Project description:EZH1 is one of polycomb group genes which positively regulates transcription in the genome-wide scale. However, the underlying mechanisms still remain elusive. Here we report that EZH1 physically interacts with UXT, one small chaperon-like transcription co-activator of NF-κB. UXT specifically interacts with EZH1 and SUZ12, but not EED or EZH2. Similar to UXT, RNA interference of EZH1 and SUZ12 in the cell impairs the transcriptional activation of NF-κB target genes after TNFα treatment, and increases the induced cell death. Then RNA-Sequencing analysis was used to analysis the transcriptome in HCT116 cells after EZH1 or UXT knockdown. EZH1 or UXT deficiency nearly impaired the induced expression of all the genes by TNFα. ChIP-Sequencing was used to analysis the H3K27me1, H3K27me2 and H3K27me3 levels in HCT116 cells after EZH1 or UXT knockdown. However, the results show that H3K27 mono-, di- and trimethylation on NF-κB target genes are not affected with EZH1 or UXT deficiency. EZH1 does not affect the translocation of RELA/p65 from cytosol to nuclear either. Instead, EZH1 regulates the recruitment of RELA/p65 and RNA POLII to target genes. Taken together, our study demonstrates EZH1 as a positive regulator for NF-κB signaling and reveals the underlying mechanism how EZH1 and UXT work together in transcription regulation.
Project description:Polycomb Repressive Complex 2 (PRC2) plays crucial roles in transcriptional regulation and stem cell development. However, the context-specific functions associated with alternative subunits remain largely unexplored. Here we show that the related enzymatic subunits EZH1 and EZH2 undergo an expression switch during hematopoiesis. We examine the in vivo stoichiometry of the PRC2 complexes by quantitative proteomics and reveal the existence of an EZH1-SUZ12 sub-complex lacking EED. We provide evidence that EZH1 together with SUZ12 form a non-canonical PRC2 complex, occupy active chromatin domains in the absence of H3K27me3, and positively regulate gene expression. Loss of EZH2 expression leads to global repositioning of EZH1 chromatin occupancy to EZH2 targets. Moreover, we demonstrate that an erythroid-specific enhancer mediates transcriptional activation of EZH1, and a switch from GATA2 to GATA1 controls the developmental EZH1/2 switch by differential association with EZH1 enhancers during erythropoiesis. Thus, the lineage- and developmental stage-specific regulation of PRC2 expression and subunit composition leads to a switch from canonical silencing to non-canonical PRC2 functions during blood stem cell specification. Analysis of genomic occupancy of EZH1, EZH2, EED, SUZ12, various histone marks and transcription factors in primary human fetal liver proerythroblasts by ChIP-seq. Sample GSM970262 was used as the input DNA sample.
Project description:Polycomb Repressive Complex 2 (PRC2) plays crucial roles in transcriptional regulation and stem cell development. However, the context-specific functions associated with alternative subunits remain largely unexplored. Here we show that the related enzymatic subunits EZH1 and EZH2 undergo an expression switch during hematopoiesis. We examine the in vivo stoichiometry of the PRC2 complexes by quantitative proteomics and reveal the existence of an EZH1-SUZ12 sub-complex lacking EED. We provide evidence that EZH1 together with SUZ12 form a non-canonical PRC2 complex, occupy active chromatin domains in the absence of H3K27me3, and positively regulate gene expression. Loss of EZH2 expression leads to global repositioning of EZH1 chromatin occupancy to EZH2 targets. Moreover, we demonstrate that an erythroid-specific enhancer mediates transcriptional activation of EZH1, and a switch from GATA2 to GATA1 controls the developmental EZH1/2 switch by differential association with EZH1 enhancers during erythropoiesis. Thus, the lineage- and developmental stage-specific regulation of PRC2 expression and subunit composition leads to a switch from canonical silencing to non-canonical PRC2 functions during blood stem cell specification. Transcriptional profiling in primary human fetal liver proerythroblasts upon lentiviral shRNA-mediated knockdown of EZH1, EZH2, EED, or SUZ12 by RNA-seq analysis.
Project description:Pseudogenes are thought to be inactive gene sequences, but recent evidence of extensive pseudogene transcription raised the question of potential function. Here we discover and characterize the sets of lncRNAs induced by inflammatory signaling via TNFα. TNFα regulates hundreds of lncRNAs, including 54 pseudogene lncRNAs, several of which show exquisitely selective expression in response to specific cytokines and microbial components in a NF-κB-dependent manner. Lethe, a pseudogene lncRNA, is selectively induced by proinflammatory cytokines via NF-κB or glucocorticoid receptor agonist, and functions in negative feedback signaling to NF-κB. Lethe interacts with NF-κB subunit RelA to inhibit RelA DNA binding and target gene activation. Lethe level decreases with organismal age, a physiological state associated with increased NF-κB activity. These findings suggest that expression of pseudogenes lncRNAs are actively regulated and constitute functional regulators of inflammatory signaling. RNA profiles of wild type (WT) MEFs treated with TNF-alpha were generated by deep sequencing using Illumina GAIIx. Examination of H3K4me3 histome modification in MEF.
Project description:Polycomb Repressive Complex 2 (PRC2) plays crucial roles in transcriptional regulation and stem cell development. However, the context-specific functions associated with alternative subunits remain largely unexplored. Here we show that the related enzymatic subunits EZH1 and EZH2 undergo an expression switch during hematopoiesis. We examine the in vivo stoichiometry of the PRC2 complexes by quantitative proteomics and reveal the existence of an EZH1-SUZ12 sub-complex lacking EED. We provide evidence that EZH1 together with SUZ12 form a non-canonical PRC2 complex, occupy active chromatin domains in the absence of H3K27me3, and positively regulate gene expression. Loss of EZH2 expression leads to global repositioning of EZH1 chromatin occupancy to EZH2 targets. Moreover, we demonstrate that an erythroid-specific enhancer mediates transcriptional activation of EZH1, and a switch from GATA2 to GATA1 controls the developmental EZH1/2 switch by differential association with EZH1 enhancers during erythropoiesis. Thus, the lineage- and developmental stage-specific regulation of PRC2 expression and subunit composition leads to a switch from canonical silencing to non-canonical PRC2 functions during blood stem cell specification.
Project description:Polycomb Repressive Complex 2 (PRC2) plays crucial roles in transcriptional regulation and stem cell development. However, the context-specific functions associated with alternative subunits remain largely unexplored. Here we show that the related enzymatic subunits EZH1 and EZH2 undergo an expression switch during hematopoiesis. We examine the in vivo stoichiometry of the PRC2 complexes by quantitative proteomics and reveal the existence of an EZH1-SUZ12 sub-complex lacking EED. We provide evidence that EZH1 together with SUZ12 form a non-canonical PRC2 complex, occupy active chromatin domains in the absence of H3K27me3, and positively regulate gene expression. Loss of EZH2 expression leads to global repositioning of EZH1 chromatin occupancy to EZH2 targets. Moreover, we demonstrate that an erythroid-specific enhancer mediates transcriptional activation of EZH1, and a switch from GATA2 to GATA1 controls the developmental EZH1/2 switch by differential association with EZH1 enhancers during erythropoiesis. Thus, the lineage- and developmental stage-specific regulation of PRC2 expression and subunit composition leads to a switch from canonical silencing to non-canonical PRC2 functions during blood stem cell specification.
Project description:By binding to specific DNA elements, known collectively as “κB sites”, contained within the promoters/enhancers of target genes, NF-κB regulates gene expression. We found that the identity of the central base pair (bp) of κB sites profoundly impacts the transcriptional activity of NF-κB dimers. RelA dimers prefer an A/T bp at this position for optimum transcriptional activation (A/T-centric) and discriminate against G/C-centric κB sites. The p52 homodimer, in contrast, activates transcription from G/C-centric κB sites in complex with Bcl3 but represses transcription from the A/T-centric sites. The p52:Bcl3 complex binds to these two classes of κB sites in distinct modes permitting recruitment of coactivator, corepressor, or both coactivator and corepressor complexes in promoters containing G/C, A/T or both G/C and A/T-centric sites. Therefore, through sensing of bp differences within κB sites, NF-κB dimers modulate biological programs by activating, repressing and altering expression of effector genes. Total RNA extracted from bone marrow derived macrophages (BMDMs) with Bcl3 siRNA knockdown or mouse scramble siRNA knockdown were subjected to LPS stimulation.
Project description:Pseudogenes are thought to be inactive gene sequences, but recent evidence of extensive pseudogene transcription raised the question of potential function. Here we discover and characterize the sets of lncRNAs induced by inflammatory signaling via TNFα. TNFα regulates hundreds of lncRNAs, including 54 pseudogene lncRNAs, several of which show exquisitely selective expression in response to specific cytokines and microbial components in a NF-κB-dependent manner. Lethe, a pseudogene lncRNA, is selectively induced by proinflammatory cytokines via NF-κB or glucocorticoid receptor agonist, and functions in negative feedback signaling to NF-κB. Lethe interacts with NF-κB subunit RelA to inhibit RelA DNA binding and target gene activation. Lethe level decreases with organismal age, a physiological state associated with increased NF-κB activity. These findings suggest that expression of pseudogenes lncRNAs are actively regulated and constitute functional regulators of inflammatory signaling.
Project description:NF-κB has an essential role in innate immune response and inflammation and is involved in cancer development and progression. We apply the SEC-PCP-SILAC method incorporating metabolic labeling, size exclusion chromatography and protein correlation profiling to construct a complex network of interactome rearrangement in response to NF-κB modulation in breast cancer cells. Our interaction network represents a complex insight into the dynamics of MCF-7 protein interactome associated with NF-κB pathway. Our dataset could serve as a basis for future studies characterizing role of NF-κB in breast cancer cellular pathways. This PRIDE project includes results from SILAC labeled and label-free replicates from the SEC-PCP-SILAC analysis of protein complexes in MCF-7 cells with inhibited and uninhibited NF-κB pathway, results from the immunoprecipitation experiment aimed at interaction partners of NF-κB factor RELA, analysis of total proteome after NF-κB inhibition, and results from SEC fractionation of untreated and unlabeled MCF-7 cells.
Project description:Using RNA-seq we characterized gene expression changes occuring upon knockout of EZH2, EZH1, EZH1+EZH2 or SUZ12 in a neurofibroma cell line. We also investigated the transcriptional consequences of EZH1+EZH2 double knockout in a SUZ12-mutant MPNST cell line.