Genomic footprinting and sequencing of human beta-globin locus. Tissue specificity and cell line artifact.

摘要: In order to gain further insights of the regulatory mechanisms human beta-like globin gene switch during erythroid development, we have studied protein-DNA interaction in vivo at adult beta and fetal gamma promoters their upstream enhancer, 5'HS-2, purified erythroblasts, which beta, but not or epsilon, is actively transcribing. This genomic footprinting analysis erythroblasts was carried out conjunction with those different non-erythroid tissues, an embryonic/fetal cell line K562, several lines. Protein-DNA binding promoter, particular two CACC promoter boxes CCAAT box, detectable only erythroblasts. As expected, were bound specific nuclear factors expressing K562 cells, tissues Relatively weak protein could also be detected vicinities inactive Although patterns factor-DNA NF-E2/AP1, GATA-1, GT-I motifs 5'HS-2 enhancer are similar identified a previously undetected factor-binding motif that protected identical sequence 3'-CACC box it well conserved same location among all mammalian enhancers, suggesting important role this element transcription All above four free factor them, NF-E2/AP1 GT-I, some lines others. The functional implications these data tissue-specific CpG methylation obtained by sequencing discussed terms positive negative regulation development.