Systematic Dissection of Sequence Features Affecting the Binding Specificity of a Pioneer Factor Reveals Binding Synergy Between FOXA1 and AP-1
Ontology highlight
ABSTRACT:
ORGANISM(S): synthetic construct Homo sapiens
PROVIDER: GSE247432 | GEO | 2023/11/09
REPOSITORIES: GEO
Similar Datasets
Project description:Pioneer factors (PFs) are a subset of transcription factors (TFs) that can bind to nucleosomal DNA and invade closed chromatin. Despite that nucleosomes do not present a strong barrier to PF binding, PF can only bind to a small fraction of motifs in the genome. The underlying mechanism of such binding selectivity is not well understood. Here, we design a high-throughput assay named Chromatin Immunoprecipitation over Integrated Synthetic Oligonucleotides (ChIP-ISO) to systematically dissect the sequence features affecting the binding specificity of a classic PF, FOXA1, in A549 human lung carcinoma cells. This method involves integrating thousands of synthetic sequences containing FOXA1 motifs into a fixed genomic locus, followed by FOXA1 chromatin immunoprecipitation (ChIP) and amplicon sequencing. We find that 1) FOXA1 binding is affected by motif strength and co-binding TFs AP-1 and CEBPB, with AP-1 playing a major role in promoting FOXA1 binding, 2) FOXA1 binding in vivo and in vitro are poorly correlated, and FOXA1 and AP-1 show binding cooperativity in vitro, 3) FoxA1’s binding specificity is mostly determined by the local sequences, whereas chromatin context, including heterochromatin marks, only plays a minor role, and 4) AP-1 is at least partially responsible for differential binding of FOXA1 in different cell types. Finally, neural network analysis shows that AP-1 and CEBPB motifs are predictive of FOXA1 ChIP-seq peaks in A549, but not in some other cell types. In summary, combining ChIP-ISO with in vitro and in silico analyses, our study provides insights into the genetic rules underlying PF binding specificity and reveals a mechanism for its regulation during cell differentiation.
2023-11-09 | GSE247431 | GEO
Project description:Pioneer factors (PFs) are a subset of transcription factors (TFs) that can bind to nucleosomal DNA and invade closed chromatin. Despite that nucleosomes do not present a strong barrier to PF binding, PF can only bind to a small fraction of motifs in the genome. The underlying mechanism of such binding selectivity is not well understood. Here, we design a high-throughput assay named Chromatin Immunoprecipitation over Integrated Synthetic Oligonucleotides (ChIP-ISO) to systematically dissect the sequence features affecting the binding specificity of a classic PF, FOXA1, in A549 human lung carcinoma cells. This method involves integrating thousands of synthetic sequences containing FOXA1 motifs into a fixed genomic locus, followed by FOXA1 chromatin immunoprecipitation (ChIP) and amplicon sequencing. We find that 1) FOXA1 binding is affected by motif strength and co-binding TFs AP-1 and CEBPB, with AP-1 playing a major role in promoting FOXA1 binding, 2) FOXA1 binding in vivo and in vitro are poorly correlated, and FOXA1 and AP-1 show binding cooperativity in vitro, 3) FoxA1’s binding specificity is mostly determined by the local sequences, whereas chromatin context, including heterochromatin marks, only plays a minor role, and 4) AP-1 is at least partially responsible for differential binding of FOXA1 in different cell types. Finally, neural network analysis shows that AP-1 and CEBPB motifs are predictive of FOXA1 ChIP-seq peaks in A549, but not in some other cell types. In summary, combining ChIP-ISO with in vitro and in silico analyses, our study provides insights into the genetic rules underlying PF binding specificity and reveals a mechanism for its regulation during cell differentiation.
2023-11-09 | GSE247414 | GEO
Project description:Pioneer factors (PFs) are a subset of transcription factors (TFs) that can bind to nucleosomal DNA and invade closed chromatin. Despite that nucleosomes do not present a strong barrier to PF binding, PF can only bind to a small fraction of motifs in the genome. The underlying mechanism of such binding selectivity is not well understood. Here, we design a high-throughput assay named Chromatin Immunoprecipitation over Integrated Synthetic Oligonucleotides (ChIP-ISO) to systematically dissect the sequence features affecting the binding specificity of a classic PF, FOXA1, in A549 human lung carcinoma cells. This method involves integrating thousands of synthetic sequences containing FOXA1 motifs into a fixed genomic locus, followed by FOXA1 chromatin immunoprecipitation (ChIP) and amplicon sequencing. We find that 1) FOXA1 binding is affected by motif strength and co-binding TFs AP-1 and CEBPB, with AP-1 playing a major role in promoting FOXA1 binding, 2) FOXA1 binding in vivo and in vitro are poorly correlated, and FOXA1 and AP-1 show binding cooperativity in vitro, 3) FoxA1’s binding specificity is mostly determined by the local sequences, whereas chromatin context, including heterochromatin marks, only plays a minor role, and 4) AP-1 is at least partially responsible for differential binding of FOXA1 in different cell types. Finally, neural network analysis shows that AP-1 and CEBPB motifs are predictive of FOXA1 ChIP-seq peaks in A549, but not in some other cell types. In summary, combining ChIP-ISO with in vitro and in silico analyses, our study provides insights into the genetic rules underlying PF binding specificity and reveals a mechanism for its regulation during cell differentiation.
2023-11-09 | GSE247412 | GEO
Project description:Pioneer factors (PFs) are a subset of transcription factors (TFs) that can bind to nucleosomal DNA and invade closed chromatin. Despite that nucleosomes do not present a strong barrier to PF binding, PF can only bind to a small fraction of motifs in the genome. The underlying mechanism of such binding selectivity is not well understood. Here, we design a high-throughput assay named Chromatin Immunoprecipitation over Integrated Synthetic Oligonucleotides (ChIP-ISO) to systematically dissect the sequence features affecting the binding specificity of a classic PF, FOXA1, in A549 human lung carcinoma cells. This method involves integrating thousands of synthetic sequences containing FOXA1 motifs into a fixed genomic locus, followed by FOXA1 chromatin immunoprecipitation (ChIP) and amplicon sequencing. We find that 1) FOXA1 binding is affected by motif strength and co-binding TFs AP-1 and CEBPB, with AP-1 playing a major role in promoting FOXA1 binding, 2) FOXA1 binding in vivo and in vitro are poorly correlated, and FOXA1 and AP-1 show binding cooperativity in vitro, 3) FoxA1’s binding specificity is mostly determined by the local sequences, whereas chromatin context, including heterochromatin marks, only plays a minor role, and 4) AP-1 is at least partially responsible for differential binding of FOXA1 in different cell types. Finally, neural network analysis shows that AP-1 and CEBPB motifs are predictive of FOXA1 ChIP-seq peaks in A549, but not in some other cell types. In summary, combining ChIP-ISO with in vitro and in silico analyses, our study provides insights into the genetic rules underlying PF binding specificity and reveals a mechanism for its regulation during cell differentiation.
2023-11-09 | GSE247411 | GEO
Project description:The compaction of nucleosomal structures creates a barrier for DNA-binding transcription factors (TFs) to access their cognate cis-regulatory elements. Pioneer factors (PFs) such as FOXA1 are able to directly access these cis-targets within compact chromatin. However, how these PFs interplay with nucleosomes remains to be elucidated, and is critical for us to understand the underlying mechanism of gene regulation. Here, we have conducted a computational analysis on a strand-specific paired-end ChIP-exo (termed as ChIP-ePENS) data of FOXA1 in LNCaP cells by our novel algorithm ePEST. We find that FOXA1 chromatin binding occurs via four distinct border modes (or footprint boundary patterns), with a preferential footprint boundary patterns relative to FOXA1 motif orientation. In addition, from this analysis three fundamental nucleotide positions (oG, oS and oH) emerged as major determinants for blocking exo-digestion and forming these four distinct border modes. By integrating histone MNase-seq data, we found an astonishingly consistent, 'well-positioned' configuration occurs between FOXA1 motifs and dyads of nucleosomes genome-wide. We further performed ChIP-seq of eight chromatin remodelers and found an increased occupancy of these remodelers on FOXA1 motifs for all four border modes (or footprint boundary patterns), indicating the full occupancy of FOXA1 complex on the three blocking sites (oG, oS and oH) likely produces an active regulatory status with well-positioned phasing for protein binding events. Together, our results suggest a positional-nucleosome-oriented accessing model for PFs seeking target motifs, in which FOXA1 can examine each underlying DNA nucleotide and is able to sense all potential motifs regardless of whether they face inward or outward from histone octamers along the DNA helix axis.
| S-EPMC5027512 | biostudies-literature
Project description:A transcription factor functions differentially and/or identically in multiple cell types. However, the mechanism for cell-specific regulation of a transcription factor remains to be elucidated. We address how a single transcription factor, forkhead box protein A1 (FOXA1), forms cell-specific genomic signatures and differentially regulates gene expression in four human cancer cell lines (HepG2, LNCaP, MCF7, and T47D). FOXA1 is a pioneer transcription factor in organogenesis and cancer progression. Genomewide mapping of FOXA1 by chromatin immunoprecipitation sequencing annotates that target genes associated with FOXA1 binding are mostly common to these cancer cells. However, most of the functional FOXA1 target genes are specific to each cancer cell type. Further investigations using CRISPR-Cas9 genome editing technology indicate that cell-specific FOXA1 regulation is attributable to unique FOXA1 binding, genetic variations, and/or potential epigenetic regulation. Thus, FOXA1 controls the specificity of cancer cell types. We raise a "flower-blooming" hypothesis for cell-specific transcriptional regulation based on these observations.
| S-EPMC4803482 | biostudies-literature
Project description:Transcription factors (TFs) bind specifically to discrete regions of mammalian genomes called cis-regulatory elements. Among those are enhancers, which play key roles in regulation of gene expression during development and differentiation. Despite the recognized central regulatory role exerted by chromatin in control of TF functions, much remains to be learned regarding the chromatin structure of enhancers and how it is established. Here, we have analyzed on a genomic-scale enhancers that recruit FOXA1, a pioneer transcription factor that triggers transcriptional competency of these cis-regulatory sites. Importantly, we found that FOXA1 binds to genomic regions showing local DNA hypomethylation and that its cell-type-specific recruitment to chromatin is linked to differential DNA methylation levels of its binding sites. Using neural differentiation as a model, we showed that induction of FOXA1 expression and its subsequent recruitment to enhancers is associated with DNA demethylation. Concomitantly, histone H3 lysine 4 methylation is induced at these enhancers. These epigenetic changes may both stabilize FOXA1 binding and allow for subsequent recruitment of transcriptional regulatory effectors. Interestingly, when cloned into reporter constructs, FOXA1-dependent enhancers were able to recapitulate their cell type specificity. However, their activities were inhibited by DNA methylation. Hence, these enhancers are intrinsic cell-type-specific regulatory regions of which activities have to be potentiated by FOXA1 through induction of an epigenetic switch that includes notably DNA demethylation.
| S-EPMC3065703 | biostudies-literature
Project description:Prostate cancer is the most commonly diagnosed non-cutaneous cancers in North American men. While androgen deprivation has remained as the cornerstone of prostate cancer treatment, resistance ensues leading to lethal disease. Forkhead box A1 (FOXA1) encodes a pioneer factor that induces open chromatin conformation to allow the binding of other transcription factors. Through direct interactions with the Androgen Receptor (AR), FOXA1 helps to shape AR signaling that drives the growth and survival of normal prostate and prostate cancer cells. FOXA1 also possesses an AR-independent role of regulating epithelial-to-mesenchymal transition (EMT). In prostate cancer, mutations converge onto the coding sequence and cis-regulatory elements (CREs) of FOXA1, leading to functional alterations. In addition, FOXA1 activity in prostate cancer can be modulated post-translationally through various mechanisms such as LSD1-mediated protein demethylation. In this review, we describe the latest discoveries related to the function and regulation of FOXA1 in prostate cancer, pointing to their relevance to guide future clinical interventions.
| S-EPMC7815845 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2016-10-07 | GSE87712 | GEO
Project description:This SuperSeries is composed of the SubSeries listed below.
2019-01-31 | GSE111856 | GEO