Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA277859 | ENA |
REPOSITORIES: ENA
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Project description:HIF1 is essential for regulation of the transcriptional response to hypoxia. Recently we showed that the transcriptional repressors E2F7 and E2F8 interact and transcriptionally cooperate with HIF1. Here we further explored this cooperation by performing genome-wide analysis, screening for novel HIF1-E2F7 targets. We show that specifically E2F7 is induced in hypoxia by HIF1. Furthermore, chip-sequencing for E2F7 and HIF1 revealed a large number of common targets of which a subset was also regulated by the complex as examined by microarray analysis. Our data show that the HIF1-E2F7 complex can function both as a repressor or activator. Notably, we identify neuropilin 1 (NRP1) as a novel HIF1-E2F7 target, which is repressed by HIF1-E2F7 in vitro and during zebrafish development, depending on E2F-binding sites present in the NRP1 promoter. In addition we show that regulation of NRP1 by the HIF1-E2F7 complex is required for normal axon guidance of spinal motorneurons in vivo. ChIP-seq analysis of HIF1a and E2F7 binding
2015-12-11 | E-GEOD-66956 | biostudies-arrayexpress
Project description:HIF1 is essential for regulation of the transcriptional response to hypoxia. Recently we showed that the transcriptional repressors E2F7 and E2F8 interact and transcriptionally cooperate with HIF1. Here we further explored this cooperation by performing genome-wide analysis, screening for novel HIF1-E2F7 targets. We show that specifically E2F7 is induced in hypoxia by HIF1. Furthermore, chip-sequencing for E2F7 and HIF1 revealed a large number of common targets of which a subset was also regulated by the complex as examined by microarray analysis. Our data show that the HIF1-E2F7 complex can function both as a repressor or activator. Notably, we identify neuropilin 1 (NRP1) as a novel HIF1-E2F7 target, which is repressed by HIF1-E2F7 in vitro and during zebrafish development, depending on E2F-binding sites present in the NRP1 promoter. In addition we show that regulation of NRP1 by the HIF1-E2F7 complex is required for normal axon guidance of spinal motorneurons in vivo.
2015-12-11 | GSE66956 | GEO
Project description:Genome-wide analysis reveals NRP1 as a critical HIF1-E2F7 target gene in the regulation of motorneuron guidance in vivo
| PRJNA278464 | ENA
Project description:In this study, we explored the existence of a transcriptional network co-regulated by E2F7 and HIF1α, as we show that expression of E2F7, like HIF1α, is induced in hypoxia, and because of the previously reported ability of E2F7 to interact with HIF1α. Our genome-wide analysis uncovers a transcriptional network that is directly controlled by HIF1α and E2F7, and demonstrates both stimulatory and repressive functions of the HIF1α -E2F7 complex. Among this network we reveal Neuropilin 1 (NRP1) as a HIF1α-E2F7 repressed gene. By performing in vitro and in vivo reporter assays we demonstrate that the HIF1α-E2F7 mediated NRP1 repression depends on a 41 base pairs 'E2F-binding site hub', providing a molecular mechanism for a previously unanticipated role for HIF1α in transcriptional repression. To explore the biological significance of this regulation we performed in situ hybridizations and observed enhanced nrp1a expression in spinal motorneurons (MN) of zebrafish embryos, upon morpholino-inhibition of e2f7/8 or hif1α. Consistent with the chemo-repellent role of nrp1a, morpholino-inhibition of e2f7/8 or hif1α caused MN truncations, which was rescued in TALEN-induced nrp1a(hu10012) mutants, and phenocopied in e2f7/8 mutant zebrafish. Therefore, we conclude that repression of NRP1 by the HIF1α-E2F7 complex regulates MN axon guidance in vivo.
2016-01-04 | GSE66750 | GEO
Project description:In this study, we explored the existence of a transcriptional network co-regulated by E2F7 and HIF1α, as we show that expression of E2F7, like HIF1α, is induced in hypoxia, and because of the previously reported ability of E2F7 to interact with HIF1α. Our genome-wide analysis uncovers a transcriptional network that is directly controlled by HIF1α and E2F7, and demonstrates both stimulatory and repressive functions of the HIF1α -E2F7 complex. Among this network we reveal Neuropilin 1 (NRP1) as a HIF1α-E2F7 repressed gene. By performing in vitro and in vivo reporter assays we demonstrate that the HIF1α-E2F7 mediated NRP1 repression depends on a 41 base pairs 'E2F-binding site hub', providing a molecular mechanism for a previously unanticipated role for HIF1α in transcriptional repression. To explore the biological significance of this regulation we performed in situ hybridizations and observed enhanced nrp1a expression in spinal motorneurons (MN) of zebrafish embryos, upon morpholino-inhibition of e2f7/8 or hif1α. Consistent with the chemo-repellent role of nrp1a, morpholino-inhibition of e2f7/8 or hif1α caused MN truncations, which was rescued in TALEN-induced nrp1a(hu10012) mutants, and phenocopied in e2f7/8 mutant zebrafish. Therefore, we conclude that repression of NRP1 by the HIF1α-E2F7 complex regulates MN axon guidance in vivo. The following samples were analyzed by microarrays: RNA isolated from HeLa cells transfected with either control (scr), E2F7, HIF1a, E2F7 and E2F8, or E2F7 and HIF1a siRNAs. Cells were harvested 48h after transfection, and were grown the last 16h in hypoxia. RNA isolated from scr-transfected, normoxic HeLa cells was used as common reference RNA. Within each group of two biological replicates, sample versus common reference hybridisations were performed in balanced dye-swap. Microarrays used were human whole genome gene expression microarrays V1 (Agilent, Belgium).
2016-01-04 | E-GEOD-66750 | biostudies-arrayexpress
Project description:The high rates of mortality associated with epithelial ovarian cancer (EOC) are a direct consequence of its metastatic nature. Metastasis is dependent on many factors, among which activation of angiogenesis is most significant. Angiogenesis is, in turn, contingent upon the cellular response to hypoxia within the tumor microenvironment. Hypoxia-inducible factor 1 (HIF1) is a transcription factor composed of HIF1alpha and HIF1beta subunits and is the master regulator of the hypoxic response. It is therefore a critical mediator of tumor angiogenesis and metastasis. Regulation of HIF1 is primarily at the level of protein. In normoxia, the HIF1alpha subunit is hydroxylated via an oxygen- and iron-dependent mechanism and targeted for destruction. In hypoxia, low oxygen levels preclude hydroxylation and HIF1alpha is stabilized, allowing for its association with constitutively expressed HIF1beta to form bioactive HIF1. We have identified a novel mechanism of HIF1alpha regulation in EOC cells that involves microRNAs (miRs), ~22 nucleotide, non-coding RNA molecules that repress translation of target mRNAs by binding their 3’ untranslated regions (UTRs). Using microarray and qPCR analysis, we found that levels of miR-199a-1, a miR that is predicted in silico to target the HIF1alpha 3’ UTR, were reduced under hypoxia in EOC cells. We further demonstrated that miR-199a-1 directly targets the HIF1alpha 3’ UTR and overexpression of miR-199a-1 suppresses HIF1alpha protein levels and HIF1-driven gene expression. Moreover, cells stably overexpressing miR-199a-1 exhibit marked defects in migratory ability. These data were corroborated by our in vivo findings, which demonstrated that overexpression of miR-199a-1 causes significant reductions in tumor vessel density and tumor burden in nude mice. These findings provide insight into non-canonical, miR- and iron-based mechanisms of HIF1 regulation that may have important implications in the progression of EOC. miRNA expression analysis of A2780 epithelial ovarian cancer cells by microarrays
2011-09-23 | E-GEOD-32313 | biostudies-arrayexpress
Project description:Neural circuits governing complex motor behaviors in vertebrates rely on the proper development of motor neurons and their precise targeting of limb muscles. Transcription factors are essential for motor neuron development, regulating their specification, migration, and axonal targeting. While transcriptional regulation of the early stages of motor neuron specification is well-established, much less is known about the role of transcription factors in the later stages of maturation and terminal arborization. Defining the molecular mechanisms of these later stages is critical for elucidating how motor circuits are constructed. Here, we demonstrate that the transcription factor Nuclear Factor-IA (NFIA) is required for motor neuron positioning, axonal branching, and neuromuscular junction formation. Moreover, we find that NFIA is required for proper mitochondrial function and ATP production, providing a new and important link between transcription factors and metabolism during motor neuron development. Together, these findings underscore the critical role of NFIA in instructing the assembly of spinal circuits for movement.
2024-07-16 | GSE268394 | GEO
Project description:Neural circuits governing complex motor behaviors in vertebrates rely on the proper development of motor neurons and their precise targeting of limb muscles. Transcription factors are essential for motor neuron development, regulating their specification, migration, and axonal targeting. While transcriptional regulation of the early stages of motor neuron specification is well-established, much less is known about the role of transcription factors in the later stages of maturation and terminal arborization. Defining the molecular mechanisms of these later stages is critical for elucidating how motor circuits are constructed. Here, we demonstrate that the transcription factor Nuclear Factor-IA (NFIA) is required for motor neuron positioning, axonal branching, and neuromuscular junction formation. Moreover, we find that NFIA is required for proper mitochondrial function and ATP production, providing a new and important link between transcription factors and metabolism during motor neuron development. Together, these findings underscore the critical role of NFIA in instructing the assembly of spinal circuits for movement.
2024-07-16 | GSE268393 | GEO
Project description:Neural circuits governing complex motor behaviors in vertebrates rely on the proper development of motor neurons and their precise targeting of limb muscles. Transcription factors are essential for motor neuron development, regulating their specification, migration, and axonal targeting. While transcriptional regulation of the early stages of motor neuron specification is well-established, much less is known about the role of transcription factors in the later stages of maturation and terminal arborization. Defining the molecular mechanisms of these later stages is critical for elucidating how motor circuits are constructed. Here, we demonstrate that the transcription factor Nuclear Factor-IA (NFIA) is required for motor neuron positioning, axonal branching, and neuromuscular junction formation. Moreover, we find that NFIA is required for proper mitochondrial function and ATP production, providing a new and important link between transcription factors and metabolism during motor neuron development. Together, these findings underscore the critical role of NFIA in instructing the assembly of spinal circuits for movement.
2024-05-27 | GSE268391 | GEO
Project description:Egr3 is a zinc-finger transcription factor involved in growth and development. Egr3-deficient mice have severe sensory ataxia due to failed development of muscle spindle stretch receptors. Sensory and motor neurons that normally innervate spindles are absent in Egr3-deficient mice, presumably as a secondary consequence to the loss of trophic signals produced by spindles during development that are required for innervation and neuron survival. The molecular mechanisms involving motor neuron fate specification, target derived growth factor dependencies, and specification of target innervation have been difficult to study since select markers for functionally specific motor neurons are very poorly characterized. A more thorough understanding of the molecular mediators of motor neuron biology will be important to evaluate the efficacy of new strategies devised to thwart neuron death that occurs in a variety of human motor neuronopathies and neuropathies. To identify genes specifically expressed by spinal cord fusimotor neurons: Many motor neuron specific genes have been described over the years. However, none have been described that distinguish fusimotor neurons from skeletomotor neurons despite the fact that they have distinct muscle targets (muscle spindle stretch receptors) and comprise 25-30% of the spinal motor neuron populations. Since these motor neurons have remarkably different target innervation and function, we hypothesize that they express genes that establish their specific phenotypes during development. We hypothesize that fusimotor neurons can be distinguished in the spinal cord by characterizing fusimotor neuron specific gene expression. Once fusimotor neuron specific genes are identified, they will be used as markers to identify fusimotor neurons in complex neuroglial cell populations in vivo and in vitro. We hypothesize that by characterizing fusimotor neuron specific genes, unique marker molecules will be identified for in vivo and in vitro study of this functionally distinct and important motor neuron subtype. Moreover, we hypothesize that many of the genes that are specifically expressed by fusimotor neurons will be involved in mechanisms related to their fate specification, target innervation and growth factor dependent biology. We will use the Affymetrix microarray platform to identify genes that are specifically expressed by fusimotor neurons in mouse spinal cord. The differential expression analysis will be performed on microdissected segments of spinal cord (L3-L5) from wild type and Egr3-deficient mice. Postnatal Egr3-deficient mice lack muscle spindles and fusimotor neurons in their spinal cords. By comparing gene expression from microdissected segments of spinal cord (L3-L5) between wild type and Egr3-deficient mice, we hypothesize that fusimotor neuron selective genes can be identified. We will microdissect L3-L5 segments of spinal cord using precise anatomical landmarks to ensure that comparable spinal cord regions are anlayzed from each animal. For each microarray experiment, total RNA will be extracted from L3-L5 cords (approximately 2 mm length of spinal cord). The integrity of each RNA sample will be verified by gel electrophoresis. The intact RNA samples from mice of similar genotype will be pooled from three (3) 27-day old animals. The intact cord dissection is easier in young animals (eg: 27-day old) and the phenotype is known to exist at this developmental stage. The RNA from each animal of a similar genotype will be pooled into a single sample to minimize false positive gene calls that may represent genes related to the specific state of vigilance of a particular animal at the time of sacrifice (eg: activity dependent genes). Thus, each of the two RNA samples to be analyzed for a particular microarray experiment will represent RNA from three (3) spinal cords of each genotype. RNA amplification for probe synthesis should not be necessary since we will provide 7 ug of intact pooled total RNA for each sample. For statistical analysis, the experiment will be performed twice. Since the RNA samples are precious, they will be provided to the Array Consortium in two shipments with each of the experiments performed independently.
2008-06-11 | E-GEOD-1830 | biostudies-arrayexpress