Global mechanisms defining the gene expression programs specific for hematopoiesis are still not fully understood. Here, we show that promoter DNA demethylation is associated with the activation of hematopoietic-specific genes. Using genome-wide promoter methylation arrays, we identified 694 hematopoietic-specific genes repressed by promoter DNA methylation in human embryonic stem cells and whose loss of methylation in hematopoietic can be associated with gene expression. The association between promoter methylation and gene expression was studied for many hematopoietic-specific genes including CD45, CD34, CD28, CD19, the T cell receptor (TCR), the MHC class II gene HLA-DR, perforin 1 and the phosphoinositide 3-kinase (PI3K) and results indicated that DNA demethylation was not always sufficient for gene activation. Promoter demethylation occurred either early during embryonic development or later on during hematopoietic differentiation. Analysis of the genome-wide promoter methylation status of induced pluripotent stem cells (iPSCs) generated from somatic CD34+ HSPCs and differentiated derivatives from CD34+ HSPCs confirmed the role of DNA methylation in regulating the expression of genes of the hemato-immune system, and indicated that promoter methylation of these genes may be associated to stemness. Together, these data suggest that promoter DNA demethylation might play a role in the tissue/cell-specific genome-wide gene regulation within the hematopoietic compartment.
Bacterial heat-labile (LT) enterotoxins signal through tightly regulated interactions with host cell gangliosides. LT-IIa and LT-IIb of Escherichia coli bind preferentially to gangliosides with a NeuAcα2-3Galβ1-3GalNAc terminus, with key distinctions in specificity. LT-IIc, a newly discove ... mehr
Phosphate deficiency is characteristic for many natural habitats, resulting in different physiological responses in plants and bacteria including the replacement of phospholipids by glycolipids and other phosphorous-free lipids. The plant pathogenic bacterium Agrobacterium tumefaciens, whi ... mehr
A tryptophan side chain was introduced into subsite +1 of family GH-18 (class V) chitinases from Nicotiana tabacum and Arabidopsis thaliana (NtChiV and AtChiC, respectively) by the mutation of a glycine residue to tryptophan (G74W-NtChiV and G75W-AtChiC). The specific activity toward glyco ... mehr