ChIP-exonuclease (ChIP-exo) is a modified ChIP-seq approach for high resolution mapping of transcription factor DNA sites. We describe an Illumina-based ChIP-exo method which provides a global improvement of the data quality of estrogen receptor (ER) ChIP and insights into the motif structure for key ER-associated factors. ChIP-exo of the ER pioneer factor FoxA1 identifies protected DNA with a predictable 8 bp overhang from the Forkhead motif, which we term mesas. We show that mesas occur in mul ...[more]
Project description:Using a transcriptional network derived from 2000 breast cancer gene expression profiles we identify the master regulators (MRs) of FGFR2 signalling. To validate the identified regulons, we examined whether there was enrichment of TF binding near the transcription start sites (TSS) of genes found in the regulons of a particular MR. For ESR1 and SPDEF, ChIP-seq experiments were performed in MCF-7 cells, while existing data was analysed for FOXA1 (Hurtado et al. Nature Genetics, 43:27–33, 2010) and GATA3 (Theodorou, et al., Genome Res 23: 12-22, 2013). ChIP-seq experiments were performed on three biological replicates per each transcription factor. For each sample, 36bp single-end reads were obtained. Peak regions were identified in all ChIP-seq TF data sets using the peak caller algorithm MACS (Zhang et al., Genome Biology, 9(9):R137, 2008) with default parameters.
Project description:We performed a comparision of AR binding sites as well as the histone modifications H3K27 acetylation and H3K4 monomethylation in the presence and absence of FoxA1 in the molecular apocrine breast cancer cell line, MDA-MB-453. We also probed AP2alpha binding in asynchronous MDA-MB-453 cells.
Project description:We performed androgen receptor (AR) ChIP-seq after GFP control or FOXA1 over-expression in two AR driven cancer models; LNCaP prostate cancer cell line and MDA-MB-453 molecular apocrine breast cancer cell line.
Project description:The aim of this project is to locate the precise binding of the ONECUT1 transcription factor. NOTE: This study was updated on 7th May 2014. All samples, experiments, runs and files were replaced. This was due to an incorrect reagent being used in the earlier version.
Project description:Breast cancer (BC) is the most common cancer in women worldwide, and is classified in multiple subtypes, including the so called triple-negative BC (TNBC). This is characterized by lack of estrogen receptor alpha (ERα), progesterone receptor (PR) and epidermal growth factor receptor 2 (HER2/neu), that represent common targets for BC treatment. Their absence limits the number of therapies that may be applied for TNBC treatment, suggesting the need to identify novel therapeutic targets against this disease. Several studies reported that the beta ER subtype (ERβ) is expressed in a sizeable fraction of TNBCs where its presence correlates with improved patient outcome. We evaluated ERβ expression in TNBC tissues by immunohistochemistry using two validated antibodies, demonstrating presence of this protein in 28% of samples. To investigate, in this context, the role of this estrogen receptor in TNBC biology, ERβ-expressing cell lines, representing different TNBC subtypes, were generated. Cellular and functional assays confirmed the antiproliferative activity of ERβ in TNBCs. Interaction proteomics revealed in BC nuclei the presence of several protein complexes associated with this receptor involved in chromatin remodeling, miRNA maturation and mRNA transcription. Transcriptome analyses pointed out tumor subtype-specific signaling pathways deregulation. Interestingly, among these the cholesterol biosynthesis pathway was commonly downregulated in all cell lines tested. Global analyses of ERβ binding to the genome showed its recruitment to regulatory sites of Sterol Regulatory Element-Binding Protein 1 (SREBP1), indicating a direct regulation of this pathway by the receptor. These findings suggest that drugs targeting components of cholesterol biosynthesis pathway may be new potential therapeutic options for TNBC treatment.
Project description:To test the conservation and evolution of long non-coding RNAs across multiple rodent species by transcriptome sequencing and histone modification mapping. Part of experiment series: E-MTAB-867 RNA-Seq, E-MTAB-959 ChIP-Seq.
Project description:We explored the microevolutionary trends of CTCF binding evolution by preforming ChIP-seq experiments in five closely related Mus strains, subspecies and species: Mus musculus domesticus, Mus musculus castaneus, Mus spretus, Mus caroli and Mus pahari. All experiments were performed in adult male liver samples in 3 biological replicates and with an input control set. Complementary RNA-seq data from this same study have been deposited in ArrayExpress under accession numebr E-MTAB-5768 ( https://www.ebi.ac.uk/arrayexpress/experiments/E-MTAB-5768 ).
Project description:This project aims to study human repetitive elements on human chromosome 21 (HsChr21) in a heterologous mouse environment (Tc1 mouse). The in vivo, HsChr21-wide enrichment of active histone modified regions (H3K4me3) and transcription factor binding sites was profiled by ChIP-seq in Human and Tc1 mouse tissue in order to determine the unbiased regulation of the human genome.
Project description:Methods for identifying protein-protein interactions have mostly been limited to tagged exogenous expression approaches. We now establish a rapid, robust and comprehensive method for finding interacting proteins using endogenous proteins from limited cell numbers. We apply this approach called ‘Rapid IP-Mass Spectrometry of Endogenous proteins (RIME)’ to identify ER, FoxA1 and E2F4 interacting proteins in breast cancer cells. From small numbers of starting cells, we find a comprehensive collection of known ER, FoxA1 and E2F4 targets, plus a number of novel unexpected interactors. One of the most ER (and FoxA1) associated interactors is GREB1, an estrogen induced gene with almost no known function. We apply RIME, in parallel with ER ChIP-seq, to identify ER protein interactors and ER binding events from solid tumor xenografts, resulting in the validation of the ER-GREB1 interactions. Furthermore, we establish a method for identifying endogenous interacting proteins from solid primary breast cancer samples, whih we apply to validate ER interactions with GREB1 and additional co-factors. Mechanistically, we show that GREB1 is recruited with ER to the chromatin where it functions as an essential estrogen-mediated regulatory factor required for effective ER transcriptional activity. Our novel approach enables, for the first time, the ability for discovery and validation of protein-protein interactions in whole tissue and solid tumors, revealing significant insight into ER regulatory factors. Examination of ERGREB1 and E2F4 genomic binding patterns in cell line and xenograft tumour models
Project description:We explored the relationship between the evolutionary dynamics of CTCF binding and the functional stability of higher order genome structures, by performing ChIP-seq experiments in closely related Mus species or strains and intersecting with Hi-C-derived topologically associating domains (TADs) and expression data. Experiments were performed in adult male liver samples, using input control sets.