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Morphological‐Biochemical Correlations in Rabbit Red Cell Precursors Synchronized by Actinomycin Administration
Author(s) -
Hershko Ch.,
Schwartz R.,
Izak G.
Publication year - 1969
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1969.tb01408.x
Subject(s) - rna , dna synthesis , biology , in vitro , microbiology and biotechnology , population , protein biosynthesis , messenger rna , dactinomycin , dna , basophilic , bone marrow , biochemistry , immunology , gene , pathology , medicine , environmental health
S ummary . By making use of the selective toxicity of Actinomycin D, homogenous erythroid populations of various stages of maturation had been obtained in the rabbit. Comparison of the morphological characteristics of red cell precursors with in vitro synthetic activity as measured by the rate of incorporation of 32 P, 59 Fe and [2‐ 14 C]glycine into DNA, RNA, haem and protein respectively, revealed the following: The rate of haem synthesis was negligible in pronormoblasts and early basophilic normoblasts, highest 1 day after Actinomycin administration, i.e. corresponding to a more advanced stage of erythroid maturation, and again lower in orthochromatic normoblasts. The rate of RNA synthesis was extremely low in the first 2 days following exposure to Actinomycin D. While our data could not permit distinction between interference of the drug with DNA‐dependent RNA synthesis and a spontaneous loss of RNA synthetic activity brought about by maturation, it was clear that this reduction in RNA synthesis did not affect the rate of protein synthesis. This observation lends further support to earlier claims for the existence of a stable messenger RNA in erythroid cells. Proliferation of undifferentiated mononuclear cells preceded the restitution of bone marrow population after the toxic action of Actinomycin D. Factors affecting their in vitro differentiation are currently being investigated in our laboratory.