Project description:CTCF and cohesinSA-1 are regulatory proteins involved in a number of critical cellular processes including transcription, maintenance of chromatin domain architecture, and insulator function. To assess changes in the CTCF and cohesinSA-1 interactomes during erythropoiesis, chromatin immunoprecipitation coupled with high throughput sequencing and mRNA transcriptome analyses via RNA-seq were performed in primary human HSPC hematopoietic stem and progenitor cells (HSPC) and primary human erythroid cells from single donors. Sites of CTCF and cohesinSA-1 co-occupancy were enriched in gene promoters in HSPC and erythroid cells compared to single CTCF or cohesin sites. Cell type-specific CTCF sites in erythroid cells were linked to highly expressed genes, with the opposite pattern observed in HSPCs. Chromatin domains were identified by ChIP-seq with antibodies against trimethylated lysine 27 histone 3, a modification associated with repressive chromatin. Repressive chromatin domains increased in both number and size during hematopoiesis, with many more repressive domains in erythroid cells than HSPCs. CTCF and cohesinSA-1 marked the boundaries of these repressive chromatin domains in a cell-type specific manner. These genomic data support the hypothesis that CTCF and cohesinSA-1 have multiple roles in the regulation of gene expression during erythropoiesis including transcriptional regulation at gene promoters and maintenance of chromatin architecture. 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 CTCF, Cohesin SA1 and H3K27me3, along with a total input control. Two replicates for CTCF and Cohesin SA1 were obtained.
Project description:Purpose:The purpose of this study is to create unbiased, stage-specific transcriptomes by RNA-seq analyses of pure populations of both murine and human erythroblasts at distinct developmental stages. Methods: Recently developed FACS-based methods (Chen et al, PNAS, Liu et al, Blood, Hu et al Blood) were employed to purify morphologically and functionally discrete populations of cells, each representing specific stages of terminal erythroid differentiation. RNA was prepared from these cells and subjected to RNA-seq analyses. Results: There were vast temporal changes in gene expression across the differentiation stages, with each stage exhibiting unique transcriptomes.Clustering and network analyses revealed that differing stage-specific patterns of expression across differentiation were transcriptionally enriched for genes of differing function. Numerous differences were present between human and murine transcriptomes, with significant variation in the global patterns of gene expression. Conclusions: These data provide a significant resource for studies of normal and perturbed erythropoiesis, allowing a deeper understanding of mechanisms of erythroid development, differentiation, and inherited and acquired disease. Both murine and human erythroblasts at distinct developmental stage mRNA profiles were generated by deep sequencing, in triplicate, using IlluminaHiSeq 2000.
Project description:CTCF and cohesinSA-1 are regulatory proteins involved in a number of critical cellular processes including transcription, maintenance of chromatin domain architecture, and insulator function. To assess changes in the CTCF and cohesinSA-1 interactomes during erythropoiesis, chromatin immunoprecipitation coupled with high throughput sequencing and mRNA transcriptome analyses via RNA-seq were performed in primary human HSPC hematopoietic stem and progenitor cells (HSPC) and primary human erythroid cells from single donors. Sites of CTCF and cohesinSA-1 co-occupancy were enriched in gene promoters in HSPC and erythroid cells compared to single CTCF or cohesin sites. Cell type-specific CTCF sites in erythroid cells were linked to highly expressed genes, with the opposite pattern observed in HSPCs. Chromatin domains were identified by ChIP-seq with antibodies against trimethylated lysine 27 histone 3, a modification associated with repressive chromatin. Repressive chromatin domains increased in both number and size during hematopoiesis, with many more repressive domains in erythroid cells than HSPCs. CTCF and cohesinSA-1 marked the boundaries of these repressive chromatin domains in a cell-type specific manner. These genomic data support the hypothesis that CTCF and cohesinSA-1 have multiple roles in the regulation of gene expression during erythropoiesis including transcriptional regulation at gene promoters and maintenance of chromatin architecture. 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 cells differentiated into R3/R4 nucleated erythroid cells. RNA was isolated from three biological replicates of each cell type and sequencing libraries were prepared from poly A selected RNA.
Project description:<p> <ol> <li>Implement an efficient, highly reproducible and 'scalable' system for the production of large numbers of sickle cell anemia-specific iPS cells (iPSC).</li> <li>Derive and characterize a novel, in vitro system for the production of an unlimited supply of erythroid lineage cells from the directed differentiation of 'clinical grade' transgene-free iPS cells; use this system to recapitulate erythroid-lineage ontogeny in vitro with the sequential development of primitive and definitive erythropoiesis, accompanied by the appropriate expression of stage-specific globin genes.</li> <li>Identify developmental gene expression profile differences between erythroid precursors that produce primarily HbF and those that produce primarily HbA or HbS.</li> <li>Determine the effects of the three known HbF major quantitative trait loci (QTL) on globin gene expression in disease-specific iPS cells during in vitro erythropoiesis.</li> <li>Search for novel HbF genetic modifiers associated with markedly elevated HbF levels found in sickle cell anemia patients naturally, or in response to hydroxyurea treatment, by examining gene expression profiles and mRNA sequence of their iPSC-derived erythroid cells.</li> <li>Develop and use a CRISPR-based gene editing platform to study the effect of novel HbF genetic modifiers, explore globin switching, and correct the HbS mutation in sickle iPSC lines.</li> </ol> </p>
Project description:Mammalian erythroid cells development can be divided into three period: hematopoietic stem and progenitor cells (HSPC), erythroid progenitor (Ery-Pro) and erythroid precursor (Ery-Pre). To better understand human erythropoiesis and its regulation, we performed genome-wide studies of chromatin architecture, enhancer and select transcription factors binding, and transcriptomics profiling utilizing modified strategy to obtain defined progenitor and precursor populations from primary human erythroid cells. Integration and analysis of these data reveals that the TAD structure is stable but promoter - enhancer interactions are highly dynamic in a stage specific manner. Erythroid master regulator - GATA1 involves in the P-E interactions stepwisely. GATA1 binding is largely stable in erythroid progenitor and precursor, but dynamic GATA1 binding during this process regulate a productive erythroid gene expression and local chromatin rewiring. Additionally, we also have showed that dosage of GATA1 control the erythroid progenitor behavior and the erythroid progression. The valuable chromatin architecture and epigenome data will provide more comprehensive insight of human erythropoiesis and dynamic gene regulation of cellular differentiation even more broadly.
Project description:Mammalian erythroid cells development can be divided into three period: hematopoietic stem and progenitor cells (HSPC), erythroid progenitor (Ery-Pro) and erythroid precursor (Ery-Pre). To better understand human erythropoiesis and its regulation, we performed genome-wide studies of chromatin architecture, enhancer and select transcription factors binding, and transcriptomics profiling utilizing modified strategy to obtain defined progenitor and precursor populations from primary human erythroid cells. Integration and analysis of these data reveals that the TAD structure is stable but promoter - enhancer interactions are highly dynamic in a stage specific manner. Erythroid master regulator - GATA1 involves in the P-E interactions stepwisely. GATA1 binding is largely stable in erythroid progenitor and precursor, but dynamic GATA1 binding during this process regulate a productive erythroid gene expression and local chromatin rewiring. Additionally, we also have showed that dosage of GATA1 control the erythroid progenitor behavior and the erythroid progression. The valuable chromatin architecture and epigenome data will provide more comprehensive insight of human erythropoiesis and dynamic gene regulation of cellular differentiation even more broadly.