CIRCLE-seq analyais for -175 site
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE228569 | GEO | 2023/04/28
REPOSITORIES: GEO
Similar Datasets
Project description:Adenosine base editing to recreate the HPFH mutations is a promising approach to induce HbF. To measure Cas-independent off-target editing of mRNA, we electroporated CD34+ cells from three different donors with RNP consisting of ABE7.10 or ABE8e complexed with the -globin −175 A>G targeting sgRNA. Six days later, this was followed by high-depth RNA-seq. The rates of A-to-I conversion were similar in edited and unedited control cells, which is consistent with previous reports that off-target RNA editing was not detected after high-level adenine base editing of HUDEP2 cells or HSPCs.
2023-04-28 | GSE228821 | GEO
Project description:Naturally occurring mutations in the γ-globin promoters can result in hereditary persistence of fetal hemoglobin (HPFH), a benign condition that ameliorates the severity of β-hemoglobinopathies through increased post-natal fetal hemoglobin (HbF) expression. Base editing to recreate the HPFH mutations is a promising approach to induce HbF. Compared with Cas9-generated indels, base-editing approaches were more potent, with the −175 A>G conversion resulting in the strongest induction of HbF by creating a new TAL1 binding motif that stimulates long-range interaction with the locus control region (LCR), a powerful upstream enhancer. Micro-Capture-C analysis showed that introducing the −175 A>G variant stimulated long-range interaction between the γ-globin promoters and the LCR in erythroid progenitor cell line. Together, these findings show that the −175 A>G variant creates a bipartite GATA–TAL1 motif, resulting in the assembly of a GATA1/TAL1/LMO2/LDB1 complex, which activates γ-globin gene transcription by enhancing its physical association with the LCR.
2023-04-28 | GSE228570 | GEO
Project description:Naturally occurring mutations in the γ-globin promoters can result in hereditary persistence of fetal hemoglobin (HPFH), a benign condition that ameliorates the severity of β-hemoglobinopathies through increased post-natal fetal hemoglobin (HbF) expression. Mutations in the γ-globin promoters result in loss or de novo recruitment of transcription factors, yet the cis-regulatory elements involved in γ-globin transcription in the context of HPFH are not clearly defined. We demonstrate that the -115 cluster of HPFH mutations require GATA1 binding to at -186 in cooperation with NF-Y at the proximal CCAAT box at -85 for γ-globin expression. We show that multiple HPFH mutations increase HbF in an erythroid cell line and result in GATA1 binding at -186. Mutation of the -186 GATA motif in HPFH erythroid cell lines and erythroid-differentiated CD34+ cells resulted in loss of GATA1 binding and reduction in fetal hemoglobin. NF-Y ChIP-seq in HPFH erythroid cell lines demonstrated binding to the proximal CCAAT box at -85 was also found to be critical for HPFH-mediated γ-globin expression. Together, the -186 GATA motif and -85 proximal CCAAT box function in an additive and independent manner. Our results reveal detailed evidence for common, positive acting cis-regulatory elements that may provide more general mechanisms for erythroid gene expression.
2021-04-22 | GSE152338 | GEO
Project description:Hereditary Persistence of Fetal Hemoglobin (HPFH) is characterized by persistent high levels of fetal hemoglobin (HbF) in adults. Several contributory factors, both genetic and environmental, have been identified, but others remain elusive. Ten of twenty-seven members from a Maltese family presented with HPFH. A genome-wide SNP scan followed by linkage analysis revealed a candidate region on chromosome 19p13.12-13. Sequencing identified a nonsense mutation in the KLF1 gene, p.K288X, ablating the DNA binding domain of this key erythroid transcriptional regulator. Only HPFH family members were heterozygote carriers of this mutation. Expression profiling on primary erythroid progenitors revealed down-regulation of KLF1 target genes in HPFH samples. Functional assays demonstrated that, in addition to its established role in adult globin expression, KLF1 is a critical activator of the BCL11A gene, encoding a suppressor of HbF expression. These observations provide a rationale for the effects of KLF1 haploinsufficiency on HbF levels. To identify differentially expressed genes, RNA was isolated from erythroid progenitors (HEPs) cultured from peripheral blood of four HPFH (KLF1 p.K288X/wt) and four non-HPFH family members (wt/wt) and used for genome-wide expression analysis. A minimum of 1.5E6 HEPs were harvested at day12 of culture and RNA was extracted with Trizol reagent (Sigma) and purified using the RNeasy Mini Kit (Qiagen, Crawley, UK), including an on-column DNaseI digestion, according to the manufacturer’s instructions. RNA yield was determined using the 2100 Bioanalyzer (Agilent Technologies, Santa Clara, CA, USA). 8-10 micr-g of total RNA was analysed by microarrays using cells from day 12 of culture. Quality of the total RNA samples and the resulting cRNA was assessed on the Bioanalyzer. Fragmented biotinylated cRNA was prepared and 15μg hybridized to HG-U133 plus 2 GeneChips, according to the manufacturer’s protocols (Affymetrix). The data was normalized by Robust Multi-Array average (RMA) algorithm.
2010-08-31 | E-GEOD-22109 | biostudies-arrayexpress
Project description:Hereditary Persistence of Fetal Hemoglobin (HPFH) is characterized by persistent high levels of fetal hemoglobin (HbF) in adults. Several contributory factors, both genetic and environmental, have been identified, but others remain elusive. Ten of twenty-seven members from a Maltese family presented with HPFH. A genome-wide SNP scan followed by linkage analysis revealed a candidate region on chromosome 19p13.12-13. Sequencing identified a nonsense mutation in the KLF1 gene, p.K288X, ablating the DNA binding domain of this key erythroid transcriptional regulator. Only HPFH family members were heterozygote carriers of this mutation. Expression profiling on primary erythroid progenitors revealed down-regulation of KLF1 target genes in HPFH samples. Functional assays demonstrated that, in addition to its established role in adult globin expression, KLF1 is a critical activator of the BCL11A gene, encoding a suppressor of HbF expression. These observations provide a rationale for the effects of KLF1 haploinsufficiency on HbF levels. To identify differentially expressed genes, RNA was isolated from erythroid progenitors (HEPs) cultured from peripheral blood of four HPFH (KLF1 p.K288X/wt) and four non-HPFH family members (wt/wt) and used for genome-wide expression analysis.
2010-08-31 | GSE22109 | GEO
Project description:Genetic manipulations to increase fetal hemoglobin (HbF, α2γ2) in postnatal red blood cells (RBCs) can alleviate β-thalassemia and sickle cell disease. We compared five strategies in CD34+ hematopoietic stem and progenitor cells, using either Cas9 nuclease, which creates uncontrolled indel mixtures, or adenine base editors (ABE), which generate more precise nucleotide changes. The most potent modification was ABE generation of γ-globin (HBG1/HBG2) −175 A>G, which creates a promoter binding motif for the transcriptional activator TAL1. In erythroid colonies with >87.5% on-target edits, those with −175 A>G expressed 81 ± 7% HbF, versus 17 ± 11% in unedited controls. In comparison, HbF levels were lower and more variable in erythroid cells modified with either of two Cas9 nuclease strategies with similar editing efficiencies, being 32 ± 19% when a BCL11A repressor binding motif in the γ-globin promoter was targeted and 52 ± 13% when the +58 BCL11A erythroid enhancer was targeted. Contrary to currently accepted models of γ-globin regulation, HbF levels varied significantly with different Cas9 indels that disrupted the γ-globin promoter BCL11A binding motif. The −175 A>G base edit also induced HbF more potently than did the Cas9 nuclease approaches in RBCs generated after transplantation of modified normal or SCD patient CD34+ cells into mice. Our data suggest a strategy for potent, uniform induction of HbF and provide insights into γ-globin gene regulation. More generally, we demonstrate that diverse indels generated by Cas9 nuclease can cause unexpected variations in biological outcomes that can be circumvented by base editing, with important implications for therapeutic gene editing efforts.
2023-04-28 | GSE228819 | GEO
Project description:We used microarrays to investigate differential microRNA (miRNA) expression in reticulocytes comparing reticulocytes from control individuals with normal fetal hemoglobin (HbF) level to hereditary persistence of fetal hemoglobin (HPFH) and β-thalssemia minor with high HbF, and try to find out some miRNAs associated with the mechanisms of HbF induction.
2018-01-01 | GSE93973 | GEO
Project description:Vicious circle of some key proteins is critical in the process of tumor development. Nevertheless, the mechanism of how the epigenetic modifiers are involved in was seldom reported and has not been clearly illustrated. We found the expression of lysine specific demethylase 1 (LSD1), the first identified histone lysine demethylase, is positively correlated with transforming growth factor beta 1 (TGF β1) in gastric cancer tissues and can be promoted by TGF β1 activated (p-EKR)-(NF-κB)-p300 signaling pathway, which resulted in the progression of epithelial-mesenchymal transition (EMT) in human gastric cancer cells. On the other hand, abrogation of LSD1 leads to the down regulation of TGF β1 as well as the EMT. But in benign cells, this circle was blocked by TGF β1 induced inactivation of ERK, which suggested the distinct roles of TGF β1 against LSD1 in gastric cancer cells and benign cells. This vicious cycle may illustrate a novel mechanism for EMT in gastric cancer mediate by TGF β1 and LSD1 but not in benign cells and may serve as a new strategy for the prevention of EMT for gastric cancer. Nuclear extracts prepared from MGC803 cells stably expressing Lenti-CAS9-sgRNA-puro for LSD1 or empty vector were used in immunoprecipitation reactions with antibodies against H3K4me2 and H3K9me2. Sequencing libraries were prepared using the TruSeq DNA Sample Prep Kit (Illumina) and sequencing was performed on a HiSeq2000 (Illumina).
2016-07-19 | E-GEOD-84487 | biostudies-arrayexpress
Project description:To explore long noncoding RNA (lncRNA) expression and the biological functions of lncRNAs in fetal hemoglobin (HbF) induction, we surveyed lncRNA and mRNA expression profiles using circulating reticulocytes isolated from individuals with hereditary persistence of fetal hemoglobin (HPFH) and β-thalassaemia minor with high HbF.
2018-01-01 | GSE93971 | GEO
Project description:B-hemoglobinopathies such as Sickle Cell Disease (SCD) and b-thalassemia result from mutations in the adult b-globin gene. Reactivating the developmentally silenced fetal g-globin gene is a therapeutic goal for treating SCD and b-thalassemia1. Some forms of Hereditary Persistence of Fetal Hemoglobin (HPFH), a rare benign condition in which individuals express g‑globin throughout adulthood, are caused by point mutations in the g‑globin gene promoter at regions residing ~115 and 200 base pairs upstream of the transcription start site. Here we show that the major fetal globin repressors BCL11A and ZBTB7A/LRF directly bind to the -115 and ‑200 sites, respectively. Furthermore, introduction of naturally occurring HPFH mutations into erythroid cells by CRISPR/Cas9 disrupts repressor binding and raises g‑globin expression. These findings resolve the mystery surrounding how these HPFH mutations operate and demonstrate that BCL11A and ZBTB7A/LRF are major direct repressors of the fetal globin gene.
2018-01-29 | GSE103445 | GEO