methylcellulose and Thalassemia

Human hemoglobin messenger RNA was isolated by sucrose gradient centrifugation from reticulocytes of patients having various hemolytic anemias. Using a messenger RNA-dependent cell-free system derived entirely from rabbit reticulocytes, the human hemoglobin messenger RNA has been translated and the products analyzed by carboxymethylcellulose column chromatography. Normal messenger RNA directs synthesis of normal human alpha- and beta-globin chains in nearly equal amounts. Sickle cell anemia messenger RNA directs the synthesis of normal alpha- and sickle beta-chains, beta-thalassemia messenger RNA directs the synthesis of normal alpha- and beta-chains, but the amount of beta-globin synthesized is markedly reduced. Thus the inability of the thalassemia reticulocyte to produce beta-globin is clearly attributable to the beta-globin messenger RNA.

Topics: Anemia, Sickle Cell; Animals; Carbon Isotopes; Cell-Free System; Centrifugation, Density Gradient; Chromatography; Globins; Hemoglobins; Hemoglobins, Abnormal; Humans; Leucine; Methylcellulose; Peptide Biosynthesis; Rabbits; Reticulocytes; Ribosomes; RNA, Messenger; Thalassemia

Human ribosomes obtained from the reticulocytes of patients having either homozygous beta-thalassemia (thalassemia ribosomes) or a hematological disorder unrelated to thalassemia ("normal" ribosomes) have been utilized in a cell-free system highly active in the synthesis of intact human globin chains. This system is dependent on the addition of a ribosomal wash fraction from reticulocytes that contains factors necessary for chain initiation. In response to the ribosomal wash fraction, isolated from either thalassemia, normal human, or rabbit reticulocytes, normal human ribosomes synthesize equal amounts of alpha and beta chains. In contrast, in response to all three types of ribosomal wash fractions, thalassemia ribosomes synthesize 8-times more alpha than beta chains, a ratio similar to that produced in the intact cells of these patients. The molecular defect in beta-thalassemia, therefore, does not appear to be associated with initiation factors.

Topics: Anemia, Hemolytic, Autoimmune; Anemia, Sickle Cell; Animals; Carbon Isotopes; Cell-Free System; Chromatography; Hemoglobins; Humans; In Vitro Techniques; Leucine; Lysine; Methylcellulose; Rabbits; Reticulocytes; Ribosomes; Thalassemia; Tritium

Topics: Chromatography, Ion Exchange; Hemoglobins; Hemolysis; Heterozygote; Humans; Methylcellulose; Molecular Biology; Peptides; Sodium; Thalassemia

The synthesis of alpha, beta, and gamma chains in samples of cord blood was measured by the incorporation of leucine labeled with carbon-14 into these chains. In a newborn affected with beta thalassemia trait, the presence of one beta thalassemia gene was revealed on the 1st day of life by the lower specific radioactivity of the beta chain.

Topics: Birth Weight; Carbon Isotopes; Chromatography, Ion Exchange; Gestational Age; Hemoglobins, Abnormal; Heterozygote; Humans; Infant, Newborn; Leucine; Methylcellulose; Molecular Biology; Peptide Biosynthesis; Thalassemia; Umbilical Cord

Topics: Carbon Isotopes; Chromatography, Ion Exchange; Genetic Code; Hemoglobins, Abnormal; Humans; Leucine; Methylcellulose; Peptide Biosynthesis; Peptides; Reticulocytes; Ribosomes; RNA, Messenger; Thalassemia; Tritium