TFIIIC binding to Alu elements controls gene expression via chromatin looping and histone acetylation
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PROVIDER: PRJNA491819 | ENA |
REPOSITORIES: ENA
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Project description:How repetitive elements, epigenetic modifications and architectural proteins interact ensuring proper genome expression remains poorly understood. Here we report regulatory mechanisms unveiling a central role of Alu elements (AEs) and RNA polymerase III transcription factor C (TFIIIC) in structurally and functionally modulating the genome via chromatin looping and histone acetylation. Upon serum deprivation, a subset of AEs pre-marked by the Activity-Dependent Neuroprotector Homeobox protein (ADNP) and located near cell cycle genes recruits TFIIIC, which alters their chromatin accessibility by direct acetylation of histone H3 lysine-18 (H3K18). This facilitates the contacts of AEs with distant CTCF sites near promoter of other cell cycle genes, which also become hyperacetylated at H3K18. These changes ensure basal transcription of cell cycle genes and are critical for their re-activation upon serum re-exposure. Our study reveals how direct manipulation of the epigenetic state of AEs by a general transcription factor regulates 3D genome folding and expression.
2019-11-21 | GSE120162 | GEO
Project description:Folding of the mammalian genome is governed by architectural proteins, such asCTCF. TFIIIC, a RNA polymerase III transcription factor, has been identified as aninsulator but its role in genome topology is totally unknown. Here, we show that TFIIICestablishes long-range genomic interactions that affect gene expression. Upon serumstarvation (SS), TFIIIC occupancy increases at Alu elements (AEs) near promoters ofcell cycle-related genes. Bound AEs become H3K18 hyper-acetylated and fold tocontact distal pre-loaded CTCF sites near other cell cycle genes. The promoters ofthese genes also become hyper-acetylated ensuring their basal transcription during SSand their increased expression during serum re-exposure. Ablation of TFIIIC ordeletion of the TFIIIC-bound AE that loops to the G2/M cycling F (CCNF) locus affectsits expression and nuclear positioning. These results illustrate a novel function ofhuman TFIIIC in changing 3D genome topology through the epigenetic state of AEs.
2020-05-26 | PXD011250 | Pride
Project description: Not available
| S-EPMC7014570 | biostudies-literature
Project description:Transcription factors (TFs) bind DNA in a sequence-specific manner and have been proven to serve as anchors to the 3D genome organization. These TFs are generally cell type-specific factor and/or developmental master regulators. General TFs (GTFs) which serve RNA polymerase recruitment to specific promoter sequences, however, can be part of very large protein complexes but their roles in genome architecture have not been carefully explored. Here, we used a bio-informatic approach of ChIP-seq and Hi-C data analysis to depict the role of one GTF of the RNA polymerase III system (TFIIIC) in several human cell lines, both normal and transformed. We find that TFIIIC occupancy within the genome mainly occurs at specific regions which largely correspond to Alu elements but also at characteristic classes of repetitive elements (REs) such as MIR, FLAMC and ALR/alpha, depending on the cell’s developmental origin. We then show that these TFIIIC-enriched regions are involved in cell type-specific DNA looping within the genome and do not depend on colocalization with the master architectural protein CTCF. This work extends previous knowledge about the role of TFIIIC as a bona fide genome organizer whose action can lead to cell type-dependent 3D genome looping via binding to REs.
2022-02-22 | GSE195499 | GEO
Project description:Enhancers determine spatiotemporal gene expression programs by engaging with long-range promoters. However, it remains unknown how enhancers find their cognate promoters. We recently developed a RIC-seq technology to identify enhancer-promoter connectivity using pairwise interacting enhancer RNAs and promoter-derived noncoding RNAs in HeLa cells. Here, we apply this technology to generate high-confidence enhancer-promoter RNA interaction (EPRI) maps in six additional cell lines. Using these maps, we discover that 37.9% of the enhancer-promoter RNA interaction sites are overlapped with Alu sequences. These pairwise interacting Alu and non-Alu RNA sequences tend to be complementary and potentially form duplexes. Knockout of Alu elements compromises enhancer-promoter looping, whereas Alu insertion or CRISPR-dCasRx-mediated Alu tethering to unregulated promoter RNAs can create new loops to homologous enhancers. Importantly, mapping 535,404 noncoding risk variants back to the EPRI maps enabled us to construct variant-to-function maps for interpreting their molecular functions, including 15,318 deletions or insertions in 11,677 Alu elements that affect 6,497 protein-coding genes. We further demonstrate that polymorphic Alu insertion at PTK2 enhancer can promote tumorigenesis. Our study uncovers a principle for determining enhancer-promoter pairing specificity and provides a framework to link noncoding risk variants to their molecular functions.
2023-05-11 | GSE190214 | GEO
Project description:Paired-end sequencing of methylated DNA fragments in B cell subsets revealed widespread loss of methylation at Alu elements upon B cell activation. DNA methylation pattern was analyzed in purified naïve and germinal-center B cells derived from 1 patient
2013-03-01 | E-GEOD-42386 | biostudies-arrayexpress
Project description:Paired-end sequencing of methylated DNA fragments in B cell subsets revealed widespread loss of methylation at Alu elements upon B cell activation.
2013-03-01 | GSE42386 | GEO
Project description:Alu retrotransposons, forming the largest family of mobile DNA elements in the human genome, have recently come to attention as a potential source of regulatory novelties, most notably by participating in enhancer function. Even though Alu transcription by RNA polymerase III is subjected to tight epigenetic silencing, their bulk expression has long been known to increase in response to various types of stress, including viral infection. Here we show that, in primary human fibroblasts, adenovirus small e1a triggered derepression of hundreds of individual Alus, by promoting TFIIIB recruitment by Alu-bound TFIIIC. Epigenome profiling revealed an e1a-induced decrease of H3K27 acetylation and increase of H3K4 monomethylation at derepressed Alus, making them resemble poised enhancers. The enhancer nature of e1a-targeted Alus was confirmed by the enrichment, in their upstream regions, of the EP300/CBP acetyltransferase and of the YAP1 and FOS transcription factors. The physical interaction of e1a with the chromatin remodeler EP400 turned out to be critical for Alu derepression, and upstream enrichment of EP400 was found to commonly demarcate expression-prone Alus. Our data suggest that e1a targets a subset of enhancer Alus whose transcriptional activation, mediated by e1a-EP400 interaction, may participate in the manipulation of enhancer activity by adenovirus.
2024-03-31 | GSE208716 | GEO
Project description:Alu retrotransposons, forming the largest family of mobile DNA elements in the human genome, have recently come to attention as a potential source of regulatory novelties, most notably by participating in enhancer function. Even though Alu transcription by RNA polymerase III is subjected to tight epigenetic silencing, their bulk expression has long been known to increase in response to various types of stress, including viral infection. Here we show that, in primary human fibroblasts, adenovirus small e1a triggered derepression of hundreds of individual Alus, by promoting TFIIIB recruitment by Alu-bound TFIIIC. Epigenome profiling revealed an e1a-induced decrease of H3K27 acetylation and increase of H3K4 monomethylation at derepressed Alus, making them resemble poised enhancers. The enhancer nature of e1a-targeted Alus was confirmed by the enrichment, in their upstream regions, of the EP300/CBP acetyltransferase and of the YAP1 and FOS transcription factors. The physical interaction of e1a with the chromatin remodeler EP400 turned out to be critical for Alu derepression, and upstream enrichment of EP400 was found to commonly demarcate expression-prone Alus. Our data suggest that e1a targets a subset of enhancer Alus whose transcriptional activation, mediated by e1a-EP400 interaction, may participate in the manipulation of enhancer activity by adenovirus.
2024-03-31 | GSE208685 | GEO
Project description:Alu elements are major contributors to lineage-specific new exons in primate and human genomes. Recent studies indicate that some Alu exons have high transcript inclusion levels or tissue-specific splicing profiles, and may play important regulatory roles in modulating mRNA degradation or translational efficiency. However, the contribution of Alu exons to the human proteome remains unclear and controversial. The prevailing view is that exons derived from young repetitive elements, such as Alu elements, are restricted to regulatory functions and have not had adequate evolutionary time to be incorporated into stable, functional proteins. We adopt a proteotranscriptomics approach to systematically assess the contribution of Alu exons to the human proteome. Using RNA sequencing, ribosome profiling and proteomics data from human tissues and cell lines, we provide evidence for the translational activities of Alu exons and the presence of Alu exon derived peptides in human proteins. These Alu exon peptides represent species-specific protein differences between primates and other mammals, and in certain instances between humans and closely related primates. In the case of the RNA editing enzyme ADARB1, which contains an Alu exon peptide in its catalytic domain, RNA sequencing analyses of A-to-I editing demonstrate that both the Alu exon skipping and inclusion isoforms encode active enzymes. The Alu exon derived peptide may fine tune the overall editing activity and, in limited cases, the site selectivity of ADARB1 protein products. Our data indicate that Alu elements have contributed to the acquisition of novel protein sequences during primate and human evolution.
2015-12-10 | GSE65999 | GEO