scholarly journals Inactivation of the human beta-globin gene by targeted insertion into the beta-globin locus control region.

1992 ◽  
Vol 6 (6) ◽  
pp. 928-938 ◽  
Author(s):  
C G Kim ◽  
E M Epner ◽  
W C Forrester ◽  
M Groudine
Keyword(s):  
Control Region ◽  
Globin Gene ◽  
Locus Control Region ◽  
Beta Globin ◽  
Beta Globin Gene

scholarly journals Synergistic regulation of human beta-globin gene switching by locus control region elements HS3 and HS4.

1995 ◽  
Vol 9 (24) ◽  
pp. 3083-3096 ◽  
Author(s):  
J Bungert ◽  
U Dave ◽  
K C Lim ◽  
K H Lieuw ◽  
J A Shavit ◽  
...  
Keyword(s):  
Control Region ◽  
Globin Gene ◽  
Locus Control Region ◽  
Beta Globin ◽  
Beta Globin Gene ◽  
Synergistic Regulation ◽  
Gene Switching

scholarly journals A novel deletion of approximately 27 kb including the beta-globin gene and the locus control region 3'HS-1 regulatory sequence: beta zero- thalassemia or hereditary persistence of fetal hemoglobin?

Blood ◽  
1994 ◽  
Vol 83 (3) ◽  
pp. 822-827 ◽  
Author(s):  
AJ Dimovski ◽  
V Divoky ◽  
AD Adekile ◽  
E Baysal ◽  
JB Wilson ◽  
...  
Keyword(s):  
Control Region ◽  
Globin Gene ◽  
Fetal Hemoglobin ◽  
Locus Control Region ◽  
Regulatory Sequence ◽  
Beta Globin ◽  
Gamma Chain ◽  
Beta Globin Gene ◽  
Gamma Globin

Abstract A novel deletion of approximately 27 kb with the 5′ breakpoint 1.5 to 2.2 kb upstream of the beta-globin gene, and the 3′ breakpoint approximately 24 kb downstream of the beta-globin gene, has been found in five members of two families from Southeast Asia (Vietnam and Cambodia). Six members of another family from China, previously reported from our laboratory, have also been shown to carry this deletion. The patients presented with mild hypochromia and microcytosis, a hemoglobin (Hb) A2 level of approximately 4.0%, and a markedly increased, heterocellularly distributed, Hb F level (14.0 to 26.0%). In vitro globin-chain synthesis showed a mild imbalance with appreciable gamma-chain compensation (alpha/beta + gamma ratio of 1.46). The 3′ end of this deletion includes the 3′HS-1, and we hypothesize that removal of this region results in the loss of its gamma-globin gene-silencing effect, which causes a markedly elevated Hb F level with a modest increase in Hb A2 levels, unlike the situation in other deletional beta zero-thalassemias. The possible influence of particular sequence variations in the locus control region 5′HS-2 and the G gamma promoter, present on the chromosome with this deletion, on the overall gamma-globin gene should also be considered.

scholarly journals The human beta-globin locus control region confers an early embryonic erythroid-specific expression pattern to a basic promoter driving the bacterial lacZ gene

Development ◽  
1996 ◽  
Vol 122 (12) ◽  
pp. 3991-3999 ◽  
Author(s):  
R. Tewari ◽  
N. Gillemans ◽  
A. Harper ◽  
M. Wijgerde ◽  
G. Zafarana ◽  
...  
Keyword(s):  
Expression Pattern ◽  
Control Region ◽  
Globin Gene ◽  
Locus Control Region ◽  
Developmental Expression ◽  
Chromatin Conformation ◽  
Lacz Gene ◽  
Beta Globin ◽  
Beta Globin Gene ◽  
Hypersensitive Sites

The beta-globin locus control region (LCR) is contained on a 20 kb DNA fragment and is characterized by the presence of five DNaseI hypersensitive sites in erythroid cells, termed 5′HS1-5. A fully active 6.5 kb version of the LCR, called the muLCR, has been described. Expression of the beta-like globin genes is absolutely dependent on the presence of the LCR. The developmental expression pattern of the genes in the cluster is achieved through competition of the promoters for the activating function of the LCR. Transgenic mice experiments suggest that subtle changes in the transcription factor environment lead to the successive silencing of the embryonic epsilon-globin and fetal gamma-globin promoters, resulting in the almost exclusive transcription of the beta-globin gene in adult erythropoiesis. In this paper, we have asked the question whether the LCR and its individual hypersensitive sites 5′HS1-4 can activate a basic promoter in the absence of any other globin sequences. We have employed a minimal promoter derived from the mouse Hsp68 gene driving the bacterial beta-galactosidase (lacZ) gene. The results show that the muLCR and 5′HS3 direct erythroid-specific, embryonic expression of this construct, while 5′HS1, 5′HS2 and 5′HS4 are inactive at any stage of development. Expression of the muLCR and 5′HS3 transgenes is repressed during fetal stages of development. The transgenes are in an inactive chromatin conformation and the lacZ gene is not transcribed, as shown by in situ hybridization. These data are compatible with the hypothesis that the LCR requires the presence of an active promoter to adopt an open chromatin conformation and with models proposing progressive heterochromatization during embryogenesis. The results suggest that the presence of a beta-globin gene is required for LCR function as conditions become more stringent during development.

scholarly journals Large Deletions Involving the Beta Globin Gene Complex: Genotype-Phenotype Correlation of 119 Cases

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3374-3374
Author(s):  
Molly Susan Hein ◽  
Jennifer L Oliveira ◽  
Kenneth C Swanson ◽  
Patrick A Lundquist ◽  
Joella A Yungerberg ◽  
...  
Keyword(s):  
Control Region ◽  
Globin Gene ◽  
Locus Control Region ◽  
Microcytic Anemia ◽  
Beta Thalassemia ◽  
Gene Complex ◽  
Beta Globin ◽  
Gamma Delta ◽  
Beta Globin Gene ◽  
Large Deletions

Abstract Background: Large deletions involving the beta globin complex are relatively rare. They can be categorized generally into five groups by deletion size and/or location: 1) beta zero thalassemia (BZT); 2) delta beta thalassemia (DBT); 3) hereditary persistence of fetal hemoglobin (HPFH); 4) gamma delta beta thalassemia (GDBT); and 5) epsilon gamma delta beta thalassemia (EGDBT). These deletions are not well understood but often have significant clinical impact, either when present alone or in combination with other hemoglobin mutations. In this study, we analyze phenotypic and molecular data on a large number of cases with deletions in the beta globin gene complex to better classify these five groups of deletions as they occur in isolation. Methods: A query of the routine clinical testing patient files from the Mayo Clinic Metabolic Hematology and Molecular Genetics Laboratories from 2010 to 2015 identified 179 patients with a deletion confirmed by a Multiplex Ligation-dependent Probe Amplification (MLPA) assay. Twenty-four probes sets were placed from the 5' locus control region (LCR) to the 3' hypersensitivity region, spanning the beta globin gene complex. Using a Luminex LX200 flow cytometer, a gene dosage ratio was calculated for each probe set using the median fluorescent intensity value collected. The size and location of the deletion and patient phenotype were compared. Results: Of the 179 total cases, the following large deletions were identified: beta gene (HBB) (n = 47), delta (HBD) through HBB (n = 105), A-gamma (HBG2) through HBB (n = 20), and locus control region (LCR) through HBB (n = 7). One case had a deletion involving the LCR epsilon with the rest of the complex left intact. A subset (n = 60) of cases had compound hemoglobin mutations that altered the phenotype. The BZT cases had relatively high Hb A2 levels and variable Hb F levels consistent with promotor region loss. The main differences between DBT and HPFH included Hb F and Hb A2 levels. GDBT cases presented with median Hb F levels higher than that observed in DBTs, normal Hb A2, and microcytic anemia. EGDBT cases had variable features according to age of the patient and Hb F level; severe microcytic anemia was observed in neonates, milder microcytic anemia in young children, and microcytosis without anemia in an adult case. The phenotypic features of 119 patients with isolated large deletions are compiled in table 1. Conclusion: In general, all five categories of large deletions in an isolated heterozygous state can present with microcytic anemia and are typically benign with the exception of transient severe microcytic anemia in neonatal EGDBT cases. Although phenotypes associated with large deletions involving the beta globin gene complex are frequently distinctive, significant phenotypic overlap can be seen in a subset of cases. These cases require molecular analysis due to their clinical importance when in combination with another beta globin gene complex mutation for an adequate diagnosis and treatment approach. Table 1. Deletion type Age n HbF (%) HbA2 (%) Hb (g/dL) MCV (fL) RBC (10^12/L) RDW (%) MCH (pg/cell) BZT 20 6.3 (0.6-94.4) 6.8 (3.4-11.6) 11.1 (8.3-14.5) 65.4 (60.8-77.2) 5.4 (4.2-6.2) 19.2 (16.6-21.2) 20.9 (18.3-25.7) DBT 56 10.6 (2.7-22.4) 2.7 (2.5-3.1) 11.7 (8.6-14.4) 68.9 (61.3-83.5) 5.3 (4.1-7.3) 21.4 (18.2-26.8) 21.6 (19.9-39.2) HPFH 23 25.9 (17.6-39.7) 2.0 (1.5-2.4) 11.6 (8.1-16.7) 78.4 (60.2-101.9) 4.4 (3.0-6.3) 17.5 (14.1-22.3) 25.4 (17.6-29.7) GDBT 14 13.3 (8.2-19.0) 2.6 (1.8-2.7) 11.0 (8.6-14.1) 72.5 (57.9-82.1) 5.1 (3.5-6.2) 20.6 (17.4-23.5) 22 (17.9-25.1) EGDBT* 28 Y 1 0.3 3 13.3 59.4 6.9 15.4 19.2 1-4 Y 3 0.9 (0-1.6) 3.2 (2.9-3.5) 9.5 (8.8-13.3) 57.8 (57.6-59.4) 5.2 (4.9-6.9) 16.6 (15.4-17.4) 18.5 (18.1-19.2) <6 month 2 21.4 (14.8-27.9) 2.6 (2.2-2.9) 6.3 (6.0-6.6) 61.3 (59.9-62.6) 3.4 (3.3-3.3) 21.5 (21.2-21.7) 18.4 (18.1-18.7) medians, (min, max); *stratified by age Disclosures No relevant conflicts of interest to declare.

Reduced beta-Globin Gene Expression in Adult Mice Containing Deletions of Locus Control Region 5' HS-2 or 5' HS-3a

1998 ◽  
Vol 850 (1 COOLEY'S ANEM) ◽  
pp. 45-53 ◽  
Author(s):  
TIMOTHY J. LEY ◽  
BRUCE HUG ◽  
STEVEN FIERING ◽  
ELLIOT EPNER ◽  
M. A. BENDER ◽  
...  
Keyword(s):  
Gene Expression ◽  
Control Region ◽  
Globin Gene ◽  
Locus Control Region ◽  
Beta Globin ◽  
Beta Globin Gene ◽  
Adult Mice ◽  
Globin Gene Expression

scholarly journals A novel deletion of approximately 27 kb including the beta-globin gene and the locus control region 3'HS-1 regulatory sequence: beta zero- thalassemia or hereditary persistence of fetal hemoglobin?

Blood ◽  
1994 ◽  
Vol 83 (3) ◽  
pp. 822-827
Author(s):  
AJ Dimovski ◽  
V Divoky ◽  
AD Adekile ◽  
E Baysal ◽  
JB Wilson ◽  
...  
Keyword(s):  
Control Region ◽  
Globin Gene ◽  
Fetal Hemoglobin ◽  
Locus Control Region ◽  
Regulatory Sequence ◽  
Beta Globin ◽  
Gamma Chain ◽  
Beta Globin Gene ◽  
Gamma Globin

A novel deletion of approximately 27 kb with the 5′ breakpoint 1.5 to 2.2 kb upstream of the beta-globin gene, and the 3′ breakpoint approximately 24 kb downstream of the beta-globin gene, has been found in five members of two families from Southeast Asia (Vietnam and Cambodia). Six members of another family from China, previously reported from our laboratory, have also been shown to carry this deletion. The patients presented with mild hypochromia and microcytosis, a hemoglobin (Hb) A2 level of approximately 4.0%, and a markedly increased, heterocellularly distributed, Hb F level (14.0 to 26.0%). In vitro globin-chain synthesis showed a mild imbalance with appreciable gamma-chain compensation (alpha/beta + gamma ratio of 1.46). The 3′ end of this deletion includes the 3′HS-1, and we hypothesize that removal of this region results in the loss of its gamma-globin gene-silencing effect, which causes a markedly elevated Hb F level with a modest increase in Hb A2 levels, unlike the situation in other deletional beta zero-thalassemias. The possible influence of particular sequence variations in the locus control region 5′HS-2 and the G gamma promoter, present on the chromosome with this deletion, on the overall gamma-globin gene should also be considered.

scholarly journals Hypersensitive site 5 of the human beta locus control region functions as a chromatin insulator

Blood ◽  
1994 ◽  
Vol 84 (5) ◽  
pp. 1399-1401 ◽  
Author(s):  
Q Li ◽  
G Stamatoyannopoulos
Keyword(s):  
Control Region ◽  
Globin Gene ◽  
Locus Control Region ◽  
Beta Globin ◽  
Hypersensitive Site ◽  
Reporter Expression ◽  
Chromatin Insulator ◽  
Hypersensitive Sites ◽  
Globin Gene Expression ◽  
Beta Gene

Abstract The human beta locus control region (LCR) consists of five DNAse I hypersensitive sites (HS), four of which are erythroid specific and one, the further upstream located 5′HS5, is constitutive. To characterize the function of 5′HS5 we analyzed globin gene expression of various constructs containing HS3 as an enhancer, HS5, and the beta gene as a reporter. Expression was analyzed in stably transfected MEL cells. We found that the enhancing effect of hypersensitive site 3 is blocked when the HS5 is interposed between HS3 and the beta globin gene. These data suggest that the human 5′HS5 has the properties of a chromatin insulator.

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