Project description:Binding profiles for H3 and H4ac were determined as cells transition from log growth to quiescence. We found that massive chromatin changes that reflect global transcriptional repression occur after the diauxic shift in an Rpd3-dependent manner. Binding of Rpd3 is dramatically expanded to reflect binding at thousands of genes after quiescence entry, demonstrating an Rpd3-driven mechanism to change chromatin and repress transcription after entry into quiescence.
Project description:The S. cerevisiae Rpd3 large (Rpd3L) and small (Rpd3S) histone deacetylase (HDAC) complexes are prototypes for understanding transcriptional repression in eukaryotes [1]. The current view is that they function by deacetylating chromatin, thereby limiting accessibility of transcriptional factors to the underlying DNA. However, an Rpd3 catalytic mutant retains substantial repression capability when targeted to a promoter as a LexA fusion protein [2]. We investigated the HDAC-independent properties of the Rpd3 complexes biochemically and discovered a chaperone function, which promotes histone deposition onto DNA, and a novel activity, which prevents nucleosome eviction but not remodeling mediated by the ATP-dependent RSC complex. These HDAC-independent activities inhibit Pol II transcription on a nucleosomal template. The functions of the endogenous Rpd3 complexes can be recapitulated with recombinant Rpd3 core complex comprising Sin3, Rpd3, and Ume1. To test the hypothesis that Rpd3 contributes to chromatin stabilization in vivo, we measured histone H3 density genomewide and found that it was reduced at promoters in an Rpd3 deletion mutant but partially restored in a catalytic mutant. Importantly, the effects on H3 density are most apparent on RSC-enriched genes [3]. Our data suggest that the Rpd3 core complex could contribute to repression via a novel nucleosome stabilization function.
Project description:Strand-specific RNA sequencing was performed on wild type yeast in log phase, after diauxic shift, and after entry into quiescence with incorporation of external ERCC RNA spike-in controls to account for global changes in RNA abundance. We find that RNA profiles undergo at least two transitions: 1) From log-to-diauxic shift where stress response genes are induced and translational machinery is massively repressed. 2) From diauxic shift-to-quiescence, where global transcript abundance is repressed 15-fold. The transition from diauxic shift to quiescence was found to require Rpd3, as deletion of Rpd3 prevented the global repression of the transcriptome after the diauxic shift.
Project description:The S. cerevisiae Rpd3 large (Rpd3L) and small (Rpd3S) histone deacetylase (HDAC) complexes are prototypes for understanding transcriptional repression in eukaryotes [1]. The current view is that they function by deacetylating chromatin, thereby limiting accessibility of transcriptional factors to the underlying DNA. However, an Rpd3 catalytic mutant retains substantial repression capability when targeted to a promoter as a LexA fusion protein [2]. We investigated the HDAC-independent properties of the Rpd3 complexes biochemically and discovered a chaperone function, which promotes histone deposition onto DNA, and a novel activity, which prevents nucleosome eviction but not remodeling mediated by the ATP-dependent RSC complex. These HDAC-independent activities inhibit Pol II transcription on a nucleosomal template. The functions of the endogenous Rpd3 complexes can be recapitulated with recombinant Rpd3 core complex comprising Sin3, Rpd3, and Ume1. To test the hypothesis that Rpd3 contributes to chromatin stabilization in vivo, we measured histone H3 density genomewide and found that it was reduced at promoters in an Rpd3 deletion mutant but partially restored in a catalytic mutant. Importantly, the effects on H3 density are most apparent on RSC-enriched genes [3]. Our data suggest that the Rpd3 core complex could contribute to repression via a novel nucleosome stabilization function. H3 were ChIP'd from yeast strains and normalized to input.
Project description:This SuperSeries is composed of the following subset Series: GSE38232: HSF1 drives a transcriptional program distinct from heat shock to support highly malignant human cancers [gene expression] GSE38901: HSF1 drives a transcriptional program distinct from heat shock to support highly malignant human cancers [ChIP-Seq] Refer to individual Series
Project description:modENCODE_submission_5599 This submission comes from a modENCODE project of Gary Karpen. For full list of modENCODE projects, see http://www.genome.gov/26524648 Project Goal: We aim to determine the locations of 125 chromosomal proteins across the Drosophila melanogaster genome. The proteins under study are involved in basic chromosomal functions such as DNA replication, gene expression, gene silencing, and inheritance. We will perform Chromatin ImmunoPrecipitation (ChIP) using the Illumina NGS platform. We will initially assay localizations using chromatin from three cell lines and two embryonic stages, and will then extend the analysis of a subset of proteins to four additional animal tissues/stages 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: Mixed Adult; Genotype: wild type; EXPERIMENTAL FACTORS: Strain Oregon-R(official name : Oregon-R-modENCODE genotype : wild type ); tissue (organism part) ; Antibody RPD3-Q3451 (target is RPD3); Developmental Stage Mixed Adult
Project description:Quiescent stem cells are periodically activated to maintain tissue homeostasis or occasionally called into action upon injury. Molecular mechanisms that constitutively maintain stem cell identity or promote stem cell proliferation and differentiation upon activation have been extensively studied. However, it is unclear how quiescent stem cells maintain identity and reinforce quiescence when they transition from quiescence to activation. Here we show mouse hair follicle stem cell compartment induces a transcription factor, Foxc1, when activated. Importantly, deletion of Foxc1 in the activated but not quiescent stem cells compromises stem cell identity, fails to re-establish quiescence and subsequently drives premature stem cell activation.These findings uncover a dynamic, cell-intrinsic mechanism employed by hair follicle stem cells to reinforce stemness in response to activation. Poly(A)-enriched transcriptome RNA-seq on HFSCs isolated in WT and K14Cre cKO mice at anagen and early telogen stage of hair cycle.