Similar Datasets
Project description:Guanylate Binding Proteins (GBPs) are prominent regulators of immunity unknown to be required for nuclear envelope formation and function. The Arabidopsis GBP orthologue AtGBPL3 was identified as a novel component of the plant lamina, with essential functions in mitotic nuclear envelope reformation. AtGBPL3 is preferentially expressed in mitotically active root tips, accumulates at the nuclear envelope and interacts with further components of the nuclear lamina. To investigate effects of defective lamina components on gene expression, we analysed the transcriptomes of 4 day old wild-type, gbpl3-5, crwn4-1, crwn1-1crwn4-1, as well as gbpl3-5 mutants expressing GBPL3-GFP or the GTPase-dead GBPL3(K83A)-GFP under control of the AtGBPL3-promoter.
2022-12-23 | GSE221661 | GEO
Project description:Guanylate Binding Proteins (GBPs) are prominent regulators of immunity unknown to be required for nuclear envelope formation and function. The Arabidopsis GBP orthologue AtGBPL3 was identified as a novel component of the plant lamina, with essential functions in mitotic nuclear envelope reformation. AtGBPL3 is preferentially expressed in mitotically active root tips and accumulates at the nuclear envelope. Furthermore, fluorescent lifetime imaging experiments in the presence or absence of the chromatin-labelling dye Sytox-Orange suggested that GBPL3 might be able to interact with chromatin. Chromatin-immunoprecipitation followed by sequencing (ChIP-Seq) revealed only few GBPL3-associated chromatin domains, which were concentrated particularly within or near centromeric regions.
2022-12-23 | GSE221668 | GEO
Project description:The large GTPase AtGBPL3 links nuclear envelope formation to lamina-associated gene silencing
| PRJNA915350 | ENA
Project description:The large GTPase AtGBPL3 links nuclear envelope formation to lamina-associated gene silencing [RNA-seq]
| PRJNA915344 | ENA
Project description:The large GTPase AtGBPL3 links nuclear envelope formation to lamina-associated gene silencing [ChIP-Seq]
| PRJNA915355 | ENA
Project description:The Ran GTPase regulates nuclear import and export by controlling the assembly state of transport complexes. This involves the direct action of RanGTP, which is generated in the nucleus by the chromatin-associated nucleotide exchange factor, RCC1. Ran interactions with RCC1 contribute to formation of a nuclear:cytoplasmic (N:C) Ran protein gradient in interphase cells. In previous work, we showed that the Ran protein gradient is disrupted in fibroblasts from Hutchinson-Gilford progeria syndrome (HGPS) patients. The Ran gradient disruption in these cells is caused by nuclear membrane association of a mutant form of Lamin A, which induces a global reduction in heterochromatin marked with Histone H3K9me3 and Histone H3K27me3. Here, we have tested the hypothesis that heterochromatin controls the Ran gradient. Chemical inhibition and depletion of the histone methyltransferases (HMTs) G9a and GLP in normal human fibroblasts reduced heterochromatin levels and caused disruption of the Ran gradient, comparable to that observed previously in HGPS fibroblasts. HMT inhibition caused a defect in nuclear localization of TPR, a high molecular weight protein that, owing to its large size, displays a Ran-dependent import defect in HGPS. We reasoned that pathways dependent on nuclear import of large proteins might be compromised in HGPS. We found that nuclear import of ATM requires the Ran gradient, and disruption of the Ran gradient in HGPS causes a defect in generating nuclear ?-H2AX in response to ionizing radiation. Our data suggest a lamina-chromatin-Ran axis is important for nuclear transport regulation and contributes to the DNA damage response.
| S-EPMC6351833 | biostudies-other
Project description:Transposable elements (TEs) are mobile genomic sequences that are normally repressed to avoid proliferation and genome instability. Gene silencing mechanisms repress TEs by RNA degradation or heterochromatin formation. Heterochromatin maintenance is therefore important to keep TEs silent. Loss of heterochromatic domains has been linked to lamin mutations, which have also been associated with derepression of TEs. In fact, lamins are structural components of the nuclear lamina (NL), which is considered a pivotal structure in the maintenance of heterochromatin domains at the nuclear periphery in a silent state. Here, we show that a lethal phenotype associated with Lamin loss-of-function mutations is influenced by Drosophilagypsy retrotransposons located in euchromatic regions, suggesting that NL dysfunction has also effects on active TEs located in euchromatic loci. In fact, expression analysis of different long terminal repeat (LTR) retrotransposons and of one non-LTR retrotransposon located near active genes shows that Lamin inactivation determines the silencing of euchromatic TEs. Furthermore, we show that the silencing effect on euchromatic TEs spreads to the neighboring genomic regions, with a repressive effect on nearby genes. We propose that NL dysfunction may have opposed regulatory effects on TEs that depend on their localization in active or repressed regions of the genome.
| S-EPMC7140440 | biostudies-literature
Project description:The nuclear lamina is a proteinaceous network of filaments that provide both structural and gene regulatory functions by tethering proteins and large domains of DNA, the so-called lamina-associated domains (LADs), to the periphery of the nucleus. LADs are a large fraction of the mammalian genome that are repressed, in part, by their association to the nuclear periphery. The genesis and maintenance of LADs is poorly understood as are the proteins that participate in these functions. In an effort to identify proteins that reside at the nuclear periphery and potentially interact with LADs, we have taken a two-pronged approach. First, we have undertaken an interactome analysis of the inner nuclear membrane bound LAP2β to further characterize the nuclear lamina proteome. To accomplish this, we have leveraged the BioID system, which previously has been successfully used to characterize the nuclear lamina proteome. Second, we have established a system to identify proteins that bind to LADs by developing a chromatin-directed BioID system. We combined the BioID system with the m6A-tracer system which binds to LADs in live cells to identify both LAD proximal and nuclear lamina proteins. In combining these datasets, we have further characterized the protein network at the nuclear lamina, identified putative LAD proximal proteins and found several proteins that appear to interface with both micro-proteomes. Importantly, several proteins essential for LAD function, including heterochromatin regulating proteins related to H3K9 methylation, were identified in this study.
| S-EPMC8008952 | biostudies-literature
Project description:Small GTPases of the Rho family are binary molecular switches that regulate a variety of processes including cell migration and oriented cell divisions. Known Cdc42 effectors include proteins involved in cytoskeletal remodeling and kinase-dependent transcription induction, but none are involved in the maintenance of nuclear envelope integrity or ER morphology. Maintenance of nuclear envelope integrity requires the EndoSomal Complexes Required for Transport (ESCRT) proteins, but how they are regulated in this process remains unknown. Here, we show by live-cell imaging a novel Cdc42 localization with ESCRT proteins at sites of nuclear envelope and ER fission and, by genetic analysis of cdc42 mutant yeast, uncover a unique Cdc42 function in regulation of ESCRT proteins at the nuclear envelope and sites of ER tubule fission. Our findings implicate Cdc42 in nuclear envelope sealing and ER remodeling, where it regulates ESCRT disassembly to maintain nuclear envelope integrity and proper ER architecture.
| S-EPMC7401818 | biostudies-literature
Project description:In the fission yeast Schizosaccharomyces pombe, the centromeres of each chromosome are clustered together and attached to the nuclear envelope near the site of the spindle pole body during interphase. The mechanism and functional importance of this arrangement of chromosomes are poorly understood. In this paper, we identified a novel nuclear protein, Csi1, that localized to the site of centromere attachment and interacted with both the inner nuclear envelope SUN domain protein Sad1 and centromeres. Both Csi1 and Sad1 mutants exhibited centromere clustering defects in a high percentage of cells. Csi1 mutants also displayed a high rate of chromosome loss during mitosis, significant mitotic delays, and sensitivity to perturbations in microtubule-kinetochore interactions and chromosome numbers. These studies thus define a molecular link between the centromere and nuclear envelope that is responsible for centromere clustering.
| S-EPMC3514793 | biostudies-literature