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PROVIDER: PRJNA107575 | ENA |
REPOSITORIES: ENA
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Project description:This SuperSeries is composed of the following subset Series: GSE10697: Self-Self Hybridisation were used to set confidence 99% intervals GSE10698: The effects of artificial tethering of chromosomes to the nuclear periphery using LacI/lap2b anchorage constructs 1 GSE10699: The effects of artificial tethering of chromosomes to the nuclear periphery using LacI/lap2b anchorage constructs 2 Background: The spatial organisation of the genome in the nucleus has a role in the regulation of gene expression. In mammals, chromosomal regions with low gene-density are located close to the nuclear periphery. Correlations have also been made between the transcriptional state of some genes and their location near the nuclear periphery. However, a crucial issue is whether this level of nuclear organisation directly affects gene function, rather than merely reflecting it. Methodology: To directly investigate whether proximity to the nuclear periphery can influence gene expression in mammalian cells. here we relocate specific human chromosomes to the nuclear periphery by tethering them to a protein of the inner nuclear membrane. Principal findings: We show that this can reversibly suppress the expression of some endogenous human genes located near the tethering sites, and even genes further away. However, the expression of many other genes is not detectably reduced and we show that location at the nuclear periphery is not incompatible with active transcription. The dampening of gene expression around the nuclear periphery is dependent on the activity of histone deacetylases. Significance: Our data show that the radial position within the nucleus can influence the expression of some, but not all, genes. This is compatible with the suggestion that re-localisation of genes to the peripheral zone of the nucleus could be used by metazoans to modulate the expression of selected genes during development and differentiation. Keywords: SuperSeries Refer to individual Series
2010-05-26 | E-GEOD-10701 | biostudies-arrayexpress
Project description:The effects of artificial tethering of chromosomes to the nuclear periphery using LacI/lap2b anchorage constructs, part 2
| PRJNA108853 | ENA
Project description:The effects of artificial tethering of chromosomes to the nuclear periphery using LacI/lap2b anchorage constructs, part 1
| PRJNA108851 | ENA
Project description:Background: The spatial organisation of the genome in the nucleus has a role in the regulation of gene expression. In mammals, chromosomal regions with low gene-density are located close to the nuclear periphery. Correlations have also been made between the transcriptional state of some genes and their location near the nuclear periphery. However, a crucial issue is whether this level of nuclear organisation directly affects gene function, rather than merely reflecting it. Methodology: To directly investigate whether proximity to the nuclear periphery can influence gene expression in mammalian cells. here we relocate specific human chromosomes to the nuclear periphery by tethering them to a protein of the inner nuclear membrane. Principal findings: We show that this can reversibly suppress the expression of some endogenous human genes located near the tethering sites, and even genes further away. However, the expression of many other genes is not detectably reduced and we show that location at the nuclear periphery is not incompatible with active transcription. The dampening of gene expression around the nuclear periphery is dependent on the activity of histone deacetylases. Significance: Our data show that the radial position within the nucleus can influence the expression of some, but not all, genes. This is compatible with the suggestion that re-localisation of genes to the peripheral zone of the nucleus could be used by metazoans to modulate the expression of selected genes during development and differentiation. This SuperSeries is composed of the SubSeries listed below.
2008-03-04 | GSE10701 | GEO
Project description:Nuclear compartmentalization appears to play an important role in regulating metazoan genes. While studies on immunoglobulin (Ig) and other loci have correlated positioning at the nuclear lamina with gene repression, the functional consequences of this compartmentalization remain untested. We devised an approach for inducible tethering of genes to the inner nuclear membrane (INM) and demonstrate with 3D DNA-ImmunoFISH, repositioning of chromosomal regions to the nuclear lamina. Relocalization requires mitotic nuclear envelope breakdown and reformation. Tethering leads to the accumulation of lamin and INM proteins but not to association with pericentromeric heterochromatin or nuclear pore complexes. Recruitment of genes to the INM can result in their transcriptional repression. Using DamID we show that as is the case for our model system, inactive Ig loci at the nuclear periphery are contacted by INM and lamina components. We propose that such molecular interactions are used to compartmentalize and limit the accessibility of Ig loci. Experiment Overall Design: We used microarray to analyze the transcription status of genomic regions are inducibly tethered to the INM
2008-06-11 | E-GEOD-10176 | biostudies-arrayexpress
Project description:Nuclear compartmentalization appears to play an important role in regulating metazoan genes. While studies on immunoglobulin (Ig) and other loci have correlated positioning at the nuclear lamina with gene repression, the functional consequences of this compartmentalization remain untested. We devised an approach for inducible tethering of genes to the inner nuclear membrane (INM) and demonstrate with 3D DNA-ImmunoFISH, repositioning of chromosomal regions to the nuclear lamina. Relocalization requires mitotic nuclear envelope breakdown and reformation. Tethering leads to the accumulation of lamin and INM proteins but not to association with pericentromeric heterochromatin or nuclear pore complexes. Recruitment of genes to the INM can result in their transcriptional repression. Using DamID we show that as is the case for our model system, inactive Ig loci at the nuclear periphery are contacted by INM and lamina components. We propose that such molecular interactions are used to compartmentalize and limit the accessibility of Ig loci. Keywords: Inducible
2008-01-16 | GSE10176 | GEO
Project description:Spatial organization of the mammalian genome influences gene expression and cell identity. While association of genes with the nuclear periphery is commonly linked to transcriptional repression, also active, expressed genes can localize at the nuclear periphery. The transcriptionally active MyoD1 gene, a master regulator of myogenesis, exhibits peripheral localization in proliferating myoblasts, yet the underlying mechanisms remain elusive. Using a newly generated reporter cell line, we demonstrate here that peripheral association of the MyoD1 locus is independent of mechanisms involved in heterochromatin anchoring. We identify a set of nuclear envelope transmembrane proteins, particularly WFS1, that actively tether MyoD1 to the nuclear periphery. WFS1 primarily associates with active distal enhancer elements upstream of MyoD1, and with a subset of enhancers enriched in active histone marks genome-wide, which are linked to expressed myogenic genes. Overall, our data identify a novel mechanism involved in tethering active genes to the nuclear periphery. This research was funded in whole or in part by the Austrian Science Fund (FWF) [P29713-B28, P32512-B and P36503-B] to Roland Foisner and a doctorate program funded by the Austrian Science Fund (FWF) [W1261-B28].
2025-01-20 | GSE253460 | GEO
Project description:Transcriptionally silent heterochromatin preferentially localizes at the nuclear periphery, but, despite this, certain budding yeast genes relocate to the nuclear periphery following gene activation, implicating the nuclear envelope in both transcriptional activation and silencing. It is unclear how these distinct chromatin domains are established, maintained and distinguished from one another at the nuclear envelope. Here we report that nuclear pore complexes (NPCs) facilitate the transition between chromatin states by providing a platform to which chromatin-remodeling and chromatin-modifying complexes bind. In particular, we show that the RSC chromatin-remodeling complex associates with NPCs and that the nucleoporin Nup170p nucleates heterochromatin formation at telomeres through recruitment of Sir4p. Deletion of NUP170 altered subtelomeric chromatin structure, reduced SIR complex binding at telomeres, impaired telomeric silencing and abated telomere tethering. These results support a model in which telomeric heterochromatin formation occurs through telomere-NPC interactions that both promote Sir4p binding at telomeres and permit chromatin-remodeling complexes to mediate the transition between chromatin states. Examination of genome-wide nucleosome positions in WT and nup170∆ cells via next-generation sequencing of mononucleosomal DNA.
2013-02-28 | E-GEOD-36792 | biostudies-arrayexpress
Project description:Neurodegenerative diseases are accompanied by dynamic changes in gene expression, including the upregulation of hallmark stress-responsive genes. While the transcriptional pathways that impart adaptive and maladaptive gene expression signatures have been the focus of intense study, the role of higher order nuclear organization in this process is less clear. Here, we examine the role of the nuclear lamina in genome organization during the degeneration of rod photoreceptors. Two proteins had previously been shown to be necessary and sufficient to tether heterochromatin at the nuclear envelope. The lamin B receptor (Lbr) is expressed during development, but downregulates upon rod differentiation. A second tether is the intermediate filament lamin A (LA), which is not normally expressed in murine rods. Here, we show that in the rd1 model of retinitis pigmentosa, LA ectopically upregulates in rod photoreceptors at the onset of degeneration. LA upregulation correlated with increased heterochromatin tethering at the nuclear periphery in rd1 rods, suggesting that LA reorganizes the nucleus. To determine how heterochromatin tethering affects the genome, we used in vivo electroporation to misexpress LA or Lbr in mature rods in the absence of degeneration, resulting in the restoration of conventional nuclear architecture. Using scRNA-seq, we show that reorganizing the nucleus via LA/Lbr misexpression has relatively minor effects on rod gene expression. Next, using ATAC-seq, we show that LA and Lbr both lead to marked increases in genome accessibility. Novel ATAC-seq peaks tended to be associated with stress-responsive genes. Together, our data reveal that heterochromatin tethers have a global effect on genome accessibility, and suggest that heterochromatin tethering primes the photoreceptor genome to respond to stress.
2023-11-02 | GSE240312 | GEO
Project description:PIWI-interacting RNAs (piRNAs) are germline-specific small RNAs that form effector complexes with PIWI proteins (Piwi–piRNA complexes), and plays a critical role for preserving genomic integrity by repressing transposable elements (TEs). Drosophila Piwi transcriptionally silences specific targets through heterochromatin formation, and increases H3K9me3 and histone H1. Additionally, Nxf2, a nuclear RNA export factor variant, has been identified as a co-factor. Using ChEP and DamID-seq, we uncover Piwi/Nxf2-dependent target association with nuclear lamins. Hi-C analysis of Piwi or Nxf2 depleted cells reveals decreased intra-TAD and increased inter-TAD interaction in regions harboring Piwi–piRNA target TEs. Using a forced tethering system, we analyze the functional effects of Piwi–piRNA/Nxf2-mediated recruitment of piRNA target regions to the nuclear periphery. Removal of active histone marks is followed by transcriptional silencing, chromatin conformational changes, and H3K9me3 and H1 association. Our data show that the Piwi–piRNA pathway can induce stepwise changes in nuclear architecture and chromatin state at target loci for transcriptional silencing.
2021-07-01 | GSE158082 | GEO