Study of HP1 Knock Down on gene expression and splicing regulation in Human HeLa cells
Histone H3 lysine 9 trimethylation and HP1γ favor inclusion of alternative exons.
Cell line
View SamplesTranscriptome analysis of depletion of DYRK1A in HeLa cells
DYRK1A phoshorylates histone H3 to differentially regulate the binding of HP1 isoforms and antagonize HP1-mediated transcriptional repression.
Specimen part, Cell line
View SamplesWe studied the changes that occur in gene transcription during seasonal senescence in Populus trichocarpa pioneer leaves and fine roots. Plant senescence is a strictly regulated physiological process that allows relocating of valuable nutrients from senescent tissues before death. It might be induced by internal or external factors and among them, phytohormones play an undoubtedly significant role. Senescence was extensively studied in leaves, but the aging of other ephemeral organs, located underground, and its drivers are still poorly understood. We focused on collective results to fill in the knowledge gap about senescence of fine, absorptive roots and leaves in order to check if there are universal mechanisms involved during plant organ senescence. Transcriptional profiling was conducted with the use of microarrays to identify genes involved in developmental PCD. Samples were collected three times during a growth season. The first collection was considered as a control and was collected in early summer (July 7–15) when leaves and the root system were fully developed and functional. The second group of leaf and root samples were harvested in early autumn (October 1–7) when chlorophyll levels in leaves had decreased by approximately 40% and when fine roots had changed in color from white to brown. The third group of samples were harvested in the middle of autumn (November 2–9) when chlorophyll levels in leaves decreased by approximately 65% and fine roots were dark brown or black color. Our results reveal the important role of phytohormones in regulating the senescence of both studied organs. The transcriptomic analyses showed significant changes in gene expression that are associated with phytohormones, especially with ABA and jasmonates. We conclude that phytohormonal regulation of senescence in roots and leaves is organ-specific. In roots, phytohormones are involved indirectly in regulation of senescence by increasing tolerance for cold or resistance for pathogens, whereas such correlation was not observed in leaves.
Allies or Enemies: The Role of Reactive Oxygen Species in Developmental Processes of Black Cottonwood (<i>Populus trichocarpa</i>).
Specimen part
View SamplesPhosphorylation of histone H3 at Serine 10 emerges as a mechanism increasing chromatin accessibility of the transcription factor NF-kB for a particular set of immune genes. Here we report that a bacterial pathogen uses this strategy to shape the transcriptional response of infected host cells. We identify the Shigella flexneri type III protein effector OspF as a Dual Specific Phosphatase. OspF dephosphorylates MAP kinases within the nucleus impairing histone H3 phosphorylation at Serine 10 in a gene-specific manner. Therefore, OspF reprograms the transcriptional response for inactivation of a subset of NF-kB responsive genes. This regulation leads to repression of polymorphonuclear leukocytes recruitment in infected tissues. Thus, pathogens have evolved the ability to precisely modulate host cell epigenetic information as a strategy to repress innate immunity.
An injected bacterial effector targets chromatin access for transcription factor NF-kappaB to alter transcription of host genes involved in immune responses.
No sample metadata fields
View SamplesWe have here followed the transcriptional effect of stimulation with the phorbol ester PMA in mouse fibroblasts from HP1gamma null mice recomplemented with either wild-type HP1gamma or an HP1g with an S83A mutation Overall design: Spontaneously immortalized mouse embryonic fibroblasts from HP1gamma null mice were used to stably integrate either an empty expression vector, or expression vectors for either WT or S83A mutant HP1gamma. These cells were then stimulated with PMA for 0 or 60 min. and used for transcriptome analysis by Next Generation sequencing.
Shigella flexneri targets the HP1γ subcode through the phosphothreonine lyase OspF.
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View SamplesGene silencing via heterochromatin formation plays a major role in cell differentiation and maintenance of homeostasis. Here, we report the identification and characterization of a novel heterochromatinization factor in vertebrates, Bromo Adjacent Homology Domain-containing protein 1 (BAHD1). BAHD1 interacts with HP1, MBD1, HDAC5 and with several transcription factors. Through electron and immunofluorescence microscopy studies, we show that BAHD1 overexpression directs HP1 to specific nuclear sites and promotes formation of large heterochromatic domains, which lack acetyl histone H3 and are enriched in H3 trimethylated at lysine 27. Furthermore, ectopically expressed BAHD1 colocalizes with the heterochromatic X inactive chromosome. As highlighted by whole genome microarray analysis of BAHD1 knock down cells, BAHD1 represses several proliferation and survival genes and in particular, the insulin-like growth factor II gene (IGF2). BAHD1 specifically binds the CpG-rich P3 promoter of IGF2. This region contains DNA binding sequences for the transcription factor SP1, with which BAHD1 co-immunoprecipitates. Collectively, these findings provide evidence that BAHD1 acts as a silencer by recruiting proteins that coordinate heterochromatin assembly at specific sites in the genome.
Human BAHD1 promotes heterochromatic gene silencing.
Cell line
View SamplesThe present research is devoted to the identification of gene(s) severely affected by EMD mutations, leading to striated muscle laminopathies and more specifically the cardiomyopathy. For this purpose, we developped a large-scale gene expression approach on heart and skeletal tissues from Emd KO mouse model.
Activation of MAPK in hearts of EMD null mice: similarities between mouse models of X-linked and autosomal dominant Emery Dreifuss muscular dystrophy.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Activation of MAPK pathways links LMNA mutations to cardiomyopathy in Emery-Dreifuss muscular dystrophy.
No sample metadata fields
View SamplesThe present research is devoted to the identification of gene(s) severely affected by LMNA mutations, leading to striated muscle laminopathies and more specifically the cardiomyopathy. For this purpose, we developped a large-scale gene expression approach on heart and skeletal tissues from Lmna H222P heterozygous Knock-In mouse model.
Activation of MAPK pathways links LMNA mutations to cardiomyopathy in Emery-Dreifuss muscular dystrophy.
No sample metadata fields
View SamplesThe present research is devoted to the identification of gene(s) severely affected by LMNA mutations, leading to striated muscle laminopathies and more specifically the cardiomyopathy. For this purpose, we developped a large-scale gene expression approach on heart and skeletal tissues from Lmna H222P heterozygous Knock-In mouse model.
Activation of MAPK pathways links LMNA mutations to cardiomyopathy in Emery-Dreifuss muscular dystrophy.
No sample metadata fields
View Samples