Analysis of Drosophila melanogaster nascent transcription start sites
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ABSTRACT:
ORGANISM(S): Drosophila melanogaster
PROVIDER: GSE203135 | GEO | 2022/10/26
REPOSITORIES: GEO
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Project description:Analysis of Drosophila melanogaster nascent transcription start sites
| PRJNA838629 | ENA
Project description:To assess the impact of the proteasome inhibitor MG132 on nascent transcription inMDA-MB-453 cells, csRNA-seq was conducted to compare transcript abundances between treated and DMSO control cells. Analysis of transcripts following MG132 treatment showed that APOBEC3A is one of the most differentially expressed genes. Comparison to other APOBEC family genes, revealed APOBEC3A is unique in its transcriptional upregulation by MG132. Analysis of transcription factor binding sites enriched in the promoter regions of genes changed greater than 2-fold in expression highlighted potential transcription factors driving increased APOBEC3A transcription.
2023-12-05 | GSE248016 | GEO
Project description:We have generated single-nucleotide resolution, nascent transcription profiles from HeLa cells by developing Native Elongation Transcript sequencing technology for mammalian chromatin (mNET-seq). Our extensive data sets provide a substantial resource to study mammalian nascent transcript profiles. We reveal unanticipated phosphorylation states for RNA polymerase II C-terminal domain (Pol II CTD) at both gene ends. We also observe that following 5’ splice site cleavage by the spliceosome, upstream exon transcripts are tethered to Pol II CTD phosphorylated on the serine 5 position (S5P) which is accumulated over downstream exons. We further show that depletion of termination factors substantially reduces Pol II pausing at gene ends leading to termination defects. Remarkably termination factors play an additional promoter role by restricting non-productive RNA synthesis and redistributing Pol II CTD S2P to promoters. These data demonstrate that CTD phosphorylation is more dynamic and variably distributed across mammalian transcription units than previously envisaged. To monitor nascent RNA within the mammalian Pol II complex, and its association with different CTD phosphorylation states, we employed mNET-seq methodology on HeLa cells, complemented with direct sequencing of chromatin-bound RNA (ChrRNA-seq). mNET-seq was preformed using the antibodies 8WG16, CMA602, CMA603 and CMA601, which are specific for unphosphorylated CTD, Ser2 phosphorylation, Ser5 phosphorylation and all CTD isoforms, respectively. In another experiment, to evaluate the effect of transcription termination factors in nascent RNA production by Pol II, mNET-seq and complemented with ChrRNA-seq was preformed on HeLa cells transfected with siRNA against PTBP1, CPSF73, CstF64+CstF64tau or Xrn2, and the gene profiles were compared with profiles from HeLa transfected with siRNA for Luciferase generated by the same protocol.
2015-04-23 | E-GEOD-60358 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the following subset Series: GSE36871: Nascent-Seq Reveals Novel Features of Mouse Circadian Transcriptional Regulation [RNA-Seq] GSE36872: Nascent-Seq Reveals Novel Features of Mouse Circadian Transcriptional Regulation [Nascent-Seq] GSE36873: Nascent-Seq Reveals Novel Features of Mouse Circadian Transcriptional Regulation [StrandSpe_NascentSeq] GSE36874: Nascent-Seq Reveals Novel Features of Mouse Circadian Transcriptional Regulation [ChIP-seq] Refer to individual Series
2012-11-09 | E-GEOD-36916 | biostudies-arrayexpress
Project description:The spatial and temporal regulation of transcription initiation is pivotal for controlling gene expression. Here, we introduce capped-small RNA-seq (csRNA-seq), which uses total RNA as starting material to detect transcription start sites (TSS) of both stable and unstable RNAs at single-nucleotide resolution. csRNA-seq is highly sensitive to acute changes in transcription and identifies an order of magnitude more regulated transcripts than RNA-seq. Interrogating tissues from species across the eukaryotic kingdoms identified unstable transcripts resembling enhancer RNAs, pre-miRNAs, antisense transcripts and promoter upstream transcripts in multicellular animals, plants and fungi spanning 1.6 million years of evolution. Integration of epigenomic data from these organisms revealed that histone H3 trimethylation (H3K4me3) was largely confined to TSS of stable transcripts, while H3K27ac marked nucleosomes downstream of all active TSS, suggesting an ancient role for post-translational histone modifications in transcription. Our findings demonstrate that total RNA is sufficient to identify transcribed regulatory elements and capture the dynamics of initiated stable and unstable transcripts at single nucleotide resolution in eukaryotes.
2019-09-16 | GSE135498 | GEO
Project description:Over the past decade, genome-wide assays have underscored the broad sweep of circadian gene expression. A substantial fraction of the transcriptome undergoes oscillations in many organisms and tissues, which governs the many biochemical, physiological and behavioral functions under circadian control. Based predominantly on the transcription feedback loops important for core circadian timekeeping, it is commonly assumed that this widespread mRNA cycling reflects circadian transcriptional cycling. To address this issue, we directly measured dynamic changes in mouse liver transcription using Nascent-Seq. Many genes are rhythmically transcribed over the 24h day, which include precursors of several non-coding RNAs as well as the expected set of core clock genes. Surprisingly however, nascent RNA rhythms overlap poorly with mRNA abundance rhythms assayed by RNA-seq. This is because most mouse liver genes with rhythmic mRNA expression manifest poor transcriptional rhythms, indicating a prominent role of post-transcriptional regulation in setting mRNA cycling amplitude. To gain further insight into circadian transcriptional regulation, we also characterized the rhythmic transcription of liver genes targeted by the transcription factors CLOCK and BMAL1; they directly target other core clock genes and sit at the top of the molecular circadian clock hierarchy in mammals. CLK:BMAL1 rhythmically bind at the same discrete phase of the circadian cycle to all target genes, which not surprisingly have a much higher percentage of rhythmic transcription than the genome as a whole. However, there is a surprisingly heterogeneous set of cycling transcription phases of direct target genes, which even include core clock genes. This indicates a disconnect between rhythmic DNA binding and the peak of transcription, which is likely due to other transcription factors that collaborate with CLK:BMAL1. In summary, the application of Nascent-Seq to a mammalian tissue provides surprising insights into the rhythmic control of gene expression and should have broad applications beyond the analysis of circadian rhythms. Mouse liver nascent RNA profile over 6 time points of the 24h light:dark cycle, in duplicate, sequenced using Ilumina GAII (Nascent-Seq); Mouse liver mRNA profile over 6 time points of the 24h light:dark cycle, in duplicate, sequenced using Ilumina HiSeq2000 (RNA-Seq); CLK and BMAL1 DNA binding profile in the mouse liver at ZT8, sequenced along an Input sample using GAII (ChIP-Seq); Mouse liver strand-specific nascent RNA profile over 6 time points of the 24h light:dark cycle, in duplicate, sequenced using Ilumina HiSeq2000 (Strand-specific Nascent-Seq); Supplementary file NascentSeq_Mouse_Liver_NormalizedGeneSignal.txt represents Nascent RNA abundance (reads per base pair) for each sample.
2012-11-10 | E-GEOD-36872 | biostudies-arrayexpress
Project description:Transcription by RNA polymerase (RNAP) is interrupted by pauses that play diverse regulatory roles. Although individual pauses have been studied in vitro, the determinants of pauses in vivo and their distribution throughout the bacterial genome remain unknown. Using nascent transcript sequencing we identify a 16 nt consensus pause sequence in E. coli that accounts for known regulatory pause sites as well as ~20,000 new in vivo pause sites. In vitro single-molecule and ensemble analyses demonstrate that these pauses result from RNAP/nucleic-acid interactions that inhibit next-nucleotide addition. The consensus sequence also leads to pausing by RNAPs from diverse lineages and is enriched at translation start sites in both E. coli and B. subtilis. Our results thus implicate a conserved mechanism unifying known and newly identified pause events. Examination of nascent transcripts in E. coli and B. subtilis. 6 samples of E. coli NET-seq, 1 sample of E. coli mRNA-seq, and 1 sample of B. subtilis NET-seq.
2014-05-05 | E-GEOD-56720 | biostudies-arrayexpress
Project description:RNA sequences are expected to be identical to their corresponding DNA sequences. Advances in technologies have enabled deep sequencing of nucleic acids that uncovered exceptions to the one-to-one relationship between DNA and RNA sequences. Previously in human cells, post-transcriptional RNA editing was the only known mechanism that changes RNA sequences from the underlying DNA sequences. Here, we sequenced nascent RNA and found all 12 types of RNA-DNA differences. Using various experimental analyses, we validated this finding. Our results showed that sequences of nascent RNAs within 40 nucleotides of the exit channel of RNA polymerase II already differ from the corresponding DNA sequences. These RNA-DNA differences are mediated by RNA processing steps closely coupled with transcription and not by known deaminase-mediated RNA editing mechanisms nor during NTP incorporation by Pol II. This finding identifies sequence substitution as part of co-transcriptional RNA processing. We sequenced nascent RNA using global run-on sequencing, GRO-seq from human B-cells from two individuals and a variant of the GRO-seq procedure, known as precision run-on sequencing, PRO-seq. The RNAs are prepared after a short run-on assay performed with isolated nuclei in the presence of Br-UTP. The isolated RNAs are base hydrolyzed to ~100 nucleotides and affinity purified with anti-BrU beads three times at each successive step of preparing the RNAs for orientation-specific sequencing using Illumina technology. The 5M-bM-^@M-^Y ~half of each sequence represents nascent RNA made in the cell and the 3M-bM-^@M-^Y ~half represents sequences made in vitro during the run-on reaction. The precision variation, PRO-seq, incorporates one or at most a few biotin-labeled nucleoside triphosphates during the run-on, and sequencing from the 3M-bM-^@M-^Y end of this affinity purified, nascent RNA maps the cellular location of engaged polymerases with near single nucleotide precision. We obtained ~ 100 million 100-nucleotide uniquely mapped GRO-seq reads from B-cells of two individuals. For one subject, we also carried out pGRO-seq and obtained 60 million uniquely mapped reads. In addition, we sequenced ~135 million uniquely mapped RNA-seq reads, and the corresponding DNA of the two individuals to 30X and 60X coverage. Additionally, we isolated and sequenced nascent RNA with an alternate method described by Wuarin and Schibler (1994) in order to compare chromatin-bound RNA to the very nascent RNA from PRO-seq. We obtained ~190 million uniquely mapped reads from chormatin-bound RNA-seq.
2014-02-21 | E-GEOD-39878 | biostudies-arrayexpress
Project description:miRNAs are key post-transcriptional regulators of gene expression. However, it is still poorly understood how miRNAs themselves are regulated, mainly due to the sparse annotation of miRNA transcription start sites (TSSs). Here, we developed a novel method for identifying active miRNA TSSs from nascent transcriptomes generated by nuclear run-on sequencing. With the least data requirement, our method demonstrated better performance than existing methods. Moreover, it provided ways not only to recognize miRNA TSSs but also to quantify primary miRNA expression in one experiment, which is very useful for revealing miRNAs directly regulated by the regulator(s) of interest.
2017-04-20 | GSE97143 | GEO