Similar Datasets
Project description:The transcriptional regulation is often controlled by the epigenetic modifications or by chromatin associated proteins. To understand this regulation, chromatin immunoprecipitation (ChIP) followed by next generation sequencing is an invaluable and powerful technique. However, the major limitation of this approach is often the requirement of large amount of starting material for generating high-quality datasets, and often the workflow is laborious. This limitation also results in application of this approach to study of rare cell populations even more challenging, if not impossible. Here, we present a tagmentation-assisted fragmentation ChIP (TAF-ChIP) and sequencing method to generate high quality dataset from as few as 100 human and 1000 Drosophila cells. The method itself is straightforward and is by far less labor-intensive than conventional library preparation, and other contemporary low amount ChIP-Seq methods. Furthermore, this approach can be applied directly on 100 cells rather than relying on de-multiplexing strategies to generate the profile from limited number of cells. This can be extremely useful when the access to the starting material is very restricted, for example clinically isolated cells from patients. Using this approach we generated the H3K4Me3 and H3K9Me3 profiles from 100 K562 cells and 1000 sorted neural stem cells (NSC) from Drosophila. We benchmarked our TAF-ChIP datasets from K562 cells against the Encode datasets. For validating the TAF-ChIP datasets obtained from Drosophila NSCs we took advantage of Notch induced over proliferation specifically in type II NSCs. The epigenetic profile obtained from conventional ChIP-Seq approach and TAF-ChIP approach shows high degree of agreement, thereby underlining the utility of this approach for generating ChIP-Seq profiles from very low cell numbers.
2021-07-28 | GSE144244 | GEO
Project description:RNA modification has emerged as an important layer in the control of gene expression. The N6-methyladenosine (m6A) RNA modification is the most prevalent and influences several processes including pre-mRNA splicing, alternative polyadenylation, mRNA decay and translation. Here, we show that m6A regulates transcription by controlling promoter proximal pause release of RNA Pol II. Our results show that the m6A methyltransferase complex together with the nuclear reader Ythdc1 are recruited to gene promoters. Loss of m6A methyltransferase complex leads to increased levels of promoter proximal pausing of RNA Pol II, decrease in Ser2P occupancy on gene body, and affects nascent RNA transcription. Furthermore, we show that the binding of the complex is Spt6-dependent and can be predicted by collective features, with Pol II and pause factors (GAF and M1BP) binding being the most important. We also demonstrate that tethering Mettl3 to a heterologous gene promoter was sufficient to increase the release of RNAP II from the promoter, and this effect was dependent on its m6A catalytic domain. Collectively our data indicate that m6A RNA feeds back to the transcription machinery via its recruitment to the chromatin, and thus uncovering an important link between epigenetic modification of RNA and transcription.
2021-07-28 | GSE144245 | GEO
Project description:m6A RNA methylation regulates promoter proximal pausing of RNA Pol II
| PRJNA603113 | ENA
Project description:Promoter-proximal pausing of RNA polymerase II (Pol II) is a major checkpoint in transcription. An unbiased search for new human proteins that could regulate paused Pol II at the HSPA1B gene identified TRIM28. In vitro analyses indicated HSF1-dependent attenuation of Pol II pausing upon TRIM28 depletion, whereas in vivo data revealed de novo expression of HSPA1B and other known genes regulated by paused Pol II upon TRIM28 knockdown. These results were supported by genome-wide ChIP-sequencing analyses of Pol II occupancy that revealed a global role for TRIM28 in regulating Pol II pausing and pause release. Furthermore, in vivo and in vitro mechanistic studies suggest that transcription-coupled phosphorylation regulates Pol II pause release by TRIM28. Collectively, our findings identify TRIM28 as a new factor that modulates Pol II pausing and transcriptional elongation at a large number of mammalian genes.
| S-EPMC4189995 | biostudies-literature
Project description:RNA polymerase II (RNAPII) transcription is governed by the pre-initiation complex (PIC), which contains TFIIA, TFIIB, TFIID, TFIIE, TFIIF, TFIIH, RNAPII, and Mediator. After initiation, RNAPII enzymes pause after transcribing less than 100 bases; precisely how RNAPII pausing is enforced and regulated remains unclear. To address specific mechanistic questions, we reconstituted human RNAPII promoter-proximal pausing in vitro, entirely with purified factors (no extracts). As expected, NELF and DSIF increased pausing, and P-TEFb promoted pause release. Unexpectedly, the PIC alone was sufficient to reconstitute pausing, suggesting RNAPII pausing is an inherent PIC function. In agreement, pausing was lost upon replacement of the TFIID complex with TATA-binding protein (TBP), and PRO-seq experiments revealed widespread disruption of RNAPII pausing upon acute depletion (t = 60 min) of TFIID subunits in human or Drosophila cells. These results establish a TFIID requirement for RNAPII pausing and suggest pause regulatory factors may function directly or indirectly through TFIID.
| S-EPMC7245555 | biostudies-literature
Project description:m6A RNA methylation regulates promoter proximal pausing of RNA Pol II (ChIP-Seq)
| PRJNA603118 | ENA
Project description:RNA polymerase II (RNA Pol II) is generally paused at promoter-proximal regions in most metazoans, and based on in vitro studies, this function has been attributed to the negative elongation factor (NELF). Here, we show that upon rapid depletion of NELF, RNA Pol II fails to be released into gene bodies, stopping instead around the +1 nucleosomal dyad-associated region. The transition to the 2nd pause region is independent of positive transcription elongation factor P-TEFb. During the heat shock response, RNA Pol II is rapidly released from pausing at heat shock-induced genes, while most genes are paused and transcriptionally downregulated. Both of these aspects of the heat shock response remain intact upon NELF loss. We find that NELF depletion results in global loss of cap-binding complex from chromatin without global reduction of nascent transcript 5' cap stability. Thus, our studies implicate NELF functioning in early elongation complexes distinct from RNA Pol II pause-release.
| S-EPMC7402197 | biostudies-literature
Project description:m6A RNA methylation regulates promoter proximal pausing of RNA Pol II (DRB-4sU-seq)
| PRJNA603117 | ENA
Project description:The highly conserved histone chaperone FACT (Facilitates Chromatin Transcription) is thought to contribute to the disassembly and reassembly of nucleosomes in the wake of RNA Polymerase II (Pol II) passage through chromatin. However, FACT’s roles in chromatin biology and transcriptional regulation in vivo in higher eukaryotes are not well understood. Here, we report that depletion of FACT leads to a reduction in the duration of promoter-proximal pausing by Pol II in Drosophila S2 cells. In addition, FACT depletion leads to a modest decrease in the occupancy of histone H3, and to decrease in occupancy of histone H2A.v in promoter-proximal nucleosomes. Finally, we observed a dramatic 5’ to 3’ repositioning of the co-transcriptionally deposited histone modifications H3K4me3 and H3K36me3 in the FACT depleted cells. Taken together, our findings are consistent with the model that FACT contributes to the interplay between chromatin architecture and control of Pol II promoter-proximal pausing.
2019-06-18 | GSE129235 | GEO
Project description:Regulation of transcription is a tightly choreographed process. The establishment of RNA polymerase II promoter proximal pausing soon after transcription initiation and the release of Pol II into productive elongation are key regulatory processes that occur in early elongation. We describe the techniques and tools that have become available for the study of promoter proximal pausing and their utility for future experiments. We then provide an overview of the factors and interactions that govern a multipartite pausing process and address emerging questions surrounding the mechanism of RNA polymerase II's subsequent advancement into the gene body. Finally, we address remaining controversies and future areas of study.
| S-EPMC8184617 | biostudies-literature