Huntington’s disease as a lamin B1 nuclear envelopathy
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE139884 | GEO | 2020/11/10
REPOSITORIES: GEO
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Project description:Lamins, the major components of the nuclear lamina, have diverse functions in many cellular processes. Despite broad expression, lamins have been implicated in cell type-specific roles in development, aging and disease by regulating gene expression. Yet, due to the lack of in depth lineage-specific functional studies, it remains unclear whether or how lamins regulate cell type-specific functions. Using targeted knockout of lamin B1 in the olfactory sensory neuron lineage, we show that lamin B1 is not required for early stages of olfactory sensory neuron differentiation but is needed for formation of mature neurons that properly respond to odor stimulation. Lamin B1 mutant cells exhibited decreased expression of genes involved in mature neuron function, increased expression of genes atypical of the olfactory lineage and clustered nuclear pore distribution. These results demonstrate that the universally expressed lamin B1 regulates cell type-specific gene expression and terminal differentiation.
2017-05-01 | GSE80044 | GEO
Project description:Lamins, the major components of the nuclear lamina, have diverse functions in many cellular processes. Despite broad expression, lamins have been implicated in cell type-specific roles in development, aging and disease by regulating gene expression. Yet, due to the lack of in depth lineage-specific functional studies, it remains unclear whether or how lamins regulate cell type-specific functions. Using targeted knockout of lamin B1 in the olfactory sensory neuron lineage, we show that lamin B1 is not required for early stages of olfactory sensory neuron differentiation but is needed for formation of mature neurons that properly respond to odor stimulation. Lamin B1 mutant cells exhibited decreased expression of genes involved in mature neuron function, increased expression of genes atypical of the olfactory lineage and clustered nuclear pore distribution. These results demonstrate that the universally expressed lamin B1 regulates cell type-specific gene expression and terminal differentiation.
2017-05-01 | GSE80290 | GEO
Project description:Lamins are components of the peripheral nuclear lamina and interact with heterochromatic genomic regions, termed lamina-associated domains (LADs). In contrast to lamin B1, lamin A/C also localizes throughout the nucleus, where it associates with the chromatin-binding protein lamina-associated polypeptide (LAP) 2alpha. Here we show lamin A/C also interacts with euchromatin, as determined by chromatin immunoprecipitation analyses of eu- and heterochromatin-enriched samples. By way of contrast, lamin B1 was only found associated with heterochromatin. Euchromatic regions occupied by lamin A/C overlap with those bound by LAP2alpha, the depletion of which shifts binding of lamin A/C towards more heterochromatic regions. These alterations in lamin A/C chromatin interaction affect epigenetic histone marks in euchromatin without significantly affecting gene expression, while loss of lamin A/C in heterochromatic regions increased gene expression. Our data show a novel role of nucleoplasmic lamin A/C and LAP2alpha in regulating euchromatin. Examination of LaminA, LaminB and Lap2a DNA binding in Lap2alpha +/+ and Lap2a -/- cells and according changes in Histone modifications and gene expression
2016-01-19 | E-GEOD-70148 | biostudies-arrayexpress
Project description:Lamins are components of the peripheral nuclear lamina and interact with heterochromatic genomic regions, termed lamina-associated domains (LADs). In contrast to Lamin B11, lamin A/C also localizes throughout the nucleus, where it associates with the chromatin-binding protein lamina-associated polypeptide (LAP) 2alpha. Here we show lamin A/C also interacts with euchromatin, as determined by chromatin immunoprecipitation analyses of eu- and heterochromatin-enriched samples. By way of contrast, Lamin B11 was only found associated with heterochromatin. Euchromatic regions occupied by lamin A/C overlap with those bound by LAP2alpha, the depletion of which shifts binding of lamin A/C towards more heterochromatic regions. These alterations in lamin A/C chromatin interaction affect epigenetic histone marks in euchromatin without significantly affecting gene expression, while loss of lamin A/C in heterochromatic regions increased gene expression. Our data show a novel role of nucleoplasmic lamin A/C and LAP2alpha in regulating euchromatin. Examination of Lamin A/C, Lamin B1 and Lap2a DNA binding in Lap2alpha +/+ and Lap2a -/- cells and according changes in Histone modifications and gene expression
2016-01-19 | E-GEOD-70147 | biostudies-arrayexpress
Project description:Lamins are components of the peripheral nuclear lamina and interact with heterochromatic genomic regions, termed lamina-associated domains (LADs). In contrast to lamin B1, lamin A/C also localizes throughout the nucleus, where it associates with the chromatin-binding protein lamina-associated polypeptide (LAP) 2alpha. Here we show lamin A/C also interacts with euchromatin, as determined by chromatin immunoprecipitation analyses of eu- and heterochromatin-enriched samples. By way of contrast, lamin B1 was only found associated with heterochromatin. Euchromatic regions occupied by lamin A/C overlap with those bound by LAP2alpha, the depletion of which shifts binding of lamin A/C towards more heterochromatic regions. These alterations in lamin A/C chromatin interaction affect epigenetic histone marks in euchromatin without significantly affecting gene expression, while loss of lamin A/C in heterochromatic regions increased gene expression. Our data show a novel role of nucleoplasmic lamin A/C and LAP2alpha in regulating euchromatin.
2016-01-19 | GSE70148 | GEO
Project description:In mammals, the nuclear lamina interacts with hundreds of large genomic regions, termed lamina-associated domains (LADs) that are generally in a transcriptionally repressed state. Lamins form the major structural component of the lamina and have been reported to bind DNA and chromatin. Here we systematically evaluated whether lamins are necessary for the peripheral localization of LADs in murine embryonic stem cells. Surprisingly, removal of essentially all lamins did not have any detectable effect on the genome-wide interaction pattern of chromatin with the inner nuclear membrane. This suggests that other components of the inner nuclear membrane mediate these interactions. 2 samples, each with a biological replicate: wt mESC, B type lamin null (dKO) dKO mESC
2015-03-10 | E-GEOD-62684 | biostudies-arrayexpress
Project description:Autophagy is a catabolic membrane trafficking process involved in degradation of cellular constituents through lysosomes, which maintains cell and tissue homeostasis. While much attention has been focused on autophagic turnover of cytoplasmic materials, little is known regarding the role of autophagy in degrading nuclear components. Here we report that autophagy machinery mediates degradation of nuclear lamina in mammalian cells, a process we term laminophagy. The autophagy protein LC3 is present in the nucleus and directly interacts with the nuclear lamina protein Lamin B1, and associates with lamin-associated domains (LADs) on chromatin. This interaction does not downregulate Lamin B1 during starvation, but mediates nuclear lamina degradation upon tumorigenic insults, such as by oncogenic Ras. Laminophagy is achieved by nucleus-to-cytosol transport that delivers Lamin B1 to lysosome for degradation. Inhibiting autophagy or LC3-Lamin B1 interaction prevents oncogenic Ras-induced Lamin B1 loss and delays oncogene-induced cell cycle arrest. Our study unveils a role of autophagy in degrading nuclear materials, and suggests laminophagy as a guarding mechanism protecting cells from tumorigenesis.
2015-10-08 | GSE63440 | GEO
Project description:To investigate the molecular basis for male-specific steatohepatitis in Lamin A/C-deficient livers, microarray gene expression analysis was performed on total liver RNA isolated from 26- to 39-week-old, male LMNA+/+, LMNA flx/+, and LMNA flx/flx; Alb-Cre+ C57BL/6 mice fed either normal chow (NC) or high fat diet plus carbohydrate-supplemented water (HFD). Lamins are nuclear intermediate filament proteins that comprise the major components of the nuclear lamina in metazoan cells. Mutations in LMNA, which encodes lamins A/C, cause diseases termed laminopathies, including lipodystrophy, cardiomyopathy, and premature aging. The lamin A/C mutation-associated Dunnigan familial partial lipodystrophy is typically accompanied by fatty liver disease. The role of lamins in the liver is unknown, and it is unclear whether laminopathy-associated liver disease is due to primary hepatocyte defects or systemic alterations. To address these questions, mice carrying a hepatocyte-specific deletion of Lmna (KO mice) were generated. KO hepatocytes manifested abnormal nuclear morphology, and KO mice developed spontaneous male-selective hepatosteatosis, with increased susceptibility to high fat diet-induced steatohepatitis and fibrosis. The molecular mechanism by which liver-specific Lamin A/C deficiency induces male-specific steatohepatitis is unknown. The microarray data presented here demonstrates that hepatic Lmna deficiency is associated with upregulated expression of fatty acid transporters, lipid biosynthetic enzymes, lipid-droplet associated proteins, and interferon-regulated genes and other pro-inflammatory mediators.
2017-01-16 | GSE93643 | GEO
Project description:Purpose: to qualify and quantify the rearrangement of interactions of nuclear lamins A/C and B with the genome, in relation to nuclearradial repositioning of loci and changes in gene expression, in HepG2 cells exposed to cyclosporin A. .To compare HepG2 cell line transcriptome profiling (RNA-seq) with radially positioning of the chromatin anchored at the nuclear periphery before and after CsA treatment. Methods: To this end, we mapped lamin A and lamin B lamina-associated domains (LADs) by chromatin immunoprecipitation-sequencing (ChIP-seq) of lamin A/C (antibody sc7292x, Santa Cruz Biotechnology) and lamin B1 (antibody ab16048, Abcam), respectively. HepG2 cells were either cultured under proliferative conditions (controls) or exposed for 3 days to 10 uM cyclosporin A. We also assesed the transcriptome by RNA-seq under each condition in duplicate cultures. Results: CsA elicits accumulation of pre-lamin A in HepG2 cells, raising the hypothesis of a global rearrangement of lamin-chromatin interactions. We show here the existence of overlapping and distinct lamin A and B lamina-associated domains (which we refer to as A- and B-LADs, respectively). Whereas B-LADs largely remain constitutive, CsA elicits the formation of facultative A-LADs. Re-localization of A-LADs occur mainly on preexisting B-LADs. However, LAD rearrangement does not correlate with systematic changes in gene expression within LADs. We find a reorganization of A- and B-LADs after CsA treatment, entailing distinct contributions of A- and B- type lamins. to genome organization. Indeed, classification of lamin A LADs and lamin B LADs into properties of ‘A-only’, ‘B-only’ and ‘A-B’ LADs show an overall loss of A-only LADs after CsA treatment. A- only and B-only LADs are highly dynamic with A-B LADs being more stable.The rearrangement of lamin association after CsA treatment correlates with repositioning of loci in the nuclear space with, notably, a loss of lamin B associated with a re-localization of loci towards the nuclear center and conversely, a gain of lamin B linked to a repositioning of loci towards the nuclear periphery. Predictions on radial repositioning of LADs, and of loci within, from 3D structural models of the genome were supported by fluorescence in situ hybridization (FISH) analyses. Conclusions: We show that, while they amply co-localize on well-conserved LADs, lamins A and B also interact with distinct genomic regions that can interchange (switch) between lamin A and B upon CsA treatment. We unveil distinct lamin A and B interactions with chromatin, suggesting complementary contributions to genome conformation. Our data suggest that and lamins A and B may differentially modulate genome organization.
2019-02-19 | GSE119631 | GEO
Project description:Nuclear lamin B1 constitutes one of the major structural proteins in the lamina mesh. We silenced the expression of lamin B1 by RNA interference in the colon cancer cell line DLD-1 and showed a dramatic redistribution of H3K27me3 from the periphery to a more homogeneous nuclear dispersion; in addition we observed an increased frequency of micronuclei and nuclear blebs. By 3D-FISH analyses, we demonstrate that the volume and surface of chromosome territories were significantly larger in LMNB1-depleted cells, suggesting that lamin B1 is required to maintain chromatin condensation in interphase nuclei. These changes led to a prolonged S-phase due to activation of Chk1 and telomere attrition. Finally, silencing of LMNB1 resulted in extensive changes in alternative splicing of multiple genes and in a higher number of enlarged nuclear speckles. Taken together, our results suggest a mechanistic role of the nuclear lamina in the organization of chromosome territories, maintenance of genome integrity and proper gene splicing. This dataset includes the comparison of gene transcripts between cells with silenced lamin B1 and empty vector negative control transfected cells. Single cell clones were generated after transfection of DLD-1 cells with shRNA against LMNB1. Two different constructs were used. For clone number 2, three replicates of the the same clone were included in the analysis. The rest of the clones correspond to biological replicates. As control, we used three different cones transfected with an empty vector control as well as wild type cells.
2014-07-16 | E-GEOD-53546 | biostudies-arrayexpress