors that contribute broadly to the Telencephalon and found that two molecularly distinct progenitor subtypes in the RPC make different contributions to the developing forebrain.
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Ldb1 is essential for development of Nkx2.1 lineage derived GABAergic and cholinergic neurons in the Telencephalon.
Developmental biology, 2013Co-Authors: Yangu Zhao, Heiner Westphal, Pierre Flandin, Daniel Vogt, Alexander Blood, Edit Hermesz, John L.r. RubensteinAbstract:The progenitor zones of the embryonic mouse ventral Telencephalon give rise to GABAergic and cholinergic neurons. We have shown previously that two LIM-homeodomain (LIM-HD) transcription factors, Lhx6 and Lhx8, that are downstream of Nkx2.1, are critical for the development of telencephalic GABAergic and cholinergic neurons. Here we investigate the role of Ldb1, a nuclear protein that binds directly to all LIM-HD factors, in the development of these ventral Telencephalon derived neurons. We show that Ldb1 is expressed in the Nkx2.1 cell lineage during embryonic development and in mature neurons. Conditional deletion of Ldb1 causes defects in the expression of a series of genes in the ventral Telencephalon and severe impairment in the tangential migration of cortical interneurons from the ventral Telencephalon. Similar to the phenotypes observed in Lhx6 or Lhx8 mutant mice, the Ldb1 conditional mutants show a reduction in the number of both GABAergic and cholinergic neurons in the Telencephalon. Furthermore, our analysis reveals defects in the development of the parvalbumin-positive neurons in the globus pallidus and striatum of the Ldb1 mutants. These results provide evidence that Ldb1 plays an essential role as a transcription co-regulator of Lhx6 and Lhx8 in the control of mammalian Telencephalon development.
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Patterning of the basal Telencephalon and hypothalamus is essential for guidance of cortical projections.
Development (Cambridge England), 2002Co-Authors: Oscar Marín, Luis Puelles, Joshua Baker, John L.r. RubensteinAbstract:We have investigated the mechanisms that control the guidance of corticofugal projections as they extend along different subdivisions of the forebrain. To this aim, we analyzed the development of cortical projections in mice that lack Nkx2-1, a homeobox gene whose expression is restricted to two domains within the forebrain: the basal Telencephalon and the hypothalamus. Molecular respecification of the basal Telencephalon and hypothalamus in Nkx2-1-deficient mice causes a severe defect in the guidance of layer 5 cortical projections and ascending fibers of the cerebral peduncle. These axon tracts take an abnormal path when coursing through both the basal Telencephalon and hypothalamus. By contrast, loss of Nkx2-1 function does not impair guidance of corticothalamic or thalamocortical axons. In vitro experiments demonstrate that the basal Telencephalon and the hypothalamus contain an activity that repels the growth of cortical axons, suggesting that loss of this activity is the cause of the defects observed in Nkx2-1 mutants. Furthermore, analysis of the expression of candidate molecules in the basal Telencephalon and hypothalamus of Nkx2-1 mutants suggests that Slit2 contributes to this activity.
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interneuron migration from basal forebrain to neocortex dependence on dlx genes
Science, 1997Co-Authors: Stewart A. Anderson, David D. Eisenstat, John L.r. RubensteinAbstract:Although previous analyses indicate that neocortical neurons originate from the cortical proliferative zone, evidence suggests that a subpopulation of neocortical interneurons originates within the subcortical Telencephalon. For example, γ-aminobutyric acid (GABA)–expressing cells migrate in vitro from the subcortical Telencephalon into the neocortex. The number of GABA-expressing cells in neocortical slices is reduced by separating the neocortex from the subcortical Telencephalon. Finally, mice lacking the homeodomain proteins DLX-1 and DLX-2 show no detectable cell migration from the subcortical Telencephalon to the neocortex and also have few GABA-expressing cells in the neocortex.
Peter J Park - One of the best experts on this subject based on the ideXlab platform.
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phenotypic plasticity of the threespine stickleback gasterosteus aculeatus Telencephalon in response to experience in captivity
Current Zoology, 2012Co-Authors: Peter J Park, Ivan D Chase, Michael A BellAbstract:Threespine stickleback were used to examine phenotypic plasticity of telencephala in relation to inferred ecology. Fish from derived, allopatric, freshwater populations were sampled from three shallow, structurally complex lakes with ben- thic-foraging stickleback (benthics) and from three deep, structurally simple lakes with planktivores (limnetics). The telencepha- lon of specimens preserved immediately after capture (field-preserved), field-caught fish held in aquaria for 90 days (lab-held), and lab-bred fish from crosses and raised in aquaria were compared. Field-preserved sea-run (ancestral) stickleback were col- lected from two separate sites, and parents of lab-bred sea-run stickleback were collected from one of these sites. In field-preserved and lab-held fish, the telencephala of limnetics exhibited triangular dorsal shape, while those of benthics and sea-run fish had rounder shapes. No such pattern was detected in lab-bred fish. Within each treatment type, benthics had larger relative Telencephalon sizes, using overall brain size as the covariate, than limnetics. Among field-preserved samples, sea-run fish had smaller Telencephalon sizes than lake fish. Intra-population analyses of lake samples showed that field-preserved fish consis- tently had larger relative Telencephalon sizes than lab-bred fish. The opposite was true of the sea-run population. In a separate study using one benthic population and one limnetic population, samples were preserved in the field immediately or held in the lab for 30, 60, and 90 days before they were sacrificed. In both populations, the Telencephalon shapes of lab-held fish were similar to those of field-preserved fish but became progressively more like lab-bred ones over 90 days. In contrast, relative Telencephalon size decreased dramatically by 30 days after which there was little change. In freshwater threespine stickleback, the Telencephalon exhibits considerable phenotypic plasticity, which was probably present in the ancestor (Current Zoology 58 (1): 189-210, 2012).
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variation of Telencephalon morphology of the threespine stickleback gasterosteus aculeatus in relation to inferred ecology
Journal of Evolutionary Biology, 2010Co-Authors: Peter J Park, Michael A BellAbstract:We tested the hypothesis that increased Telencephalon size has evolved in threespine stickleback fish (Gasterosteus aculeatus) from structurally complex habitats using field-caught samples from one sea-run (ancestral) and 18 ecologically diverse freshwater (descendant) populations. Freshwater habitats ranged from shallow, structurally complex lakes with benthic-foraging stickleback (benthics), to deeper, structurally simple lakes in which stickleback depend more heavily on plankton for prey (generalists). Contrary to our expectations, benthics had smaller telencephala than generalists, but the shape of the Telencephalon of the sea-run and benthic populations were more convex laterally. Convex Telencephalon shape may indicate enlargement of the dorsolateral region, which is homologous with the tetrapod hippocampus. Telencephalon morphology is also sexually dimorphic, with larger, less convex telencephala in males. Freshwater stickleback from structurally complex habitats have retained the ancestral Telencephalon morphology, but populations that feed more in open habitats on plankton have evolved larger, laterally concave telencephala.
Fu-chin Liu - One of the best experts on this subject based on the ideXlab platform.
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Genetic patterning of the mammalian Telencephalon by morphogenetic molecules and transcription factors.
Birth defects research. Part C Embryo today : reviews, 2006Co-Authors: Hiroshi Takahashi, Fu-chin LiuAbstract:Patterning centers that produce gradients of morphogenetic molecules, including fibroblast growth factor (FGF), bone morphogenetic proteins (BMP), Wnt, Sonic hedgehog (Shh), and retinoic acid (RA), are located in telencephalic anlage during early stages of development. Genetic evidence based on loss-of-function and gain-of-function studies indicate that they are involved in regional specification of the dorsal, ventral, and lateral Telencephalon. For patterning of the dorsal Telencephalon, FGF8 controls the anteroposterior patterning, while BMP and Wnt molecules regulate the mediolateral patterning. Shh and retinoic acid regulate patterning of the ventral and the lateral Telencephalon. The regionalization of Telencephalon is accompanied by expression of region-specific codes of transcription factors, which in turn regulate different phases of neuronal development to generate different cell types in each brain region. Therefore, bioactive signals of morphogenetic molecules are translated into transcription factor codes for regional specification, which subsequently leads to neurogenesis of the diversity of cell types in different regions of the Telencephalon.
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Retinoid signaling competence and RARbeta-mediated gene regulation in the developing mammalian Telencephalon.
Developmental Dynamics, 2005Co-Authors: Wen-lin Liao, Hsiao-fang Wang, Hsiu-chao Tsai, Pierre Chambon, Michael Wagner, Akira Kakizuka, Fu-chin LiuAbstract:To study retinoid signaling in the developing Telencephalon, we transfected a retinoid reporter gene into different regions of developing Telencephalon. We found that the ventral Telencephalon was more competent to retinoid signaling than the dorsal Telencephalon. Moreover, among all retinoic acid receptors (RARs) and retinoid X receptors (RXRs), RARbeta was strongly induced by retinoic acid in the ventral Telencephalon, suggesting that RARbeta might be involved in retinoid signaling competence. The RT-PCR analysis indicated that RARbeta was selectively expressed in the developing striatum of ventral Telencephalon. We then demonstrated that null mutations of RARbeta gene resulted in reduction of striatal-enriched tyrosine phosphatase (STEP) mRNA in the striatum of RARbeta-/- mutant mice. Conversely, the gain-of-function study showed that ectopic expression of RARbeta1 in the cerebral cortex enhanced STEP expression, and the effect was RARbeta-isoform specific. Our study identified RARbeta as an important molecule for transducing retinoid signals in developing ventral Telencephalon.
