Project description:KLF1 (EKLF) regulates a diverse suite of genes to direct erythroid cell differentiation from bi-potent progenitors. To determine the local cis-regulatory contexts and transcription factor networks in which KLF1 operates, we performed KLF1 ChIP-seq in the mouse. We found at least 945 sites in the genome of E14.5 fetal liver erythroid cells which are occupied by endogenous KLF1. Many of these recovered sites reside in erythroid gene promoters such as β-globin, but the majority are distant to any known gene. Our data suggests KLF1 directly regulates most aspects of terminal erythroid differentiation including production of α and β-globin protein chains, heme biosynthesis, co-ordination of proliferation and anti-apoptotic pathways, and construction of the red cell membrane and cytoskeleton by functioning primarily as a transcriptional activator. Additionally, we suggest new mechanisms for KLF1 co-operation with other transcription factors, in particular the erythroid transcription factor GATA1, to maintain homeostasis in the erythroid compartment. Examination of KLF1 occupancy in primary erythroid cells. KLF1-ChIP and input samples were run on AB SOLiD Systems 2.0 and 3.0. The genomic alignment files (*sorted.txt) and peak file (*bed) contain the combined System 2.0 and 3.0 data.
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.
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.
Project description:KLF1 (EKLF) regulates a diverse suite of genes to direct erythroid cell differentiation from bi-potent progenitors. To determine the local cis-regulatory contexts and transcription factor networks in which KLF1 operates, we performed KLF1 ChIP-seq in the mouse. We found at least 945 sites in the genome of E14.5 fetal liver erythroid cells which are occupied by endogenous KLF1. Many of these recovered sites reside in erythroid gene promoters such as β-globin, but the majority are distant to any known gene. Our data suggests KLF1 directly regulates most aspects of terminal erythroid differentiation including production of α and β-globin protein chains, heme biosynthesis, co-ordination of proliferation and anti-apoptotic pathways, and construction of the red cell membrane and cytoskeleton by functioning primarily as a transcriptional activator. Additionally, we suggest new mechanisms for KLF1 co-operation with other transcription factors, in particular the erythroid transcription factor GATA1, to maintain homeostasis in the erythroid compartment.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Klf1 (formerly known as Eklf) regulates the development of erythroid cells from bi-potent progenitor cells via the transcriptional activation of a diverse set of genes. Mice lacking Klf1 die in utero prior to E15 from severe anemia due to the inadequate expression of genes controlling hemoglobin production, cell membrane and cytoskeletal integrity, and the cell cycle and proliferation. We have recently described the full repertoire of Klf1 binding sites in vivo by performing Klf1 ChIP-seq in primary erythroid tissue (E14.5 fetal liver). Here we describe the Klf1-dependent erythroid transcriptome by comparing mRNA-seq from Klf1+/+ and Klf1-/- erythroid tissue. This has revealed novel target genes not previously obtainable by traditional microarray technology and provided novel insights into the function of Klf1 as a transcriptional activator such as interactions with Gata1, Scl/Tal1 and p300. We also describe a set of erythroid specific promoters not previously identified that drive high level expression of otherwise ubiquitously expressed genes in erythroid cells. Additionally, our study has identified for the first time two novel lnc-RNAs that are dynamically expressed during erythroid differentiation as well as a role for Klf1 in directing apoptotic gene expression to drive the terminal stages of erythroid maturation. Examination of mRNA expression in 3 Klf1-/- and 3 Klf1+/+ fetal livers This submission represents mRNA-Seq component of study.
Project description:Identification of cell-type specific enhancers is important for understanding the regulation of programs controlling cellular development and differentiation. Enhancers are typically marked by the co-transcriptional activator protein p300 or by groups of cell-expressed transcription factors. We hypothesized that a unique set of enhancers regulates gene expression in human erythroid cells, a highly specialized cell type evolved to provide adequate amounts of oxygen throughout the body. Using chromatin immunoprecipitation followed by massively parallel sequencing, genome-wide maps of candidate enhancers were constructed for p300 and four transcription factors, GATA1, NF-E2, KLF1, and SCL, using primary human erythroid cells. These data were combined with gene expression analyses and candidate enhancers identified. Consistent with their predicted function as candidate enhancers, there was statistically significant enrichment of p300 and combinations of co-localizing erythroid transcription factors within 1-50 kb of the TSS of genes highly expressed in erythroid cells. Candidate enhancers were also enriched near genes with known erythroid cell function or erythroid cell phenotypes. Candidate enhancers exhibited only moderate conservation with mouse and minimal conservation with nonplacental vertebrates. Candidate enhancers were mapped to a data set of erythroid-associated, biologically relevant, SNPs from the GWAS catalog of the NHGRI. Fourteen candidate enhancers, representing 10 genetic loci, mapped to sites associated with biologically relevant erythroid traits. Fragments from these loci directed statistically significant expression in reporter gene assays. Identification of enhancers in human erythroid cells will allow a better understanding of erythroid cell development, differentiation, structure, and function, and provide insights into inherited and acquired hematologic disease. CD34+-selected stem and progenitor cells were expanded for three days in the absence of EPO. The cells were further cultured in the presence of EPO, and formaldehyde crosslinked chromatin was isolated after cells differentiated into R3/R4 nucleated erythroid cells. Chromatin Immunoprecipitation followed by sequencing (chIP-seq) was performed using antibodies against GATA1, KLF1, NFE2, TAL1, p300, H3K4me2 and H3K4me3, along with a total input control. Raw data (fastq, SRA) is missing for the TAL1 chIP-seq dataset
Project description:In this project we did a proteomic analysis from iPSCs-derived macrophages with the activation of thranscription factor KLF1, upon tamoxifen induction. These macrophages are a model for the study of the erythroid island (EI) niche in adult hematopoietic tissues, such as bone marrow and spleen. We wanted to assess the upregulated proteins in macrophages upon KLF1 activation to further study the interactions between macrophages and erythroid cells whithin the EI niche.