A Study of the Quantitative Variation of Histones, and Their Relationship to RNA Synthesis, during Erythropoiesis in the Adult Chicken

Defined cell populations representing limited periods in the erythropoietic sequence of adult chickens have been obtained by buoyant density centrifugation of bone marrow cells on bovine serum albumin gradients. The histones of these various populations and of circulating erythrocytes have been compared quantitatively by polyacrylamide gel electrophoresis. No change in the relative amounts of F1, F2a1, F2a2 (and possibly F3 + 2b), could be detected between the early polychromatic erythrocyte and the mature erythrocyte, although changes in the distribution of the F1 subfractions were observed. The amount of the erythrocyte specific histone (F2c), however, increases approximately 2.5‐fold during this period. These events were correlated with a parallel decrease in RNA synthesis, both in whole cells and when measured in isolated nuclei. The results are discussed in relation to possible mechanisms of chromatin condensation and genome repression.