The intricacies of β-globin gene expression

1994 ◽  
Vol 72 (9-10) ◽  
pp. 377-380 ◽  
Author(s):  
Christi Andrin ◽  
Charlotte Spencer
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Gene Locus ◽  
Developmental Regulation ◽  
Globin Gene ◽  
Globin Genes ◽  
Specific Expression ◽  
Complicated Process ◽  
The Individual ◽  
Globin Gene Expression

Gene expression is an extremely complicated process in which several mechanisms are involved. Owing to its developmental and tissue-specific expression, the β-globin gene is an excellent model for studying gene expression. β-Globin gene expression involves an interplay between several different mechanisms. Chromatin structure is thought to be altered by the locus control region (LCR) located far upstream of the β-globin gene locus. As well, multiple transcription factors come into play both in the LCR and in the individual promoters and enhancers of the β-globin genes. The interaction between these then allows for delicate regulation of β-globin gene expression. In the following review the elaborate system of β-globin gene expression will briefly be examined.Key words: β-globin, gene expression, chromatin, GATA-I, NF-E2, developmental regulation.

Transcriptional Regulation of Erythropoiesis.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. SCI-7-SCI-7
Author(s):  
Mitchell J. Weiss
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Transcriptional Activation ◽  
Zinc Finger Protein ◽  
Conflicts Of Interest ◽  
Globin Gene ◽  
Globin Genes ◽  
Erythroid Development ◽  
Globin Gene Expression

Abstract Abstract SCI-7 Efforts to define the mechanisms of globin gene expression and transcriptional control of erythrocyte formation have provided key insights into our understanding of developmental hematopoiesis. Our group has focused on GATA-1, a zinc finger protein that was initially identified through its ability to bind a conserved cis element that regulates globin gene expression. GATA-1 is essential for erythroid development and mutations in the GATA1 gene are associated with human cytopenias and leukemia. Several general principles have emerged through studies to define the mechanisms of GATA-1 action. First, GATA-1 activates not only globin genes, but also virtually every gene that defines the erythroid phenotype. This observation sparked successful gene discovery efforts to identify new components of erythroid development and physiology. Second, GATA-1 also represses transcription through multiple mechanisms. This property may help to explain how GATA-1 regulates hematopoietic lineage commitment and also how GATA1 mutations contribute to cancer, since several directly repressed targets are proto-oncogenes. Third, GATA-1 regulates not only protein coding genes, but also microRNAs, which in turn, modulate erythropoiesis through post-transcriptional mechanisms. Fourth, GATA-1 interacts with other essential erythroid-specific and ubiquitous transcription factors. These protein interactions regulate gene expression by influencing chromatin modifications and controlling three-dimensional proximity between widely spaced DNA elements. Recently, we have combined transcriptome analysis with ChIP-chip and ChIP-seq studies to correlate in vivo occupancy of DNA by GATA-1 and other transcription factors with mRNA expression genome-wide in erythroid cells. These studies better elucidate how GATA-1 recognizes DNA, discriminates between transcriptional activation versus repression and interacts functionally with other nuclear proteins. I will review published and new aspects of our work in these areas. Disclosures No relevant conflicts of interest to declare.

scholarly journals The Human β Globin Locus Introduced by YAC Transfer Exhibits a Specific and Reproducible Pattern of Developmental Regulation in Transgenic Mice

Blood ◽  
1997 ◽  
Vol 90 (11) ◽  
pp. 4602-4609 ◽  
Author(s):  
Susanna Porcu ◽  
Michael Kitamura ◽  
Ewa Witkowska ◽  
Zemin Zhang ◽  
Annick Mutero ◽  
...  
Keyword(s):  
Gene Expression ◽  
Developmental Regulation ◽  
Globin Gene ◽  
Regulatory Elements ◽  
Regulatory Sequences ◽  
Mrna Levels ◽  
Globin Genes ◽  
Globin Mrna ◽  
Specific Expression ◽  
Artificial Chromosomes

Abstract The human β globin locus spans an 80-kb chromosomal region encompassing both the five expressed globin genes and the cis-acting elements that direct their stage-specific expression during ontogeny. Sequences proximal to the genes and in the locus control region, 60 kb upstream of the adult β globin gene, are required for developmental regulation. Transgenic studies have shown that altering the structural organization of the locus disrupts the normal pattern of globin gene regulation. Procedures for introducing yeast artificial chromosomes (YACs) containing large genetic loci now make it possible to define the sequences required for stage-restricted gene expression in constructs that preserve the integrity of the β globin locus. We demonstrate that independent YAC transgenic lines exhibit remarkably similar patterns of globin gene expression during development. The switch from γ to β globin predominant expression occurs between day 11.5 and 12.5 of gestation, with no more than twofold differences in human β globin mRNA levels between lines. Human β globin mRNA levels were twofold to fourfold lower than that of mouse βmaj, revealing potentially significant differences in the regulatory sequences of the two loci. These findings provide an important basis for studying regulatory elements within the β globin locus.

Role of gene order in developmental control of human gamma- and beta-globin gene expression

1993 ◽  
Vol 13 (8) ◽  
pp. 4836-4843
Author(s):  
K R Peterson ◽  
G Stamatoyannopoulos
Keyword(s):  
Gene Expression ◽  
Gene Order ◽  
Developmental Regulation ◽  
Globin Gene ◽  
Gene Promoters ◽  
Globin Genes ◽  
Beta Globin ◽  
Gamma Globin ◽  
Globin Gene Expression ◽  
Beta Gene

To determine the effect of gene order on globin gene developmental regulation, we produced transgenic mice containing two tandemly arranged gamma- or beta-globin or gamma beta- and beta gamma-globin genes linked to a 2.5-kb cassette containing sequences of the locus control region (LCR). Analysis of constructs containing two identical gamma or beta genes assessed the effect of gene order on globin gene expression, while analysis of constructs containing tandemly arranged gamma and beta genes assessed any additional effects of the trans-acting environment. When two gamma genes were tandemly linked to the LCR, expression from the proximal gamma gene was three- to fourfold higher than expression from the distal gamma gene, and the ratio of proximal to distal gene expression remained unchanged throughout development. Similarly, when two beta genes were tandemly linked to the LCR, the proximal beta gene was predominantly expressed throughout development. These results indicate that proximity to LCR increases gene expression, perhaps by influencing the frequency of interaction between the LCR and globin gene promoters. An arrangement where the gamma gene was proximal and the beta gene distal to the LCR resulted in predominant gamma-gene expression in the embryo. When the order was reversed and the gamma gene was placed distally to the LCR, gamma-gene expression in the embryo was still up to threefold higher than expression of the LCR-proximal beta gene. These findings suggest that the embryonic trans-acting environment interacts preferentially with the gamma genes irrespective of their order or proximity to the LCR. We conclude that promoter competition rather than gene order plays the major role in globin gene switching.

Differences in the Pattern of Histone H3 (K4) and (K27) Methylation throughout the β-Globin Gene Locus in Baboon Fetal Liver and Adult Bone Marrow Erythroblasts Pre- and Post-Decitabine Treatment.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1584-1584
Author(s):  
Janet Chin ◽  
Donald Lavelle ◽  
Kestis Vaitkus ◽  
Maria Hankewych ◽  
Joseph DeSimone
Keyword(s):  
Gene Expression ◽  
Intergenic Region ◽  
Gene Locus ◽  
Fetal Liver ◽  
Globin Gene ◽  
Histone H3 ◽  
Globin Genes ◽  
Alu Sequence ◽  
Adult Bone ◽  
Globin Gene Expression

Abstract Understanding the role of chromatin structure in specifying the pattern of β-like globin gene expression during development would be important in the design of future pharmacologic therapies to increase fetal hemoglobin in patients with sickle cell disease and β-thalassemia. The baboon is an important 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 man, and HbF levels are greatly increased in baboons treated with the DNA methyltransferase inhibitor decitabine (5-aza-2′-deoxycytidine). To investigate the relationship between chromatin structure, DNA methylation, and globin gene regulation, the distribution of acetyl histone H3 (ac-H3), acetyl histone H4 (ac-H4), histone H3 (K4) dimethyl and trimethyl, and histone H3 (K27) dimethyl throughout the β-globin gene locus was determined in purified primary erythroblasts from baboon fetal liver (FL), and adult bone marrow (BM) pre- and post-decitabine treatment. Analysis was performed by chromatin immunoprecipitation (ChIP) of formaldehyde-fixed chromatin followed by real time PCR using 18 primer sets spanning the baboon β-globin gene locus from the 5′ region of the ε-globin gene to the β-globin gene. Comparison of the pattern of ac-H3 and ac-H4 suggested the presence of three subdomains of chromatin within the β-globin locus characterized by different levels of histone acetylation that exhibited a differential response to decitabine treatment. Histone H3 (K4) dimethyl was relatively enriched in the region containing the ε- and γ-globin genes and in the γ-β intergenic region 5′ to the duplicated Alu sequence in FL. Levels associated with the ε-, γ-, and γ-globin genes in adult BM were similar and relatively unaffected by decitabine treatment. In contrast, high levels of histone H3 (K4) trimethylation and pol II distribution were associated with the promoters and transcribed regions of active genes. Differences in the levels of H3 (K4) trimethylation and pol II associated with individual genes were well correlated with differences in their relative levels of expression in FL and adult BM pre- and post-decitabine treatment. The level of histone H3 (K4) trimethyl associated with the promoter of the developmentally inactive ε-globin gene was very low and not enriched compared to inactive necdin gene or the γ-β intergenic regon in adult BM suggesting that the ε-globin gene is not maintained in a “poised” transcriptional state by the presence of the histone H3 (K4) trimethyl mark near the ε-globin promoter. The pattern of histone H3 (K27) dimethyl differed in FL and adult BM. Levels of H3 (K27) dimethyl associated with the ε- and γ-globin genes in FL were 2–4 fold less than near the duplicated Alu sequence in the γ-β intergenic region, while levels were 4–10 fold higher near the ε- and γ-globin genes and γ-β intergenic region compared to the promoter and transcribed region of the β-globin gene in adult BM. Reactivation of γ-globin expression following decitabine treatment was associated with a relative decrease in the level of H3 (K27) dimethyl near the γ-globin gene. Increased H3 (K27) methylation in regions surrounding the silenced ε- and γ-globin genes suggests that the polycomb group (PcG) protein EZH2, a histone H3 (K27) methyltransferase, may be involved in globin gene silencing.

scholarly journals The Human β Globin Locus Introduced by YAC Transfer Exhibits a Specific and Reproducible Pattern of Developmental Regulation in Transgenic Mice

Blood ◽  
1997 ◽  
Vol 90 (11) ◽  
pp. 4602-4609 ◽  
Author(s):  
Susanna Porcu ◽  
Michael Kitamura ◽  
Ewa Witkowska ◽  
Zemin Zhang ◽  
Annick Mutero ◽  
...  
Keyword(s):  
Gene Expression ◽  
Developmental Regulation ◽  
Globin Gene ◽  
Regulatory Elements ◽  
Regulatory Sequences ◽  
Mrna Levels ◽  
Globin Genes ◽  
Globin Mrna ◽  
Specific Expression ◽  
Artificial Chromosomes

The human β globin locus spans an 80-kb chromosomal region encompassing both the five expressed globin genes and the cis-acting elements that direct their stage-specific expression during ontogeny. Sequences proximal to the genes and in the locus control region, 60 kb upstream of the adult β globin gene, are required for developmental regulation. Transgenic studies have shown that altering the structural organization of the locus disrupts the normal pattern of globin gene regulation. Procedures for introducing yeast artificial chromosomes (YACs) containing large genetic loci now make it possible to define the sequences required for stage-restricted gene expression in constructs that preserve the integrity of the β globin locus. We demonstrate that independent YAC transgenic lines exhibit remarkably similar patterns of globin gene expression during development. The switch from γ to β globin predominant expression occurs between day 11.5 and 12.5 of gestation, with no more than twofold differences in human β globin mRNA levels between lines. Human β globin mRNA levels were twofold to fourfold lower than that of mouse βmaj, revealing potentially significant differences in the regulatory sequences of the two loci. These findings provide an important basis for studying regulatory elements within the β globin locus.

scholarly journals Role of gene order in developmental control of human gamma- and beta-globin gene expression.

1993 ◽  
Vol 13 (8) ◽  
pp. 4836-4843 ◽  
Author(s):  
K R Peterson ◽  
G Stamatoyannopoulos
Keyword(s):  
Gene Expression ◽  
Gene Order ◽  
Developmental Regulation ◽  
Globin Gene ◽  
Gene Promoters ◽  
Globin Genes ◽  
Beta Globin ◽  
Gamma Globin ◽  
Globin Gene Expression ◽  
Beta Gene

To determine the effect of gene order on globin gene developmental regulation, we produced transgenic mice containing two tandemly arranged gamma- or beta-globin or gamma beta- and beta gamma-globin genes linked to a 2.5-kb cassette containing sequences of the locus control region (LCR). Analysis of constructs containing two identical gamma or beta genes assessed the effect of gene order on globin gene expression, while analysis of constructs containing tandemly arranged gamma and beta genes assessed any additional effects of the trans-acting environment. When two gamma genes were tandemly linked to the LCR, expression from the proximal gamma gene was three- to fourfold higher than expression from the distal gamma gene, and the ratio of proximal to distal gene expression remained unchanged throughout development. Similarly, when two beta genes were tandemly linked to the LCR, the proximal beta gene was predominantly expressed throughout development. These results indicate that proximity to LCR increases gene expression, perhaps by influencing the frequency of interaction between the LCR and globin gene promoters. An arrangement where the gamma gene was proximal and the beta gene distal to the LCR resulted in predominant gamma-gene expression in the embryo. When the order was reversed and the gamma gene was placed distally to the LCR, gamma-gene expression in the embryo was still up to threefold higher than expression of the LCR-proximal beta gene. These findings suggest that the embryonic trans-acting environment interacts preferentially with the gamma genes irrespective of their order or proximity to the LCR. We conclude that promoter competition rather than gene order plays the major role in globin gene switching.

scholarly journals Identification of a Novel Enhancer/Chromatin Opening Element Associated with High-Level γ-Globin Gene Expression

2018 ◽  
Vol 38 (19) ◽  
Author(s):  
Yong Shen ◽  
MacLean A. Bassett ◽  
Aishwarya Gurumurthy ◽  
Rukiye Nar ◽  
Isaac J. Knudson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Globin Gene ◽  
Erythroid Cell ◽  
Globin Genes ◽  
Chromosome 11 ◽  
Erythroleukemia Cell ◽  
High Level ◽  
Globin Gene Expression

ABSTRACT The organization of the five β-type globin genes on chromosome 11 reflects the timing of expression during erythroid cell development, with the embryonic ε-globin gene being located at the 5′ end, followed by the two fetal γ-globin genes, and with the adult β- and δ-globin genes being located at the 3′ end. Here, we functionally characterized a DNase I-hypersensitive site (HS) located 4 kb upstream of the Gγ-globin gene (HBG-4kb HS). This site is occupied by transcription factors USF1, USF2, EGR1, MafK, and NF-E2 in the human erythroleukemia cell line K562 and exhibits histone modifications typical for enhancers. We generated a synthetic zinc finger (ZF) DNA-binding domain targeting the HBG-4kb HS (HBG-4kb ZF). The HBG-4kb ZF interacted with the target site in vitro and in the context of cells with a high affinity and specificity. Direct delivery of the HBG-4kb ZF to K562 and primary human erythroid cells caused a reduction in γ-globin gene expression which was associated with decreased binding of transcription factors and active histone marks at and downstream of the HS. The data demonstrate that the HBG-4kb HS is important for fetal globin production and suggest that it may act by opening chromatin in a directional manner.

scholarly journals Mi2β-mediated silencing of the fetal γ-globin gene in adult erythroid cells

Blood ◽  
2013 ◽  
Vol 121 (17) ◽  
pp. 3493-3501 ◽  
Author(s):  
Maria Amaya ◽  
Megha Desai ◽  
Merlin Nithya Gnanapragasam ◽  
Shou Zhen Wang ◽  
Sheng Zu Zhu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Major Part ◽  
Globin Gene ◽  
Globin Genes ◽  
Erythroid Cells ◽  
Key Points ◽  
Globin Gene Expression ◽  
Partial Depletion

Key Points Mi2β exerts a major part of its silencing effect on embryonic and fetal globin genes by positively regulating the BCL11A and KLF1 genes. Partial depletion of Mi2β induces increased γ-globin gene expression in primary human erythroid cells without impairing differentiation.

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 Targeted inactivation of the major positive regulatory element (HS-40) of the human alpha-globin gene locus

Blood ◽  
1995 ◽  
Vol 86 (3) ◽  
pp. 1202-1211 ◽  
Author(s):  
A Bernet ◽  
S Sabatier ◽  
DJ Picketts ◽  
R Ouazana ◽  
F Morle ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Locus ◽  
Regulatory Element ◽  
Globin Gene ◽  
Marker Gene ◽  
Regulatory Elements ◽  
Target System ◽  
Flp Recombinase ◽  
Alpha Globin ◽  
Globin Gene Expression

Abstract We have examined the role of the major positive upstream regulatory element of the human alpha-globin gene locus (HS-40) in its natural chromosomal context. Using homologous recombination, HS-40 was replaced by a neo marker gene in a mouse erythroleukemia hybrid cell line containing a single copy of human chromosome 16. In clones from which HS-40 had been deleted, human alpha-globin gene expression was severely reduced, although basal levels of alpha 1 and alpha 2-globin mRNA expression representing less than 3% of the level in control cell lines were detected. Deletion of the neo marker gene, by using FLP recombinase/FLP recombinase target system, proved that the phenotype observed was not caused by the regulatory elements of this marker gene. In the targeted clones, deletion of HS-40 apparently does not affect long-range or local chromatin structure at the alpha promoters. Therefore, these results indicate that, in the experimental system used, HS-40 behaves as a strong inducible enhancer of human alpha- globin gene expression.

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