Identification by ChIP-on-Chip of ARX target genes, a transcription factor implicated in mental retardation and epilepsy
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE29985 | GEO | 2011/12/22
SECONDARY ACCESSION(S): PRJNA155349
REPOSITORIES: GEO
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Project description:Genetic investigations of X-linked intellectual disabilities have implicated the ARX (Aristaless-related homeobox) gene in a wide spectrum of disorders extending from phenotypes characterised by severe neuronal migration defects such as lissencephaly, to mild or moderate forms of mental retardation without apparent brain abnormalities but with associated features of dystonia and epilepsy. Analysis of Arx spatio-temporal localisation profile in mouse revealed expression in telencephalic structures, mainly restricted to populations of GABAergic neurons at all stages of development. Furthermore, studies of the effects of ARX loss of function in humans and animal models revealed varying defects, suggesting multiple roles of this gene during brain development. However, to date, little is known about how ARX functions as a transcription factor and the nature of its targets. To better understand its role, we combined chromatin immunoprecipitation and mRNA expression with microarray analysis and identified a total of 1006 gene promoters bound by Arx in transfected neuroblastoma (N2a) cells and in mouse embryonic brain. Some of these promoters were enriched for a sequence very similar to a motif previously identified as Arx-binding motif and approximately 24% of Arx-bound genes were found to show expression changes following Arx overexpression or knock-down. Several of the Arx target genes we identified are known to be important for a variety of functions in brain development, including axonal guidance and synaptic plasticity and some of them suggest new functions for Arx. Overall, these results identified multiple new candidate targets for Arx and should help to better understand the pathophysiological mechanisms of intellectual disability and epilepsy associated with ARX mutations. N2a cells were transfected with either Arx or the corresponding empty vector. Eight different independent experiments were performed. The 16 samples were randomly distributes on the 2 expression microarrays.
2011-12-22 | E-GEOD-30190 | biostudies-arrayexpress
Project description:Genetic investigations of X-linked intellectual disabilities have implicated the ARX (Aristaless-related homeobox) gene in a wide spectrum of disorders extending from phenotypes characterised by severe neuronal migration defects such as lissencephaly, to mild or moderate forms of mental retardation without apparent brain abnormalities but with associated features of dystonia and epilepsy. Analysis of Arx spatio-temporal localisation profile in mouse revealed expression in telencephalic structures, mainly restricted to populations of GABAergic neurons at all stages of development. Furthermore, studies of the effects of ARX loss of function in humans and animal models revealed varying defects, suggesting multiple roles of this gene during brain development. However, to date, little is known about how ARX functions as a transcription factor and the nature of its targets. To better understand its role, we combined chromatin immunoprecipitation and mRNA expression with microarray analysis and identified a total of 1006 gene promoters bound by Arx in transfected neuroblastoma (N2a) cells and in mouse embryonic brain. Some of these promoters were enriched for a sequence very similar to a motif previously identified as Arx-binding motif and approximately 24% of Arx-bound genes were found to show expression changes following Arx overexpression or knock-down. Several of the Arx target genes we identified are known to be important for a variety of functions in brain development, including axonal guidance and synaptic plasticity and some of them suggest new functions for Arx. Overall, these results identified multiple new candidate targets for Arx and should help to better understand the pathophysiological mechanisms of intellectual disability and epilepsy associated with ARX mutations. ChIP-Chip experiments were performed with either Arx transfected N2a cells or mouse embryonic brains (E15.5). Three replicates were performed for each condition.
2011-12-22 | E-GEOD-29985 | biostudies-arrayexpress
Project description:Genetic investigations of X-linked intellectual disabilities have implicated the ARX (Aristaless-related homeobox) gene in a wide spectrum of disorders extending from phenotypes characterised by severe neuronal migration defects such as lissencephaly, to mild or moderate forms of mental retardation without apparent brain abnormalities but with associated features of dystonia and epilepsy. Analysis of Arx spatio-temporal localisation profile in mouse revealed expression in telencephalic structures, mainly restricted to populations of GABAergic neurons at all stages of development. Furthermore, studies of the effects of ARX loss of function in humans and animal models revealed varying defects, suggesting multiple roles of this gene during brain development. However, to date, little is known about how ARX functions as a transcription factor and the nature of its targets. To better understand its role, we combined chromatin immunoprecipitation and mRNA expression with microarray analysis and identified a total of 1006 gene promoters bound by Arx in transfected neuroblastoma (N2a) cells and in mouse embryonic brain. Some of these promoters were enriched for a sequence very similar to a motif previously identified as Arx-binding motif and approximately 24% of Arx-bound genes were found to show expression changes following Arx overexpression or knock-down. Several of the Arx target genes we identified are known to be important for a variety of functions in brain development, including axonal guidance and synaptic plasticity and some of them suggest new functions for Arx. Overall, these results identified multiple new candidate targets for Arx and should help to better understand the pathophysiological mechanisms of intellectual disability and epilepsy associated with ARX mutations.
2011-12-22 | GSE30190 | GEO
Project description:Arx is a paired-box homeodomain transcription factor and the vertebrate ortholog to the Drosophila aristaless (al) gene. Mutations in Arx are associated with a variety of human diseases, including X-linked infantile spasm syndrome (OMIM: 308350), X-linked myoclonic epilepsy with mental retardation and spasticity (OMIM: 300432), X-linked lissencephaly with ambiguous genitalia (OMIM: 300215), X-linked mental retardation 54 (OMIM: 300419), and agenesis of the corpus callosum with abnormal genitalia (OMIM: 300004). Arx-deficient mice exhibit a complex, pleiotrophic phenotype, including decreased proliferation of neuroepithelial cells of the cortex, dysgenesis of the thalamus and olfactory bulbs, and abnormal nonradial migration of GABAergic interneurons. It has been suggested that deficits in interneuron specification, migration, or function lead to loss of inhibitory neurotransmission, which then fails to control excitatory activity and leads to epilepsy or spasticities. Given that Arx mutations are associated with developmental disorders in which epilepsy and spasticity predominate and that Arx-deficient mice exhibit deficits in interneuron migration, understanding the function of Arx in interneuron migration will prove crucial to understanding the pathology underlying interneuronopathies. Yet, downstream transcriptional targets of Arx, to date, remain unidentified. The aim of this project is to identify bona fide transcriptional targets for the Arx, a transcription factor required for normal migration of interneurons from the ganglionic eminences to the cortex, and to investigate the functions of these genes in the Arx-dependent pathway regulating nonradial neuronal migration. We hypothesize that the genes regulated by the Arx transcription factor will play a critical role in the nonradial migration of interneurons and that the results of this study will provide novel insights into the molecular mechanisms of nonradial neuronal migration, in particular, and possibly the molecular and biochemical pathogenesis underlying epilepsy, mental retardation, infantile spasm syndromes, and other so-called interneuronopathies;; We have recently generated a transgenic mouse with a floxed Arx allele (Arxflox). We have generated conditional knockouts in which Arx is removed specifically from the brain by mating Arxflox mice with transgenic mice expressing Cre behind the neural tube-specific transcriptional regulatory elements of the POU domain, class 3, transcription factor 4 promoter. Preliminary analyses of these mice suggest that conditional knockout mice recapitulate the nonradial migration defects associated with conventional knockout mice. We will compare the gene expression profiles of ganglion eminences (GEs; the anatomical source for nonradially migrating interneurons) from male Arxflox mice that express Pou3f-Cre to those from male mice without Arxflox allele. Animals will be prepared and sacrificed following our institutional protocol. Tissue will be rapidly dissected from E14.5 (the temporal peak of interneuron migration) GEs (MGE and LGE from both left and right hemispheres). Preliminary experiments suggest that the amounts of RNA that can be isolated from a pair of GEs is in the range of 2000-3500 ng, which should be sufficient for microarray analysis following linear amplification of RNA. The GEs from each animal will be combined, snap frozen in liquid nitrogen, and stored at -80 C until RNA is extracted. Total RNA will be extracted using Trizol followed by RNA purification with the RNeasy cleanup kit. We will be providing total RNA samples from four wildtype and four transgenic animals (true biological replicates) from three separate litters to mitigate any expression differences resulting from mouse to mouse or litter to litter variation.
2008-10-25 | E-GEOD-12609 | biostudies-arrayexpress
Project description:Arx is a paired-box homeodomain transcription factor and the vertebrate ortholog to the Drosophila aristaless (al) gene. Mutations in Arx are associated with a variety of human diseases, including X-linked infantile spasm syndrome (OMIM: 308350), X-linked myoclonic epilepsy with mental retardation and spasticity (OMIM: 300432), X-linked lissencephaly with ambiguous genitalia (OMIM: 300215), X-linked mental retardation 54 (OMIM: 300419), and agenesis of the corpus callosum with abnormal genitalia (OMIM: 300004). Arx-deficient mice exhibit a complex, pleiotrophic phenotype, including decreased proliferation of neuroepithelial cells of the cortex, dysgenesis of the thalamus and olfactory bulbs, and abnormal nonradial migration of GABAergic interneurons. It has been suggested that deficits in interneuron specification, migration, or function lead to loss of inhibitory neurotransmission, which then fails to control excitatory activity and leads to epilepsy or spasticities. Given that Arx mutations are associated with developmental disorders in which epilepsy and spasticity predominate and that Arx-deficient mice exhibit deficits in interneuron migration, understanding the function of Arx in interneuron migration will prove crucial to understanding the pathology underlying interneuronopathies. Yet, downstream transcriptional targets of Arx, to date, remain unidentified. The aim of this project is to identify bona fide transcriptional targets for the Arx, a transcription factor required for normal migration of interneurons from the ganglionic eminences to the cortex, and to investigate the functions of these genes in the Arx-dependent pathway regulating nonradial neuronal migration. We hypothesize that the genes regulated by the Arx transcription factor will play a critical role in the nonradial migration of interneurons and that the results of this study will provide novel insights into the molecular mechanisms of nonradial neuronal migration, in particular, and possibly the molecular and biochemical pathogenesis underlying epilepsy, mental retardation, infantile spasm syndromes, and other so-called interneuronopathies; We have recently generated a transgenic mouse with a floxed Arx allele (Arxflox). We have generated conditional knockouts in which Arx is removed specifically from the brain by mating Arxflox mice with transgenic mice expressing Cre behind the neural tube-specific transcriptional regulatory elements of the POU domain, class 3, transcription factor 4 promoter. Preliminary analyses of these mice suggest that conditional knockout mice recapitulate the nonradial migration defects associated with conventional knockout mice. We will compare the gene expression profiles of ganglion eminences (GEs; the anatomical source for nonradially migrating interneurons) from male Arxflox mice that express Pou3f-Cre to those from male mice without Arxflox allele. Animals will be prepared and sacrificed following our institutional protocol. Tissue will be rapidly dissected from E14.5 (the temporal peak of interneuron migration) GEs (MGE and LGE from both left and right hemispheres). Preliminary experiments suggest that the amounts of RNA that can be isolated from a pair of GEs is in the range of 2000-3500 ng, which should be sufficient for microarray analysis following linear amplification of RNA. The GEs from each animal will be combined, snap frozen in liquid nitrogen, and stored at -80 C until RNA is extracted. Total RNA will be extracted using Trizol followed by RNA purification with the RNeasy cleanup kit. We will be providing total RNA samples from four wildtype and four transgenic animals (true biological replicates) from three separate litters to mitigate any expression differences resulting from mouse to mouse or litter to litter variation.
2008-08-30 | GSE12609 | GEO
Project description:The Aristaless-related homeobox (ARX) gene is a transcription factor involved in the development of GABAergic and cholinergic neurons in the forebrain. ARX mutations have been associated with a wide spectrum of neurodevelopemental disorders in humans, among which the most frequent, the 24 bp duplication in the protein polyalanine tract 2 (c.428_451dup24), gives rise to intellectual disability (ID), fine motor defects with or without epilepsy. To understand the physiological and functional consequences of this mutation, we generated and characterized a humanized mouse model carrying the c.428_451dup24 duplication (Arxdup24/0). Arxdup24/0 males presented with hyperactivity, enhanced stereotypies and altered contextual fear memory. Specific fine motor skills were also affected in Arxdup24/0 males, with reaching and grasping abilities alteration and fine motor coordination and balance defect. Transcriptome analysis of Arxdup24/0 forebrains at E15.5 showed a down-regulation of genes specifically expressed in interneurons associated with an up-regulation of interneuron silenced genes, suggesting abnormal interneuron development. Accordingly, interneuron migration and development were altered particularly in the cortex and the striatum between stages E15.5, P0 and adult. We also revealed a perturbation of the inhibitory/excitatory balance in Arxdup24/0 basolateral amygdala. Altogether, we showed that the c.428_451dup24 mutation modifies Arx function with a direct consequence on interneuron development, leading to hyperactivity and defects in precise motor movement control and in associative memory. Finally, we presented a new review of the clinical features of 33 male patients with ARX c.428_451dup24 mutation and showed striking similarities between their clinical features and the mouse phenotype.
2018-04-05 | GSE90036 | GEO
Project description:This SuperSeries is composed of the following subset Series: GSE29985: Identification by ChIP-on-Chip of ARX target genes, a transcription factor implicated in mental retardation and epilepsy GSE30190: Comparison of gene expression between Arx-transfected N2a cells and cells transfected by the corresponding empty vector Refer to individual Series
2011-12-22 | E-GEOD-30191 | biostudies-arrayexpress
Project description:After their destruction in adult mice, insulin-producing pancreatic beta-cells slowly regenerate from other islet cells, like glucagon-producing alpha-cells. However the molecular basis of this conversion is unknown. Moreover it remains unclear if this intra-islet cell conversion is relevant to human diseases with extensive beta-cell loss, like in type 1 diabetes (T1D). Here, we show that subsets of glucagon-expressing cells in subjects with T1D produce Insulin and other molecular features of beta-cells, accompanied by loss of the alpha-cell regulators DNA methyltransferase 1 (Dnmt1) and Aristaless-related homeobox (Arx). We generated mice permitting lineage tracing and inactivation of Dnmt1 and Arx in adult alpha-cells. Within 3 months of Dnmt1 and Arx loss, 50% of alpha-cells converted into cells producing insulin protein but not glucagon, changes not observed in alpha-cells after only Arx or Dnmt1 loss. Single cell isolation and high-throughput RNA sequencing revealed efficient and extensive alpha-cell conversion into progeny indistinguishable by global gene expression from native beta-cells. Our work reveals pathways regulated by Arx and Dnmt1 sufficient for achieving targeted generation of beta-cells from adult pancreatic alpha-cells.
2017-02-16 | GSE79457 | GEO
Project description:The homeobox containing gene Arx is expressed during ventral telencephalon development and it is required for correct GABAergic interneuron tangential migration from the ganglionic eminences to the olfactory bulbs, cerebral cortex and striatum. Its human ortholog is associated with a variety of neurological clinical manifestations whose syntoms are compatible with a loss of cortical interneurons and altered basal ganglia related-activities in humans. Herein, we reported the identification by global expression profiling of a group of genes whose expression is consistently altered in Arx mutant ganglionic eminences. Following analysis revealed the striking ectopic expression in the ganglionic eminences of a number of genes normally not, or only marginally, expressed in the ventral telencephalon. Among them, we functionally analyzed Ebf3, whose ectopic expression in ventral telencephalon is preventingneuronal tangential migration. Further, we showed that Arx is sufficient to repress Ebf3 endogenous expression and that its silencing in Arx mutant tissue might marginally rescue tangential cell movements. Together, these data provide an initial analysis of the molecular pathways regulated by Arx and how their networking might regulate those specific cellular processes during telencephalon development strongly altered by loss of Arx. Three timed-pregnant Arx heterozygous dams crossed with C57Bl/6 males were sacrificed at E14.5, the embryos harvested and placed into cold PBS. After brain isolarion, meninges and olfactory bulbs were removed, and the ventral telencephalon separated from the overlying cerebral cortex. The same procedure was repeated for 5 wt and 5 Arx mutant embryos.
2010-03-09 | E-GEOD-12956 | biostudies-arrayexpress
Project description:The enteroendocrine lineage secretes hormones which direct the digestion, absorption, and motility of the intestine. Arx is a transcription factor expressed specifically in the enteroendocrine cells. With intestinal-specific loss of Arx, hormonal expression is disrupted. We used microarrays to determine the differential expression of genes from the whole duodenum after removal of Arx, a gene specifically expressed in the enteroendocrine lineage, in the intestinal epithelium compared to littermate controls at postnatal day 5.
2017-12-08 | GSE107828 | GEO