Dynamic coupling of R-loops with transcriptional pausing modulates tissue development in Drosophila
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PROVIDER: PRJNA1035041 | ENA |
REPOSITORIES: ENA
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Project description:The R-loop in the genome participates in modulating transcription, replication and DNA damage repair, yet its regulation and biologic impact on development in vivo remain to be explored. Here, we modified CUT&Tag strategy and established R-loop profiles of Drosophila across multiple developmental stages. While lack of GC preference, the broad class of R-loops in Drosophila all highly follow the RNAPII pausing, which is also a conserved R-loop regulatory mechanism in mammals. Meanwhile, RNAPII-regulated R-loop may be regulated by multiple developmental specificity and universality transcription factors. To test the specificity and universality of transcription factor-mediated R-loop involvement in development, we knocked out the transcription elongation factor Spt6, upregulated R-loop and increased RNAPII pausing, and altered the expression of critical genes and cutin genes, thereby affecting Drosophila lifespan and cutin development. Interestingly, complementation of rnh1 could partially rescue the transcription factor deletion phenotype. We conclude that RNAPII is a conserved mechanism of R-loop regulation across species and organism specific damage caused by R-loop dysregulation is mediated by the functions of transcription factors.
2024-11-02 | GSE246878 | GEO
Project description:R-loop, a three-stranded RNA/DNA structure, has been linked to induced genome instability and regulated gene expression. To enable precision analysis of R-loops in vivo, we develop an RNase H-based approach, revealing predominant R-loop formation near gene promoters with strong G/C skew and propensity to form G-quadruplex in non-template DNA, corroborating with all biochemically established properties of R-loops. Transcription perturbation experiments further indicate that R-loop induction correlates to transcriptional pausing. Interestingly, we note that most mapped R-loops are each linked to a nearby free RNA end, and by using a ribozyme to co-transcriptionally cleave nascent RNA, we demonstrate that such free RNA end coupled with a G/C-skewed sequence is necessary and sufficient to induce R-loop. These findings provide a topological solution for RNA invasion into duplex DNA and suggest an order for R-loop initiation and elongation in an opposite direction to that previously proposed.
2017-10-12 | GSE97072 | GEO
Project description:R-loops are involved in many biological processes in cells, yet the regulatory principles for R-loops in vivo and their impact on development remain to be explored. Here, we modified the CUT&Tag strategy to profile R-loops in Drosophila at multiple developmental stages. While high GC content promotes R-loop formation in mammalian cells, it is not required in Drosophila. In contrast, RNAPII abundance on chromatin appears to be a universal inducing factor for R-loop formation in the Drosophila genome, including active promoters and enhancers, and H3K27me3 decorated repressive regions and intergenic repeat sequences. Importantly, such a regulatory relationship is dynamically maintained throughout development and many development-related transcription factors that may regulate RNAPII activation and R-loop dynamics were uncovered. By ablating the elongation factor Spt6, we further showed the global R-loop induction coupled with RNAPII pausing, genome instability, and defects in larvae survival and cuticle development. Overexpression of rnh1 largely reversed the upregulation or downregulation of gene expression depending on gene length, DNA damage, and defects in survival and cuticle development. Altogether, our findings indicate that dynamic R-loop regulation is dictated by RNAP pausing and transcription activity, and plays a feedback role in gene regulation, genome stability maintenance, and Drosophila development.
2024-10-03 | GSE270095 | GEO
Project description:Global coupling of R-loops with transcription dynamics modulates early development and survival of Drosophila
| PRJNA1124981 | ENA
Project description:The formation of R-loops is a natural consequence of the transcription process, caused by invasion of the DNA duplex by nascent transcripts. These structures have been considered rare transcriptional by-products with potential harmful effects on genome integrity, due to the fragility of the displaced DNA coding strand. However R-loops may also possess beneficial effects as their widespread formation has been detected over CpG island promoters in human genes. Furthermore we have previously shown that R-loops are particularly enriched over G-rich terminator elements. These facilitate RNA polymerase II (Pol II) pausing prior to efficient termination. Here we reveal an unanticipated link between R-loops and RNA interference (RNAi)-dependent H3K9me2 formation over pause site termination regions of mammalian protein coding genes. We show that R-loops induce antisense transcription over these pause elements which in turn lead to the generation of double-strand RNA (dsRNA) and recruitment of Dicer, Ago1, Ago2, and G9a histone lysine methyltransferase (HKMT). Consequently an H3K9me2 repressive mark is formed and Heterochromatin Protein 1γ (HP1γ) is recruited, that reinforces Pol II pausing prior to efficient transcriptional termination. We predict that R-loops promote a chromatin architecture that defines the termination region for a substantial subset of mammalian genes. PolIIS2ph ChIP-seq and input in untreated condition and treated with BIX and RNaseH1 overexpression in HeLa cells. The 4 samples have been multiplexed, pooled and sequenced on 3 lanes of Illumina HiSeq2000.
2014-09-29 | E-GEOD-59878 | biostudies-arrayexpress
Project description:R-loop, a three-stranded RNA/DNA structure, has been linked to induced genome instability and regulated gene expression. To enable precision analysis of R-loops in vivo, we develop an RNase-H-based approach; this reveals predominant R-loop formation near gene promoters with strong G/C skew and propensity to form G-quadruplex in non-template DNA, corroborating with all biochemically established properties of R-loops. Transcription perturbation experiments further indicate that R-loop induction correlates to transcriptional pausing. Interestingly, we note that most mapped R-loops are each linked to a nearby free RNA end; by using a ribozyme to co-transcriptionally cleave nascent RNA, we demonstrate that such a free RNA end coupled with a G/C-skewed sequence is necessary and sufficient to induce R-loop. These findings provide a topological solution for RNA invasion into duplex DNA and suggest an order for R-loop initiation and elongation in an opposite direction to that previously proposed.
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Project description:The NELF complex is a metazoan-specific factor essential for establishing transcription pausing. Although NELF has been implicated in cell fate regulation, the cellular regulation of NELF and its intrinsic role in specific lineage differentiation remains largely unknown. Using mammalian hematopoietic differentiation as a model system, here we identified a dynamic change of NELF-mediated transcription pausing as a novel mechanism regulating hematopoietic differentiation. We found a sharp decrease of NELF protein abundance during granulocytic differentiation with a consequent genome-wide reduction of transcription pausing. This loss of pausing coincides with activation of granulocyte-affiliated genes and diminished expression of progenitor markers. Functional studies revealed that sustained expression of NELF inhibits granulocytic differentiation, whereas NELF depletion in progenitor cells leads to premature differentiation towards the granulocytic lineage. Our results thus uncover a previously unrecognized regulation of transcription pausing by modulating NELF protein abundance to control cellular differentiation.
2019-05-31 | GSE98555 | GEO
Project description:Interactions between transcriptional promoters and their distal regulatory elements play an important role in transcriptional regulation; however, the extent to which these interactions are subject to rapid modulations in response to signals is unknown. Here, we use promoter capture Hi-C to demonstrate a rapid reorganization of promoter anchored chromatin loops within four hours after induction of differentiation of 3T3-L1 preadipocytes. This reorganization is tightly coupled to dynamic changes in target gene expression. The formation of promoter-enhancer loops is tightly linked to the activation of poised (histone H3 lysine 4 mono- and dimethylated) enhancers, as evidenced by the acquisition of histone H3 lysine 27 acetylation and the binding of MED1, SMC1 and P300 proteins to these regions. Intriguingly, formation of loops connecting activated enhancers and promoters is also associated with extensive recruitment of corepressors such as NCoR and HDACs, indicating that this class of coregulators may play a previously unrecognized role during enhancer activation.
2017-04-26 | GSE95533 | GEO
Project description:Numerous classes of riboswitches have been found to regulate bacterial gene expression in response to physiological cues, offering new paths to antibacterial drugs. As common studies of isolated riboswitches lack the functional context of the transcription machinery, we here combine single-molecule, biochemical, and simulation approaches to investigate the coupling between co-transcriptional folding of the pseudoknot-structured preQ1 riboswitch and RNA polymerase (RNAP) pausing. We show that pausing at a site immediately downstream of the riboswitch requires a ligand-free pseudoknot in the nascent RNA, a precisely spaced sequence resembling the pause consensus, and electrostatic and steric interactions with the RNAP exit channel. While interactions with RNAP stabilize the native fold of the riboswitch, binding of the ligand signals RNAP release from the pause. Our results demonstrate that the nascent riboswitch and its ligand actively modulate the function of RNAP and vice versa, a paradigm likely to apply to other cellular RNA transcripts.
| S-EPMC6565381 | biostudies-literature
Project description:Embryonic stem (ES) cells and embryos reversibly pause via chemical mTOR inhibition. In this study, we investigate the tissue-specific response to mTORi-induced pausing in ES and trophoblast stem (TS) cells. To resolve the sequential rewiring of the proteome, we conducted a time-series proteomics experiment at 1, 3, 6, 12, 24, and 48 hours upon induction of pausing, and at 1, 3, 6, 12, 24, and 48 hours upon release of pausing in ES and TS cells. We find that ES, but not TS cells pause reversibly. To optimise developmental pausing conditions, we reasoned that by understanding the difference in pausing response of ES and TS cells, we could identify which pathways are essential for pausing. We found that KEGG pathways related to amino acid degradation, fatty acid degradation, and DNA repair are upregulated in ES cells, but downregulated in TS cells during entry into pausing. Moreover, by targeted metabolomics, we found a depletion of short chain carnitines in the paused ES cells. To extend the length of developmental pausing, we supplemented paused embryos with L-carnitine. The L-carnitine supplementation facilitates lipid usage and prolongs the pausing length by 19 days through the establishment of a more dormant state.
2023-11-06 | PXD041325 | Pride