In:
Blood, American Society of Hematology, Vol. 114, No. 22 ( 2009-11-20), p. 2535-2535
Abstract:
Abstract 2535 Poster Board II-512 We used a high throughput approach to determine the chromatin profiles of the human β and α globin loci and their upstream and downstream regions in human undifferentiated ES cells, ES cell-derived erythroid cells, human fetal and adult origin erythroid cells and in primary cells and cell lines of endo-meso and ectodermal origins. All DNase I hypersensitive sites of the b-locus were absent in undifferentiated human ES cells except for HS2 of the b-globin locus control region. The chromatin profiles of the β and α globin loci of ES cell-derived erythroid cells were identical to those of fetal liver erythroid cells except that the hypersensitive site of the embryonic globin gene was more prominent. DNase I hypersensitive site 2 of the b-globin LCR, a potent enhancer, was present in all the cell lines and primary lineages we studied, providing direct evidence that it is ubiquitous. Several new erythroid specific DHSs were detected upstream of 5′HS7 of the β-LCR, raising the possibility that they play a role in the regulation of the β globin locus. The region downstream to 3′HS1 was depleted of DHSs except for the previously identified DHS mapping near the breakpoint of HPFH 1. Since DHSs are absent near the breakpoints of deletional HPFHs and db thalassemias and since enhancers are typically DHS positive, our results argue against the hypothesis of imported enhancers in the pathogenesis of deletional HPFH and db thalassemia mutants. All the previously identified erythroid specific DHSs of the α globin locus were absent in human ES cells. The α globin locus of ES cells, however, displayed three very prominent DHSs, which were located almost symmetrically about 40 Kb apart from each other and they were constitutively formed in all the lineages and cell lines we have studied; the 3′ and 5′ DHSs carried CTCF sites by ChIP-Seq assay raising the possibility that they mark the sites of chromatin insulators. Overall these results demonstrate the power of the new high throughput chromatin profiling approaches and their ability to uncover features of chromatin that may be of regulatory relevance. Disclosures: No relevant conflicts of interest to declare.
Type of Medium:
Online Resource
ISSN:
0006-4971
,
1528-0020
DOI:
10.1182/blood.V114.22.2535.2535
Language:
English
Publisher:
American Society of Hematology
Publication Date:
2009
detail.hit.zdb_id:
1468538-3
detail.hit.zdb_id:
80069-7
