Similar Datasets
Project description:Transcription factors (TFs) activate enhancers to drive cell-specific gene expression in response to signals, but our understanding of enhancer assembly in signaling events is incomplete. Here we show that Androgen Receptor (AR), a steroid hormone signaling-regulated transcription factor, forms phase-separated condensates in response to androgen to activate enhancers. We demonstrate that the intrinsically disordered NTD of AR drives condensate formation and that NTD deletion or aromatic residue mutation reduces AR self-association and abolishes AR transcriptional activity. AR NTD can be substituted by some IDRs from other proteins for AR condensation capacity and transactivation function. Extending the polyQ tract within AR NTD strengthens AR phase separation and also leads to impaired transcriptional activity. PolyQ expansion does not affect AR binding on enhancers, but instead impairs enhancer assembly. These results suggest that AR phase separation mediates enhancer assembly, and an optimal level of AR condensation is required for its proper function in mediating AR-AR homotypic and AR-cofactor heterotypic interactions to regulate transcription in response to signals. Our study supports that alteration of the fine-tuned protein condensation might underlie AR-related human pathologies, therefore providing novel molecular insights for potential therapeutic strategies to treat prostate cancer and other AR-involved diseases by targeting AR condensation.
2023-10-31 | GSE215160 | GEO
Project description:Transcription factors (TFs) activate enhancers to drive cell-specific gene expression in response to signals, but our understanding of enhancer assembly in signaling events is incomplete. Here we show that Androgen Receptor (AR), a steroid hormone signaling-regulated transcription factor, forms phase-separated condensates in response to androgen to activate enhancers. We demonstrate that the intrinsically disordered NTD of AR drives condensate formation and that NTD deletion or aromatic residue mutation reduces AR self-association and abolishes AR transcriptional activity. AR NTD can be substituted by some IDRs from other proteins for AR condensation capacity and transactivation function. Extending the polyQ tract within AR NTD strengthens AR phase separation and also leads to impaired transcriptional activity. PolyQ expansion does not affect AR binding on enhancers, but instead impairs enhancer assembly. These results suggest that AR phase separation mediates enhancer assembly, and an optimal level of AR condensation is required for its proper function in mediating AR-AR homotypic and AR-cofactor heterotypic interactions to regulate transcription in response to signals. Our study supports that alteration of the fine-tuned protein condensation might underlie AR-related human pathologies, therefore providing novel molecular insights for potential therapeutic strategies to treat prostate cancer and other AR-involved diseases by targeting AR condensation.
2023-10-31 | GSE215162 | GEO
Project description:Transcription factors (TFs) activate enhancers to drive cell-specific gene expression in response to signals, but our understanding of enhancer assembly in signaling events is incomplete. Here we show that Androgen Receptor (AR), a steroid hormone signaling-regulated transcription factor, forms phase-separated condensates in response to androgen to activate enhancers. We demonstrate that the intrinsically disordered NTD of AR drives condensate formation and that NTD deletion or aromatic residue mutation reduces AR self-association and abolishes AR transcriptional activity. AR NTD can be substituted by some IDRs from other proteins for AR condensation capacity and transactivation function. Extending the polyQ tract within AR NTD strengthens AR phase separation and also leads to impaired transcriptional activity. PolyQ expansion does not affect AR binding on enhancers, but instead impairs enhancer assembly. These results suggest that AR phase separation mediates enhancer assembly, and an optimal level of AR condensation is required for its proper function in mediating AR-AR homotypic and AR-cofactor heterotypic interactions to regulate transcription in response to signals. Our study supports that alteration of the fine-tuned protein condensation might underlie AR-related human pathologies, therefore providing novel molecular insights for potential therapeutic strategies to treat prostate cancer and other AR-involved diseases by targeting AR condensation.
2023-10-31 | GSE215161 | GEO
Project description:Protein secretion is initiated at the endoplasmic reticulum by the COPII coat, which self-assembles to form vesicles. Here, we examine the mechanisms by which a cargo-bound inner coat layer recruits and is organized by an outer scaffolding layer to drive local assembly of a stable structure rigid enough to enforce membrane curvature. An intrinsically disordered region in the outer coat protein, Sec31, drives binding with an inner coat layer via multiple distinct interfaces, including a newly defined charge-based interaction. These interfaces combinatorially reinforce each other, suggesting coat oligomerization is driven by the cumulative effects of multivalent interactions. The Sec31 disordered region could be replaced by evolutionarily distant sequences, suggesting plasticity in the binding interfaces. Such a multimodal assembly platform provides an explanation for how cells build a powerful yet transient scaffold to direct vesicle traffic.
| S-EPMC7594496 | biostudies-literature
Project description:Enhancer RNAs (eRNAs) are long non-coding RNAs that originate from enhancers. Although eRNA transcription is a canonical feature of activated enhancers, the molecular features required for eRNA function and the mechanism of how eRNAs impinge on target gene transcription have not been established. Thus, using eRNA-dependent RNA polymerase II (Pol II) pause release as a model, we here investigate the requirement of sequence, structure and length of eRNAs for their ability to stimulate Pol II pause release by detaching NELF from paused Pol II. We find eRNAs not to exert their function through common structural or sequence motifs. Instead, eRNAs that exhibit a length >200 nucleotides and that contain unpaired guanosines make multiple, allosteric contacts with NELF subunits -A and -E to trigger efficient NELF release. By revealing the molecular determinants of eRNA function, our study establishes eRNAs as an important player in Pol II pause release, and it provides new insight into the regulation of metazoan transcription.
| S-EPMC9068813 | biostudies-literature
Project description:In budding yeast, which possesses simple point centromeres, we discovered that all of its centromeres express long noncoding RNAs (cenRNAs), especially in S phase. Induction of cenRNAs coincides with CENP-ACse4 loading time and is dependent on DNA replication. Centromeric transcription is repressed by centromere-binding factor Cbf1 and histone H2A variant H2A.ZHtz1 Deletion of CBF1 and H2A.Z HTZ1 results in an up-regulation of cenRNAs; an increased loss of a minichromosome; elevated aneuploidy; a down-regulation of the protein levels of centromeric proteins CENP-ACse4, CENP-A chaperone HJURPScm3, CENP-CMif2, SurvivinBir1, and INCENPSli15; and a reduced chromatin localization of CENP-ACse4, CENP-CMif2, and Aurora BIpl1 When the RNA interference system was introduced to knock down all cenRNAs from the endogenous chromosomes, but not the cenRNA from the circular minichromosome, an increase in minichromosome loss was still observed, suggesting that cenRNA functions in trans to regulate centromere activity. CenRNA knockdown partially alleviates minichromosome loss in cbf1Δ, htz1Δ, and cbf1Δ htz1Δ in a dose-dependent manner, demonstrating that cenRNA level is tightly regulated to epigenetically control point centromere function.
| S-EPMC6442628 | biostudies-literature
Project description:UV-light-induced protein-RNA cross-linking followed by MS analysis was used to identify RNA-binding regions of enhancer RNAs (eRNAs) to the negative elongation factor (NELF) complex, and NELF as part of the paused elongation complex (PEC) of human RNA polymerase II.
2022-03-08 | PXD030569 | Pride
Project description:Enhancer activation serves as the main mechanism regulating signal-dependent transcriptional programs, ensuring cellular plasticity, yet central questions persist regarding their mechanism of activation. Here, by successfully mapping topoisomerase I-DNA covalent complexes genome-wide, we find that most, if not all, acutely activated enhancers, including those induced by 17β-estradiol, dihydrotestosterone, tumor necrosis factor alpha and neuronal depolarization, are hotspots for topoisomerase I-DNA covalent complexes, functioning as epigenomic signatures read by the classic DNA damage sensor protein, Ku70. Ku70 in turn nucleates a heterochromatin protein 1 gamma (HP1γ)-mediator subunit Med26 complex to facilitate acute, but not chronic, transcriptional activation programs. Together, our data uncover a broad, unappreciated transcriptional code, required for most, if not all, acute signal-dependent enhancer activation events in both mitotic and postmitotic cells.
| S-EPMC9935399 | biostudies-literature
Project description:Erythropoietin receptor (EpoR) binding mediates neuroprotection by endogenous Epo or by exogenous recombinant human (rh)Epo. The level of EpoR gene expression may determine tissue responsiveness to Epo. Thus, harnessing the neuroprotective power of Epo requires an understanding of the Epo-EpoR system and its regulation. We tested the hypothesis that neuronal expression of EpoR is required to achieve optimal neuroprotection by Epo. The ventral limbic region (VLR) in the rat brain was used because we determined that its neurons express minimal EpoR under basal conditions, and they are highly sensitive to excitotoxic damage, such as occurs with pilocarpine-induced status epilepticus (Pilo-SE). We report that (i) EpoR expression is significantly elevated in nearly all VLR neurons when rats are subjected to 3 moderate hypoxic exposures, with each separated by a 4-day interval; (ii) synergistic induction of EpoR expression is achieved in the dorsal hippocampus and neocortex by the combination of hypoxia and exposure to an enriched environment, with minimal increased expression by either treatment alone; and (iii) rhEpo administered after Pilo-SE cannot rescue neurons in the VLR, unless neuronal induction of EpoR is elicited by hypoxia before Pilo-SE. This study thus demonstrates using environmental manipulations in normal rodents, the strict requirement for induction of EpoR expression in brain neurons to achieve optimal neuroprotection. Our results indicate that regulation of EpoR gene expression may facilitate the neuroprotective potential of rhEpo.
| S-EPMC2701030 | biostudies-literature
Project description:We use flow cytometry to characterize equilibrium binding of a fluorophore-labeled trivalent model antigen to bivalent IgE-FcepsilonRI complexes on RBL cells. We find that flow cytometric measurements are consistent with an equilibrium model for ligand-receptor binding in which binding sites are assumed to be equivalent and ligand-induced receptor aggregates are assumed to be acyclic. However, this model predicts extensive receptor aggregation at antigen concentrations that yield strong cellular secretory responses, which is inconsistent with the expectation that large receptor aggregates should inhibit such responses. To investigate possible explanations for this discrepancy, we evaluate four rule-based models for interaction of a trivalent ligand with a bivalent cell-surface receptor that relax simplifying assumptions of the equilibrium model. These models are simulated using a rule-based kinetic Monte Carlo approach to investigate the kinetics of ligand-induced receptor aggregation and to study how the kinetics and equilibria of ligand-receptor interaction are affected by steric constraints on receptor aggregate configurations and by the formation of cyclic receptor aggregates. The results suggest that formation of linear chains of cyclic receptor dimers may be important for generating secretory signals. Steric effects that limit receptor aggregation and transient formation of small receptor aggregates may also be important.
| S-EPMC2800967 | biostudies-literature