Genomic positioning in LBR and Lamin A K562 knockout cells
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE263012 | GEO | 2024/04/04
REPOSITORIES: GEO
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Project description:The most common cytogenetic abnormality found in complex karyotype high risk MDS/AML is del5q. Disease is often identified through visual inspection and recognition of abnormalities such as pseudo-Pelger-Huet anomaly (PPHA), which presents as deviations of normal neutrophil nuclear morphology. The link between PPHA and leukemia is unknown, but mutations in the lamin B1 receptor (LBR) have been identified as the cause of benign presence in otherwise normal individuals. Lamin B1 (LMNB1) is the ligand for LBR and is important for maintaining nuclear lamina integrity and influencing 3D gene structural changes that impact transcription; the LMNB1 gene locus is also contained with chromosome 5q, so we hypothesized that appearance of PPHA is potentially caused by del5q in MDS/AML containing the LMNB1. To help characterize the potential role of LMNB1 in normal hematopoietic stem and progenitor cells (HSPCs), we infected CD34+ cord blood HSPCs with lentiviruses expressing shRNAs targeting LMNB1 (LB1) and luciferase (C11) as a control and assessed changes in transcription due to LMNB1 disruption via RNSeq and 3D genome structural changes through HiC. Neutrophils were also differentiated from LMNB1 shRNA and control treated CD34+ cord blood HSPCs and transcriptional/structural changes identified via RNAseq and HiC. Additionally, to understand long-term in vivo effects of LMNB1 loss on self-renewal and lineage bias, we engrafted control and LMNB1 shRNA infected CD34+ HSPCs into NSG mice and harvest hCD34+ cells 12 weeks later for scRNAseq.
2022-03-11 | GSE174533 | GEO
Project description:Xist orchestrates X chromosome inactivation, a process that entails chromosome-wide silencing and remodeling of the 3-dimensional structure of the X chromosome. Yet, it remains unclear whether these changes in nuclear structure are mediated by Xist and whether they are required for silencing. Here we show that Xist directly interacts with the Lamin B Receptor (LBR), an integral component of the nuclear lamina, and that this interaction is required for Xist-mediated silencing. We show that this interaction recruits the inactive X to the nuclear lamina and by doing so enables Xist to spread to actively transcribed genes across the X. Our results demonstrate that lamina recruitment changes the accessibility of DNA thereby enabling Xist, and its silencing proteins, to spread across the X to silence transcription. We examined the genomic localization of the Xist lncRNA using RNA Antisense Purification (RAP) in male mouse ES cells where the endogenous Xist promoter is replaced by a tet-inducible one (pSM33) containing 1) wild-type Xist (WT), 2) A-repeat deletion Xist (dA), 3) LBR binding site deletion Xist (dLBS), 4) dLBS-Xist rescued with LMNB1 (LMNB1Res), 5) LBR CRISPRi knock down (LBRKD), or 6) SHARP CRISPRi knock down (SHARPKD).
2016-07-24 | E-GEOD-80510 | biostudies-arrayexpress
Project description:Senescence is a stress responsive form of stable cell cycle exit. Senescent cells have a distinct gene expression profile, which is often accompanied by the spatial redistribution of heterochromatin into senescence-associated heterochromatic foci (SAHFs). Studying a key component of the nuclear lamina, lamin B1 (LMNB1), we report dynamic alterations in its genomic profile and their implications for SAHF formation and gene regulation during senescence. Genome-wide mapping reveals that LMNB1 is depleted during senescence, preferentially from the central regions of lamina-associated domains (LADs), which are enriched for H3K9me3. LMNB1 knockdown facilitates the spatial relocalization of perinuclear H3K9me3, thus promoting SAHF formation, which is inhibited by ectopic LMNB1 expression. Furthermore, despite the global reduction in LMNB1 protein levels, LMNB1 binding increases during senescence in a small subset of gene-rich regions where H3K27me3 also increases and gene expression becomes repressed. These results suggest that LMNB1 may contribute to senescence in at least two ways due to its uneven genomewide redistribution: firstly through the spatial re-organization of chromatin and, secondly, through gene repression. ChIP-seq for Lamin B1 in Growing and Ras Induced Senescence
2013-08-22 | E-GEOD-49341 | biostudies-arrayexpress
Project description:Senescence is a stress responsive form of stable cell cycle exit. Senescent cells have a distinct gene expression profile, which is often accompanied by the spatial redistribution of heterochromatin into senescence-associated heterochromatic foci (SAHFs). Studying a key component of the nuclear lamina, lamin B1 (LMNB1), we report dynamic alterations in its genomic profile and their implications for SAHF formation and gene regulation during senescence. Genome-wide mapping reveals that LMNB1 is depleted during senescence, preferentially from the central regions of lamina-associated domains (LADs), which are enriched for H3K9me3. LMNB1 knockdown facilitates the spatial relocalization of perinuclear H3K9me3, thus promoting SAHF formation, which is inhibited by ectopic LMNB1 expression. Furthermore, despite the global reduction in LMNB1 protein levels, LMNB1 binding increases during senescence in a small subset of gene-rich regions where H3K27me3 also increases and gene expression becomes repressed. These results suggest that LMNB1 may contribute to senescence in at least two ways due to its uneven genomewide redistribution: firstly through the spatial re-organization of chromatin and, secondly, through gene repression.
2013-08-22 | GSE49341 | GEO
Project description:The goal of this study was to identify accessible chromatin peaks in lamina-associated domains of senescent cells. To establish senescence we used ionizing radiation (IR), overexpression of miR-340-5p, and knockdown of Lamin B Receptor (LBR).One of the cellular processes influenced by microRNAs is senescence, a state of indefinite growth arrest triggered by sublethal cell damage. Here, through bioinformatic analysis and experimental validation, we identified miR-340-5p as a novel miRNA that foments cellular senescence. miR340-5p was highly abundant in diverse senescence models, and miR-340-5p overexpression in proliferating cells rendered them senescent. Among the target mRNAs, miR-340-5p prominently reduced the levels of LBR mRNA, encoding Lamin B Receptor (LBR). Loss of LBR by ectopic overexpression of miR-340-5p derepressed heterochromatin in lamina-associated domains (LADs), promoting the expression of DNA repetitive elements characteristic of senescence. Importantly, overexpressing miR-340-5p enhanced cellular sensitivity to senolytic compounds, while antagonization of miR-340-5p reduced senescent-cell markers and engendered resistance to senolytic-induced cell death. We propose that miR-340-5p can be exploited for clearing senescent cells to restore tissue homeostasis and mitigate damage by senescent cells in aging human pathologies.
2021-06-25 | GSE165465 | GEO
Project description:Interactions between the nuclear lamina (NL) and chromatin are thought to occur through large lamin association domains (LADs) and correlate with gene repression in these domains. We show that binding of lamin A/C (LMNA) to promoters occurs on discrete domains that are associated with distinct transcriptional outputs. Chromatin immunoprecipitation identifies thousands of LMNA-bound promoters, primarily linked to signaling functions. LMNA often occupies narrow domains on promoters, yet LMNA-bound promoters are often contiguous. LMNA-bound genes are overall repressed, but repression correlates with co-enrichment in repressive histone marks rather than LMNA occupancy per se. Genes marked by LMNA and H3K4me3 escape LMNA-associated repression in the absence of repressive histone marks. Positioning of LMNA on promoters relative to the TSS correlates with distinct transcriptional outputs: whereas upstream-distal binding can be transcriptionally permissive, TSS occupancy is associated with promoter inactivity. Perturbation in NL organization causes reorganization of lamin promoter occupancy and uncouples LMNA binding from promoter inactivity. Our results show the existence of many spatially restricted LMNA binding events on promoter regions, with distinct position-dependent transcriptional outputs. Total RNA obtained from ASCs and ASCs depleted of LMNA (LMNA-KD) and processed for microarray hybridization.
2013-07-14 | E-GEOD-42523 | biostudies-arrayexpress
Project description:We tested overall gene expression change upon chromatin architecture disruption. RNA-seq was performed using nuclear architecture-disrupted mice carrying a loss-of-function mutation in LBR (Lbric-J/ic-J; LBR-null mice). LBR is an INM protein that tethers heterochromatin to the nuclear envelope whose level is decreased in various aging contexts.
2021-06-01 | GSE169240 | GEO
Project description:The nuclear lamina interacts with the genome through megabase-size lamina-associated domains (LADs). LADs have been identified in proximity labeling assays and recently by chromatin immunoprecipitation-sequencing (ChIP-seq) of A- and B-type lamins. LADs localize mainly to the nuclear periphery, they are gene-poor and largely heterochromatic. Here, we show that the mode of chromatin fragmentation for ChIP, namely either bath sonication (used to date for ChIP of nuclear lamins) or digestion with micrococcal nuclease (MNase) leads to the discovery of distinct sets of lamin-interacting domains (which we refer to as LiDs) with distinct gene content, histone composition enrichment and relationship to lamin B1-interacting domains. We find that total genome coverage by lamin A/C ('LMNA') LiDs identified in sonicated or MNase-digested chromatin is similar (~730 megabases). Over half of these domains, however, are uniquely detected in sonicated or MNase-digested chromatin. Whereas sonication-specific LMNA LiDs are gene-poor and devoid of a broad panel of histone modifications, MNase-specific LMNA LiDs are of higher gene density and are enriched in H3K9me3, H3K27me3 and in histone variant H2A.Z. Analysis of published LMNB1 LADs and of LMNB1 LiDs identified by ChIP-seq further shows that LMNA can associate with 'open' chromatin domains displaying euchromatin features which are not associated with LMNB1. The differential genetic and epigenetic properties of lamin-interacting chromatin domains indicate the existence of distinct LiD populations identifiable in different chromatin contexts, including nuclease-accessible 'open' regions presumably localized in the nuclear interior.
2015-03-24 | GSE57149 | GEO
Project description:Interactions between the nuclear lamina (NL) and chromatin are thought to occur through large lamin association domains (LADs) and correlate with gene repression in these domains. We show that binding of lamin A/C (LMNA) to promoters occurs on discrete domains that are associated with distinct transcriptional outputs. Chromatin immunoprecipitation identifies thousands of LMNA-bound promoters, primarily linked to signaling functions. LMNA often occupies narrow domains on promoters, yet LMNA-bound promoters are often contiguous. LMNA-bound genes are overall repressed, but repression correlates with co-enrichment in repressive histone marks rather than LMNA occupancy per se. Genes marked by LMNA and H3K4me3 escape LMNA-associated repression in the absence of repressive histone marks. Positioning of LMNA on promoters relative to the TSS correlates with distinct transcriptional outputs: whereas upstream-distal binding can be transcriptionally permissive, TSS occupancy is associated with promoter inactivity. Perturbation in NL organization causes reorganization of lamin promoter occupancy and uncouples LMNA binding from promoter inactivity. Our results show the existence of many spatially restricted LMNA binding events on promoter regions, with distinct position-dependent transcriptional outputs. ChIPs were done from cultured untreated and LMNA-downregulated adipose stem cell (ASC) chromatin. MeDIPs were done from LMNA-downregulated ASCs. ChIP and MeDIP DNA was hybridized onto the aforementioned HG-18 Nimbegen promoter arrays.
2013-07-14 | E-GEOD-42522 | biostudies-arrayexpress
Project description:This study addresses the mechanisms regulating the identity of oligodendrocyte progenitor cells (OPC) in physiological conditions and the pathological mechanisms leading to autosomal adrenoleukodystrophy (ADLD), a disease caused by persistence of lamin B1 (LMNB1) expression in oligodendrocytes (OL). Using mouse primary OPCs and a novel technique for the study of DNA-protein interaction, we identify the genomic regions showing dynamic interactions with LMNB1. The transition from ESC to OPC revealed increased association of gene involved in pluripotency and neuronal function and decreased association of gene categories associated with the differentiation of OPC into OL (including genes regulating epigenetic modifiers, RNA processing and protein phosphorylation). Since LMNB1 declines during the transition from OPC to OL, and its persistent expression has been linked to pathological conditions, such as ADLD, we further identified the molecular maps of genome-lamina reorganization in OPC differentiating into OL which continue to express LMNB1 (mOLLMNB1). The transition from OPC to mOLLMNB1 revealed increased association to LMNB1 of genomic regions encoding for lipid metabolism and protein phosphorylation, and decreased association of genes negatively regulating differentiation. These data highlight the importance of LMNB1 in physiological conditions and identify mechanisms responsible for late onset ADLD.
2020-03-16 | GSE135834 | GEO