Epigenetic dysregulation of GATA1 is involved in myelodysplastic syndromes dyserythropoiesis (original) (raw)
Related papers
Experimental Hematology, 2007
Deregulated epigenetic mechanisms are likely involved in the pathogenesis of myelodysplastic syndromes (MDSs). Which genes are silenced by aberrant promotor methylation during MDS hematopoiesis has not been equivalently investigated. Using an in vitro differentiation model of human hematopoiesis, we generated defined differentiation stages (day 0, day 4, day 7, day 11) of erythro-, thrombo-and granulopoiesis from 13 MDS patients and seven healthy donors. Promotor methylation analysis of key regulatory genes involved in cell cycle control (p14, p15, p16, CHK2), DNA repair (hMLH1), apoptosis (p73, survivin, DAPK), and differentiation (RARb, WT1) was performed by methylation-specific polymerase chain reaction. Corresponding gene expression was analyzed by microarray (Affymetrix, HG-U133A). We provide evidence that p16, survivin, CHK2, and WT1 are affected by promotor hypermethylation in MDSs displaying a selective International Prognostic Scoring System risk association. A methylation-associated mRNA downregulation for specific hematopoietic lineages and differentiation stages is demonstrated for survivin, CHK2, and WT1. We identified a suppressed survivin mRNA expression in methylated samples during erythropoiesis, whereas WT1 and CHK2 methylation-related reduction of mRNA expression was found during granulopoiesis in all MDS risk types. Our data suggest that lineage-specific methylation-associated gene silencing of survivin, CHK2, and WT1 in MDS hematopoietic precursor cells may contribute to the MDS-specific phenotype.
Abstract Background: Vast variety of intermediate factors including cell cycle regulators, growth factors, transcription factors, and signaling pathways are involved in hematopoietic stem cell (HSC) commitment and differentiation into distinct lineages. VHL, Ecad, and RUNX3 are among these. Epigenetics is currently introduced as a potential mechanism to control the gene regulation. The aim of this study is to reveal the correlation between the expression level and methylation pattern of mentioned genes after in vitro differentiation of cord blood HSCs into erythroid lineage mediated by erythropoietin. Materials and Methods: After isolation and expansion, the CD34+ cord blood stem cells were divided into two parts. The first part was used to extract the DNA and RNA and the second to differentiate into erythroid lineage. Methylation specific PCR (MSP) and Real-time PCR were used to determine the methylation status and expression levels of the genes, respectively. Results: Although the...
Journal of Biological Chemistry, 2013
Background: Not much is known about epigenomic changes during the differentiation of human stem cells into mature enucleated red cells. Results: Methylome analysis during human erythropoiesis revealed that global hypomethylation occurs during this process and correlates with transcriptomic changes. Conclusion: Integrative analysis also allowed us to identify novel regulatory areas of the genome. Significance: Progressive functional hypomethylation during human erythroid differentiation changes the current paradigm. Differentiation of hematopoietic stem cells to red cells requires coordinated expression of numerous erythroid genes and is characterized by nuclear condensation and extrusion during terminal development. To understand the regulatory mechanisms governing these widespread phenotypic changes, we conducted a high resolution methylomic and transcriptomic analysis of six major stages of human erythroid differentiation. We observed widespread epigenetic differences between early and late stages of erythropoiesis with progressive loss of methylation being the dominant change during differentiation. Gene bodies, intergenic regions, and CpG shores were preferentially demethylated during erythropoiesis. Epigenetic changes at transcription factor binding sites correlated significantly with changes in gene expression and were enriched for binding motifs for SCL, MYB, GATA, and other factors not previously implicated in erythropoiesis. Demethylation at gene promoters was associated with increased expression of genes, whereas epigenetic changes at gene bodies correlated inversely with gene expression. Important gene networks encoding erythrocyte membrane proteins, surface receptors, and heme synthesis proteins were found to be regulated by DNA methylation. Furthermore, integrative analysis enabled us to identify novel, potential regulatory areas of the genome as evident by epigenetic changes in a predicted PU.1 binding site in intron 1 of the GATA1 gene. This intronic site was found to be conserved across species and was validated to be a novel PU.1 binding site by quantitative ChIP in erythroid cells. Altogether, our study provides a comprehensive analysis of methylomic and transcriptomic changes during erythroid differentiation and demonstrates that human terminal erythropoiesis is surprisingly associated with hypomethylation of the genome.
Epigenetic regulation of hematopoiesis by DNA methylation
eLife, 2016
During embryonic development, cell type-specific transcription factors promote cell identities, while epigenetic modifications are thought to contribute to maintain these cell fates. Our understanding of how genetic and epigenetic modes of regulation work together to establish and maintain cellular identity is still limited, however. Here, we show that DNA methyltransferase 3bb.1 (dnmt3bb.1) is essential for maintenance of hematopoietic stem and progenitor cell (HSPC) fate as part of an early Notch-runx1-cmyb HSPC specification pathway in the zebrafish. Dnmt3bb.1 is expressed in HSPC downstream from Notch1 and runx1, and loss of Dnmt3bb.1 activity leads to reduced cmyb locus methylation, reduced cmyb expression, and gradual reduction in HSPCs. Ectopic overexpression of dnmt3bb.1 in non-hematopoietic cells is sufficient to methylate the cmyb locus, promote cmyb expression, and promote hematopoietic development. Our results reveal an epigenetic mechanism supporting the maintenance of ...
Scientific reports, 2017
The Notch1 pathway plays important roles in modulating erythroid and megakaryocyte differentiation. To screen the Notch1-related genes that regulate differentiation fate of K562 and HEL cells, the expression of transient receptor potential ankyrin 1 (TRPA1) was induced by Notch1 receptor intracellular domain (N1IC), the activated form of Notch1 receptor. N1IC and v-ets erythroblastosis virus E26 oncogene homolog 1 (Ets-1) bound to TRPA1 promoter region to regulate transcription in K562 cells. Transactivation of TRPA1 promoter by N1IC depended on the methylation status of TRPA1 promoter. N1IC and Ets-1 suppressed the DNA methyltransferase 3B (DNMT3B) level in K562 cells. Inhibition of TRPA1 expression after Notch1 knockdown could be attenuated by nanaomycin A, an inhibitor of DNMT3B, in K562 and HEL cells. Functionally, hemin-induced erythroid differentiation could be suppressed by TRPA1, and the reduction of erythroid differentiation of both cells by N1IC and Ets-1 occurred via TRPA...
Gene Function & Disease, 2000
Promoter 1 of LMO2, a master gene for hematopoiesis, is regulated by the erythroid specific transcription factor GATA1 The T cell oncogene LMO2 was first identified at the site of the translocation t(11;14)(p13;q11) in T-acute lymphocytic leukemia (T-ALL) and encodes a cysteine-rich protein with LIM-motifs. It was later shown to have an essential role in yolk sac and adult erythropoiesis. LMO2 encodes two alternative transcripts differing in the length of the 5' untranslated region, but encoding the same protein. Transcription start site mapping revealed the 5Ј-end of the longer transcript, LMO2a and promoter 1. Sequencing identified two putative GATA1 sites and an overlapping SP1 site close to the transcription start site, suggesting that promoter 1 (P1) is an erythroid specific promoter. Using EMSA analysis with an oligonucleotide from promoter 1 we now show that GATA1 and SP1 bind to these sites. DNaseI hypersensitive site (DHS) mapping upstream of the transcription start site revealed four erythroid specific sites, corresponding to putative GATA1 motifs and one non-lineage specific site. Reporter gene experiments with P1 and a mutant, where both GATA sites were inactivated, showed that GATA1 plays a functional role in the erythroid specific transcriptional control of LMO2 from P1. These studies confirm that promoter 1 of the LMO2 gene is an erythroid specific promoter.