Ontology highlight
ABSTRACT:
PROVIDER: PRJNA892950 | ENA |
REPOSITORIES: ENA
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Project description:The nucleosome is a fundamental unit of chromatin in eukaryotes, and generally prevents the binding of transcription factors to genomic DNA. Pioneer transcription factors overcome the nucleosome barrier, and bind their target DNA sequences in chromatin. OCT4 is a representative pioneer transcription factor that plays a role in stem cell pluripotency. In the present study, we biochemically analyzed the nucleosome binding by OCT4. Crosslinking mass spectrometry showed that OCT4 binds the nucleosome.
2020-05-13 | PXD019160 | JPOST Repository
Project description:Previous unbiased screening for the nucleosome binding affinity of transcription factors predicts that POU domain transcription factors have strong nucleosome binding potential. Here using reprogramming strategy we found that POU4F3 has pioneer factor activity at ATOH1 target elements that require POU4F3 for their accessibility.
2021-07-09 | GSE150279 | GEO
Project description:Though the in vitro structural and in vivo spatial characteristics of transcription factor (TF) binding are well defined, TF interactions with chromatin and other companion TFs during development are poorly understood. To analyze such interactions in vivo, we profiled several TFs across a time course of human embryonic stem cell differentiation via CUT&RUN epigenome profiling, and studied their interactions with nucleosomes and co-occurring TFs by Enhanced Chromatin Occupancy (EChO), a computational strategy for classifying TF binding characteristics across time and space. EChO shows that at different enhancer targets, the same TF can employ either direct DNA binding, or “pioneer” nucleosome binding to access them. Pioneer binding is correlated with local binding of other TFs and enhancer motif character, including degeneracy at key bases in the pioneer factor target motif. Our strategy reveals a dynamic exchange of TFs at enhancers across developmental time that is aided by pioneer nucleosome binding.
2019-06-25 | GSE128499 | GEO
Project description:BAF complex is one major group of chromatin remodeling factors in mammals. However, how BAF regulated nucleosomes and other histone modifications is not clear. Here we delete BAF250a, a major component in esBAF to study the nucleosome and histone changes in ESCs. We find that deletion of BAF250a leads to nucleosome occupancy increase in TSS regions and non-pioneer transcription factor binding sites. BAF250a deletion also cause overall decrease of H3K27me3 modification. Collectively, these results reveals how BAF complex coordinates nucleosome, histone modification to control ESC function. Sample 1-4: Nucleosome profiles in WT and BAF250a KO ESCs. Sample 5-10: profiling of H3K4me3 and H3K27me3 in WT and BAF250 KO ESCs.
2015-08-03 | E-GEOD-59082 | biostudies-arrayexpress
Project description:Purpose: The dynamic nucleosome reorganization is the interplay among nucleosome and regulated by pioneer factors, which can access target DNA sequences on nucleosomes.The goals of this study are revealing the dynamic nucleosome footprint and how GATA2 is capable of resetting crowding array to primed, or accessible edge nucleosome states. Methods: LNCaP cells between passage number 30-35 were used for assay. cell nucleus was extracted, digested by MNase to Mono-nucleosome and ChIP/ChIP-exo was performed, the ChIP products were further used to generate library with illumina ChIP-seq kit. Hi-seq 3000 was used for sequencing and the data was analyzed by MACS2 for peaks. Results: GATA2 is associated with condensed nucleosome states and nucleosomes could unwrapped and be more accessible in pioneer factor GATA2 binding sites. Conclusions: Our study represents the first detailed nucleosome footprint of LNCap cells and analysis of the relationship between pioneer factor GATA2 and nucleosome reorganization in whole genomic DNA. These results demonstrated GATA2 play a critical role in an AR-independent manner in prostate cancer.
2021-04-14 | GSE148935 | GEO
Project description:Pioneer factor-nucleosome binding events during differentiation are motif-encoded
| PRJNA527856 | ENA
Project description:Summary: Pioneer transcription factors engage nucleosomal DNA in chromatin to initiate gene regulatory events that control cell fate 1 . To determine how different pioneer transcription factors initiate the formation of a locally accessible environment within silent, compacted chromatin and collaborate with an ATP-dependent chromatin remodeler, we generated nucleosome arrays in vitro with a central nucleosome that can be targeted by the hematopoietic ETS factor PU.1 and bZIP factors C/EBPα, and C/EBPβ. Each class of factor can expose target nucleosomes on linker histone-compacted arrays, but with different hypersensitivity patterns, as discerned by long-read sequencing. The DNA binding domain of PU.1 is sufficient for mononucleosome binding but requires an additional intrinsically disordered domain to bind and open compacted chromatin. The canonical mammalian SWI/SNF (BAF) complex, cBAF, was unable to act upon two forms of locally open chromatin, in the presence of linker histone, unless cBAF was enabled by the acidic- and glutamine-enriched transactivation domain of PU.1. However, cBAF complexes potentiate the nucleosome binding DBD of PU.1 to weakly open chromatin in the absence of the PU.1 unstructured domain. Together our findings provide a mechanism for how pioneer factors initially target chromatin structures to provide specificity for action by nucleosome remodelers that further open local domains.
2022-11-03 | GSE216065 | GEO
Project description:Previous studies indicate that eukaryotic promoters display a stereotypical chromatin landscape characterized by a well-positioned +1 nucleosome near the transcription start site and an upstream -1 nucleosome that together demarcate a nucleosome-free (or depleted) region. Here we present evidence that there are two distinct types of promoters distinguished by the resistance of the -1 nucleosome to micrococcal nuclease digestion. These different architectures are characterized by two sequence motifs that are broadly deployed at one set of promoters where a nuclease-sensitive ("fragile") nucleosome forms, but concentrated in a more narrow, nucleosome-free region at all other promoters. The RSC nucleosome remodeler acts through the motifs to establish stable +1 and -1 nucleosome positions, while binding of a small set of general regulatory (pioneer) factors at fragile nucleosome promoters plays a key role in their destabilization. We propose that the fragile nucleosome promoter architecture is adapted for regulation of highly expressed, growth-related genes. MNase-seq profiles obtained with various MNase concentrations from wild-type cells and cells depleted of different factors. ChIP-seq using anti-RNA polymerase II antibody, anti-histone H2A antibody, and anti-histone H3 antibody.
2015-11-05 | E-GEOD-73337 | biostudies-arrayexpress
Project description:Nucleosome driven transcription factor binding and gene regulation [ChIP-Seq]
| PRJNA177082 | ENA
Project description:The aim of this study is to dissect the transcription factor OCT4 and reveal which parts of the protein are essential for interaction with nucleosomes and access to closed chromatin. We revealed that the DNA-binding domain mediates the interaction of OCT4 with nucleosomes. Remarkably, nucleosome-binding can be uncoupled from DNA-binding, diminishing the ability of OCT4 to access to closed chromatin, thus losing the pioneer function. We show that the pioneer function of OCT4 is not only essential during reprogramming differentiated cells to pluripotency but also during pluripotency maintenance of embryonic stem cells. Overall, this study shows how pioneer transcription factors interact with nucleosomes to engage the genome and control cellular identity, highlighting that nucleosomes are not always barriers to genome accessibility.
2021-06-24 | GSE168141 | GEO