Decreased ribosomal RNA content and in vitro RNA synthesis in purified bone marrow erythroblasts of patients with idiopathic ineffective erythropoiesis and DiGuglielmo disease.

Ribsomal RNA content and in vitro 3H-uridine and 3H-thymidine incorporation with examined in purified marrow erythroblasts of patients with idiopathic ineffective erythropoiesis (IIE) and DiGuglielmo disease (DD) and compared with cells from normal marrows. Whereas 3H-thymidine incorporation rates were normal in all patients, 3H-uridine incorporation was 42%--75% of normal in cells from patients examined. Ribosomal RNA content was measured by spectrophotometric scanning of RNA electrophoresed on polyacrylamide gels and corrections made for contamination of the erythroblast preparations with ribosome bearing reticulocytes. In cells from every patient examined RNA content was decreased to 60--76% of normal. Uridine incorporation and rRNA content of patients with beta thalassemia minor and megaloblastic anemia were normal, suggesting that the defects observed in IIE and DD were not due to ineffective erythropoiesis per se. Since erythroblast ribosomes may be rate limiting in protein synthesis, we postulate that even a minor decrease in ribosome content might engender the ubiquitous abnormalities reported in erythroid cells in both IIE and DD.