An archaeal chromatin protein condenses DNA through bridging-induced phase separation
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ABSTRACT:
PROVIDER: PRJNA1046133 | ENA |
REPOSITORIES: ENA
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Project description:Phase separation serves an important role in the three-dimensional chromosome organization and remodeling in eukaryotes. Whether this process is involved in archaeal chromosome organization is unknown. Here we demonstrate that archaeal DNA condensing protein1 (aDCP1) from the hyperthermophilic crenarchaeon Sulfolobus islandicus is able to bridge DNA efficiently and form large protein-DNA condensates with a droplet- or gel-like morphology in vitro. Within the condensates, aDCP1 exhibits a fast dynamic while the DNA appears in a solid-like state. At the single-molecule level, aDCP1 efficiently compacts DNA through a three-step mechanism, which presumably entails the clustering of aDCP1 on the DNA and the subsequent fusion of the clusters. Deletion of the aDCP1 gene results in noticeable changes in chromosome conformation in S. islandicus, which are characterized by enhanced interactions between the A and B compartments and reduced interactions within the self-interacting domains as well as between domains in the same compartment. Taken together, our results indicate that aDCP1 is capable of inducing DNA bridging-induced phase separation and serves a role in chromosome organization in the organism.
2024-11-01 | GSE248862 | GEO
Project description:In order to explore the impact of phase separation of CPSF6 on APA, we identified the structural domains that affect its phase separation formation and performed mutations. In addition, we also found that the phosphorylation of CPSF6 can also affect its phase separation effect, and identified key kinases. We performed IVT-SAPAS sequencing on both cases mentioned above.
2023-09-03 | GSE231823 | GEO
Project description:Enhanced Phase Separation Mediated Oncogenicity
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Project description:RNA-binding proteins with intrinsically disordered regions (IDRs) such as Rbm14 can phase separate in vitro. To what extent the phase separation contributes to their physiological functions is however unclear. Here we show that zebrafish rbm14 regulates embryonic dorsoventral patterning through phase separation. Zebrafish rbm14 morphants displayed dorsalized phenotypes associated with attenuated BMP signaling. Consistently, depletion of mammalian Rbm14 downregulated BMP regulators and effectors Nanog, Smad4/5, and Id1/2, whereas overexpression of the BMP-related proteins in the morphants significantly restored the developmental defects. Importantly, rbm14's IDR demixed into liquid droplets in vitro despite poor sequence conservation with its mammalian counterpart. While its phase separation mutants or IDR failed to rescue the morphants, its chimeric proteins containing an IDR from other phase-separation proteins were effective. Rbm14 complexed with proteins involved in RNA metabolism and phase separated into cellular ribonucleoprotein compartments. Consistently, RNA deep sequencing analysis on the morphant embryos revealed increased alternative splicing events as well as largescale transcriptomic downregulations. Our results suggest that Rbm14 functions in ribonucleoprotein compartments through phase separation to modulate multiple aspects of RNA metabolism. Furthermore, IDRs conserve in phase separation ability but not primary sequence and can be functionally interchangeable.
2019-08-05 | GSE128984 | GEO
Project description:Bacterial Heterochromatin Formation Through Liquid-Liquid Phase Separation
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Project description:Chromosome translocation is known to generate oncogenes such as SS18-SSX1, but the underlying mechanism remains unknown. Here we show that enhanced phase separation acquired by translocation mediates oncogenic transformation. SSX fusion dramatically enhances the phase separation property of SS18 protein through H2AK119ub. Super condensates generated by SS18-SSX recruit acetyltransferases CBP/P300 as wild type SS18, but exclude HDACs such that H3K27ac accumulates abnormally at loci from those normally occupied by SS18, resulting aberrant silencing and activation of target genes. Consistently, we show that inhibition of H3K27ac can attenuate the tumorigenicity of the fusion oncoprotein. These results provide the first case for phase separation as a transforming event to generate oncogene and super phase separation can be targeted for cancer therapy.
2024-05-24 | GSE240467 | GEO
Project description:Eukaryotic chromosomes fold into topologically associating domains (TADs), which further gather in active (A) or inactive (B) genomic compartments. Here we show that Scaffold Attachment Factor B (SAFB), a nuclear matrix-associated protein with RNA binding functions, modulates global chromatin condensation in a dosage-dependent manner. Upon the depletion of SAFB, the genome coverage of Lamina-associated-domains (LADs) decreases from 53.33% to 45.93%, and both inter- and intra-TAD chromatin-chromatin interactions in compartment B decrease significantly. In the nucleus, SAFB favorably co-localizes with H3K9me3, a marker of heterochromatin, and the disruption of SAFB leads to a collapse of H3K9me3 foci. Furthermore, we show that SAFB proteins can form liquid-liquid phase separation in the cell and in vitro. Intriguingly, SAFB interacts with RNAs from repetitive elements enriched in heterochromatin (e.g., Major Satellites and LINE1), which can promote SAFB-mediated phase separation, depending on the density of SAFB recognizing motifs in the RNAs.
2019-12-01 | GSE141113 | GEO
Project description:Enhanced Phase Separation Mediated Oncogenicity [HiC]
| PRJNA1003850 | ENA
Project description:An RNA-involved phase-separation model has been proposed for transcription control. Yet, the molecular links that connect RNA to the transcription machinery remain missing. Here we find RNA-binding proteins (RBPs) constitute half of the chromatin proteome in embryonic stem cells (ESCs), and some are colocalized with RNA polymerase (Pol) II at promoters and enhancers. Biochemical analyses of representative RBPs show that the paraspeckle protein PSPC1 inhibits the RNA-induced premature release of Pol II, and makes use of RNA as multivalent molecules to enhance the formation of transcription condensates and subsequent phosphorylation and release of Pol II. This synergistic interplay enhances polymerase engagement and activity via the RNA-binding and phase-separation activities of PSPC1. In ESCs, auxin-induced acute degradation of PSPC1 leads to genome-wide defects in Pol II binding and nascent transcription. We propose that promoter-associated RNAs and their binding proteins synergize the phase separation of polymerase condensates to promote active transcription.
2020-05-12 | GSE150399 | GEO
Project description:Chromosome translocation is known to generate oncogenes such as SS18-SSX1, but the underlying mechanism remains unknown. Here we show that enhanced phase separation acquired by translocation mediates oncogenic transformation. SSX fusion dramatically enhances the phase separation property of SS18 protein through H2AK119ub. Super condensates generated by SS18-SSX recruit acetyltransferases CBP/P300 as wild type SS18, but exclude HDACs such that H3K27ac accumulates abnormally at loci from those normally occupied by SS18, resulting aberrant silencing and activation of target genes. Consistently, we show that inhibition of H3K27ac can attenuate the tumorigenicity of the fusion oncoprotein (we do not have the data in your figures?). These results provide the first case for phase separation as a transforming event to generate oncogene and super phase separation can be targeted for cancer therapy.
2024-05-24 | GSE211455 | GEO