Is the trimodality of Hb Leslie (alpha 2 beta 2 131 Gln---O) in heterozygotes the result of a variable number of active alpha-chain genes? Evidence for posttranslational control of hemoglobin synthesis.
Whether the trimodality in the relative concentration of the hemoglobin variant Hb Leslie in heterozygotes (Huisman, Hemoglobin 1:349-382, 1977) is due to a polymorphism of the alpha-chain structural genes was investigated by conventional incubation of reticulocytes with 14C-leucine. In addition, an aliquot from each of the incubations was incubated under the same conditions but without isotope. Three Hb Leslie heterozygotes with presumably four, three (heterozygous alpha-thalassemia-2), and two (homozygous alpha-thalassemia-2) active alpha-chain genes and with 33%, 22% and 11% Hb Leslie respectively, and one patient with the Hb Leslie beta(0)-thalassemia condition with more than 85% Hb Leslie were studied. The data indicate that betaLeslie chains have a lower affinity for alpha chains that betaA chains. A concomitant alpha-chain deficiency results in a reduced incorporation of betaLeslie chains into the tetrameric Hb Leslie molecules, while the quantity of Hb Leslie produced correlates with the degree of alpha-chain deficiency. Excess of betaLeslie chains is preferentially degraded.
D005260:Female; D005796:Genes; D005914:Globins / Q000096:biosynthesis / Q000378:metabolism; D006455:Hemoglobins, Abnormal / Q000096:biosynthesis / Q000235:genetics*; D006461:Hemolysis; D006579:Heterozygote; D006801:Humans; D007700:Kinetics; D014176:Protein Biosynthesis; D013789:Thalassemia / Q000097:blood; D013997:Time Factors
D006455:Hemoglobins, Abnormal; D005914:Globins