HP1β has distinct subnuclear localizations, chromatin binding features and functions in embryonic stem cells and differentiating cells
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE65122 | GEO | 2015/08/02
SECONDARY ACCESSION(S): PRJNA273152
REPOSITORIES: GEO
Similar Datasets
Project description:We used microarrays to identify the gene expression changes in Cbx1-/- (HP1beta) knockout embryonic stem cells (ESCs) and Cbx5-/- (HP1alpha) knockout ESCs compared to WT ESCs and in embryoid bodies (EBs) differentiated from those three ESC types.
2015-08-02 | GSE65121 | GEO
Project description:In recent years, several chromatin-related proteins have been shown to regulate ESC pluripotency and/or differentiation, although the role of the major heterochromatin proteins in pluripotency remains largely unknown. Here we identify heterochromatin protein 1-beta (HP1β) to be differentially localized and associated with chromatin in pluripotent and differentiated cells, to be essential for proper ESC differentiation as well as for the maintenance of the pluripotent state. Microscopy analysis supported by biochemical fractionations and chromatin immunoprecipitation (ChIP) experiments demonstrate that unlike its prominent localization in heterochromatic chromocenters in differentiated cells, HP1β is diffuse in the ESC nucleoplasm, poorly bound to chromatin, and highly expressed. The fraction of HP1β that does associate with chromatin in ESCs is highly enriched in genic regions. HP1β-knockout ESCs but not HP1α knockout ESCs exhibit a loss of the morphological and proliferative characteristics of embryonic pluripotent cells. HP1β depletion in ESCs results in reduced expression of pluripotency factors and aberrant differentiation. In contrast, HP1β depletion in differentiated cells perturbs the maintenance of differentiation, and facilitates reprogramming to induced pluripotent stem cells. Our results demonstrate a dual role for HP1β, in ESCs it is essential for pluripotency maintenance, and in differentiated cells for proper differentiation. ChIP-Seq of HP1β in mouse embryonic stem cells.
2015-08-02 | E-GEOD-64946 | biostudies-arrayexpress
Project description:In recent years, several chromatin-related proteins have been shown to regulate ESC pluripotency and/or differentiation, although the role of the major heterochromatin proteins in pluripotency remains largely unknown. Here we identify heterochromatin protein 1-beta (HP1β) to be differentially localized and associated with chromatin in pluripotent and differentiated cells, to be essential for proper ESC differentiation as well as for the maintenance of the pluripotent state. Microscopy analysis supported by biochemical fractionations and chromatin immunoprecipitation (ChIP) experiments demonstrate that unlike its prominent localization in heterochromatic chromocenters in differentiated cells, HP1β is diffuse in the ESC nucleoplasm, poorly bound to chromatin, and highly expressed. The fraction of HP1β that does associate with chromatin in ESCs is highly enriched in genic regions. HP1β-knockout ESCs but not HP1α knockout ESCs exhibit a loss of the morphological and proliferative characteristics of embryonic pluripotent cells. HP1β depletion in ESCs results in reduced expression of pluripotency factors and aberrant differentiation. In contrast, HP1β depletion in differentiated cells perturbs the maintenance of differentiation, and facilitates reprogramming to induced pluripotent stem cells. Our results demonstrate a dual role for HP1β, in ESCs it is essential for pluripotency maintenance, and in differentiated cells for proper differentiation.
2015-08-02 | GSE64946 | GEO
Project description:We used microarrays to identify the gene expression changes in Cbx1-/- (HP1beta) knockout embryonic stem cells (ESCs) and Cbx5-/- (HP1alpha) knockout ESCs compared to WT ESCs and in embryoid bodies (EBs) differentiated from those three ESC types. ESCs were grown and the pluripotent SSEA1-positive cells from all ESC types using MACS were sorted and harvested or sorted and differentiated into EBs. Total RNA from all samples was extracted.
2015-08-02 | E-GEOD-65121 | biostudies-arrayexpress
Project description:Heterochromatin in eukaryotic interphase cells frequently localizes to the nucleolar periphery (nucleolus-associated domains (NADs)) and the nuclear lamina (lamina-associated domains (LADs)). Gene expression in somatic cell NADs is generally low, but NADs have not been characterized in mammalian stem cells. Here, we generated the first genome-wide map of NADs in mouse embryonic stem cells (mESCs) via deep sequencing of chromatin associated with biochemically purified nucleoli. As we had observed in mouse embryonic fibroblasts (MEFs), the large type I subset of NADs overlaps with constitutive LADs and is enriched for features of constitutive heterochromatin, including late replication timing and low gene density and expression levels. Conversely, the type II NAD subset overlaps with loci that are not lamina-associated, but in mESCs, type II NADs are much less abundant than in MEFs. mESC NADs are also much less enriched in H3K27me3 modified regions than are NADs in MEFs. Additionally, comparision of MEF and mESC NADs revealed enrichment of developmentally regulated genes in cell-type-specific NADs. Together, these data indicate that NADs are a developmentally dynamic component of heterochromatin. These studies implicate association with the nucleolar periphery as a mechanism for developmentally regulated gene expression and will facilitate future studies of NADs during mESC differentiation.
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Project description:The chromatin remodeler CHD8 represents a high-confidence risk factor in autism, a multistage progressive neurologic disorder, however the underlying stage-specific functions remain elusive. In this study, by analyzing Chd8 conditional knock-out mice (male and female), we find that CHD8 controls cortical neural stem/progenitor cell (NSC) proliferation and survival in a stage-dependent manner. Strikingly, inducible genetic deletion reveals that CHD8 is required for the production and fitness of transit-amplifying intermediate progenitors (IPCs) essential for upper-layer neuron expansion in the embryonic cortex. p53 loss of function partially rescues apoptosis and neurogenesis defects in the Chd8-deficient brain. Further, transcriptomic and epigenomic profiling indicates that CHD8 regulates the chromatin accessibility landscape to activate neurogenesis-promoting factors including TBR2, a key regulator of IPC neurogenesis, while repressing DNA damage- and p53-induced apoptotic programs. In the adult brain, CHD8 depletion impairs forebrain neurogenesis by impeding IPC differentiation from NSCs in both subventricular and subgranular zones; however, unlike in embryos, it does not affect NSC proliferation and survival. Treatment with an antidepressant approved by the Federal Drug Administration (FDA), fluoxetine, partially restores adult hippocampal neurogenesis in Chd8-ablated mice. Together, our multistage functional studies identify temporally specific roles for CHD8 in developmental and adult neurogenesis, pointing to a potential strategy to enhance neurogenesis in the CHD8-deficient brain.SIGNIFICANCE STATEMENT The role of the high-confidence autism gene CHD8 in neurogenesis remains incompletely understood. Here, we identify a stage-specific function of CHD8 in development of NSCs in developing and adult brains by conserved, yet spatiotemporally distinct, mechanisms. In embryonic cortex, CHD8 is critical for the proliferation, survival, and differentiation of both NSC and IPCs during cortical neurogenesis. In adult brain, CHD8 is required for IPC generation but not the proliferation and survival of adult NSCs. Treatment with FDA-approved antidepressant fluoxetine partially rescues the adult neurogenesis defects in CHD8 mutants. Thus, our findings help resolve CHD8 functions throughout life during embryonic and adult neurogenesis and point to a potential avenue to promote neurogenesis in CHD8 deficiency.
| S-EPMC9653284 | biostudies-literature
Project description:BackgroundEpigenetic modifications, transcription factor (TF) availability and differences in chromatin folding influence how the genome is interpreted by the transcriptional machinery responsible for gene expression. Enhancers buried in non-coding regions are found to be associated with significant differences in histone marks between different cell types. In contrast, gene promoters show more uniform modifications across cell types. Here we used histone modification and chromatin-associated protein ChIP-Seq data sets in mouse embryonic stem (ES) cells as well as genomic features to identify functional enhancer regions. Using co-bound sites of OCT4, SOX2 and NANOG (co-OSN, validated enhancers) and co-bound sites of MYC and MYCN (limited enhancer activity) as enhancer positive and negative training sets, we performed multinomial logistic regression with LASSO regularization to identify key features.ResultsCross validations reveal that a combination of p300, H3K4me1, MED12 and NIPBL features to be top signatures of co-OSN regions. Using a model from 10 signatures, 83% of top 1277 putative 1 kb enhancer regions (probability greater than or equal to 0.8) overlapped with at least one TF peak from 7 mouse ES cell ChIP-Seq data sets. These putative enhancers are associated with increased gene expression of neighbouring genes and significantly enriched in multiple TF bound loci in agreement with combinatorial models of TF binding. Furthermore, we identified several motifs of known TFs significantly enriched in putative enhancer regions compared to random promoter regions and background. Comparison with an active H3K27ac mark in various cell types confirmed cell type-specificity of these enhancers.ConclusionsThe top enhancer signatures we identified (p300, H3K4me1, MED12 and NIPBL) will allow for the identification of cell type-specific enhancer regions in diverse cell types.
| S-EPMC3406964 | biostudies-literature
Project description:Many organisms, including plants, use the circadian clock to measure the duration of day and night. Daily rhythms in the plant circadian system are generated by multiple interlocked transcriptional/translational loops and also by spatial regulations such as nuclear translocation. GIGANTEA (GI), one of the key clock components in Arabidopsis, makes distinctive nuclear bodies like other nuclear-localized circadian regulators. However, little is known about the dynamics or roles of GI subnuclear localization. Here, we characterize GI subnuclear compartmentalization and identify unexpected dynamic changes under diurnal conditions. We further identify EARLY FLOWERING 4 (ELF4) as a regulator of GI nuclear distribution through a physical interaction. ELF4 sequesters GI from the nucleoplasm, where GI binds the promoter of CONSTANS (CO), to discrete nuclear bodies. We suggest that the subnuclear compartmentalization of GI by ELF4 contributes to the regulation of photoperiodic flowering.
| S-EPMC3917306 | biostudies-literature
Project description:X chromosome inactivation (XCI) is the dosage compensation mechanism that evolved in female mammals to correct the genetic imbalance of X-linked genes between sexes. X chromosome inactivation occurs in early development when one of the two X chromosomes of females is nearly-completely silenced. Differentiating Embryonic Stem cells (ESC) are regarded as a useful tool to study XCI, since they recapitulate many events occurring during early development. In this review we aim to summarise the advances in the field and to discuss the close connection between cell differentiation and X chromosome inactivation, with a particular focus on mouse ESCs.
| S-EPMC4561061 | biostudies-literature
Project description:BackgroundThe repair of spontaneous and induced DNA lesions is a multistep process. Depending on the type of injury, damaged DNA is recognized by many proteins specifically involved in distinct DNA repair pathways.ResultsWe analyzed the DNA-damage response after ultraviolet A (UVA) and γ irradiation of mouse embryonic fibroblasts and focused on upstream binding factor 1 (UBF1), a key protein in the regulation of ribosomal gene transcription. We found that UBF1, but not nucleolar proteins RPA194, TCOF, or fibrillarin, was recruited to UVA-irradiated chromatin concurrently with an increase in heterochromatin protein 1β (HP1β) level. Moreover, Förster Resonance Energy Transfer (FRET) confirmed interaction between UBF1 and HP1β that was dependent on a functional chromo shadow domain of HP1β. Thus, overexpression of HP1β with a deleted chromo shadow domain had a dominant-negative effect on UBF1 recruitment to UVA-damaged chromatin. Transcription factor UBF1 also interacted directly with DNA inside the nucleolus but no interaction of UBF1 and DNA was confirmed outside the nucleolus, where UBF1 recruitment to DNA lesions appeared simultaneously with cyclobutane pyrimidine dimers; this occurrence was cell-cycle-independent.ConclusionsWe propose that the simultaneous presence and interaction of UBF1 and HP1β at DNA lesions is activated by the presence of cyclobutane pyrimidine dimers and mediated by the chromo shadow domain of HP1β. This might have functional significance for nucleotide excision repair.
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