scholarly journals Structural and Functional Cross-Talk between a Distant Enhancer and the ɛ-Globin Gene Promoter Shows Interdependence of the Two Elements in Chromatin

1999 ◽  
Vol 19 (11) ◽  
pp. 7600-7609 ◽  
Author(s):  
Jennifer C. McDowell ◽  
Ann Dean
Keyword(s):  
Globin Gene ◽  
Gene Promoter ◽  
Transcription Activation ◽  
Tata Box ◽  
Globin Genes ◽  
Hypersensitive Site ◽  
Nuclease Digestion ◽  
Dnase I Hypersensitive Site ◽  
Globin Promoter ◽  
Gata Motif

ABSTRACT We investigated the requirements for enhancer-promoter communication by using the human β-globin locus control region (LCR) DNase I-hypersensitive site 2 (HS2) enhancer and the ɛ-globin gene in chromatinized minichromosomes in erythroid cells. Activation of globin genes during development is accompanied by localized alterations of chromatin structure, and CACCC binding factors and GATA-1, which interact with both globin promoters and the LCR, are believed to be critical for globin gene transcription activation. We found that an HS2 element mutated in its GATA motif failed to remodel the ɛ-globin promoter or activate transcription yet HS2 nuclease accessibility did not change. Accessibility and transcription were reduced at promoters with mutated GATA-1 or CACCC sites. Strikingly, these mutations also resulted in reduced accessibility at HS2. In the absence of a globin gene, HS2 is similarly resistant to nuclease digestion. In contrast to observations in Saccharomyces cerevisiae, HS2-dependent promoter remodeling was diminished when we mutated the TATA box, crippling transcription. This mutation also reduced HS2 accessibility. The results indicate that the ɛ-globin promoter and HS2 interact both structurally and functionally and that both upstream activators and the basal transcription apparatus contribute to the interaction. Further, at least in this instance, transcription activation and promoter remodeling by a distant enhancer are not separable.

scholarly journals Substitution of the Human β-Spectrin Promoter for the Human Aγ-Globin Promoter Prevents Silencing of a Linked Human β-Globin Gene in Transgenic Mice

1998 ◽  
Vol 18 (11) ◽  
pp. 6634-6640 ◽  
Author(s):  
Denise E. Sabatino ◽  
Amanda P. Cline ◽  
Patrick G. Gallagher ◽  
Lisa J. Garrett ◽  
George Stamatoyannopoulos ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Fetal Liver ◽  
Globin Gene ◽  
Gene Promoter ◽  
Yolk Sac ◽  
Globin Genes ◽  
Erythroid Cells ◽  
Globin Mrna ◽  
Globin Promoter ◽  
In Erythroid Cells

ABSTRACT During development, changes occur in both the sites of erythropoiesis and the globin genes expressed at each developmental stage. Previous work has shown that high-level expression of human β-like globin genes in transgenic mice requires the presence of the locus control region (LCR). Models of hemoglobin switching propose that the LCR and/or stage-specific elements interact with globin gene sequences to activate specific genes in erythroid cells. To test these models, we generated transgenic mice which contain the human Aγ-globin gene linked to a 576-bp fragment containing the human β-spectrin promoter. In these mice, the β-spectrin Aγ-globin (βsp/Aγ) transgene was expressed at high levels in erythroid cells throughout development. Transgenic mice containing a 40-kb cosmid construct with the micro-LCR, βsp/Aγ-, ψβ-, δ-, and β-globin genes showed no developmental switching and expressed both human γ- and β-globin mRNAs in erythroid cells throughout development. Mice containing control cosmids with the Aγ-globin gene promoter showed developmental switching and expressed Aγ-globin mRNA in yolk sac and fetal liver erythroid cells and β-globin mRNA in fetal liver and adult erythroid cells. Our results suggest that replacement of the γ-globin promoter with the β-spectrin promoter allows the expression of the β-globin gene. We conclude that the γ-globin promoter is necessary and sufficient to suppress the expression of the β-globin gene in yolk sac erythroid cells.

scholarly journals Transcriptional role of a conserved GATA-1 site in the human epsilon-globin gene promoter.

1991 ◽  
Vol 11 (5) ◽  
pp. 2558-2566 ◽  
Author(s):  
Q H Gong ◽  
J Stern ◽  
A Dean
Keyword(s):  
Globin Gene ◽  
Point Mutations ◽  
Gene Promoter ◽  
Globin Genes ◽  
Mobility Shift ◽  
Dnase I Footprinting ◽  
Nuclear Extracts ◽  
Protein Dna Interactions ◽  
Globin Promoter

The epsilon-globin gene is the first of the human beta-like globin genes to be expressed during development. We have analyzed protein-DNA interactions in the epsilon-globin promoter region by DNase I footprinting and electrophoretic mobility shift experiments using nuclear extracts from K562 human erythroid cells and from nonerythroid HeLa cells. A restricted set of ubiquitous proteins, including Sp1, bound to regions of the promoter including the CACCC and CCAAT sites. Three interactions, at positions -213, -165, and +3 relative to the transcription start site, were erythroid specific and corresponded to binding of GATA-1, a transcription factor highly restricted to the erythroid lineage. Interestingly, the GATA-1 site at -165 has been conserved in the promoters of 10 mammalian embryonic globin genes. Point mutations demonstrate that GATA-1 binding to this site is necessary for interaction with an erythroid-specific enhancer but that in the absence of an enhancer, GATA-1 does not increase transcription.

Methylation of α-type embryonic globin gene απrepresses transcription in primary erythroid cells

Blood ◽  
2002 ◽  
Vol 100 (12) ◽  
pp. 4217-4222 ◽  
Author(s):  
Rakesh Singal ◽  
Jane M. vanWert ◽  
Larry Ferdinand
Keyword(s):  
Globin Gene ◽  
Gene Promoter ◽  
Luciferase Reporter ◽  
Globin Genes ◽  
Erythroid Cells ◽  
Histone H4 ◽  
Luciferase Reporter Gene ◽  
Cpg Dinucleotides ◽  
Expression Construct ◽  
Globin Promoter

The inverse relationship between expression and methylation of β-type globin genes is well established. However, little is known about the relationship between expression and methylation of avian α-type globin genes. The embryonicαπ-globin promoter was unmethylated, andαπ-globin RNA was easily detected in 5-day chicken erythroid cells. A progressive methylation of the CpG dinucleotides in the απ promoter associated with loss of expression of απ-globin gene was seen during development in primary erythroid cells. A 315-bpαπ-globin promoter region was cloned in an expression construct (απpGL3E) containing a luciferase reporter gene and SV40 enhancer. The απpGL3E construct was transfected into primary erythroid cells derived from 5-day-old chicken embryos. Methylation of απpGL3E plasmid andαπ-globin promoter alone resulted in a 20-fold and 7-fold inhibition of expression, respectively. The fully methylated but not the unmethylated 315-bpαπ-globin gene promoter fragment formed amethyl cytosine-binding proteincomplex (MeCPC). Chromatin immunoprecipitation assays were combined with quantitative real-time polymerase chain reaction to assess histone acetylation associated with theαπ-globin gene promoter. Slight hyperacetylation of histone H3 but a marked hyperacetylation of histone H4 was seen in 5-day when compared with 14-day erythroid cells. These results demonstrate that methylation can silence transcription of an avian α-type embryonic globin gene in homologous primary erythroid cells, possibly by interacting with an MeCPC and histone deacetylase complex.

Regulation of Chromatin Looping and Transcription by PRMT1 Mediated H4R3 Methylation.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1864-1864
Author(s):  
Xingguo Li ◽  
Xin Hu ◽  
Zhuo Zhou ◽  
Yi Qiu ◽  
Gary Felsenfeld ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Long Range ◽  
Transcriptional Activation ◽  
Globin Gene ◽  
Gene Promoter ◽  
Globin Genes ◽  
Functional Link ◽  
Chromatin Interactions ◽  
Globin Promoter ◽  
Transcription Complexes

Abstract Communication between distal enhancers and proximal promoters is critical in controlling proper transcription of genes. However, the functional link between certain histone modifications and the formation of long-range chromatin interactions involved in transcriptional activation remains unknown. In the globin locus, the b-globin genes are regulated by highly organized chromatin structure that juxtaposes the locus control region (LCR) located far upstream of the genes with the proximal b-major globin promoter (bmajpromoter). We report here that the localized asymmetric dimethylation of Arg3 at histone H4 tails (dimethyl H4R3) catalyzed by the methyltransferase PRMT1 is essential for establishing the long-range chromatin interactions between the LCR and the bmaj-promoter and strongly correlates with the activation of adult b-globin gene transcription. In addition, dimethyl H4R3 potentiates the recruitment of histone acetyltransferases (HATs), CBP and PCAF, and is required for the establishment of subsequent histone acetylation at the globin locus. Suppression of PRMT1 activity disrupts the recruitment of transcription complexes, TBP and RNA polymerase II (RNA Pol II), at the active b-globin promoter, but not at the LCR. Taken together, our data implicate PRMT1-mediated dimethylation of H4R3 in the regulation of long-range enhancer/promoter communications, which are required for the efficient recruitment of transcription complexes to the active gene promoter.

Transcriptional role of a conserved GATA-1 site in the human epsilon-globin gene promoter

1991 ◽  
Vol 11 (5) ◽  
pp. 2558-2566
Author(s):  
Q H Gong ◽  
J Stern ◽  
A Dean
Keyword(s):  
Globin Gene ◽  
Point Mutations ◽  
Gene Promoter ◽  
Globin Genes ◽  
Mobility Shift ◽  
Dnase I Footprinting ◽  
Nuclear Extracts ◽  
Protein Dna Interactions ◽  
Globin Promoter

The epsilon-globin gene is the first of the human beta-like globin genes to be expressed during development. We have analyzed protein-DNA interactions in the epsilon-globin promoter region by DNase I footprinting and electrophoretic mobility shift experiments using nuclear extracts from K562 human erythroid cells and from nonerythroid HeLa cells. A restricted set of ubiquitous proteins, including Sp1, bound to regions of the promoter including the CACCC and CCAAT sites. Three interactions, at positions -213, -165, and +3 relative to the transcription start site, were erythroid specific and corresponded to binding of GATA-1, a transcription factor highly restricted to the erythroid lineage. Interestingly, the GATA-1 site at -165 has been conserved in the promoters of 10 mammalian embryonic globin genes. Point mutations demonstrate that GATA-1 binding to this site is necessary for interaction with an erythroid-specific enhancer but that in the absence of an enhancer, GATA-1 does not increase transcription.

Human globin gene promoter sequences are sufficient for specific expression of a hybrid gene transfected into tissue culture cells

1987 ◽  
Vol 7 (1) ◽  
pp. 398-402
Author(s):  
T Rutherford ◽  
A W Nienhuis
Keyword(s):  
Gene Expression ◽  
Globin Gene ◽  
Gene Promoter ◽  
Gene Promoters ◽  
Globin Genes ◽  
Specific Expression ◽  
Tissue Specific ◽  
Promoter Sequences ◽  
Erythroleukemia Cells ◽  
Murine Erythroleukemia

The contribution of the human globin gene promoters to tissue-specific transcription was studied by using globin promoters to transcribe the neo (G418 resistance) gene. After transfection into different cell types, neo gene expression was assayed by scoring colony formation in the presence of G418. In K562 human erythroleukemia cells, which express fetal and embryonic globin genes but not the adult beta-globin gene, the neo gene was expressed strongly from a fetal gamma- or embryonic zeta-globin gene promoter but only weakly from the beta promoter. In murine erythroleukemia cells which express the endogenous mouse beta genes, the neo gene was strongly expressed from both beta and gamma promoters. In two nonerythroid cell lines, human HeLa cells and mouse 3T3 fibroblasts, the globin gene promoters did not allow neo gene expression. Globin-neo genes were integrated in the erythroleukemia cell genomes mostly as a single copy per cell and were transcribed from the appropriate globin gene cap site. We conclude that globin gene promoter sequences extending from -373 to +48 base pairs (bp) (relative to the cap site) for the beta gene, -385 to +34 bp for the gamma gene, and -555 to +38 bp for the zeta gene are sufficient for tissue-specific and perhaps developmentally specific transcription.

scholarly journals Characterization of the DNase I hypersensitive site 3' of the human beta globin gene domain

Blood ◽  
1993 ◽  
Vol 81 (10) ◽  
pp. 2781-2790
Author(s):  
DE Fleenor ◽  
RE Kaufman
Keyword(s):  
Topoisomerase Ii ◽  
Globin Gene ◽  
Dnase I ◽  
Globin Genes ◽  
Beta Globin ◽  
Hypersensitive Site ◽  
Mobility Shift ◽  
Enhancer Activity ◽  
Beta Globin Gene

The members of the human beta globin gene family are flanked by strong DNase I hypersensitive sites. The collection of sites 5' to the epsilon globin gene is able to confer high levels of expression of linked globin genes, but a function has not been assigned to the site 3' to the beta globin gene (3'HS1). Our analysis of this DNase I super hypersensitive site shows that the region is composed of multiple DNase I sites. By examination of the DNA sequence, we have determined that the region is very A/T-rich and contains topoisomerase II recognition sequences, as well as several consensus binding motifs for GATA-1 and AP-1/NF-E2. Gel mobility shift assays indicate that the region can interact in vitro with GATA-1 and AP-1/NF-E2, and functional studies show that the region serves as a scaffold attachment region in both erythroid and nonerythroid cell lines. Whereas many of the physical features of 3'HS1 are shared by 5'HS2 (a component of the 5' locus control region), transient expression studies show that 3' HS1 does not share the erythroid-specific enhancer activity exhibited by 5'HS2.

scholarly journals Sardinian G gamma-HPFH: a T----C substitution in a conserved "octamer" sequence in the G gamma-globin promoter

Blood ◽  
1988 ◽  
Vol 71 (3) ◽  
pp. 815-817 ◽  
Author(s):  
S Ottolenghi ◽  
S Nicolis ◽  
R Taramelli ◽  
N Malgaretti ◽  
R Mantovani ◽  
...  
Keyword(s):  
Globin Gene ◽  
Single Point ◽  
Point Mutations ◽  
Fetal Hemoglobin ◽  
Regulatory Elements ◽  
Globin Genes ◽  
Gamma Globin ◽  
New Type ◽  
Hereditary Persistence ◽  
Globin Promoter

Abstract A survey of hemoglobinopathies in Northern Sardinia allowed the identification of two subjects heterozygous for a new type of G gamma hereditary persistence of fetal hemoglobin (HPFH). The G gamma-globin gene from the HPFH chromosome shows the presence of a T----C substitution 175 nucleotides upstream of the CAP site, adding a new example of single-point mutations occurring in the promoter region of the gamma-globin genes and linked to HPFH phenotypes. In this case the mutation affects the 3′ end nucleotide of a conserved octamer sequence known to be present in other regulatory elements of several genes.

Subdomains of the Baboon (P. anubis) β-Globin Gene Cluster Are Differentially Sensitive to Dacogen Treatment.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 525-525
Author(s):  
Janet Chin ◽  
Donald Lavelle ◽  
Bryan Roxas ◽  
Kestis Vaitkus ◽  
Maria Hankewych ◽  
...  
Keyword(s):  
Gene Expression ◽  
Histone Acetylation ◽  
Intergenic Region ◽  
Globin Gene ◽  
Globin Genes ◽  
Gene Complex ◽  
Alu Sequence ◽  
Low Levels ◽  
Globin Promoter ◽  
Globin Gene Expression

Abstract Understanding the mechanism responsible for the developmental regulation of the β-like globin genes would be important in the design of future pharmacologic therapies to increase fetal hemoglobin (HbF) in patients with sickle cell disease and β-thalassemia. The baboon is a valuable and relevant experimental animal model to study the regulation of globin gene expression because the structure of the β-globin gene complex and developmental pattern of globin gene expression are similar to human, and HbF levels are greatly increased following treatment of baboons with the DNA methyltransferase inhibitor Dacogen (5-aza-2′-deoxycytidine; DAC). To investigate the relationship between DNA methylation, chromatin structure and globin gene expression, the pattern of acetylated histone H3 (ac-H3) and H4 (ac-H4) within the β-globin gene complex was compared in purified erythroblasts from baboon fetal liver (FL; n=2) and bone marrow (ABM; n=2) of adult baboons pre and post DAC treatment. HbF increased to high levels (67.8%, 61.9%) in respective animals and methylation of 18 CpG sites within the ε- and γ globin genes was reduced >50% following DAC treatment. Enrichment of ac-H3 and ac-H4 throughout the β-globin gene complex was measured by chromatin immunoprecipitation (ChIP) followed by real time PCR. In FL, equivalent levels of ac-H3 and ac-H4 were observed near the ε-globin and γ-globin promoters that were 3 fold higher than near the Aγ-enhancer and pseudo-β gene and 5–14 fold higher than near the β-globin promoter. In pretreatment ABM, levels of ac-H3 and ac-H4 near the β-globin promoter were 4–6 fold greater than near the γ-globin promoter, Aγ-enhancer, and pseudo-β gene and 10-15 fold higher than near the ε-globin promoter. The lowest levels of histone acetylation were observed in a 6kb subdomain within the γ-β intergenic region extending from the duplicated Alu sequence to 3′ of the δ-globin gene. Following DAC treatment, histone acetylation of the ε-, γ-, and pseudo-β genes and Aγ-enhancer increased 4-10 fold, while histone acetylation of the β-globin gene remained unchanged. This resulted in equivalent levels of histone acetylation associated with the γ-globin gene, Aγ-enhancer, pseudo-β-, and β-globin genes that were 3 fold greater than with the ε-globin gene. The levels of histone acetylation within the 6 kb subdomain of the γ-β intergenic region remained low. Our results suggest that three subdomains of chromatin are present within the baboon β-globin gene complex. One subdomain that encompasses the ε-, γ-, and pseudo-β genes is characterized by high levels of histone acetylation in FL and low levels in ABM. DAC treatment increases histone acetylation within this region to levels observed near the β-globin gene. A second subdomain near the β-globin gene is characterized by high levels of histone acetylation in ABM and low levels in FL. Histone acetylation of the β-globin gene within this subdomain remains high following DAC. A third subdomain found within the γ-β intergenic region surrounding the duplicated Alu sequences is characterized by a low level of histone acetylation in both FL and ABM. The level of histone acetylation of this region remains low following DAC. We conclude that three chromatin subdomains within the β-globin gene complex are differentially sensitive to DAC-induced changes in histone acetylation.

Differential Modulation of the β-Like Globin Genes by KLFs Isolated with a γ-Globin CACCC Bait.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3637-3637
Author(s):  
Paolo Moi ◽  
Loredana Porcu ◽  
Maria G. Marini ◽  
Isadora Asunis ◽  
Maria G. Loi ◽  
...  
Keyword(s):  
Cell Lines ◽  
Globin Gene ◽  
K562 Cells ◽  
Tissue Expression ◽  
Pcr Analysis ◽  
Globin Genes ◽  
Band Shift ◽  
Hemoglobin Switching ◽  
Specific Complex ◽  
Globin Promoter

Abstract The globin CACCC boxes are absolutely required for the appropriate regulation of the β-like globin genes. While the β-globin CACCC box binds EKLF/KLF1, a likely adult switching factor, analogous factors, interacting with the γ-globin gene and predicted to regulate the fetal stage of hemoglobin switching, have so far been elusive. By using yeast one hybrid assay, we have isolated four KLFs, KLF1, 2, 4, and 6, that bound the γ-CACCC bait. To establish their role in globin regulation and in the switching of hemoglobins, these factors were compared to four other KLFs already established or putative globin regulators, KLF3, 11, 13 and 16, mainly evaluating their ability to bind and transactivate the ε-, γ- and β-globin gene. γ-CACCC binding at variable intensities was confirmed in band shift assay for all four isolated KLFs, for KLF3 and, faintly, for KLF13. The ε- and β-CACCC were bound by the same factors with similar affinities with the exception of KLF3 and KLF13 that bound stronger to the β- and ε- than to the γ-CACCC box. On the other hand, KLF11 and 16 did not produce any specific complex in band shift assays with anyone of the globin CACCC boxes. More relevant differences were observed among the factors in the transactivation of single and dual luciferase reporters in both K562 and MEL cells. In these assays, most factors presented peculiar modulatory properties and specific promoter tropism. Several factors presented bidirectional activity displaying in the same time the capacity to stimulate and repress different globin promoters. KLF1 and 4 were the strongest stimulators of the β-globin promoter in both cell lines, whereas KLF2 activated the β-promoter only in K562 cells. KLF1 and especially KLF4 consistently repressed ε-globin expression especially in MEL cells. KLF3 behaved always as a general globin repressor in MEL cells, but acted as a weak stimulator of the γ- and ε-promoter in K562 cells. KLF4 was the strongest inhibitor of the ε-globin gene. KLF13 significantly stimulated the γ-promoter in both cell lines, whereas KLF3, 4 and 6 showed statistically significant stimulation only in MEL cells. By RT-PCR analysis we found that KLFs were highly variable in their tissue expression and that KLF1, 3 and 13 had the highest expression in erythroid tissues. Thus the level of tissue expression should ultimately determine which factors are really active in physiological conditions. Taken together our binding and expression studies suggest that several KLFs have the potential to modulate the activity of the globin genes and that the resulting globin expression will depend on the vectorial sum of the relative activities of the factors expressed at any given time of development. Furthermore, as some KLFs, like KLF1 and 4, exert opposite effects on fetal and adult globin genes, their role in hemoglobin switching may be direct and not only dependent on their ability to mediate promoter competition for the LCR.

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