scholarly journals Locus assignment of two alpha-globin structural mutants from the Caribbean basin: alpha Fort de France (alpha 45 Arg) and alpha Spanish Town (alpha 27 Val)

Blood ◽  
1989 ◽  
Vol 74 (2) ◽  
pp. 833-835
Author(s):  
FE Cash ◽  
N Monplaisir ◽  
M Goossens ◽  
SA Liebhaber
Keyword(s):  
Dominant Role ◽  
Globin Gene ◽  
In Vitro Translation ◽  
Globin Mrna ◽  
Alpha Globin ◽  
Structural Mutations ◽  
The Caribbean ◽  
Spanish Town

Two alpha-globin structural mutants were mapped to their encoding loci by in vitro translation of hybrid-selected alpha 1- and alpha 2-globin mRNA. The more highly expressed mutant, alpha Spanish Town (alpha 27Val), is encoded at the alpha 2 locus and the less expressed mutant, alpha Fort de France (alpha 45Arg), is encoded at the alpha 1 locus. These results further define the distribution of alpha-globin structural mutations within the alpha-globin gene cluster and substantiate the dominant role of the alpha 2-globin locus in alpha- globin expression.

scholarly journals Locus assignment of two alpha-globin structural mutants from the Caribbean basin: alpha Fort de France (alpha 45 Arg) and alpha Spanish Town (alpha 27 Val)

Blood ◽  
1989 ◽  
Vol 74 (2) ◽  
pp. 833-835
Author(s):  
FE Cash ◽  
N Monplaisir ◽  
M Goossens ◽  
SA Liebhaber
Keyword(s):  
Dominant Role ◽  
Globin Gene ◽  
In Vitro Translation ◽  
Globin Mrna ◽  
Alpha Globin ◽  
Structural Mutations ◽  
The Caribbean ◽  
Spanish Town

Abstract Two alpha-globin structural mutants were mapped to their encoding loci by in vitro translation of hybrid-selected alpha 1- and alpha 2-globin mRNA. The more highly expressed mutant, alpha Spanish Town (alpha 27Val), is encoded at the alpha 2 locus and the less expressed mutant, alpha Fort de France (alpha 45Arg), is encoded at the alpha 1 locus. These results further define the distribution of alpha-globin structural mutations within the alpha-globin gene cluster and substantiate the dominant role of the alpha 2-globin locus in alpha- globin expression.

scholarly journals Molecular basis for alpha-thalassemia associated with the structural mutant hemoglobin Suan-Dok (alpha 2 109leu----arg) [published erratum appears in Blood 1991 Mar 15;77(6):1404]

Blood ◽  
1990 ◽  
Vol 76 (12) ◽  
pp. 2630-2636 ◽  
Author(s):  
I Weiss ◽  
FE Cash ◽  
MB Coleman ◽  
A Pressley ◽  
JG Adams ◽  
...  
Keyword(s):  
Messenger Rna ◽  
Globin Gene ◽  
Mrna Level ◽  
Early Time ◽  
In Vitro Translation ◽  
Globin Mrna ◽  
Time Points ◽  
Alpha Thalassemia ◽  
Alpha Globin

Abstract Hemoglobin (Hb) Suan-Dok (alpha 109Arg) is a rare alpha-globin structural mutation that is linked to an alpha-thalassemia (alpha-thal) determinant. When inherited in trans to an alpha-thal-1 mutation (-), it results in Hb H disease associated with low levels (9%) of the Suan- Dok Hb. The nature of the thalassemic defect associated with the alpha SD mutation has been investigated by structural and functional studies. Sequence analysis of the cloned Suan-Dok allele showed a missense mutation (T----G) at codon 109 in an otherwise normal alpha 2-globin gene. When the alpha 2SD-globin gene was introduced into mouse erythroleukemia cells, the steady state alpha-globin messenger RNA (mRNA) level was equivalent to the alpha A-globin gene control. Although in vitro translation of a synthetic alpha 2SD-globin mRNA generated levels of alpha globin equivalent to alpha 2A-globin mRNA at early time points, the ratio of alpha SD to alpha A globin decreased markedly at later time points. These data suggest that the thalassemic defect associated with the Suan-Dok mutation results from a significant instability of the alpha SD globin.

scholarly journals Molecular basis for alpha-thalassemia associated with the structural mutant hemoglobin Suan-Dok (alpha 2 109leu----arg) [published erratum appears in Blood 1991 Mar 15;77(6):1404]

Blood ◽  
1990 ◽  
Vol 76 (12) ◽  
pp. 2630-2636 ◽  
Author(s):  
I Weiss ◽  
FE Cash ◽  
MB Coleman ◽  
A Pressley ◽  
JG Adams ◽  
...  
Keyword(s):  
Messenger Rna ◽  
Globin Gene ◽  
Mrna Level ◽  
Early Time ◽  
In Vitro Translation ◽  
Globin Mrna ◽  
Time Points ◽  
Alpha Thalassemia ◽  
Alpha Globin

Hemoglobin (Hb) Suan-Dok (alpha 109Arg) is a rare alpha-globin structural mutation that is linked to an alpha-thalassemia (alpha-thal) determinant. When inherited in trans to an alpha-thal-1 mutation (-), it results in Hb H disease associated with low levels (9%) of the Suan- Dok Hb. The nature of the thalassemic defect associated with the alpha SD mutation has been investigated by structural and functional studies. Sequence analysis of the cloned Suan-Dok allele showed a missense mutation (T----G) at codon 109 in an otherwise normal alpha 2-globin gene. When the alpha 2SD-globin gene was introduced into mouse erythroleukemia cells, the steady state alpha-globin messenger RNA (mRNA) level was equivalent to the alpha A-globin gene control. Although in vitro translation of a synthetic alpha 2SD-globin mRNA generated levels of alpha globin equivalent to alpha 2A-globin mRNA at early time points, the ratio of alpha SD to alpha A globin decreased markedly at later time points. These data suggest that the thalassemic defect associated with the Suan-Dok mutation results from a significant instability of the alpha SD globin.

The switch from larval to adult globin gene expression in Xenopus laevis is mediated by erythroid cells from distinct compartments

Development ◽  
1991 ◽  
Vol 112 (4) ◽  
pp. 1021-1029
Author(s):  
R. Weber ◽  
B. Blum ◽  
P.R. Muller
Keyword(s):  
Xenopus Laevis ◽  
Globin Gene ◽  
Northern Blotting ◽  
Precursor Cells ◽  
Globin Mrna ◽  
Erythroid Precursor ◽  
Main Site ◽  
Alpha Globin ◽  
Successive Generations

The transition of hemoglobins during metamorphosis of Xenopus laevis involves replacement of the larval erythrocytes by adult ones, suggesting that the developmental control of this event depends upon the growth characteristics of the precursor cells. To identify the erythroid precursor cells and to investigate their developmental fate, we analyzed the distribution of stage-specific globin mRNAs by northern blotting in dorsal and ventral fragments of stage 32 embryos after in vitro culture as well as presumptive erythropoietic tissues of tadpoles during metamorphosis. The histological analysis shows that erythrocytes differentiate only in ventral fragments, suggesting that the ventral blood islands and most likely also the dorsolateral mesoderm are the primary sites of erythropoiesis. We also demonstrate that the first generations of erythrocytes, already express the predominating larval-specific alpha-globin mRNAs. The globin mRNA patterns obtained from presumptive erythropoietic tissues suggest an important role of circulating precursor cells in larval erythropoiesis, whereas the liver appears to be the main site of formation and maturation of the adult erythrocytes. Tentatively we propose that anuran erythropoiesis is dependent upon a self-perpetuating stem-cell line and that the larval and the adult erythrocytes are derived from successive generations of erythroid precursors, whose commitment may be imposed by the erythropoietic sites.

scholarly journals AUF-1 and YB-1 are critical determinants of β-globin mRNA expression in erythroid cells

Blood ◽  
2012 ◽  
Vol 119 (4) ◽  
pp. 1045-1053 ◽  
Author(s):  
Sebastiaan van Zalen ◽  
Grace R. Jeschke ◽  
Elizabeth O. Hexner ◽  
J. Eric Russell
Keyword(s):  
Posttranscriptional Regulation ◽  
Rna Binding ◽  
Globin Gene ◽  
K562 Cells ◽  
Erythroid Cells ◽  
Erythroid Progenitors ◽  
Globin Mrna ◽  
Affinity Enrichment

Abstract The normal accumulation of β-globin protein in terminally differentiating erythroid cells is critically dependent on the high stability of its encoding mRNA. The molecular basis for this property, though, is incompletely understood. Factors that regulate β-globin mRNA within the nucleus of early erythroid progenitors are unlikely to account for the constitutively high half-life of β-globin mRNA in the cytoplasm of their anucleate erythroid progeny. We conducted in vitro protein-RNA binding analyses that identified a cytoplasm-restricted β-globin messenger ribonucleoprotein (mRNP) complex in both cultured K562 cells and erythroid-differentiated human CD34+ cells. This novel mRNP targets a specific guanine-rich pentanucleotide in a region of the β-globin 3′untranslated region that has recently been implicated as a determinant of β-globin mRNA stability. Subsequent affinity-enrichment analyses identified AUF-1 and YB-1, 2 cytoplasmic proteins with well-established roles in RNA biology, as trans-acting components of the mRNP. Factor-depletion studies conducted in vivo demonstrated the importance of the mRNP to normal steady-state levels of β-globin mRNA in erythroid precursors. These data define a previously unrecognized mechanism for the posttranscriptional regulation of β-globin mRNA during normal erythropoiesis, providing new therapeutic targets for disorders of β-globin gene expression.

In situ hybridization reveals co-expression of embryonic and adult alpha globin genes in the earliest murine erythrocyte progenitors

Development ◽  
1992 ◽  
Vol 116 (4) ◽  
pp. 1041-1049 ◽  
Author(s):  
A. Leder ◽  
A. Kuo ◽  
M.M. Shen ◽  
P. Leder
Keyword(s):  
In Situ Hybridization ◽  
Embryonic Development ◽  
Fetal Liver ◽  
Globin Gene ◽  
Yolk Sac ◽  
Globin Genes ◽  
Globin Mrna ◽  
Mature Adult ◽  
Alpha Globin

Murine erythropoiesis begins with the formation of primitive red blood cells in the blood islands of the embryonic yolk sac on day 7.5 of gestation. By analogy to human erythropoiesis, it has been thought that there is a gradual switch from the exclusive expression of the embryonic alpha-like globin (zeta) to the mature adult form (alpha) in these early mouse cells. We have used in situ hybridization to assess expression of these two globin genes during embryonic development. In contrast to what might have been expected, we find that there is simultaneous expression of both zeta and alpha genes from the very onset of erythropoiesis in the yolk sac. At no time could we detect expression of embryonic zeta globin mRNA without concomitant expression of adult alpha globin mRNA. Indeed, adult alpha transcripts exceed those of embryonic zeta in the earliest red cell precursors. Moreover, the pattern of hybridization reveals co-expression of both genes within the same cells. Even in the fetal liver, which supersedes the yolk sac as the major site of murine fetal erythropoiesis, there is a brief co-expression of zeta and alpha genes followed by the exclusive expression of the adult alpha genes. These data indicate an important difference in hematopoietic ontogeny between mouse and that of human, where zeta expression precedes that of alpha. In addition to resolving the embryonic expression of these globin genes, our results suggest that the embryonic alpha-like globin gene zeta may be physiologically redundant, even during the earliest stages of embryonic development.

Characterization of the major regulatory element upstream of the human alpha-globin gene cluster

1991 ◽  
Vol 11 (9) ◽  
pp. 4679-4689
Author(s):  
A P Jarman ◽  
W G Wood ◽  
J A Sharpe ◽  
G Gourdon ◽  
H Ayyub ◽  
...  
Keyword(s):  
Regulatory Element ◽  
Globin Gene ◽  
Major Elements ◽  
Beta Globin ◽  
Globin Mrna ◽  
Expression Studies ◽  
Primary Element ◽  
Alpha Globin ◽  
Binding Sequence

The major positive regulatory activity of the human alpha-globin gene complex has been localized to an element associated with a strong erythroid-specific DNase I hypersensitive site (HS -40) located 40 kb upstream of the zeta 2-globin mRNA cap site. Footprint and gel shift analyses of the element have demonstrated the presence of four binding sites for the nuclear factor GATA-1 and two sites corresponding to the AP-1 consensus binding sequence. This region resembles one of the major elements of the beta-globin locus control region in its constitution and characteristics; this together with evidence from expression studies suggests that HS -40 is a primary element controlling alpha-globin gene expression.

scholarly journals Constitutive expression of GATA-1, EPOR, alpha-globin, and gamma-globin genes in myeloid clonogenic cells from juvenile chronic myelocytic leukemia

Blood ◽  
1995 ◽  
Vol 86 (1) ◽  
pp. 323-328 ◽  
Author(s):  
E Privitera ◽  
R Schiro ◽  
D Longoni ◽  
A Ronchi ◽  
A Rambaldi ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Leukemic Cells ◽  
Globin Genes ◽  
Chronic Myelocytic Leukemia ◽  
Beta Globin ◽  
Globin Mrna ◽  
Gamma Globin ◽  
Myelocytic Leukemia ◽  
Alpha Globin

Juvenile chronic myelocytic leukemia (JCML) is a rare disorder of early childhood. Characteristic of JCML are the progressive appearance of high levels of fetal hemoglobin (HbF), reflecting a true reversion to a fetal type of erythropoiesis, and the presence of colony-forming cells able to grow in vitro spontaneously in the absence of growth factors. To better understand the relationship between the erythroid abnormalities and the leukemic process, we analyzed the expression pattern of specific genes related to erythroid differentiation--GATA-1, EPOR, alpha-globin, beta-globin, and gamma-globin genes--in JCML peripheral blood (PB) cells and in vitro-derived colonies. Northern blot analysis of PB cells from five JCML patients indicated levels of GATA-1 transcripts much higher than those usually found in other types of leukemic cells, and S1 nuclease protection assay detected significantly increased expression of gamma-globin mRNA. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of single granulocyte-macrophage colony-forming unit (CFU-GM) colonies, obtained in vitro in the absence of added growth factors from four JCML patients, detected GATA-1, EPOR, and globin (alpha and gamma) transcripts in most of the colonies tested, in contrast with control CFU-GM from normal bone marrow, which were positive only for GATA-1. Single JCML colonies were tested for the presence of two different transcripts; whereas alpha- and gamma-globin genes appeared mostly coexpressed, beta-globin mRNA was detected only in a minority of the gamma-globin-positive colonies, indicating that the leukemic pattern of hemoglobin synthesis is mainly fetal. In addition, the leukemic cells occurring during blast crisis of one of our patients displayed the typical features of a stem cell leukemia (CD34+, CD19-, CD2-, myeloperoxidase-). In this sorted CD34+ population, we detected the presence of a marker chromosome, der(12)t(3;12), previously identified in bone marrow cells at diagnosis and an expression pattern superimposable to that of the JCML colonies, consistently displaying a high gamma-globin:beta-globin mRNA ratio. The expression of erythroid markers within populations of leukemic cells, both in vivo and in vitro, supports the hypothesis that abnormal JCML erythroid cells may originate from the same mutated progenitor that sustains the growth of the leukemic cells.

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