The inverse relationship between expression and methylation of -type globin genes is well established. However, little is known about the relationship between expression and methylation of avian -type globin genes. The embryonic globin promoter was unmethylated, and -globin RNA was easily detected in 5-day chicken erythroid cells. A progressive methylation of the CpG dinucleotides in the promot...

Changes in gamma-globin gene methylation accompany the fetal to adult globin switch in man. Using somatic cell hybrids made by fusing mouse erythroleukemia and human fetal erythroid cells, we asked whether methylation is a cause or a consequence of gamma-gene inactivation during development. These hybrids initially express human gamma-globin but switch with time in culture to adult globin gene ...

BACKGROUND Human globin gene expression is precisely regulated by a complicated network of transcription factors and chromatin modifying activities during development and erythropoiesis. Eos (Ikaros family zinc finger 4, IKZF4), a member of the zinc finger transcription factor Ikaros family, plays a pivotal role as a repressor of gene expression. The aim of this study was to examine the role of...

A variant of hereditary persistence of fetal hemoglobin (HPFH), first described in a patient from Seattle, was studied by structural analysis of the gamma-globin genes. A family study suggested that the determinant for this form of HPFH, in which the HbF contains both G gamma- and A gamma-globin chains, segregated with the beta S gene. No deletions or other abnormalities were detected in the fe...

We have mapped the DNase I-hypersensitive sites around the epsilon-globin and c-myc genes in two human leukemia cell lines K562 and HL60. In K562 cells in which the epsilon-globin gene is transcribed, six DNase I-hypersensitive sites are found in 6 kilobases (kb) of upstream flanking DNA; in HL60 cells in which the c-myc gene is expressed, two DNase I-hypersensitive sites are observed in 2 kb o...

Globin messenger RNA (mRNA) isolated from three patients homozygous for hemoglobin Lepore is shown to have a marked reduction of the amount of beta-like globin mRNA (Lepore-globin mRNA sequences) compared with alpha-globin mRNA by molecular hybridization. The relative amounts of alpha- and Lepore mRNA are similar to the amounts of alpha- and Lepore globin synthesized in intact cells and by isol...

Many human globin-chain mutants contain amino acid replacements that result from single base changes in the corresponding globin gene. Using recombinants, the coding sequences of each of the alpha-, beta-, Ggamma-, and Agamma-globin genes have now been determined. Those sequences of DNA that are cleaved by a number of specific restriction endonucleases have been identified and accurately positi...

Distal enhancers commonly contact target promoters via chromatin looping. In erythroid cells, the locus control region (LCR) contacts β-type globin genes in a developmental stage-specific manner to stimulate transcription. Previously, we induced LCR-promoter looping by tethering the self-association domain (SA) of Ldb1 to the β-globin promoter via artificial zinc fingers. Here, we show that tar...

The αand β-globin gene families of jawed vertebrates have diversified with respect to both gene function and the developmental timing of gene expression. Phylogenetic reconstructions of globin gene family evolution have provided suggestive evidence that the developmental regulation of hemoglobin synthesis has evolved independently in multiple vertebrate lineages. For example, the embryonic β-li...

Beta-globin gene families in eutherians (placental mammals) consist of a set of four or more developmentally regulated genes which are closely linked and, in general, arranged in the order 5'-embryonic/fetal genes-adult genes-3'. This cluster of genes is proposed to have arisen by tandem duplication of ancestral beta-globin genes, with the first duplication occurring 200 to 155 MYBP just prior ...