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

Abstract
Ribsomal RNA content and in vitro3H‐uridine and3H‐thymidine incorporation were examined in purified marrow erythroblasts of patients with idiopathic ineffective eryth‐ ropoiesis (HE) and DiGuglielmo disease (DD) and compared with cells from normal marrows. Whereas H‐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 β thalassemia minor and megaloblastic anemia were normal, suggesting that the defects observed in HE 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 HE and DD.