Downregulation of expression and activity levels of the astroglial glutamate transporter EAAT2 is thought to be implicated in motor neuron excitotoxicity in amyotrophic lateral sclerosis (ALS). We previously reported that EAAT2 is cleaved by caspase-3 at the cytosolic C-terminus domain, impairing the transport activity and generating a proteolytic fragment found to be SUMO1 conjugated (CTE-SUMO1). We show here that this fragment accumulates in the nucleus of spinal cord astrocytes in vivo throughout the disease stages of the SOD1-G93A mouse model of ALS. In vitro expression in spinal cord astrocytes of the C-terminus peptide of EAAT2 (CTE), which was artificially fused to SUMO1 (CTE-SUMO1fus) to mimic the endogenous SUMOylation reaction, recapitulates the nuclear accumulation of the fragment seen in vivo and causes caspase-3 activation and axonal growth impairment in motor neuron-derived NSC-34 cells and primary motor neurons co-cultured with CTE-SUMO1fus-expressing spinal cord astrocytes. This indicates that CTE-SUMO1fus could trigger non-cell autonomous mechanisms of neurodegeneration. Prolonged nuclear accumulation of CTE-SUMO1fus in astrocytes leads to their degeneration, although the time frame of the cell-autonomous toxicity is longer than the one for the indirect toxic effect on motor neurons. As more evidence on the implication of SUMO substrates in neurodegenerative diseases emerges, our observations strongly suggest that the nuclear accumulation in spinal cord astrocytes of a SUMOylated proteolytic fragment of the astroglial glutamate transporter EAAT2 could take part to the pathogenesis of ALS and suggest a novel, unconventional role for EAAT2 in motor neuron degeneration in ALS.
Motor neuron impairment mediated by a sumoylated fragment of the glial glutamate transporter EAAT2.
Specimen part
View SamplesThe Polycomb group (PcG) proteins form chromatin-modifying complexes that are essential for embryonic development and stem cell renewal and are commonly deregulated in cancer. Here, we identify their target genes using genome-wide location analysis in human embryonic fibroblasts. We find that Polycomb-Repressive Complex 1 (PRC1), PRC2, and tri-methylated histone H3K27 co-occupy >1000 silenced genes with a strong functional bias for embryonic development and cell fate decisions. We functionally identify 40 genes derepressed in human embryonic fibroblasts depleted of the PRC2 components (EZH2, EED, SUZ12) and the PRC1 component, BMI-1. Interestingly, several markers of osteogenesis, adipogenesis, and chrondrogenesis are among these genes, consistent with the mesenchymal origin of fibroblasts. Using a neuronal model of differentiation, we delineate two different mechanisms for regulating PcG target genes. For genes activated during differentiation, PcGs are displaced. However, for genes repressed during differentiation, we paradoxically find that they are already bound by the PcGs in nondifferentiated cells despite being actively transcribed. Our results are consistent with the hypothesis that PcGs are part of a preprogrammed memory system established during embryogenesis marking certain key genes for repressive signals during subsequent developmental and differentiation processes.
Genome-wide mapping of Polycomb target genes unravels their roles in cell fate transitions.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Yin Yang 1 extends the Myc-related transcription factors network in embryonic stem cells.
Specimen part
View SamplesPolycomb group (PcG) proteins form multiprotein complexes, called Polycomb repressive complexes (PRCs). PRC2 contains the PcG proteins EZH2, SUZ12, and EED and represses transcription through methylation of lysine (K) 27 of histone H3 (H3). Suz12 is essential for PRC2 activity and its inactivation results in early lethality of mouse embryos.
The polycomb group protein Suz12 is required for embryonic stem cell differentiation.
Specimen part
View SamplesWe have determined the global gene expression upon loss of function of the Yy1 transcription factor in mouse embryonic stem cells
Yin Yang 1 extends the Myc-related transcription factors network in embryonic stem cells.
Specimen part
View SamplesThese data include RNA Seq data generated from wild type and Eed Ko intestinal crypts from AhCre and AhCreEedf/f mice. Overall design: Total RNA extracted from wild type and Eed Ko intestinal crypts.
PRC2 preserves intestinal progenitors and restricts secretory lineage commitment.
Cell line, Subject
View SamplesThese data include RNA Seq data generated from Ring1b wild type and Ring1b KO Ring1a-/- Cdkn2a-/- Lin- HSC cells non-transduced or transduced with MLL-AF9, HOXA9 and PML-RARa. Overall design: Total RNA extracted from Ring1b wild type and Ring1b KO Ring1a-/- Cdkn2a-/- Lin- HSC cells non-transduced or transduced with MLL-AF9, HOXA9 and PML-RARa.
Maintenance of leukemic cell identity by the activity of the Polycomb complex PRC1 in mice.
No sample metadata fields
View SamplesThese data include RNA Seq data generated from wild type and Ring1a Ring1b dKO Cdkn2a-/- MLL-AF9 Leukemic cells Overall design: mRNA library preparation from Ring1a-/-;Ring1bf/f Cdkn2a-/- MLL-AF9 leukemic cells treated with OHT or EtOH
Maintenance of leukemic cell identity by the activity of the Polycomb complex PRC1 in mice.
Cell line, Treatment, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Tet proteins connect the O-linked N-acetylglucosamine transferase Ogt to chromatin in embryonic stem cells.
Specimen part
View SamplesO-linked N-acetylglucosamine (O-GlcNAc ) transferase (OGT) activity is essential for embryonic stem (ES) cell viability and mouse development. OGT is present in both cytoplasm and nucleus of different cell types and mediates serine or threonine glycosylation. The Ogt gene locus resides on the X-chromosome and its activity is required for the viability of male ES cells. Using Ogt conditional knock out (KO) ES cells it was shown the failure of establishing stable KO ES clones further suggesting that Ogt activity is required for ES cell self-renewal and pluripotency. For understanding these changes, we performed global gene expression upon silencing of Ogt mediated by esiRNA in mouse Embryonic Stem Cells.
Tet proteins connect the O-linked N-acetylglucosamine transferase Ogt to chromatin in embryonic stem cells.
Specimen part
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