In vitro synthesis of hemoglobin and hemoglobin chains in the BFUe-derived colonies form person with alpha- or beta-thalassemia.
The synthesis of alpha and non-alpha chains of human hemoglobin (Hb) was studied in reticulocytes and in BFUe-derived cell colonies from patients with alpha chain or beta chain deficiencies. The subjects included normal adults (alpha alpha/alpha alpha) with or without a beta chain variant (Hb S, Hb Leslie) or an alpha chain variant (Hb G-Georgia); alpha-thalassemia-2 heterozygotes (alpha 0 alpha/alpha alpha) with an alpha chain variant (G-Georgia or G-Philadelphia); an alpha-thalassemia-1 heterozygote (alpha 0 alpha 0/alpha alpha); alpha-thalassemia-2 homozygotes (alpha 0 alpha 0/alpha 0 alpha) with a beta chain variant (Hb S), an alpha chain variant (G-Philadelphia), a Hb S homozygosity with Hb G-Philadelphia, or a Hb G-Philadelphia homozygosity; and three black beta +-thalassemia homozygotes. Data from reticulocyte in vitro synthesis analysis showed the expected deficiencies. However, similar analyses of the Hb synthesized in cell colonies (even from the black beta-thalassemia homozygotes) gave (nearly) balanced sigma alpha/sigma non-alpha ratios. It is speculated that this balanced synthesis is due to a most effective proteolysis in the immature erythroblast which rapidly removes free alpha or beta chains. The levels of Hb F and Hb A2 were considerably increased in these proerythroblasts; a two- to threefold increase in the synthesis of Hb A2 was observed over that seen in the reticulocytes.
D000293:Adolescent; D000328:Adult; D000368:Aged; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D005260:Female; D005319:Fetal Hemoglobin / Q000096:biosynthesis; D014644:Genetic Variation; D006443:Hemoglobin A2 / Q000096:biosynthesis; D006454:Hemoglobins / Q000096:biosynthesis* / Q000235:genetics; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D012156:Reticulocytes / Q000378:metabolism*; D013789:Thalassemia / Q000097:blood* / Q000235:genetics
D006454:Hemoglobins; D006443:Hemoglobin A2; D005319:Fetal Hemoglobin