Binding of Nuclear Factors to the Proximal and Distal CACCC Motifs of the Beta-Globin Gene Promoter: Implications for the -101 (C→T) ‘Silent’ Beta-Thalassemia Mutation

1994 ◽  
Vol 91 (1) ◽  
pp. 16-20 ◽  
Author(s):  
Erol Baysal ◽  
Leticia S. Ribeiro ◽  
Titus H.J. Huisman
Keyword(s):  
Globin Gene ◽  
Gene Promoter ◽  
Beta Thalassemia ◽  
Beta Globin ◽  
Beta Globin Gene ◽  
Nuclear Factors ◽  
Thalassemia Mutation

scholarly journals Observations on the levels of Hb A2 in patients with different beta- thalassemia mutations and a delta chain variant

Blood ◽  
1990 ◽  
Vol 76 (6) ◽  
pp. 1246-1249 ◽  
Author(s):  
JF Codrington ◽  
HW Li ◽  
F Kutlar ◽  
LH Gu ◽  
M Ramachandran ◽  
...  
Keyword(s):  
Promoter Activity ◽  
Globin Gene ◽  
Gene Promoter ◽  
General Mechanism ◽  
Beta Thalassemia ◽  
Beta Globin ◽  
Beta Chain ◽  
Beta Globin Gene ◽  
In Trans ◽  
In Cis

Abstract Hb A2 and its variant B2 (alpha 2 delta 2(16)(A13)Gly----Arg) were quantitated in the blood of subjects with three different types of beta- thalassemia and with the delta-B2 anomaly in cis or in trans to the beta-thalassemia determinant. In one family, the delta-B2 mutation was in cis to a newly discovered codon 47 (+A) frameshift. The levels of Hbs A2 and B2 were nearly the same and approximately 70% higher than those in simple Hb B2 heterozygotes. In two additional families, the delta-B2 variant was in trans to either a deletional beta-thalassemia (1,393 bp) involving part of the beta-globin gene and part of the beta- globin gene promoter, or to the -88 C----T promoter mutation. In both instances, the Hb B2 level was increased by approximately 80%, but the Hb A2 level was increased by approximately 270% and 200%, respectively. These data indicate two mechanisms that will cause an increase in delta chain production. One is consistent with a general mechanism concerning the relative excess of alpha chains in beta chain deficiencies which will combine with delta chains to form variable levels of Hb A2 dependent on the severity of the beta chain deficiency. The second concerns the loss of beta-globin gene promoter activity, perhaps by an absence of (or decreased) binding of specific protein(s) to this segment of DNA and a concomitant increase in delta-globin gene promoter activity in cis.

scholarly journals Observations on the levels of Hb A2 in patients with different beta- thalassemia mutations and a delta chain variant

Blood ◽  
1990 ◽  
Vol 76 (6) ◽  
pp. 1246-1249
Author(s):  
JF Codrington ◽  
HW Li ◽  
F Kutlar ◽  
LH Gu ◽  
M Ramachandran ◽  
...  
Keyword(s):  
Promoter Activity ◽  
Globin Gene ◽  
Gene Promoter ◽  
General Mechanism ◽  
Beta Thalassemia ◽  
Beta Globin ◽  
Beta Chain ◽  
Beta Globin Gene ◽  
In Trans ◽  
In Cis

Hb A2 and its variant B2 (alpha 2 delta 2(16)(A13)Gly----Arg) were quantitated in the blood of subjects with three different types of beta- thalassemia and with the delta-B2 anomaly in cis or in trans to the beta-thalassemia determinant. In one family, the delta-B2 mutation was in cis to a newly discovered codon 47 (+A) frameshift. The levels of Hbs A2 and B2 were nearly the same and approximately 70% higher than those in simple Hb B2 heterozygotes. In two additional families, the delta-B2 variant was in trans to either a deletional beta-thalassemia (1,393 bp) involving part of the beta-globin gene and part of the beta- globin gene promoter, or to the -88 C----T promoter mutation. In both instances, the Hb B2 level was increased by approximately 80%, but the Hb A2 level was increased by approximately 270% and 200%, respectively. These data indicate two mechanisms that will cause an increase in delta chain production. One is consistent with a general mechanism concerning the relative excess of alpha chains in beta chain deficiencies which will combine with delta chains to form variable levels of Hb A2 dependent on the severity of the beta chain deficiency. The second concerns the loss of beta-globin gene promoter activity, perhaps by an absence of (or decreased) binding of specific protein(s) to this segment of DNA and a concomitant increase in delta-globin gene promoter activity in cis.

A C----T substitution at nt--101 in a conserved DNA sequence of the promotor region of the beta-globin gene is associated with “silent” beta-thalassemia

Blood ◽  
1989 ◽  
Vol 73 (6) ◽  
pp. 1705-1711 ◽  
Author(s):  
JM Gonzalez-Redondo ◽  
TA Stoming ◽  
A Kutlar ◽  
F Kutlar ◽  
KD Lanclos ◽  
...  
Keyword(s):  
Globin Gene ◽  
Beta Thalassemia ◽  
Nucleotide Position ◽  
Beta Globin ◽  
Dot Blot ◽  
Sequence Analyses ◽  
Beta Globin Gene ◽  
Chain Synthesis ◽  
Thalassemia Mutation

Sequence analyses and dot-blot analyses with synthetic oligonucleotide probes have identified eight individuals in three Turkish families and one Bulgarian family with one chromosome having a C----T mutation at nucleotide position--101 relative to the Cap site of the beta-globin gene. This nucleotide is part of one of the conserved blocks of nucleotides within the promoter region; in vitro expression analyses with the chloramphenicol acetyltransferase system showed that this substitution will decrease the effectiveness of transcription. Five subjects had a thalassemia intermedia due to the additional presence of a known classical high hemoglobin (Hb) A2 beta-thalassemia mutation on the second chromosome; their hematologic condition was relatively mild. The three persons with a heterozygosity for the--101 C----T mutation had normal hematologic data without microcytosis but with high-normal levels of Hb A2 and a mild imbalance in chain synthesis. The newly discovered mutation is considered one of the silent types of beta- thalassemia. It is relatively rare because it was absent among several hundred normal and beta-thalassemia chromosomes.

scholarly journals Molecular characterization of beta-thalassemia intermedia in patients of Italian descent and identification of three novel beta-thalassemia mutations

Blood ◽  
1991 ◽  
Vol 77 (6) ◽  
pp. 1342-1347 ◽  
Author(s):  
S Murru ◽  
G Loudianos ◽  
M Deiana ◽  
C Camaschella ◽  
GV Sciarratta ◽  
...  
Keyword(s):  
Blot Analysis ◽  
Globin Gene ◽  
Beta Thalassemia ◽  
Italian Population ◽  
Beta Globin ◽  
Thalassemia Intermedia ◽  
Dot Blot ◽  
Beta Globin Gene ◽  
Dot Blot Analysis ◽  
Thalassemia Mutation

Abstract In this study, we have defined by dot-blot analysis with allelic specific oligonucleotide probes or direct sequencing on amplified DNA the beta-thalassemia mutations in a large group of patients (23) of Italian descent with thalassemia intermedia. These patients had one parent with either the silent beta-thalassemia carrier phenotype or borderline-normal hemoglobin A2 (HbA2) levels (2.5% to 3.5%). Nearly all were genetic compounds for a severe beta-thalassemia mutation and a beta-thalassemia mutation associated with high residual output of beta- globin chains (beta + intervening sequence [IVS]-I-nt6, beta -87, beta - 101), indicating that inheritance of a mild beta-thalassemia allele, even in a single dose, is the most common molecular mechanism producing thalassemia intermedia in the Italian population. In three cases, in whom we failed to define by dot-blot analysis the mutations, we sequenced the beta + globin gene and found three novel beta-thalassemia mutations, which are certainly very rare because they have been hitherto detected solely in a single patient. These mutations consist of: (1) a T-A substitution at position 2 of IVS-I, in a patient compound heterozygote for this mutation and the -87 promoter mutation; (2) a G-C substitution at position 844 of IVS-II, in a patient heterozygous for this mutation who showed normal sequences at the in trans beta-globin gene (The reason for the presence of clinical manifestations in a beta-thalassemia heterozygote has not been defined.); and (3) a deletion of one nucleotide (-T) at codon 126, resulting in a frameshift and readthrough of the 5′ untranslated region and most likely producing an elongated Hb molecule of 156 amino acid residues, in a patient heterozygous for this mutation with normal beta- globin gene sequences at the other locus.

scholarly journals A C----T substitution at nt--101 in a conserved DNA sequence of the promotor region of the beta-globin gene is associated with “silent” beta-thalassemia

Blood ◽  
1989 ◽  
Vol 73 (6) ◽  
pp. 1705-1711 ◽  
Author(s):  
JM Gonzalez-Redondo ◽  
TA Stoming ◽  
A Kutlar ◽  
F Kutlar ◽  
KD Lanclos ◽  
...  
Keyword(s):  
Globin Gene ◽  
Beta Thalassemia ◽  
Nucleotide Position ◽  
Beta Globin ◽  
Dot Blot ◽  
Sequence Analyses ◽  
Beta Globin Gene ◽  
Chain Synthesis ◽  
Thalassemia Mutation

Abstract Sequence analyses and dot-blot analyses with synthetic oligonucleotide probes have identified eight individuals in three Turkish families and one Bulgarian family with one chromosome having a C----T mutation at nucleotide position--101 relative to the Cap site of the beta-globin gene. This nucleotide is part of one of the conserved blocks of nucleotides within the promoter region; in vitro expression analyses with the chloramphenicol acetyltransferase system showed that this substitution will decrease the effectiveness of transcription. Five subjects had a thalassemia intermedia due to the additional presence of a known classical high hemoglobin (Hb) A2 beta-thalassemia mutation on the second chromosome; their hematologic condition was relatively mild. The three persons with a heterozygosity for the--101 C----T mutation had normal hematologic data without microcytosis but with high-normal levels of Hb A2 and a mild imbalance in chain synthesis. The newly discovered mutation is considered one of the silent types of beta- thalassemia. It is relatively rare because it was absent among several hundred normal and beta-thalassemia chromosomes.

scholarly journals Molecular characterization of beta-thalassemia intermedia in patients of Italian descent and identification of three novel beta-thalassemia mutations

Blood ◽  
1991 ◽  
Vol 77 (6) ◽  
pp. 1342-1347 ◽  
Author(s):  
S Murru ◽  
G Loudianos ◽  
M Deiana ◽  
C Camaschella ◽  
GV Sciarratta ◽  
...  
Keyword(s):  
Blot Analysis ◽  
Globin Gene ◽  
Beta Thalassemia ◽  
Italian Population ◽  
Beta Globin ◽  
Thalassemia Intermedia ◽  
Dot Blot ◽  
Beta Globin Gene ◽  
Dot Blot Analysis ◽  
Thalassemia Mutation

In this study, we have defined by dot-blot analysis with allelic specific oligonucleotide probes or direct sequencing on amplified DNA the beta-thalassemia mutations in a large group of patients (23) of Italian descent with thalassemia intermedia. These patients had one parent with either the silent beta-thalassemia carrier phenotype or borderline-normal hemoglobin A2 (HbA2) levels (2.5% to 3.5%). Nearly all were genetic compounds for a severe beta-thalassemia mutation and a beta-thalassemia mutation associated with high residual output of beta- globin chains (beta + intervening sequence [IVS]-I-nt6, beta -87, beta - 101), indicating that inheritance of a mild beta-thalassemia allele, even in a single dose, is the most common molecular mechanism producing thalassemia intermedia in the Italian population. In three cases, in whom we failed to define by dot-blot analysis the mutations, we sequenced the beta + globin gene and found three novel beta-thalassemia mutations, which are certainly very rare because they have been hitherto detected solely in a single patient. These mutations consist of: (1) a T-A substitution at position 2 of IVS-I, in a patient compound heterozygote for this mutation and the -87 promoter mutation; (2) a G-C substitution at position 844 of IVS-II, in a patient heterozygous for this mutation who showed normal sequences at the in trans beta-globin gene (The reason for the presence of clinical manifestations in a beta-thalassemia heterozygote has not been defined.); and (3) a deletion of one nucleotide (-T) at codon 126, resulting in a frameshift and readthrough of the 5′ untranslated region and most likely producing an elongated Hb molecule of 156 amino acid residues, in a patient heterozygous for this mutation with normal beta- globin gene sequences at the other locus.

scholarly journals The inactive beta globin gene on a gamma delta beta thalassemia chromosome has a normal structure and functions normally in vitro

Blood ◽  
1988 ◽  
Vol 71 (3) ◽  
pp. 766-770
Author(s):  
PT Curtin ◽  
YW Kan
Keyword(s):  
Globin Gene ◽  
Large Deletion ◽  
Beta Thalassemia ◽  
Ribonuclease Protection Assay ◽  
Beta Globin ◽  
Gamma Delta ◽  
Beta Globin Gene ◽  
Thalassemia Minor

We have previously described an English family with gamma delta beta- thalassemia in which a large deletion stops 25 kilobases (kb) upstream from the beta-globin gene locus, and yet the beta-globin gene is inactive in vivo. Affected family members had a beta-thalassemia minor phenotype with a normal hemoglobin A2 level. Gene mapping showed that these subjects were heterozygous for a chromosome bearing a large deletion that began in the G gamma-globin gene, extended through the epsilon-globin gene, and continued upstream for at least 75 kb. The A gamma-, delta-, and beta-globin gene loci on this chromosome were intact. To examine the possibility that an additional defect was present in the beta-globin gene, we cloned, sequenced, and examined the expression of the beta-globin gene from the affected chromosome. No mutation was found in the beta-globin gene sequence from 990 base-pairs 5′ to the cap site to 350 basepairs 3′ to the polyadenylation signal. The gene was subcloned into an expression vector and introduced into HeLa cells. Analysis of RNA derived from these cells, using a ribonuclease protection assay, revealed qualitatively and quantitatively normal transcription. Thus a structurally and functionally normal beta-globin gene is inactive in the presence of a large deletion more than 25 kb upstream. The loss of beta-globin gene function may be due to disturbance of chromatin conformation caused by the deletion or may be the result of loss of upstream sequences that are necessary for beta-globin gene expression in vivo.

scholarly journals Molecular analysis of Japanese delta beta-thalassemia

Blood ◽  
1988 ◽  
Vol 72 (5) ◽  
pp. 1771-1776
Author(s):  
S Shiokawa ◽  
H Yamada ◽  
Y Takihara ◽  
E Matsunaga ◽  
Y Ohba ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Globin Gene ◽  
Fetal Hemoglobin ◽  
Beta Thalassemia ◽  
Globin Genes ◽  
Beta Globin ◽  
Beta Globin Gene ◽  
Gamma Globin ◽  
Large Deletions ◽  
Deletion Junction

A DNA fragment containing the deletion junction region from a Japanese individual with homozygous delta beta-thalassemia has been cloned. A clone containing the normal DNA surrounding the 3′ breakpoint of this deletion and a clone carrying the G gamma- and A gamma-globin genes of this patient were also isolated. Sequences of the deletion junction and both gamma-globin genes were determined. A comparison of these sequences with previously determined sequences of the normal counterparts revealed that the 5′ breakpoint is located between 2,134 and 2,137 base pairs (bp) 3′ to the polyA site of the A gamma-globin gene, the 5′ breakpoint is located just downstream of the 3′ border of the fetal gamma-globin duplication unit, and no molecular defects are evident within the gamma-globin gene region. A comparison between the sequences of the normal DNA surrounding the 3′ breakpoint and the normal DNA surrounding the 5′ breakpoint shows that deletion is the result of a nonhomologous recombination event. There are A+T-rich stretches near the 5′ and 3′ breakpoints in the normal DNA, and a portion of an Aly repeat is located in the region 3′ to the 3′ breakpoint. Southern blot analysis using probes 3′ to the beta-globin gene showed that the deletion extends in the 3′ direction further than any other deletions associated with delta beta-thalassemia and hereditary persistence of fetal hemoglobin (HPFH) heretofore reported. These results are discussed in terms of the mechanism generating large deletions in mammalian cells and three models for the regulation of gamma-globin and beta-globin gene expression in humans.

Sign in / Sign up

Export Citation Format

Share Document