Similar Datasets
Project description:The fetal (HbF)-to-adult (HbA) hemoglobin switch is a paradigm for developmental gene expression control with relevance to sickle cell disease and beta-thalassemia. Polycomb repressive complex (PRC) proteins regulate this switch, and an inhibitor of the EED subunit of PRC2 entered clinical trials for fetal hemoglobin activation. Yet, how PcG complexes function in this process, their target genes and relevant subunit composition are unknown. Here, we identified the PRC1 subunit BMI1 as a novel HbF repressor. We uncovered LIN28B, IGF2BP1, and IGF2BP3 as direct BMI1 targets and demonstrate that they account for the BMI1 effects. BMI1 functions as part of the canonical PRC1 (cPRC1) subcomplex as revealed by the physical and functional dissection of BMI1 protein partners. Lastly, we demonstrate that BMI1/cPRC1 acts in concert with the PRC2 to repress HbF through the same target genes. Our study illuminates how PRC silences HbF, highlighting an epigenetic mechanism involved in hemoglobin switching.
2023-03-01 | GSE218232 | GEO
Project description:The fetal (HbF)-to-adult (HbA) hemoglobin switch is a paradigm for developmental gene expression control with relevance to sickle cell disease and beta-thalassemia. Polycomb repressive complex (PRC) proteins regulate this switch, and an inhibitor of the EED subunit of PRC2 entered clinical trials for fetal hemoglobin activation. Yet, how PcG complexes function in this process, their target genes and relevant subunit composition are unknown. Here, we identified the PRC1 subunit BMI1 as a novel HbF repressor. We uncovered LIN28B, IGF2BP1, and IGF2BP3 as direct BMI1 targets and demonstrate that they account for the BMI1 effects. BMI1 functions as part of the canonical PRC1 (cPRC1) subcomplex as revealed by the physical and functional dissection of BMI1 protein partners. Lastly, we demonstrate that BMI1/cPRC1 acts in concert with the PRC2 to repress HbF through the same target genes. Our study illuminates how PRC silences HbF, highlighting an epigenetic mechanism involved in hemoglobin switching.
2023-03-01 | GSE218231 | GEO
Project description:Molecular Dissection of Polycomb Group Protein-mediated Fetal Hemoglobin Repression
| PRJNA902776 | ENA
Project description:Molecular Dissection of Polycomb Group Protein-mediated Fetal Hemoglobin Repression [CUT&RUN]
| PRJNA902781 | ENA
Project description:Molecular Dissection of Polycomb Group Protein-mediated Fetal Hemoglobin Repression [RNA-seq]
| PRJNA902782 | ENA
Project description:Enhancer of Zeste homolog 2 (EZH2) is a critical component of the polycomb-repressive complex 2 (PRC2) that regulates many essential biological processes, including embryogenesis and many developmental events. The oncogenic role of EZH2 has recently been implicated in several cancer types. In this study, we first confirmed that the over-expression of EZH2 is a frequent event in oral tongue squamous cell carcinoma (OTSCC). We further demonstrated that EZH2 over-expression is correlated with advanced stages of the disease and is associated with lymph node metastasis. Statistical analysis revealed that EZH2 over-expression was correlated with reduced overall survival. Furthermore, over-expression of EZH2 was correlated with reduced expression of tumor suppressor gene E-cadherin. These observations were confirmed in vitro, in which knockdown of EZH2-induced E-cadherin expression and reduced cell migration and invasion. In contrast, ectopic transfection of EZH2 led to reduced E-cadherin expression and enhanced cell migration and invasion. Furthermore, EZH2 may act on cell migration in part by suppressing the E-cadherin expression. Taken together, these data suggest that EZH2 plays major roles in the progression of OTSCC, and may serve as a biomarker or therapeutic target for patients at risk of metastasis.
| S-EPMC3400713 | biostudies-literature
Project description:The Polycomb group (PcG) proteins are fundamental epigenetic regulators that control the repressive state of target genes in multicellular organisms. One of the open questions is defining the mechanisms of PcG recruitment to chromatin. In Drosophila, the crucial role in PcG recruitment is thought to belong to DNA-binding proteins associated with Polycomb response elements (PREs). However, current data suggests that not all PRE-binding factors have been identified. Here, we report the identification of the transcription factor Crooked legs (Crol) as a novel PcG recruiter. Crol is a C2H2-type Zinc Finger protein that directly binds to poly(G)-rich DNA sequences. Mutation of Crol binding sites as well as crol CRISPR/Cas9 knockout diminish the repressive activity of PREs in transgenes. Like other PRE-DNA binding proteins, Crol co-localizes with PcG proteins inside and outside of H3K27me3 domains. Crol knockout impairs the recruitment of the PRC1 subunit Polyhomeotic and the PRE-binding protein Combgap at a subset of sites. The decreased binding of PcG proteins is accompanied by dysregulated transcription of target genes. Overall, our study identified Crol as a new important player in PcG recruitment and epigenetic regulation.
| S-EPMC10325914 | biostudies-literature
Project description:Enhancer of zeste homolog 2 (EZH2) is a critical component of the polycomb-repressive complex 2 (PRC2), which is involved in gene silencing and histone H3 lysine 27 methylation. EZH2 has a master regulatory function in controlling such processes as stem cell differentiation, cell proliferation, early embryogenesis and X chromosome inactivation. Although benign epithelial cells express very low levels of EZH2, increased levels of EZH2 have been observed in aggressive solid tumors such as those of the prostate, breast and bladder. The mechanism by which EZH2 mediates tumor aggressiveness is unclear. Here, we demonstrate that EZH2 mediates transcriptional silencing of the tumor suppressor gene E-cadherin by trimethylation of H3 lysine 27. Histone deacetylase inhibitors can prevent EZH2-mediated repression of E-cadherin and attenuate cell invasion, suggesting a possible mechanism that may be useful for the development of therapeutic treatments. Taken together, these observations provide a novel mechanism of E-cadherin regulation and establish a functional link between dysregulation of EZH2 and repression of E-cadherin during cancer progression.
| S-EPMC2690514 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2023-04-19 | GSE202872 | GEO
Project description:Lethal(3) malignant brain tumour like 2 (L3MBTL2) is an integral component of the polycomb repressive complex 1.6 (PRC1.6) and has been implicated in transcriptional repression and chromatin compaction. Here, we show that L3MBTL2 is modified by SUMO2/3 at lysine residues 675 and 700 close to the C-terminus. SUMOylation of L3MBTL2 neither affected its repressive activity in reporter gene assays nor it's binding to histone tails in vitro. In order to analyse whether SUMOylation affects binding of L3MBTL2 to chromatin, we performed ChIP-Seq analysis with chromatin of wild-type HEK293 cells and with chromatin of HEK293 cells stably expressing either FLAG-tagged SUMOylation-competent or SUMOylation-defective L3MBTL2. Wild-type FLAG-L3MBTL2 and the SUMOylation-defective FLAG-L3MBTL2 K675/700R mutant essentially occupied the same sites as endogenous L3MBTL2 suggesting that SUMOylation of L3MBTL2 does not affect chromatin binding. However, a subset of L3MBTL2-target genes, particularly those with low L3MBTL2 occupancy including pro-inflammatory genes, was de-repressed in cells expressing the FLAG-L3MBTL2 K675/700R mutant. Finally, we provide evidence that SUMOylation of L3MBTL2 facilitates repression of these PRC1.6-target genes by balancing the local H2Aub1 levels established by the ubiquitinating enzyme RING2 and the de-ubiquitinating PR-DUB complex.
| S-EPMC3950706 | biostudies-literature