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Biomedical subjects

J G Gilman

Publications and source records attributed to J G Gilman.

At least 37 records · Page 2Linked to original sources
PubMed1987

The 12.6 kilobase DNA deletion in Dutch beta zero-thalassaemia.

The Dutch beta zero-thalassaemia has few clinical symptoms in homozygotes, elevated fetal haemoglobin (4-11%) in heterozygotes, and has a DNA deletion previously estimated as 10 kb which removes the beta-globin gene (Gilman et al, 1984). A DNA fragment containing the breakpoints of the Dutch beta zero-thalassaemia deletion has now been cloned. Sequencing across the deletion junction region showed the 3' endpoint to be about 3 kb further 3' than originally thought, so that the deletion covers 12.6 kb. The 3' endpoint lies in a region of Kpn I (L1) repeated sequences, which is also the case for several other deletions. A six bp region of homology (AAATTT) between the 5' and 3' normal sequences at the breakpoint may have contributed to the non-homologous recombination event that led to the Dutch beta zero-thalassaemia deletion. The 12.6 kb Dutch beta zero-thalassaemia deletion is now seen to be a member of a 12-13 kb size category of deletions which also includes two delta beta-thalassaemias.

Base Sequence↗
PubMed1987

DNA sequence analysis of the Dutch beta zero-thalassemia deletion.

The Dutch beta zero-thalassemia has relatively few clinical symptoms in the homozygote. Heterozygotes have levels of fetal hemoglobin (4-11%) comparable to delta beta-thalassemia, and much higher than in typical beta zero-thalassemia. To analyze this deletion, we have cloned the abnormal 10 kb Bgl II fragment that contains the delta-globin gene into phage lambda vector EMBL4. A Hind III-Xba I fragment that includes the endpoints of the deletion was subcloned into plasmid pUC 19 and partially sequenced by the dideoxy method. The sequence of the Dutch beta zero-thalassemia DNA is like that of normal 5' DNA to 8920 (the numbering system is from reference 2). The sequence from 8915-8920 is AAATTT, which is also the normal 3' sequence from 21537-21542. From this point on, the Dutch beta zero-thalassemia sequence is like that of the normal 3' DNA. The deletion is therefore 12.6 kilobases, rather than 10 as originally estimated. It is similar to several other beta-globin gene deletions in terminating in a region of Kpn I repeated sequences, and having several base pairs of homology between 5' and 3' sequences at the break points.

Base Sequence↗
PubMed1985

DNA sequence variation associated with elevated fetal G gamma globin production.

The percentage of G gamma chains in the Hb F of SS patients and beta-thalassemia heterozygotes is generally 40%, but some have 60% to 70% G gamma. To test the hypothesis that DNA sequence variation 158 base pairs 5' of the G gamma gene is associated with this variation in G gamma values, DNA was analyzed using the restriction endonuclease Xmn I (gamma IVS-II probe). Xmn I recognizes the sequence from -157 to -166 only if T is at position -158. Individuals from five families had T at -158 for G gamma genes in both chromosomes, and the mean G gamma value was 69.7% +/- 4.6% (SD). For 13 families, individuals with T at -158 for the G gamma gene of one chromosome had a G gamma value of 60.6% +/- 5.7%. With one exception, lack of T at -158 was associated with low G gamma values (39.6% +/- 4.0%). In low Hb F G gamma-beta+-HPFH, the Xmn I site was seen 5' to both G gamma and A gamma genes, which suggests that T at -158 is associated with elevated Hb F; Pst I digestion showed that the A gamma gene T producer G gamma globin, which accounts for high levels of G gamma (87-88%). Calculations show that T at -158 is associated with a three- to 11-fold increase in production per G gamma gene, which is an order of magnitude less than that associated with the previously identified -202 C----G substitution of high Hb F G gamma-beta+-HPFH.

Anemia, Sickle Cell↗
PubMed1984

Dutch beta 0-thalassaemia: a 10 kilobase DNA deletion associated with significant gamma-chain production.

A unique beta 0-thalassaemia in a Dutch family results in fetal haemoglobin expression comparable to that of delta 0 beta 0-thalassaemia. Haemoglobin analysis and restriction endonuclease mapping studies of DNA suggest that the beta-globin gene is entirely deleted, but that the delta-globin gene is intact. The 5' break point of the deletion is 3-4 kilobases 3' to the delta-globin gene, while the 3' break point is 6-7 kilobases 3' to the beta-globin gene (relative to the normal DNA restriction map). The result is a approximately 10 kilobase deletion of DNA whose 3' end point may lie very close to that for one delta 0 beta 0-thalassaemia, within a cluster of Kpn I-family repetitive sequences. The Dutch beta 0-thalassaemia deletion is thus the shortest one which, in the absence of additional chromosomal rearrangements, results in enhancement of gamma-chain synthesis above that seen for haemoglobin Lepore. These data support the hypothesis that the region of DNA 3' to the beta-globin gene may be important to the developmental regulation of fetal gamma versus adult beta chain production.

Chromosome Deletion↗
PubMed1984

Restriction endonuclease gene mapping studies of an Indian (A gamma delta beta)zero-thalassaemia, previously identified as G gamma-HPFH.

Restriction endonuclease mapping data are presented for the DNA of a young Indian homozygous patient (and his heterozygous parents) who were identified 10 years ago as having a G gamma-hereditary persistence of fetal haemoglobin (Sukumaran et al, 1972). However, the present results indicate a genetic lesion in these persons which is similar to that observed in another Indian with (A gamma delta beta)0-thalassaemia homozygosity (Amin et al, 1979) and is characterized by two relatively short deletions and an inversion involving the A gamma, delta and beta globin genes (Jones et al, 1981a). Some additional blot hybridization studies have provided further data confirming the deletion-inversion hypothesis.

Adolescent↗
PubMed1984

Two independent genetic factors in the beta-globin gene cluster are associated with high G gamma-levels in the HbF of SS patients.

The gamma-chains of fetal hemoglobin (HbF) of newborn babies are composed of about 70% G gamma and 30% A gamma. In most babies, the G gamma value declines postnatally to 40%, but in about 20% of black SS patients from Georgia, 5 years and older, the G gamma level remains high at 60%. Moreover, some 3% to 4% of black newborns have high G gamma values of 85%. PstI digestion of DNA of one such high G gamma baby and of one normal newborn showed the former to be heterozygous for the -G gamma-G gamma- and -G gamma-A gamma-chromosomes. Only about one fourth of high G gamma SS patients were such heterozygotes, while three fourths were -G gamma-A gamma-/-G gamma-A gamma-homozygotes. Analysis of DNA of 38 SS patients without the -G gamma-G gamma-chromosome showed a correlation of G gamma values with genotype at one polymorphic restriction site: at the HincII site in the psi beta gene, all -G gamma-A gamma-/-G gamma-A gamma-homozygotes with high G gamma were +/- or +/+, while low G gamma individuals were all -/-. Family studies, involving analyses at four polymorphic sites (HindIII sites in the G gamma and A gamma genes and HincII sites in the psi beta gene and 3' to it), suggested the association of an unidentified high G gamma genetic determinant with haplotype + - + +. This indicates that a genetic factor causing high G gamma levels in SS patients is closely linked to the -G gamma-A gamma-psi beta region of the beta-globin gene cluster.

Adult↗
PubMed1983

Gamma thalassemia resulting from the deletion of a gamma-globin gene.

The first example of a deletion of one of the two gamma globin genes has been characterized through an analysis of the DNA of the heterozygous parent of a homozygous newborn, using restriction endonuclease mapping techniques. A deletion of approximately 5 kb was observed which was probably caused by an unequal crossing-over between the -G gamma- and -A gamma- genes resulting in the formation of a -G gamma A gamma- hybrid gene. Data on proportions of G gamma and A gamma chains in newborn babies assumed to be heterozygous for the hybrid and normal genes suggest that this hybrid gene may be producing its A gamma chain at levels normally seen only for the G gamma chain.

Adult↗
PubMed1983

Gene deletion as the molecular basis for the Kenya-G gamma-HPFH condition.

DNA was isolated from the white cells of a subject with the Hb S-Kenya-G gamma-HPFH condition, and digested with the restriction endonucleases Bg1 II, Xba I, and Eco RI. The resulting fragments were identified by standard techniques using [32P] labelled probes which are specific for the second intervening sequences of the beta gene and the gamma genes, respectively. A comparison with data for normal DNA indicated the presence of one additional fragment in each of the three digests, namely a 10.5 kb Bg1 II fragment, a 7.8 kb Xba I fragment, and a 2.9 kb Eco RI fragment. These observations are believed to show a large (approximately 22.5 kb) deletion in the DNA of the Kenya chromosome which includes the 3' section of the A gamma gene, the delta gene, and the 5' section of the beta gene. These results are consistent with the original hypothesis which was based on structural data for the different hemoglobin chains.

Adult↗
PubMed1983

Developmental changes of mouse red cell pyruvate kinase.

The increase in red cell 2,3-diphosphoglycerate (2,3-DPG) concentration during mouse postnatal development is highly correlated with the decrease in red cell pyruvate kinase (PK) activity. Immunoneutralization curves for newborn and adult red cell PK are parallel, which suggests that the higher PK activity in newborn mouse red cells is due primarily to a greater quantity of PK protein. Mouse newborn and adult red cell PK also differ in mobility on cellulose acetate electrophoresis (pH 7.5). This is true for two strains of mice (C57BL/6 and IS/Cam) whose adult red cell PK electrophoretic patterns differ (single vs. double bands, respectively). Trypsinization does not alter the electrophoretic mobilities of C57BL/6 newborn and adult red cell PK, but it does convert the IS/Cam adult PK to a single band of greater mobility than the single band of C57BL/6 adult PK. These data are consistent with the hypothesis that mice have structurally different forms of PK for newborn and adult red cells, analogous to the fetal gamma- and adult beta-globins of humans.

Aging↗
PubMed1981

Rat hemoglobin heterogeneity: postnatal changes in proportions of multiple components and effects of erythropoietin on marrow cell cultures.

Hemolysate from adult and newborn rats was fractionated into nine components (I-IX) using DEAE-cellulose chromatography. A subsequent chromatographic step resolved component IV into two, IVa and Ivb. A comparison of adult and newborn rat hemolysates showed that newborn had higher levels of components I, II, and IV. In the newborn, they accounted for 52% of total hemoglobin eluted, compared to 36% in the adult. Components V, VI, and VIII were less in the newborn than in the adult red cell, at 42% compared to 59%. Minor components III, VII, and IX were unchanged, at 5.8% in newborn and 5.3% in adult rats. Bone marrow cells from adult rats cultured for 46 hours, showed stimulation of eight components under the influence of erythropoietin (components IVa and IVb were not distinguished, and VII was not detected). The extent of stimulation was not consistently higher for major than for minor hemoglobins. These data show that adult rats possess at least ten hemoglobin components, that newborn rats have the same components but in different proportions, and that both major and minor components are stimulated by erythropoietin in bone marrow cell cultures.

Age Factors↗
PubMed1980

Rat embryonic and foetal erythrocytes. High 2,3-bisphosphoglycerate and ATP and low oxygen affinity in vitro for nucleated embryonic cells.

Embryonic nucleated red cells of the rat have high ATP and 2,3-bisphosphoglycerate and relatively low oxygen affinity. During foetal life they are replaced by large non-nucleated red cells with high ATP, low bisphosphoglycerate and high oxygen affinity. After birth, small non-nucleated red cells with high bisphosphoglycerate and low oxygen affinity rapidly predominate.

Adenosine Triphosphate↗