Translocation of an erythroid-specific hypersensitive site in deletion-type hereditary persistence of fetal hemoglobin.

Abstract

Hereditary persistence of fetal hemoglobin (HPFH) can involve large deletions which eliminate the 3' end of the ,8-like globin gene cluster and more than 70 kilobases (kb) of flanking DNA. Blot hybridization revealed a DNase I-hypersensitive site extending from 1.1 to 1.4 kb downstream of the HPFH-1 3' deletion endpoint. The site was found in normal fetal and adult nucleated erythroid cells and in two erythroleukemia cell lines but not in nonerythroid cells and tissues. Simian virus 40 core enhancer-like sequences were found nonrandomly distributed within the boundaries of the site, which is contained in a fragment of known enhancer activity (E. A. Feingold and B. G. Forget, Blood, in press). A second hypersensitive site was found 0.5 kb upstream of the HPFH-1 3' deletion endpoint but was not erythroid specific. A third site, most prominent in fetal liver-derived erythroid cells, was found 1 kb upstream of the HPFH-2 deletion endpoint. As predicted by the locations of the deletion endpoints, the first two sites were translocated to within 12 kb of the A_Y gene in erythroid colonies derived from an HPFH-2 heterozygote and in hybrid mouse-human erythroid cells carrying the HPFH-2 deletion chromosome. Further analysis of this region showed that it was DNase I sensitive in erythroid and myeloid cells, indicating that it resides in an open chromatin domain. These observations suggest that alterations of chromatin structure flanking the fetal globin genes may contribute to abnormal gene regulation in deletion-type HPFH.

Histone deacetylase inhibitors induce FPGS mRNA expression and intracellular accumulation of long-chain methotrexate polyglutamates in childhood acute lymphoblastic leukemia: implications for combination therapy

“…Nuclei from CCRF-CEM and NALM6 cells were prepared using 0.5% Nonidet-P-40 as described by Elder et al 23 The nuclei were then digested with 0, 10, 20 and 50 U/ml DNaseI and treated with proteinase-K, and nuclear DNA was extracted twice with phenol and chloroform:isoamyl alcohol prior to ethanol precipitation. Total genomic DNA was restricted with BamHI, size-fractionated on 1% agarose gel and transferred to a BrightStar-Plus nylon membrane (Ambion, Austin, TX, USA).…”

Transcriptional repression of the human collagenase-1 (MMP-1) gene in MDA231 breast cancer cells by all-trans-retinoic acid requires distal regions of the promoter

“…This in vivo assay is able to detect and localize domains of altered chromatin structure such as those formed by the binding of transcription factors to enhancers or promoters, and allows the screening of large regions of genomic DNA for potential regulatory elements (Elder et al, 1990;Stamatoyannopolus et al, 1995). The pattern of DNAase I digestion of nuclei from untreated cells is shown in Figure 3A.…”

Characterization of a novel deletion causing (δβ)0‐thalassemia in a Thai family

“…The first sequence located immediately downstream to the 3 0 breakpoint of the HPFH-1and HPFH-2 deletion was shown to act as enhancers in transient transfection assays and in transgenic mice. This region was marked by an erythroid specific DNase I hypersensitive site extending from 1.1 to 1.4 kb 3 0 to the HPFH-1 breakpoint [1][2][3][4]. A second region with enhancer activity in a transient system lies between the breakpoints of HPFH-6 and Chinese G g( A gdb) 0 -thalassemia [4,5].…”