Information Content Differentiates Enhancers From Silencers in Mouse Photoreceptors
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus Escherichia coli
PROVIDER: GSE165812 | GEO | 2021/01/30
REPOSITORIES: GEO
Similar Datasets
Project description:Gene expression is determined by genomic elements called enhancers, which contain short motifs bound by different transcription factors (TFs). However, how enhancer sequences and TF motifs relate to enhancer activity is unknown and general sequence requirements for enhancers or comprehensive sets of important enhancer sequence elements have remained elusive. Here, we computationally dissect thousands of functional enhancer sequences from three different Drosophila cell lines. We find that the enhancers display distinct cis-regulatory sequence signatures, which are predictive of the enhancersM-bM-^@M-^Y cell type-specific or broad activities. These signatures contain transcription factor motifs and a novel class of enhancer sequence elements, dinucleotide repeat motifs (DRMs). DRMs are highly enriched in enhancers, particularly in enhancers that are broadly active across different cell types. We experimentally validate the importance of the identified TF motifs and DRMs for enhancer function and show that they can be sufficient to create an active enhancer de novo from non-functional sequence. The function of DRMs as a novel class of general enhancer features that are also enriched in human regulatory regions might explain their implication in several diseases and provides important insights into gene regulation. STARR-seq was performed in BG3 cells with paired-end sequencing in two replicates and respective inputs.
2014-04-02 | E-GEOD-49809 | biostudies-arrayexpress
Project description:Sequence-specific transcription factors (TFs) regulate gene expression by binding to cognate motifs in promoters and enhancers. However, predicting genomic TF binding events and their quantitative contribution to expression remains a major challenge. In principle, the binding and enhancer activity of specific sites in vivo might depend on: (i) latent properties of the motif instance, (ii) cooperative interactions with other TFs that bind in the immediate vicinity, and (iii) the chromatin state of the sites in the genome. Here, we used massively parallel reporter assays (MPRA) involving 32,115 natural and synthetic enhancers, together with high-throughput in vivo assays, to systematically dissect the contributions of motif affinity, cooperative interactions, and chromatin accessibility to the binding and regulatory activity of genomic sequences that contain motifs for PPARγ, a TF that serves as a key regulator of adipogenesis. We show that PPARγ binding and enhancer activity are governed by distinct features. Genomic PPARγ binding to motif sites is largely governed by on larger-scale features, such as chromatin accessibility, whereas the degree to which a PPARγ motif site enhances transcriptional activity depends on the sequence immediately surround the motif. We detect and functionally validate a network of TFs comprised of multiple functional classes that collaborate with PPARγ to drive transcription. We extensively perturb this network, revealing functional cooperativity among classes of TFs that does not depend on precise positioning. Together, these results present a clear picture of how chromatin and TFs from distinct functional classes interact with PPARγ to determine binding and enhancer activity, and provide a paradigm for studying any TF.
2017-02-03 | GSE84888 | GEO
Project description:Gene expression is determined by genomic elements called enhancers, which contain short motifs bound by different transcription factors (TFs). However, how enhancer sequences and TF motifs relate to enhancer activity is unknown and general sequence requirements for enhancers or comprehensive sets of important enhancer sequence elements have remained elusive. Here, we computationally dissect thousands of functional enhancer sequences from three different Drosophila cell lines. We find that the enhancers display distinct cis-regulatory sequence signatures, which are predictive of the enhancers’ cell type-specific or broad activities. These signatures contain transcription factor motifs and a novel class of enhancer sequence elements, dinucleotide repeat motifs (DRMs). DRMs are highly enriched in enhancers, particularly in enhancers that are broadly active across different cell types. We experimentally validate the importance of the identified TF motifs and DRMs for enhancer function and show that they can be sufficient to create an active enhancer de novo from non-functional sequence. The function of DRMs as a novel class of general enhancer features that are also enriched in human regulatory regions might explain their implication in several diseases and provides important insights into gene regulation.
2014-04-02 | GSE49809 | GEO
Project description:FOXA pioneer transcription factors (TFs) associate with primed enhancers in endodermal organ precursors. Using a human stem cell model of pancreas differentiation, we here discover that only a subset of pancreatic enhancers is FOXA-primed, whereas the majority is unprimed and engages FOXA upon lineage induction. Primed enhancers are enriched for signal-dependent TF motifs and harbor abundant and strong FOXA motifs. Unprimed enhancers harbor fewer, more degenerate FOXA motifs, and FOXA recruitment to unprimed but not primed enhancers requires pancreatic TFs. Strengthening FOXA motifs at an unprimed enhancer near NKX6.1 renders FOXA recruitment pancreatic TF-independent, induces priming, and broadens the NKX6.1 expression domain. We make analogous observations about FOXA binding during hepatic and lung development. Our findings suggest a dual role for FOXA in endodermal organ development: First, FOXA facilitate signal-dependent lineage initiation via enhancer priming, and second, FOXA enforce organ cell type-specific gene expression via indirect recruitment by lineage-specific TFs.
2021-10-18 | GSE148368 | GEO
Project description:The nematode Caenorhabditis elegans is a powerful model for studying gene regulation, as it has a compact genome and a wealth of genomic tools. However, identification of regulatory elements has been hampered by the fact that DNA binding motifs are known for only 71 (9%) of the estimated 763 high-confidence sequence-specific transcription factors (TFs). To address this problem, we performed protein binding microarray (PBM) experiments on representatives of canonical TF families in the C. elegans TF repertoire, obtaining motifs for 129 distinct TFs. Moreover, we can infer motifs for 97 additional TFs that have DNA binding domains that are very similar to those already characterized, resulting in a total coverage of binding specificities for almost 40% of the C. elegans TF repertoire. These data highlight the diversification of binding motifs for the nuclear hormone receptor (NHR) and C2H2 zinc finger families, and reveal unexpected diversity of motifs for others, including the T-box and DM families. Enrichment of motifs in the promoters of functionally related genes is consistent with known biology in many cases, and also identifies putative new regulatory roles for poorly characterized TFs. The motifs are available at http:// http://cisbp.ccbr.utoronto.ca. Protein binding microarray (PBM) experiments were performed for a set of 129 diverse C. elegans transcription factors. Briefly, the PBMs involved binding GST-tagged DNA-binding proteins to two double-stranded 44K Agilent microarrays, each containing a different DeBruijn sequence design, in order to determine their sequence preferences. Details of the PBM protocol are described in Berger et al., Nature Biotechnology 2006.
2015-04-23 | E-GEOD-65719 | biostudies-arrayexpress
Project description:To investigate the activity of sponge enhancers in vertebrates transgenic experiments was performed where sponge enhancers were inserted into zebrafish embryos and stable lines generated abstract: Transcription factors (TFs) bind DNA enhancer sequences to regulate gene transcription in animals. Unlike TFs, the evolution of enhancers has been difficult to trace because of their fast evolution. Here, we take enhancers in the sponge Amphimedon queenslandica and test their activity in zebrafish and mouse. Of the five sponge enhancers assessed, three were located in conserved syntenic gene regions that are unique to animals (Islet–Scaper, Ccne1–Uri, Tdrd3–Diaph3). Despite diverging over 700 million years ago and a dearth of sequence identity, sponge enhancers are able to drive cell type-specific reporter gene expression in vertebrates. Analysis of the type and frequency of TF binding motifs in the sponge Islet enhancer allowed for the identification of homologous enhancers in human and mouse, which show remarkably similar reporter expression patterns to the sponge enhancer. These findings uncover an unexpected deep conservation of enhancers and suggest that enhancers established early in metazoan evolution can remain functional through retention of combinations of transcription factor binding motifs despite substantial sequence divergence.
2019-11-30 | E-MTAB-7846 | biostudies-arrayexpress
Project description:The DNA sequence preferences of the vast majority of eukaryotic transcription factors (TFs) are unknown. Using an approach designed to broadly sample both DNA-binding domain types and eukaryotic clades, we have determined DNA-binding motifs for 1,033 TFs from 131 diverse eukaryotes, encompassing 54 domain types. Closely related orthologs and paralogs typically have very similar sequence preferences; this property allows inference of motifs for roughly one third of the 166,851 known or predicted eukaryotic TFs. While the origins of most motifs can be dated to hundreds of millions of years ago, we also characterize more recent TF expansions. Sequences matching the motifs are enriched upstream of TSS in most eukaryotic lineages, and at informative eQTL SNPs in Arabidopsis promoters, demonstrating their utility in mapping transcriptional networks. The motifs are housed at http://cisbp.ccbr.utoronto.ca Protein binding microarray (PBM) experiments were performed for a set of 1048 diverse eukaryotic transcription factors. Briefly, the PBMs involved binding GST-tagged DNA-binding proteins to two double-stranded 44K Agilent microarrays, each containing a different DeBruijn sequence design, in order to determine their sequence preferences. Details of the PBM protocol are described in Berger et al., Nature Biotechnology 2006.
2014-08-01 | E-GEOD-53348 | biostudies-arrayexpress
Project description:A central question in biology is how enhancers are made accessible. The Drosophila embryo is a good model system to study this question as the gene regulatory networks regulating early developmental events have been well characterized. Zelda (Zld) is a uniformly distributed transcription factor (TF) integral to these networks, acting prior to and in collaboration with the patterning TFs to regulate target enhancers. Here we test the hypothesis that Zld directs TF binding, examplified by Dorsal (Dl) which patterns the dorsoventral axis, across the genome by displacing nucleosomes at enhancers. By performing ChIP-seq and MNase-seq experiments on early embryos with or without Zld, we demonstrated that early enhancers are characterized by an intrinsically high nucleosome barrier, which is overcome by Zld, and that without Zld, Dl binding decreases at enhancers and redistributes to open regions devoid of enhancer activity. We propose that enhancers are initially specified across the genome by the binding of Zld, which locally decreases nucleosome occupancy, thereby assisting TFs in accessing their binding motifs and promoting transcriptional activity. Zld, Dl, Pol II ChIP-seq and MNase-seq profiles comparing 2-3h wild-type (wt) and zld- embryos, and MNase-seq profiles comparing 2-4h wt and gd7 embryos, all in 2 replicates
2015-08-21 | E-GEOD-65441 | biostudies-arrayexpress
Project description:Patterns of transcriptional activity are encoded in our genome through regulatory elements such as promoters or enhancers that, paradoxically, often contain similar assortments of sequence-specific transcription factor (TF) binding sites. Knowledge of how these sequence motifs encode multiple, often overlapping gene expression programs is central to understanding gene regulation and how mutations in non-coding DNA manifest in disease. Exploiting natural genetic variation, perturbation of endogenous TF protein levels, and analysis of synthetic regulatory elements using a novel transcription start site (TSS) capturing massively parallel reporter assay approach, here we show that the outcome of TF binding on transcription initiation is position dependent. Analyzing TF motif occurrences relative to the TSS, we identified several motifs with highly preferential and superhelical positioning. We show that these patterns are a combination of a TF's distinct functional profiles: many TFs, including canonical activators like NRF1, NFY, Sp1 or YY1, activate or repress transcription initiation depending on their precise position relative to the TSS. As such, TFs can collectively guide the site and frequency of transcription initiation. More broadly, these findings reveal how similar assortments of TFs, but with different spatial relationships, can result in distinct gene regulatory outcomes and underscore a critical role for TSS data in decoding the regulatory information of our genome.
2024-04-26 | GSE199431 | GEO
Project description:Cell fate transitions are accompanied by global transcriptional, epigenetic and topological changes driven by transcription factors (TFs), as is strikingly exemplified by reprogramming somatic cells to pluripotent stem cells (PSCs) via expression of OCT4, KLF4, SOX2 and cMYC. How TFs orchestrate the complex molecular changes around their target gene loci in a temporal manner remains incompletely understood. Here, using KLF4 as a paradigm, we provide the first TF-centric view of chromatin reorganization and its association to 3D enhancer rewiring and transcriptional changes of linked genes during reprogramming of mouse embryonic fibroblasts (MEFs) to PSCs. Inducible depletion of KLF factors in PSCs caused a genome-wide decrease in the connectivity of enhancers, while disruption of individual KLF4 binding sites from PSC-specific enhancers was sufficient to impair enhancer-promoter contacts and reduce expression of associated genes. Our study provides an integrative view of the complex activities of a lineage-specifying TF during a controlled cell fate transition and offers novel insights into the order and nature of molecular events that follow TF binding.
2019-09-03 | PXD014631 | Pride