Similar Datasets
Project description:Binding sites and the core motif of CmNOR.
| PRJNA787564 | ENA
Project description:Recent genome-scale ChIP-chip studies of transcription factors have shown that a low percentage of experimentally determined binding sites contain the consensus motif for the immunoprecipitated factor. In most cases, differences between in vivo target sites that contain or lack a consensus motif have not been explored. We have previously shown that most sites to which E2F family members are bound in vivo do not contain E2F consensus motifs. The main purpose of this study was to develop an understanding of how E2F binding specificity is achieved in vivo. In particular, we have addressed how E2F family members are recruited to core promoter regions that lack a consensus motif and are excluded from other regions that contain a consensus motif. Using promoter and ENCODE arrays, we have shown that the predominant factors specifying whether E2F is recruited to an in vivo binding site are a) the site must be in a core promoter and b) the promoter region must be utilized as a promoter by the transcriptional machinery in that particular cell type. We have tested three models for recruitment of E2F to core promoters lacking a consensus site, including a) indirect recruitment, b) looping to the core promoter mediated by an E2F bound to a distal consensus motif, and c) assisted binding of E2F to a site that weakly resembles an E2F consensus motif within the core promoter. To test these models, we developed a new in vivo assay, termed eChIP, which allows analysis of transcription factor binding to isolated promoter fragments. Our findings suggest that in vivo a) the presence of a consensus motif is not sufficient to recruit E2Fs, b) E2Fs can bind to isolated regions that lack a consensus motif, and c) binding can require regions other than the best match to the E2F PWM in the core promoter. Keywords: E2F, ChIP-chip, transcription factor binding, consensus motifs 37 ChIP-chip arrays (of these, 14 array sets are biological duplicates). 22 samples are included in this series, the rest can be found in supplementary info to the following papers: Xu 2007, Jin 2006, Komashko 2008
2008-10-01 | E-GEOD-12126 | biostudies-arrayexpress
Project description:Recent genome-scale ChIP-chip studies of transcription factors have shown that a low percentage of experimentally determined binding sites contain the consensus motif for the immunoprecipitated factor. In most cases, differences between in vivo target sites that contain or lack a consensus motif have not been explored. We have previously shown that most sites to which E2F family members are bound in vivo do not contain E2F consensus motifs. The main purpose of this study was to develop an understanding of how E2F binding specificity is achieved in vivo. In particular, we have addressed how E2F family members are recruited to core promoter regions that lack a consensus motif and are excluded from other regions that contain a consensus motif. Using promoter and ENCODE arrays, we have shown that the predominant factors specifying whether E2F is recruited to an in vivo binding site are a) the site must be in a core promoter and b) the promoter region must be utilized as a promoter by the transcriptional machinery in that particular cell type. We have tested three models for recruitment of E2F to core promoters lacking a consensus site, including a) indirect recruitment, b) looping to the core promoter mediated by an E2F bound to a distal consensus motif, and c) assisted binding of E2F to a site that weakly resembles an E2F consensus motif within the core promoter. To test these models, we developed a new in vivo assay, termed eChIP, which allows analysis of transcription factor binding to isolated promoter fragments. Our findings suggest that in vivo a) the presence of a consensus motif is not sufficient to recruit E2Fs, b) E2Fs can bind to isolated regions that lack a consensus motif, and c) binding can require regions other than the best match to the E2F PWM in the core promoter. Keywords: E2F, ChIP-chip, transcription factor binding, consensus motifs
2008-10-01 | GSE12126 | GEO
Project description:A distinct motif for numerous CTCF binding sites in the murine IgH locus
| PRJNA510845 | ENA
Project description:Variations in noncoding regulatory sequences play a central role in evolution but interpreting such variations remains difficult even in the context of defined attributes such as transcription factor (TF) binding sites. Here, we systematically link variations in cis-regulatory sequences to TF binding by profiling the allele-specific binding of 27 TFs expressed in a yeast hybrid, which contains two related genomes within the same nucleus. TFs localize preferentially to sites containing their known binding motifs, but occupy only a small fraction of the potential motif-coding genomic sites. Differential binding of TFs to the two orthologues is well explained by sequence variations that alter the consensus core motif, while changes in chromatin accessibility were of little apparent effect. Motif variations that abolish binding when present in one allele show only moderately reduced binding when common to both alleles, suggesting evolutionary compensation. At the promoter level, we report cases of turnover, where binding in the two orthologues localized to different promoter regions, yet most interspecies differences resulted from higher number of binding sites in one of the alleles. Our results suggest that cis variations affecting TF binding occur primarily through the gain and loss of cis-regulatory motifs at accessible regions.
2022-04-29 | GSE196451 | GEO
Project description:Most cancer associated CTCF mutations are involved in the recognition of CTCF core binding motif. Interestingly, mutations of the currently uncharacterized ZF1 of CTCF are practically exclusive to breast cancer, where they are associated with increased metastatic ability and therapeutic resistance. Although unnecessary to bind the core-binding motif, it is still unknown if the ZF1 of CTCF promotes binding to an altered CTCF motif. Further, classical motif analysis tools are powerless to identify minute changes in core binding motif. Therefore, the biological and epigenetic mechanism of action of CTCF ZF1 mutations is still unexplored. In order to explain the impact of CTCF ZF1M in breast models, we developed a new tool, diffMotif, that allows the identification, at the single base-pair resolution, of extension or alteration of core binding motif. Using diffMotif, we identified an extension of CTCF core binding motif, necessitating a functional ZF1 to bind appropriately. Using a combination of ChIP-Seq and RNA-Seq, we discover that the inability to bind the extended motif led to altered gene expression driving increased invasive ability and drug metabolism, mimicking the harmful oncogenic phenotypes observed clinically. Our study demonstrates the oncologic relevance of the characterisation of mutation induced altered DNA binding ability, by diffMotif.
2022-06-28 | GSE190114 | GEO
Project description:Most cancer associated CTCF mutations are involved in the recognition of CTCF core binding motif. Interestingly, mutations of the currently uncharacterized ZF1 of CTCF are practically exclusive to breast cancer, where they are associated with increased metastatic ability and therapeutic resistance. Although unnecessary to bind the core-binding motif, it is still unknown if the ZF1 of CTCF promotes binding to an altered CTCF motif. Further, classical motif analysis tools are powerless to identify minute changes in core binding motif. Therefore, the biological and epigenetic mechanism of action of CTCF ZF1 mutations is still unexplored. In order to explain the impact of CTCF ZF1M in breast models, we developed a new tool, diffMotif, that allows the identification, at the single base-pair resolution, of extension or alteration of core binding motif. Using diffMotif, we identified an extension of CTCF core binding motif, necessitating a functional ZF1 to bind appropriately. Using a combination of ChIP-Seq and RNA-Seq, we discover that the inability to bind the extended motif led to altered gene expression driving increased invasive ability and drug metabolism, mimicking the harmful oncogenic phenotypes observed clinically. Our study demonstrates the oncologic relevance of the characterisation of mutation induced altered DNA binding ability, by diffMotif.
2022-06-28 | GSE190098 | GEO
Project description:Adaptation to hypoxia is mediated through a coordinated transcriptional response driven largely by Hypoxia-Inducible Factor 1 (HIF-1). The direct transcriptional targets of HIF-1 play important roles in facilitating both short-term and long-term adaptation to hypoxia. Alignment of the sequences encompassing all well-characterized HIF-1 binding sites has revealed a consensus core HRE motif of 5'-RCGTG-3' (R = A or G). Since the consensus HIF-1 binding motif is too promiscuous to accurately predict binding a priori, we used ChIP-chip to define HIF-1 chromatin binding on a genome-wide level. We integrated these results with gene expression profiling to interrogate mechanisms regulating hypoxia-induced gene expression, and to more comprehensively identify direct targets of HIF-1 transactivation.
2009-06-02 | GSE16347 | GEO
Project description:Ybx1 binding sites and Ybx1-binding m5C sites in zebrafish embryo sample.
| PRJNA493828 | ENA
Project description:Motif-enrichment analysis identified binding sites for XBP1s in Neo-2/15 stimulated BBζ NK cells following co-cultured with AsPC-1 cells, as determined using CUT&TAG-seq, were mainly at the gene encoding nuclear respiratory factor 1 (NRF1)
2023-12-31 | GSE243385 | GEO