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Biomedical subjects

S C Goff

Publications and source records attributed to S C Goff.

28 records · Page 2Linked to original sources
PubMed1981

Heterogeneity of DNA deletion in gamma delta beta-thalassemia.

By restriction endonuclease mapping, gene cloning, and DNA sequencing we have determined the region of DNA that is deleted in a family with gamma delta beta-thalassemia. The deletion removes the linked epsilon, gamma-, and delta-globin structural genes and terminates within the coding portion of the beta-globin gene. Since the extent of DNA deletion in this family differs from that reported in another family, we conclude that gamma delta beta-thalassemia is heterogeneous at the molecular level.

Base Sequence↗
PubMed1980

Hemoglobin switching: a cellular model.

Regulation of hemoglobin synthesis depends in part on the population of cells available for erythroid differentiation. Mouse erythroleukemia cells were cloned, and the clones were induced with dimethyl sulfoxide to test the relative induction of beta minor and beta major synthesis. Cells of line 745 produced approximately 35 percent beta minor after induction, and 39 clones of line 745 produced from 23 to 61 percent beta minor. Further subcloning of the clone that produced 61 percent beta minor led to three subclones, all of which produced more than 90 percent beta minor. Thus one kind of hemoglobin regulation occurs at the cellular level.

Animals↗
PubMed1980

Chemical evidence for the separation of G gamma and A gamma chains by polyacrylamide gel electrophoresis in urea and triton X-100.

Polyacrylamide gel electrophoresis in urea and Triton X-100 of a hemolysate from human fetal red blood cells produces four major protein bands: alpha, beta, and 2 gamma globin chains. We have verified that the latter two are the G gamma and A gamma globin chains which have respectively glycine or alanine at position 136. After incorporation of either [3H] alanine or [3H] glycine into newly synthesized globin each gamma chain was isolated by preparative electrophoresis. The chains were cleaved with cyanogen bromide at methionines 55 and 133, then subjected to automated sequencing, and the residues from each sequencer turn counted. Glycine incorporation was detected for the third turn (position 136) of the G gamma chain and alanine for the A gamma. Substantial metabolic conversion of [3H] glycine to serine and proline was also noted.

Alanine↗
PubMed1980

Globin chain electrophoresis: a new approach to the determination of the G gamma/A gamma ratio in fetal haemoglobin and to studies of globin synthesis.

Separation of globin chains by electrophoresis provides a simple and rapid method for the determination of the G gamma/A gamma ratio in human fetal haemoglobin, and of biosynthetic rates of the globin chains. Whole haemolysates were analysed by electrophoresis on polyacrylamide gels in urea, acetic acid and Triton X-100. Electrophoresis of haemolysates from newborn infants led to four bands: A gamma, G gamma, beta and alpha. The identity of these bands was indicated by examination of haemoglobins of known globin chain composition. In 15 samples, the % G gamma was similar by Triton gels and by amino acid analysis of the gamma CB-3 peptide. Some mutant globin chains were also separable with the electrophoretic technique. Triton gel electrophoresis provides rapid analysis of very small amounts of haemoglobin, and permits examination of globin chain composition as well as globin synthetic ratios.

Adult↗
PubMed1980

A murine model for the switch from fetal to adult hemoglobin during ontogeny.

In murine erythroleukemia cells, the minor/major hemoglobin (Hb) ratio depends on the cell line and the inducing agent. To determine whether mouse minor hemoglobin is a "fetal" hemoglobin in vivo, globin chain composition and synthesis rates were determined in DBA/2 mice of various ages ranging from 14-day embryos to > 6-mo adults. Globin chains were separated by electrophoresis on polyacrylamide gels containing urea and Triton X-100. This method separates the embryonic (x,y,z) and the adult (alpha, beta ma, beta mi) globin chains. Fourteen day embryos had only 5%-10% adult globins but approximately 30% of the adult beta chains were beta mi. The % beta mi decreased with age and reached 20% in adult mice. Biosynthetic studies led to more pronounced differences: beta mi synthesis was 45% of total beta chain production in 14-day embryos and declined to 22% in adults. Thus beta minor/total beta globin synthesis declines during mouse ontogeny. This resembles qualitatively the human switch from fetal to adult hemoglobin and provides a murine model for studies of hemoglobin regulation.

Aging↗
PubMed1978

Variable globin chain synthesis in mouse erythroleukemia cells.

Various mouse erythroleukemia cell lines show unique responses to chemical inducers. Lines 745 and 707, from DBA/2 mice, produced 25%--48% beta-minor and 78%--52% beta-major globin following culture with DMSO. Butyric acid treatment led to approximately 40% beta-minor globin, while induction with hemin resulted in over 80% beta-minor synthesis. Line FSD was developed independently. DMSO induction led to less than 10% beta-minor globin, while hemin and butyric acid both resulted in approximately 40% beta-minor synthesis. T3C12 and 5000 originated in DDD mice. With these lines all inducers led to only beta-major and no beta-minor synthesis. The inducers did not influence protein stability or initiation of globin synthesis. Translation of poly A-containing cytoplasmic RNA in a wheat germ cell-free system led to proportions of beta-minor that were the same as those seen in the intact cells. Thus regulation of the type of globin chain produced in erythroleukemia cells following culture with several inducing agents occurs at either the level of gene transcription or posttranslational processing, or by growth of a selected cell population.

Animals↗
PubMed1977

Production of mouse globin in heterokaryons of mouse erythroleukaemia cells and human fibroblasts.

In an effort to activate the globin genes of non-erythroid cells, tetraploid murine erythroleukaemia cells (Friend cells) were fused with diploid human amniotic fibroblasts. When the Friend cells were pretreated with dimethylsulphoxide, an average of 27% heterokaryons was observed. These cells stained with benzidine, an indication that they contained haemoglobin. The cells incorporated radioactive amino acids into proteins. Electrophoresis of [3H]leucine-labelled lysates on SDS urea polyacrylamide gels indicated that up to 7% of the newly synthesized protein co-electrophoresed with globin. CM cellulose chromatography demonstrated the presence of mouse but not human globin chains. Hybridization analyses of cytoplasmic RNA also revealed only mouse globin mRNA in the heterokaryons. Although heterokaryons form readily between mouse erythroleukaemia cells and human fibroblasts, and globin synthesis does occur, only the erythroid partner in the fusion system employed here directs globin production.

Animals↗
PubMed1977

Globin synthesis in mouse erythroleukemia cells in vitro: a switch in beta chains due to inducing agent.

Friend erythroleukemia cells, originally derived from DBA/2 mice, differentiate when cultured with inducing agents. Studies of the different effects of inducing agents on clone 745 have revealed that both dimethyl sulfoxide (DMSO) and hemin produce benzidine-positive cells. Butyric acid produced mature but benzidine-negative cells in this clone. All agents induced globin synthesis above the 0.1% of protein synthesis found in uninduced cells. DMSO induction stimulated globin synthesis 9%, hemin 2%, and butyric acid 3%. Total beta/alpha ratios were approximately unity with all agents. Although the inducing agents all stimulated total globin synthesis in Friend cells, the relative rates of synthesis of the two mouse beta chains were affected differently by the various agents. Hemin markedly increased the proportion of beta minor. For example, DBA/2 mouse reticulocytes synthesized 20% beta minor and 80% beta major. DMSO induction of clone 745 caused 20%-33% synthesis of beta minor. In contrast, hemin increased the proportion of beta minor to 64%-69%. Thus the Friend erythroleukemia cell system provides an in vitro approach to the study of the regulation of globin-chain switching.

Butyrates↗
PubMedDate not supplied

Cloning the gene for an inherited human disorder--chronic granulomatous disease--on the basis of its chromosomal location.

The gene that is abnormal in the X-linked form of the phagocytic disorder chronic granulomatous disease has been cloned without reference to a specific protein by relying on its chromosomal map position. The transcript of the gene is expressed in the phagocytic lineage of haematopoietic cells and is absent or structurally abnormal in four patients with the disorder. The nucleotide sequence of complementary DNA clones predicts a polypeptide of at least 468 amino acids with no homology to proteins described previously.

Amino Acid Sequence↗