A molecular mechanism for compartmentalization and silencing of chromatin domains at the nuclear lamina
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ABSTRACT: This SuperSeries is composed of the following subset Series: GSE35777: A molecular mechanism for compartmentalization and silencing of chromatin domains at the nuclear lamina [Tiling Array] GSE36048: A molecular mechanism for compartmentalization and silencing of chromatin domains at the nuclear lamina [ChIP-seq] Refer to individual Series
Project description:A large fraction of the mammalian genome is organized into inactive chromosomal domains associated with the nuclear lamina. Using genomic repositioning assays we show that Lamina associated domains (LADs), spanning the developmentally regulated IgH and Cyp3a loci, contain transportable DNA regions that associate chromatin with the nuclear lamina and repress gene activity in fibroblasts. We characterized DNA regions within LADs that are functionally capable of positioning chromatin domains at the inner nuclear membrane (INM) lamina. We mapped and characterized the IgH and other LADs in murine fibroblasts. We show that these murine LADs have a unique chromatin structure with discrete boundaries. We demonstrate DNA regions within LADs that are capable of directing the association of chromatin domains with the INM-lamina as well as the silencing of a co-integrated reporter gene.
Project description:Polycomb proteins are epigenetic regulators that localize to developmental loci in the early embryo where they mediate lineage-specific gene repression. In Drosophila, these repressors are recruited to sequence elements by DNA binding proteins associated with Polycomb repressive complex 2 (PRC2). However, the sequences that recruit PRC2 in mammalian cells have remained obscure. To address this, we integrated a series of engineered bacterial artificial chromosomes into embryonic stem (ES) cells and examined their chromatin. We found that a 44 kb region corresponding to the Zfpm2 locus initiates de novo recruitment of PRC2. We then pinpointed a CpG island within this locus as both necessary and sufficient for PRC2 recruitment. Based on this causal demonstration and prior genomic analyses, we hypothesized that large GC-rich elements depleted of activating transcription factor motifs mediate PRC2 recruitment in mammals. We validated this model in two ways. First, we showed that a constitutively active CpG island is able to recruit PRC2 after excision of a cluster of activating motifs. Second, we showed that two 1 kb sequence intervals from the E. coli genome with GC-contents comparable to a mammalian CpG island are both capable of recruiting PRC2 when integrated into the ES cell genome. Our findings demonstrate a causal role for GC-rich sequences in PRC2 recruitment and implicate a specific subset of CpG islands depleted of activating motifs as instrumental for the initial localization of this key regulator in mammalian genomes. Analysis of YY1 binding in two cell types
Project description:Hundreds of Chromatin Regulators (CRs) control chromatin structure and function by catalyzing and binding histone modifications, yet the rules governing these key processes remain obscure. Here, we present a systematic approach to infer CR function. We developed ChIP-string, a meso-scale assay that combines chromatin immunoprecipitation with a signature readout of 487 representative loci. We applied ChIP-string to screen 145 antibodies, thereby identifying effective reagents, which we used to map the genome-wide binding of 29 CRs in two cell types. We found that specific combinations of CRs co-localize in characteristic patterns at distinct chromatin environments, genes of coherent functions and distal regulatory elements. When comparing between cell types, CRs redistribute to different loci, but maintain their modular and combinatorial associations. Our work provides a multiplex method that substantially enhances the ability to monitor CR binding, presents a large resource of CR maps, and reveals common principles for combinatorial CR function. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf Study of genom-wide binding of 29 CRs in two cell types.
Project description:modENCODE_submission_4351 This submission comes from a modENCODE project of David MacAlpine. For full list of modENCODE projects, see http://www.genome.gov/26524648 Project Goal: We will precisely identify sequence elements that direct DNA replication by using chromatin immunoprecipitation of known replication initiation complexes. These experiments will be conducted in multiple cell types and developmental tissues. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf EXPERIMENT TYPE: CHIP-seq. BIOLOGICAL SOURCE: Cell Line: CME-W1-Cl.8+; Tissue: dorsal mesothoracic disc; Developmental Stage: third instar larval stage; Sex: Male; EXPERIMENTAL FACTORS: Strain ; Antibody dORC2 (target is Drosophila ORC2p); read length (read_length)
Project description:modENCODE_submission_2753 This submission comes from a modENCODE project of David MacAlpine. For full list of modENCODE projects, see http://www.genome.gov/26524648 Project Goal: We will precisely identify sequence elements that direct DNA replication by using chromatin immunoprecipitation of known replication initiation complexes. These experiments will be conducted in multiple cell types and developmental tissues. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf Keywords: CHIP-seq EXPERIMENT TYPE: CHIP-seq. BIOLOGICAL SOURCE: Cell Line: S2-DRSC; Tissue: embryo-derived cell-line; Developmental Stage: late embryonic stage; Sex: Male; EXPERIMENTAL FACTORS: Antibody dORC2
Project description:modENCODE_submission_2754 This submission comes from a modENCODE project of David MacAlpine. For full list of modENCODE projects, see http://www.genome.gov/26524648 Project Goal: We will precisely identify sequence elements that direct DNA replication by using chromatin immunoprecipitation of known replication initiation complexes. These experiments will be conducted in multiple cell types and developmental tissues. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf Keywords: CHIP-seq EXPERIMENT TYPE: CHIP-seq. BIOLOGICAL SOURCE: Cell Line: ML-DmBG3-c2; Tissue: CNS-derived cell-line; Developmental Stage: third instar larval stage; Genotype: y v f mal; Sex: Unknown; EXPERIMENTAL FACTORS: Antibody dORC2
Project description:modENCODE_submission_2755 This submission comes from a modENCODE project of David MacAlpine. For full list of modENCODE projects, see http://www.genome.gov/26524648 Project Goal: We will precisely identify sequence elements that direct DNA replication by using chromatin immunoprecipitation of known replication initiation complexes. These experiments will be conducted in multiple cell types and developmental tissues. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf Keywords: CHIP-seq EXPERIMENT TYPE: CHIP-seq. BIOLOGICAL SOURCE: Cell Line: Kc167; Tissue: embryo-derived cell-line; Developmental Stage: late embryonic stage; Genotype: se/e; Sex: Female; EXPERIMENTAL FACTORS: Antibody dORC2
Project description:modENCODE_submission_2783 This submission comes from a modENCODE project of David MacAlpine. For full list of modENCODE projects, see http://www.genome.gov/26524648 Project Goal: We will precisely identify sequence elements that direct DNA replication by using chromatin immunoprecipitation of known replication initiation complexes. These experiments will be conducted in multiple cell types and developmental tissues. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf Keywords: CHIP-seq EXPERIMENT TYPE: CHIP-seq. BIOLOGICAL SOURCE: Cell Line: Kc167; Tissue: embryo-derived cell-line; Developmental Stage: late embryonic stage; Genotype: se/e; Sex: Female; EXPERIMENTAL FACTORS: Antibody Pan MCM2-7 Antibody
Project description:Purpose: We performed RNA-Immunoprecipitation in Tandem (RIPiT) experiments against human Staufen1 (Stau1) to identify its precise RNA binding sites in a transcriptome-wide manner. To monitor the consequences of Stau1 binding in terms of target mRNA levels and ribosome occupancy, we modified the levels of endogenous Stau1 in cells by siRNA or overexpression and performed RNA-sequencing and ribosome-footprinting experiments. Staufen1 (Stau1) is a double-stranded RNA (dsRNA) binding protein implicated in mRNA transport, regulation of translation, mRNA decay and stress granule homeostasis. Here we combined RNA-Immunoprecipitation in Tandem (RIPiT) with RNase footprinting, formaldehyde crosslinking, sonication-mediated RNA fragmentation and deep sequencing to map Staufen1 binding sites transcriptome-wide. We find that Stau1 binds complex secondary structures containing multiple short helices, many of which are formed by inverted Alu elements in annotated 3'UTRs or in "strongly distal" 3'UTRs extending far beyond the canonical polyadenylation signal. Stau1 also interacts with both actively translating ribosomes and with mRNA coding sequences (CDS) and 3'UTRs in proportion to their GC-content and internal secondary structure-forming propensity. On mRNAs with high CDS GC-content, higher Stau1 levels lead to greater ribosome densities, suggesting a general role for Stau1 in modulating the ability of ribosomes to elongate through secondary structures located in CDS regions. We used HEK293 cells expressing near endogenous levels of wild-type Flag-Stau1 (65KDa isoform with an N-Terminal Flag tag). As a control we used a mutant version of Stau1 that is not functional for dsRNA binding. Formaldehyde crosslinking experiments and RNase footprinting experiments were done in two biological replicates. All RNASeq, Ribosome footprinting and PAS-Seq were done in two biological replicates.
Project description:modENCODE_submission_4192 This submission comes from a modENCODE project of David MacAlpine. For full list of modENCODE projects, see http://www.genome.gov/26524648 Project Goal: We will precisely identify sequence elements that direct DNA replication by using chromatin immunoprecipitation of known replication initiation complexes. These experiments will be conducted in multiple cell types and developmental tissues. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf EXPERIMENT TYPE: CHIP-seq. BIOLOGICAL SOURCE: Strain: Oregon-R(official name : Oregon-R-modENCODE genotype : wild type ); Developmental Stage: Embryo 4-7h; Genotype: wild type; EXPERIMENTAL FACTORS: Strain Oregon-R(official name : Oregon-R-modENCODE genotype : wild type ); read length (read_length) ; Antibody dORC2 (target is Drosophila ORC2p); Developmental Stage Embryo 4-7h