Project description:Analysis of STAT1 and IRF1 binding in IFNg treated and untreated HeLa cells for 6 hours was done using 50mer oligonucleotide probes at 30bp intervals tiling over non-repetitive 16MB gene locus (HG17).
Project description:Analysis of H3ac, H4ac, STAT1 and IRF1 binding in IFNg treated and untreated HeLa cells for 6 hours was done using 50mer oligonucletide probes at 30bp intervals tiling over non-repetitive 122kb CIITA locus(HG17) Keywords: ChIP-chip
Project description:Analysis of H3ac, H4ac, STAT1 and IRF1 binding in IFNg treated and untreated HeLa cells for 6 hours was done using 50mer oligonucletide probes at 30bp intervals tiling over non-repetitive 16MB gene locus(HG17) Keywords: ChIP-chip
Project description:Analysis of H3ac, H4ac, STAT1 and IRF1 binding in IFNg treated and untreated HeLa cells for 6 hours was done using 50mer oligonucletide probes at 30bp intervals tiling over non-repetitive 16MB gene locus(HG17) Keywords: ChIP-chip three replicates for each marker at each state.
Project description:STAT1 ChIP-chip performed on Human Hela S3 Cells for three different platforms. Nimblegen ENCODE arrays which comprise 50mer oligonucleotides spaces every 38bps (overlapping by 12nts) (5 biological replicates), custom maskless array tiling most of ENCODE with 50mer oligonucleotides end-to-end (3 biological replicates) and custom maskless array tiling most of ENCODE with 36mer oligonucleotides end-to-end (2 biological replicates). The chromatin-immunoprecipitation protocol is the same for all samples, however the labelling and hybridization protocols differ between Nimblegen and custom maskless arrays. Keywords = Transcription Factor Binding, STAT1, ChIP-chip, Human, Genome Tiling Arrays Keywords: other
Project description:STAT1 is the major transcription factor (TF) driving response to exposure to IFNg. C-JUN is a TF which has been shown to bind with STAT1 and act as a partner TF. We have expression profiled WT and CJUN-/- MEFs in order to determine the set of IFNg genes regulated by STAT1 and C-JUN. This study was designed primarily to test the accuracy of in silico cis-regulatory module prediction algorithm called SCRM. The set of genes differentially expressed after IFNg are likely to be targets of the TF STAT1. A subset of these genes will also be targeted by partner TFs of STAT1 (e.g. C-JUN). By measuring the expression of the WT IFNg responsive genes in a C-JUN-/- model, the subset of genes that are regulated by C-JUN can be ascertained. This set of genes can then be compared against those predicted to be regulated by C-JUN using the in silico approach SCRM, and therefore the accuracy of the in silico predictions can be determined. Cells were treated with both IFNg and cycloheximide (CHX) to determine direct target genes of the TF STAT1. CHX was added to reduce the downstream response of IFNg treatment (via inhibition of protein synthesis) , resulting in a high quality list of genes directly targeted by STAT1. CHX treatment also allowed for a longer (3hr rather than 1hr) IFNg treatment time, resulting in a more robust IFNg gene signature. Microarrays were analysed using the aroma package in R and the differentially expressed genes were determined through analysis using the limma package. Genes were ranked based on the FDR adjusted p-value calculated using a t-test between IFNg + CHX treated cells and untreated cells (in both WT and C-JUN-/- MEFs). Significantly upregulated genes (P<0.05) were considered direct targets of STAT1.
Project description:DUX4 activates the first wave of zygotic gene expression in the early embryo. Mis-expression of DUX4 in skeletal muscle causes facioscapulohumeral dystrophy (FSHD), whereas expression in cancers suppresses IFNg-induction of MHC Class I and contributes to immune evasion. We show that the DUX4 protein broadly suppresses immune signaling pathways—including IFNg, IFNb, DDX58, IFIH1 and cGAS mediated pathways. A conserved region containing (L)LxxL(L) motifs in the DUX4 carboxyterminal domain (CTD) was necessary to suppress interferon stimulated genes (ISGs). Co-immunoprecipitation identified DUX4-CTD interaction with multiple immune signaling factors, including STAT1. The DUX4-CTD (L)LxxL(L) region interacts with phosphorylated STAT1, sequesters it in the nucleus, modestly reduces its DNA binding, and prevents STAT1 from inducing ISG transcription. Mouse Dux similarly interacted with STAT1 and suppressed IFNg induction of ISGs. These findings identify an evolved role of the DUXC family in modulating immune signaling pathways with implications for development, cancers, and FSHD.
Project description:Interferon gamma (IFNg) is a pivotal cytokine that activates macrophages and shapes their response to subsequent inflammatory stimuli. Here, we investigated the distinct roles of STAT1 isoforms, STAT1alpha and STAT1beta, in IFNg-induced epigenetic remodelling and subsequent responses to lipopolysaccharide (LPS) in primary macrophages. We show that the STAT1 C-terminal TAD, which is missing in the STAT1beta isoform, is required for both H3K27 acetylation and deacetylation in response to IFNg. Notably, H3K27 deacetylation was associated with AP-1 motifs rather than STAT1 binding, suggesting indirect regulatory mechanisms. Functionally, IFNg pretreatment suppressed the induction of anti-inflammatory and virus response genes, including a subset of IFN-stimulated genes (ISGs), in response to LPS, while enhancing the expression of a distinct set of ISGs. Mechanistically, the STAT1 C-terminal TAD was critical for IFNg-mediated inhibition of LPS-induced enhancer activation at key regulatory genes, such as Il10 and Irak3, which are involved in negative feedback of toll-like receptor (TLR) signalling. Conversely, cooperative gene activation by IFNg and LPS was largely independent of the STAT1 C-terminal TAD, with notable exceptions, such as Ido1 and Tgtp1. Genome-wide analysis indicated that IRF1 and IRF8, rather than STAT1 homodimers, predominantly mediate in IFNg-induced H3K27 acetylation and transcription factor network analysis identified additional regulators integrating IFNg and LPS responses. Together, these findings reveal gene- and isoform-specific roles of STAT1 in coordinating IFNg-dependent chromatin remodelling and transcriptional cross-regulation, providing new insights into the control of inflammation and innate immunity.