Genome wide mapping of polyadenylation sites in proliferating and contact-inhibited cells and cells with knockdown of cleavage and polyadenylation factors
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PROVIDER: PRJNA480879 | ENA |
REPOSITORIES: ENA
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Project description:Purpose: Quiescence is a state of reversible cell cycle exit. Levels of polyadenylation factors decreases when proliferating cells become quiescent. The goals of this study are to determine the differential use of polyadenylation sites (changes in alternative polyadenylation) in quiescent vs. proliferating cells and also upon knockdown of polyadenylation factors. Methods: Two biological replicates of human dermal fibroblasts (12-1 and 12-3) were used for polyadeylation-site enriched RNA-seq on an Illumina HiSeq 2500 to compare quiescent vs. proliferating cells and polyadenylation factor knockdown vs. control cells. The reads were aligned to the human genome (hg19) uisng Tophat (2.0.14). The resulting bam files were used as an input to a python script provided by Gruber et al. (PMID: 27382025) to determine the counts for each polyadenylation site. Results: We observed a shift toward greater use of distal polyadenylation sites when the fibroblasts entered quiescence. We observed significant overlap between the genes that shift to greater distal site use with quiescence and CstF-64 or CPSF73 knockdown. Conclusions: The shift to greater distal site use with quiescence may reflect in part the reduced levels of cleavage and polyadenylation factors.
2018-08-28 | GSE117033 | GEO
Project description:Purpose: To determine genes that undergo alternative polyadenylation in proliferating versus quiescent fibroblasts. Methods: Three different biological replicates (fibroblast strains, 10-1, 12-1, and 12-2) were used for generating proliferating and quiescent (7-day contact inhibited and 7-day serum-starved) cells. RNA extracted from these cells were used for library preparation. cDNA fragments were enriched for the junction between the poly(A) site and the end of the 3' UTR using a modified high throughput sequencing protocol (GnomeGen). cDNA libraries were created according to Gnome-Gen RNA-seq library preparation kit for RNA profiling except Amgen Ampure XP beads were used instead of the Gnome-gen size selector product to remove ligation reaction products before proceeding to the reverse transcription step. The libraries were sequenced on an Illumina HiSeq 2000 instrument. The sequencing reaction wasa run for 147 cycles. Reads from pol(A) enriched cDNA libraries were aligned to the genome using the STAR alignment algorithm after the computational removal of untemplated adenosines. Results: Polyadenylation site selection was significantly altered in approximately 10% of genes in quiescent compared with proliferating fibroblasts. Contact inhibited and serum starved fibroblasts had similar polyadenylation site selection profiles. Conclusions: Quiescence is associated with changes in polyadenylation site selection.
2018-07-19 | GSE117337 | GEO
Project description:Global mapping of polyadenylation site use in proliferating and quiescent (contact-inhibited and serum-starved) cells
| PRJNA481778 | ENA
Project description:In eukaryotes, U1 small nuclear ribonucleoprotein (snRNP) forms spliceosomes in equal stoichiometry with U2, U4, U5 and U6 snRNPs; however, its abundance in human far exceeds that of the other snRNPs. Here we used antisense morpholino oligonucleotide to U1 snRNA to achieve functional U1 snRNP knockdown in HeLa cells, and identified accumulated unspliced pre-mRNAs by genomic tiling microarrays. In addition to inhibiting splicing, U1 snRNP knockdown caused premature cleavage and polyadenylation in numerous pre-mRNAs at cryptic polyadenylation signals, frequently in introns near (<5 kilobases) the start of the transcript. This did not occur when splicing was inhibited with U2 snRNA antisense morpholino oligonucleotide or the U2-snRNP-inactivating drug spliceostatin A unless U1 antisense morpholino oligonucleotide was also included. We further show that U1 snRNA–pre-mRNA base pairing was required to suppress premature cleavage and polyadenylation from nearby cryptic polyadenylation signals located in introns. These findings reveal a critical splicing-independent function for U1 snRNP in protecting the transcriptome, which we propose explains its overabundance.
2010-09-29 | GSE24179 | GEO
Project description:The PAF complex (Paf1C) has been shown to regulate chromatin modifications, gene transcription, and PolII elongation. Here, we provide the first genome-wide analysis of chromatin occupancy by the entire PAF complex in mammalian cells. We show that Paf1C is recruited not only to promoters and gene bodies, but also to regions downstream of cleavage/polyadenylation (pA) sites at 3â ends, a profile that sharply contrasted with the yeast complex. Remarkably, our studies identified novel, subunit-specific links between Paf1C and regulation of alternative cleavage and polyadenylation (APA) and upstream antisense transcription. Moreover, we found that depletion of Paf1C subunits also resulted in the accumulation of RNA polymerase II (PolII) over gene bodies, which coincided with APA. Depletion of specific Paf1C subunits leads to global loss of histone H2B ubiquitylation, but surprisingly, there is little impact of Paf1C depletion on other histone modifications, including the tri-methylation of histone H3 on lysines 4 and 36 (H3K4me3 and H3K36me3), previously associated with this complex. Our results provide surprising differences with yeast, while unifying observations that link Paf1C with PolII elongation and RNA processing, and suggest that Paf1C could play a role in protecting transcripts from premature cleavage by preventing PolII accumulation at TSS-proximal pA sites. ChIP-seq, RNA-seq and 3'READS of Paf1C factors in mouse C2C12 myoblast cells
2016-01-15 | E-GEOD-72574 | biostudies-arrayexpress
Project description:We studied the regulation of pre-messenger RNA 3'-end processing (i.e., cleavage at polyadenylation sites) in response to ultraviolet C irradiation in human cells.
2023-02-06 | GSE203517 | GEO
Project description:Purpose: Alternative polyadenylation (APA) can result in the generation of transcripts that terminate at different locations within the gene, which can result in different 3' UTRs. 3´ UTRs are known to contain RNA stabilizing and destabilizing motifs that provide a platform for binding of RNA binding proteins. Changes in 3´ UTRs for the different APA-generated isoforms of a gene could allow for inclusion or exclusion of these RNA stability elements. The goal of this study is determine the stability (half-lives based on transcript decay) of APA isoforms in proliferating and quiescent cells. Methods: The proliferating and quiescent (7-day contact inhibited) cells were treated with actinomycin D to stop transcription and the cells were harvested at different time points (0. 2, 4, 8 hours) for RNA isolation and global sequencing of 3´ ends. The adaptors and polyA sequenced were trimmed from each read. The reads were aligned to the human genome (hg19) using TopHat (v2.0.14). The aligned read files were used to determine the counts of APA isoforms of each gene using the code provided by Gruber et al. (PMID: 27382025). The counts of the APA isoforms were fit to an exponential decay model to obtain half-lives. The entire workflow was performed for two biological replicates: 12-1 and 12-3 strains of human dermal fibroblasts. Results: In two different fibroblast strains (12-1 and 12-3), we found that isoforms terminating at distal polyadenylation sites were more stable than isoforms terminating at proximal polyadenylation sites in quiescent, but not proliferating, fibroblasts. Conclusions: The transition from shorter to longer isoforms in quiescent cells is associated with stabilization of the transcripts.
2018-08-28 | GSE117121 | GEO
Project description:Cells have compensatory mechanisms to coordinate the rates of major biological processes, thereby permitting growth in a wide variety of conditions. Here, we uncover a compensatory link between cleavage/polyadenylation in the nucleus and mRNA turnover in the cytoplasm. On a global basis, same-gene 3’ mRNA isoforms with > two-fold differences in half-lives have steady-state mRNA levels that differ by significantly less than a factor of two. In addition, increased efficiency of cleavage/polyadenylation at a specific site is associated with reduced stability of the corresponding 3’ mRNA isoform. This inverse relationship between cleavage/polyadenylation and mRNA isoform half-life reduces the variability in the steady-state levels of mRNA isoforms, and it occurs in all four growth conditions tested. These observations suggest that during cleavage/polyadenylation in the nucleus, mRNA isoforms are marked in a manner that persists upon translocation to the cytoplasm and affects the activity of mRNA degradation machinery, thus influencing mRNA stability.
2022-02-02 | GSE191091 | GEO
Project description:Cleavage and polyadenylation is essential for 3’ end processing of almost all eukaryotic mRNAs. Recent studies have shown widespread alternative cleavage and polyadenylation (APA) events leading to mRNA isoforms with different 3’UTRs and/or coding sequences. Here we present a compendium of conserved cleavage and polyadenylation sites (PASs) in mammalian genes, based on ~1.2 billion 3’ end sequencing reads from over 360 human, mouse and rat samples. We show that ~80% of mammalian mRNA genes contain at least one conserved PAS, and ~50% have conserved APA events. PAS conservation generally reduces promiscuous 3’ end processing, stabling gene expression levels across species. Conservation of APA correlates with gene age, gene expression features, and gene functions. Genes with certain functions, such as cell morphology, cell proliferation, and mRNA metabolism, are particularly enriched with APA events. While tissue-specific genes typically have a low APA rate, brain-specific genes tend to evolve APA. We show enrichment of mRNA destabilizing motifs in alternative 3’UTR sequences, leading to substantial differences in mRNA stability between 3’UTR APA isoforms. Using conserved PASs, we reveal sequence motifs surrounding APA sites and a preference of adenosine at the cleavage site. Mutations of the U-rich motif around the PAS often accompany APA profile changes between species. Analysis of lncRNA PASs indicates a mechanism of PAS fixation involving evolution of A-rich motifs. Taken together, our results present a comprehensive view of PAS evolution in mammals, and a phylogenic understanding of APA functions.
2018-08-08 | GSE111134 | GEO
Project description:Cleavage and polyadenylation specificity factor (CPSF) is the central component of the 3' processing machinery for polyadenylated mRNAs in metazoans: CPSF recognizes the polyadenylation signal AAUAAA, providing sequence specificity in both pre-mRNA cleavage and polyadenylation, and catalyzes pre-mRNA cleavage. Here we show that of the seven polypeptides that have been proposed to constitute CPSF, only four, CPSF160, CPSF30, hFip1 and WDR33, are necessary and sufficient to reconstitute a CPSF subcomplex active in AAUAAA-dependent polyadenylation, whereas CPSF100, CPSF73 and symplekin are dispensable. WDR33 is required for binding of reconstituted CPSF to AAUAAA-containing RNA and can be specifically UV-crosslinked to such RNAs, as can be CPSF30. Transcriptome-wide identification of WDR33 targets by PAR-CLIP shows that WDR33 specifically binds the AAUAAA signal in vivo in contrast to any of the five other CPSF subunits tested before. Thus, our data indicate that the CPSF subunit that is mainly responsible for recognizing the polyadenylation signal is WDR33 and not CPSF160, as suggested by previous studies. Transcriptome-wide profiling of WDR33 binding sites using PAR-CLIP in HEK293 cells.
2014-09-25 | E-GEOD-61123 | biostudies-arrayexpress