TSA-Seq Mapping of Nuclear Genome Organization [array]
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE66018 | GEO | 2018/04/25
REPOSITORIES: GEO
Similar Datasets
Project description:We describe TSA-Seq, a new mapping method able to estimate mean chromosomal distances from nuclear speckles genome-wide and predict several Mbp chromosome trajectories between nuclear compartments without sophisticated computational modeling. Ensemble-averaged results reveal a clear nuclear lamina to speckle axis correlated with a striking spatial gradient in genome activity. This gradient represents a convolution of multiple, spatially separated nuclear domains, including two types of transcription ?hot-zones?. Transcription hot-zones protruding furthest into the nuclear interior and positioning deterministically very close to nuclear speckles have higher numbers of total genes, the most highly expressed genes, housekeeping genes, genes with low transcriptional pausing, and super-enhancers.
2018-04-25 | GSE81553 | GEO
Project description:Nuclear speckles are prominent nuclear bodies that contain a myriad of factors involved in gene expression. The role of nuclear speckles as activating transcriptional compartments is emerging. However, the extent that the association between speckles and DNA is regulatable, and the mechanisms that govern regulated speckle association are currently unclear. Using DNA- and RNA-FISH, we show that speckle association can be mediated by the p53 transcription factor, finding that p53 activation drives speckle association of specific p53 transcriptional targets. Analysis of a key p53 target, p21, revealed an increase in nascent transcripts at speckle-adjacent transcription sites, supporting a role for speckles in amplifying transcriptional output. Importantly, p53-regulated speckle association of p21 did not depend on transcriptional activation, demonstrating that speckle association is not merely a consequence of gene expression. In contrast, speckle association of p21 did require DNA binding functions of p53, providing a mechanism for the specificity by which speckle association is regulated. Beyond p21, a substantial subset of p53 targets have p53-regulated speckle association, while other p53 targets do not, and we find that genomic context is highly deterministic of which target genes have regulated speckle association. These findings reveal a novel means by which transcription factors may control gene expression and provide a mechanism for the specificity of regulated speckle association.
2021-01-04 | GSE154095 | GEO
Project description:MALAT-1 is a long mammalian non-coding transcript of approximately 8500 nucleotides. It is localized to nuclear speckles despite its mRNA-like characteristics, which usually result in the export of transcripts to the cytoplasm. In the present study, we report the identification of several factors that influence the nuclear speckle localization of MALAT-1, and we provide evidence that MALAT-1 is involved in the regulation of gene expression. Heterokaryon assays revealed that MALAT-1 does not shuttle between the nucleus and cytoplasm, but is stably retained within the nucleus. Analysis of MALAT-1 fragments showed that MALAT-1 contains two distinct nuclear speckle-directing elements (between nucleotides 1961 to 3040 and 6008 to 7011 of the MALAT-1 sequence). The knockdown of the nuclear speckle proteins, RNPS1, SRm160 or IBP160, resulted in the diffusion of MALAT-1 to the nucleoplasm. In addition, we have demonstrated that depletion of MALAT-1 represses the expression of several genes. This repression of gene expression also occurs in response to the delocalization of MALAT-1 from the nuclear speckles. These results suggest that RNPS1, SRm160 and IBP160 contribute to the localization of MALAT-1 to nuclear speckles where it is involved in regulating gene expression
2010-06-02 | GSE20506 | GEO
Project description:Prior work revealed nuclear-localized aminoacyl-tRNA synthetases (aaRSs) that checked newly synthesized tRNAs for charging before export to the cytoplasm. To reveal other functions, we sought to identify nuclear proteins that interact with arginyl-tRNA synthetase (ArgRS) in the nucleus. Serine/Arginine Repetitive Matrix Protein 2 (SRRM2), which is stored with RNA splicing apparatus components in nuclear speckle condensates, was found as a consistent interaction partner that co localized with SRRM2 ArgRS in nuclear speckles. Dynamic photo-bleaching experiments showed that, consistent with condensate properties, SRRM2 has a fluctuating appearance in speckles. Knock down of ArgRS impeded SRRM2 speckle trafficking and, coincidently, altered splicing processing of pre-mRNA transcripts. Among the altered spliced variants, those of tRNA synthetase family members were prominent. Thus, nuclear ArgRS shapes the dynamics of a protein in class of nuclear condensates. Also, the work expands the repertoire of nuclear tRNA synthetase roles to include regulation of RNA splicing, including of aaRS family member transcripts.
2023-04-14 | PXD015692 | Pride
Project description:The nucleus is highly organized such that factors involved in transcription and processing of distinct classes of RNA are organized within specific nuclear bodies. One example is the nuclear speckle, which is defined by high concentrations of protein and non-coding RNA regulators of pre-mRNA splicing. What functional role, if any, speckles might play in the process of mRNA splicing remains unknown. Here we show that genes localized near nuclear speckles display higher spliceosome concentrations, increased spliceosome binding to their pre-mRNAs, and higher co-transcriptional splicing levels relative to genes that are located farther from nuclear speckles. We show that directed recruitment of a pre-mRNA to nuclear speckles is sufficient to increase mRNA splicing levels. Finally, we show that gene organization around nuclear speckles is highly dynamic with differential localization between cell types corresponding to differences in splicing efficiency. Together, our results integrate the longstanding observations of nuclear speckles with the biochemistry of mRNA splicing and demonstrate a critical role for dynamic 3D spatial organization of genomic DNA in driving spliceosome concentrations and controlling the efficiency of mRNA splicing.
2024-03-22 | GSE247833 | GEO
Project description:The nucleus is composed of membrane-less subnuclear compartments, containing intrinsically disordered proteins and RNAs that phase separate (PS) and contribute to specific nuclear reactions. However, whether and how different subnuclear compartments can intercommunicate remains elusive. Here we identified nuclear bodies with PS features composed of BAZ2A, a factor associating with active chromatin. BAZ2A-bodies depend on active transcription, RNAs, and the non-disordered BAZ2A RNA-binding TAM domain. Although BAZ2A and H3K27me3 occupancies anticorrelate in the linear genome, in the nuclear space BAZ2A-bodies contact H3K27me3-bodies. Disruption of BAZ2A-bodies promotes BAZ2A invasion into H3K27me3-domains, causing H3K27me3-bodies loss, H3K27me3 decrease, and gene upregulation. BAZ2A-bodies formation is negatively regulated by the nuclear-speckles associated lncRNA Malat1 that interacts with BAZ2A and mediates BAZ2A association to chromatin at nuclear speckles, which do not contact BAZ2A-bodies. The results unravel how active compartments protect repressive compartments using PS mechanisms that are promoted or impaired according to the type of RNA interactions with RNA-binding proteins.
2024-04-09 | GSE225897 | GEO
Project description:TFIID is an essential basal transcription factor, crucial for RNA polymerase II (pol II) promoter recognition and transcription initiation. The TFIID complex consists of the TATA-binding protein (TBP) and 13 TBP-associated factors (TAFs) that contain intrinsically disordered regions (IDRs) with currently unknown functions. Here, we show that a conserved IDR drives TAF2 condensation in nuclear speckles, independently of other TFIID subunits. Quantitative mass spectrometry analyses reveal that the TAF2 IDR specifically interacts with the nuclear speckle and spliceosome-associated protein SRRM2. Consequently, TAF2 recruits SRRM2 to TFIID to form non-canonical TFIID-SRRM2 complexes. Reduced SRRM2 recruitment elicits alternative splicing events in RNAs coding for proteins involved in transcription and transmembrane transport. Further, genome-wide binding analyses suggest TAF2 shuttling between nuclear speckles and pol II promoters. This study identifies an IDR of the basal transcription machinery as a molecular guide for protein partitioning into nuclear compartments, controlling protein complex composition and pre-mRNA splicing.
2024-02-06 | GSE254080 | GEO
Project description:TFIID is an essential basal transcription factor, crucial for RNA polymerase II (pol II) promoter recognition and transcription initiation. The TFIID complex consists of the TATA-binding protein (TBP) and 13 TBP-associated factors (TAFs) that contain intrinsically disordered regions (IDRs) with currently unknown functions. Here, we show that a conserved IDR drives TAF2 condensation in nuclear speckles, independently of other TFIID subunits. Quantitative mass spectrometry analyses reveal that the TAF2 IDR specifically interacts with the nuclear speckle and spliceosome-associated protein SRRM2. Consequently, TAF2 recruits SRRM2 to TFIID to form non-canonical TFIID-SRRM2 complexes. Reduced SRRM2 recruitment elicits alternative splicing events in RNAs coding for proteins involved in transcription and transmembrane transport. Further, genome-wide binding analyses suggest TAF2 shuttling between nuclear speckles and pol II promoters. This study identifies an IDR of the basal transcription machinery as a molecular guide for protein partitioning into nuclear compartments, controlling protein complex composition and pre-mRNA splicing.
2024-02-06 | GSE254060 | GEO
Project description:We have found that depletion of the zinc finger protein ZFC3H1 inhibits the nuclear retention of these RNAs. ZFC3H1 forms a complex with MTR4 and PABPN1 (the PolyAdenylation EXosome Targeting complex (Meola et al 2016, Ogami et al 2017) and likely recruits the nuclear exosome for RNA degradation. Recently, we found that depletion of U1-70K, one protein component of the U1 snRNP spliceosomal complex, inhibits nuclear retention of 5’SS motif containing RNAs. The U1 snRNP complex recognizes and binds to the 5’SS motif and in vitro studies showed that U1-70K directly interact with a similar 5’SS motif through U1 snRNA binding (Gunderson et al 1999). Interestingly, we found that U1 snRNP is involved in targeting 5’SS motif containing mRNAs to nuclear speckles shortly following RNA transcription. In contrast, ZFC3H1 is involved in nuclear speckle localization post-transcriptionally and actively retain RNAs in these structures. Together, our results suggest a model where U1 snRNP interacts with the RNA via the 5’SS motif and targets mature mRNAs to nuclear speckles. Specifically, it suggests that misprocessed RNAs can be targeted to speckles (or other nucleoplasmic foci) and that these foci serve as a platform to recruit the nuclear exosome via ZFC3H1. Our results highlight a splicing independent role of U1 snRNP and how mRNA nuclear export function in nuclear surveillance to prevent the translation of aberrant proteins.
2022-03-31 | GSE176144 | GEO
Project description:Malat1 is an abundant long noncoding RNA that localizes to nuclear bodies known as nuclear speckles, which contain a distinct set of pre-mRNA processing factors. Previous in vitro studies have demonstrated that Malat1 interacts with pre-mRNA splicing factors, including the serine- and arginine-rich (SR) family of proteins, and regulates a variety of biological processes, including cancer cell migration, synapse formation, cell cycle progression, and responses to serum stimulation. To address the physiological function of Malat1 in a living organism, we generated Malat1-KO (KO) mice using homologous recombination. Unexpectedly, the Malat1-KO mice were viable and fertile, showing no apparent phenotypes. Nuclear speckle markers were also correctly localized in cells that lacked Malat1. However, the cellular levels of another long noncoding RNA, Neat1, which is an architectural component of nuclear bodies known as paraspeckles, were downregulated in a particular set of tissues and cells lacking Malat1. To address if the the absence of Malat1 affects the expression of other genes, including other long noncoding RNA, microarrays were used to study the impact of knocking-out Malat1 on global gene expression in mouse embryonic fibroblasts (MEFs). MEFs were prepared from E13.5 mouse embryos from wildtype and Malat1 knock-out mice. RNA harvested from these cells were hybridized to Affymetirx mouse gene expression array.
2012-06-24 | E-GEOD-37705 | biostudies-arrayexpress