Autonomous synthesis of alpha and beta hemoglobin chains in rabbit
erythroid cells
PP Dembure and MD Garrick
Hemoglobin beta-chain synthesis by rabbit erythroid cells was tested for
dependence on availability of complementary alpha-chains. Reticulocytes and
bone marrow cells were obtained from variant rabbits that have hemoglobin
with isoleucine in alpha-chains but not in beta- chains. This
characteristic permits the use of L-O-methylthreonine, a specific
isoleucine antagonist, to inhibit selectively the synthesis of hemoglobin
alpha-chains without directly affecting that of beta-chains. Study of
hemoglobin synthesis by bone marrow cells presents two problems that
require careful management: (A) the fragility of the globin-synthesizing
apparatus and (B) the isolation of globin from the various proteins made by
the mixture of nucleated cells. Disruption of synthetic activity was
minimized by collecting the bone marrow in autologous plasma then removing
fat and connective tissue while the cells were suspended in this medium.
Purification involved gel filtration of hemoglobin and globin then
CM-cellulose chromatography of globin chains. Absence of radioactive
isoleucine in beta-chains demonstrated the efficacy of this scheme in
removing isoleucine- containing proteins that otherwise elute with
beta-chains on CM- cellulose columns. In reticulocytes, when synthesis of
alpha-chains is inhibited by 30%--80%, that of beta-chains is stimulated by
20%--60%, but in marrow cells, incorporation into beta-chains stays at
control level when alpha incorporation is inhibited. The data indicate that
beta-chain synthesis is independent of the availability of complementary
alpha-chains.
Volume 57,
Issue 6,
pp. 1125-1131,
06/01/1981
Copyright © 1981 by The American Society of Hematology
