HIV-1 integration sites in the cells depleted for host facors SON, SRRM2; HIV-1 integration sites infected wild type HEK293T cells and HEK293T cells lacking CPSF6 but complemented for CPSF6 mutants.[SON_SRRM2]
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE264150 | GEO | 2025/04/01
REPOSITORIES: GEO
Similar Datasets
Project description:SON and SRRM2 were depleted in U2OS and HeLa cells and infected with HIV-1. Similarly HEK293T cells were infected with HIV-1 virus.
2025-04-01 | GSE264152 | GEO
Project description:The nucleus of higher eukaryotes is a highly compartmentalized and dynamic organelle consisting of several biological condensates that regulate gene expression at multiple levels. First reported more than 100 years ago by Ramón y Cajal, nuclear speckles (NS) are among the most prominent of such condensates, which were independently rediscovered multiple times and are also known as interchromatin granule clusters (ICGs), splicing speckles, or SC35 domains. Despite their prevalence, research on the function of NS is virtually restricted to colocalization analyses, since an organizing core, without which NS cannot form, remains unidentified. The monoclonal antibody SC35, which was raised against a spliceosomal extract, is a frequently used reagent to mark NS since its debut in 1990. Despite its prolific use, and the consensus regarding its primary target as SRSF2, clear inconsistencies between observations made with mAb SC35, and transgenic SRSF2 constructs in the same experiment are noted. Intrigued by these disparities, we carried out a systematic re-characterization of this monoclonal antibody and its cellular targets. Unexpectedly, we found no evidence for SC35 mAb recognizing SRSF2 in human cells. In contrast, our results show that the 35 kDa namesake protein recognized by SC35 mAb is SRSF7, a related but distinct SR protein. More importantly, using mass-spectrometry, CRISPR-mediated knock-ins, immunoblotting and fluorescence microscopy, we show that the main target of SC35 mAb is SRRM2, a large (300 kDa), spliceosome-associated protein with prominent intrinsically disordered regions (IDRs) that sharply localizes to NS. Analysis of protein length evolution among metazoa revealed a peculiar IDR extension specifically for SRRM2 and SON in vertebrates, a hallmark of condensate formation. Combining these results, we tested a long-standing question in the study of NS: whether NS are formed around a specific core, or various SR-proteins self-assemble into a phase-separated compartment without the need for a defined core. Here we show that, the elusive core of NS is formed by SON and SRRM2, since depletion of SON leads only to a partial disassembly of NS, while combined depletion of SON together with SRRM2, but not other NS associated factors, or depletion of SON in a cell line where IDRs of SRRM2 are genetically deleted, leads to a near-complete dissolution of NS. This work, therefore, paves the way to study the role of NS under diverse physiological and stress conditions.
2020-10-26 | PXD021814 | Pride
Project description:HIV-1 integration into the host genome favors actively transcribed genes. Prior work indicated that the nuclear periphery provides the architectural basis for integration site selection, with viral capsid-binding host cofactor CPSF6 and viral integrase-binding cofactor LEDGF/p75 contributing to selection of individual sites. Here, by investigating the early phase of infection, we determine that HIV-1 traffics throughout the nucleus for integration. CPSF6-capsid interactions allow the virus to bypass peripheral heterochromatin and penetrate the nuclear structure for integration. Loss of interaction with CPSF6 dramatically alters virus localization toward the nuclear periphery and integration into transcriptionally repressed lamina-associated heterochromatin, while loss of LEDGF/p75 does not significantly affect intranuclear HIV-1 localization. Thus, CPSF6 serves as a master regulator of HIV-1 intranuclear localization by trafficking viral preintegration complexes away from heterochromatin at the periphery toward gene-dense chromosomal regions within the nuclear interior.
| S-EPMC6368089 | biostudies-literature
Project description:Nuclear speckles (NSs) are nuclear biomolecular condensates that are postulated to arise through liquid-liquid phase separation (LLPS), although the detailed underlying forces driving NS formation remain elusive. SRRM2 and SON are 2 non-redundant scaffold proteins for NSs. How each individual protein governs assembly of NS protein network and the functional relationship between SRRM2 and SON are largely unknown. Here, we uncover immiscible multiphase of SRRM2 and SON within NSs. SRRM2 and SON are functionally independent, specifically regulating alternative splicing of subsets of mRNA targets, respectively. We further uncover that SRRM2 forms multicomponent liquid phase in cells to drive NS subcompartmentalization, which is reliant on homotypic interaction and heterotypic non-selective protein-RNA complex coacervation-driven multicomponent LLPS. SRRM2 RS domains form high-order oligomers, and can be replaced by oligomerizable synthetic modules, the serine residues within the RS domains, however, play an irreplaceable role in fine-tuning the liquidity of NSs.
2024-01-31 | GSE242898 | GEO
Project description:Srrm2 splicing factor is a novel gene implicated in developmental disorders and diseases. However, the role of Srrm2 in early mammalian development remains unexplored. Here, we show that Srrm2 expression dosage is critical for maintaining embryonic stem cell pluripotency and cell identity. Srrm2 heterozygosity promotes loss of stemness characterized by the coexistence of cells expressing naive and formative markers, together with large gene expression shifts, including in serum-response transcription factor targets and differentiation-related genes. Depletion of Srrm2 by RNA interference in embryonic stem cells identified splicing misregulation of specific genes, often linked to exon skipping. These results show that Srrm2 dosage is key in controlling stemness and cell fate decisions. Our findings unveil Srrm2’s molecular and cellular implications in development, shedding light on the involvement of splicing regulators in early embryogenesis, developmental diseases and tumorigenesis.
2024-04-12 | GSE243431 | GEO
Project description:Srrm2 splicing factor is a novel gene implicated in developmental disorders and diseases. However, the role of Srrm2 in early mammalian development remains unexplored. Here, we show that Srrm2 expression dosage is critical for maintaining embryonic stem cell pluripotency and cell identity. Srrm2 heterozygosity promotes loss of stemness characterized by the coexistence of cells expressing naive and formative markers, together with large gene expression shifts, including in serum-response transcription factor targets and differentiation-related genes. Depletion of Srrm2 by RNA interference in embryonic stem cells identified splicing misregulation of specific genes, often linked to exon skipping. These results show that Srrm2 dosage is key in controlling stemness and cell fate decisions. Our findings unveil Srrm2’s molecular and cellular implications in development, shedding light on the involvement of splicing regulators in early embryogenesis, developmental diseases and tumorigenesis.
2024-04-12 | GSE243429 | GEO
Project description:Nuclear speckles (NS) are among the most prominent biomolecular condensates. Despite their prevalence, research on the function of NS is virtually restricted to colocalization analyses, since an organizing core, without which NS cannot form, remains unidentified. The monoclonal antibody SC35, raised against a spliceosomal extract, is frequently used to mark NS. Unexpectedly, we found that this antibody was mischaracterized and the main target of SC35 mAb is SRRM2, a spliceosome-associated protein that sharply localizes to NS. Here we show that, the core of NS is likely formed by SON and SRRM2, since depletion of SON leads only to a partial disassembly of NS, while co-depletion of SON and SRRM2 or depletion of SON in a cell-line where intrinsically disordered regions (IDRs) of SRRM2 are genetically deleted, leads to a near-complete dissolution of NS. This work, therefore, paves the way to study the role of NS under diverse physiological and stress conditions.
| S-EPMC7671692 | biostudies-literature
Project description:Srrm2 splicing factor is a novel gene implicated in developmental disorders and diseases. However, the role of Srrm2 in early mammalian development remains unexplored. Here, we show that Srrm2 expression dosage is critical for maintaining embryonic stem cell pluripotency and cell identity. Srrm2 heterozygosity promotes loss of stemness characterized by the coexistence of cells expressing naive and formative markers, together with large gene expression shifts, including in serum-response transcription factor targets and differentiation-related genes. Depletion of Srrm2 by RNA interference in embryonic stem cells identified splicing misregulation of specific genes, often linked to exon skipping. These results show that Srrm2 dosage is key in controlling stemness and cell fate decisions. Our findings unveil Srrm2’s molecular and cellular implications in development, shedding light on the involvement of splicing regulators in early embryogenesis, developmental diseases and tumorigenesis.
2024-04-12 | GSE243432 | GEO
Project description:We reported the joint SRRM1/2 regulation is not the major mechanism of SRRM2-mediated alternative splicing, and that maintenance of splicing condensates by SRRM2 is important for proper alternative splicing. We knocked SRRM1/2 down with three different shRNAs, performed RNA-seq and derived the differential alternative splicing events (DASEs) using rMATS. DASEs of SRRM1/2 were largely different with little overlap, and displayed a different splicing pattern. SRRM2 deficiency induces skipping of cassette exons with short introns and weak 5’ splice. Nearly 25% of the skipped events upon SRRM2 knockdown were unannotated. More than 40% of validated DASEs upon SRRM2 suppression were associated with protein domain change (>50% domain removed by splicing). Domain changes, and especially large region removal by multiple exon skipping is a significant mechanism for protein dysfunction. Thus, alternative splicing is the major mechanism for the maintenance of protein function and cell homeostasis by SRRM2.
2022-08-30 | GSE199720 | GEO
Project description:The study examined proviral and neighboring gene transcription at sites of intact latent HIV-1 integration in cultured T cells obtained directly from people living with HIV, as well as engineered primary T cells and cell lines and showed that the site of integration has a dominant effect on the transcriptional activity of intact HIV-1 proviruses in the latent reservoir
2024-06-25 | GSE267988 | GEO