A special repressor/activator system controls distribution of mRNA between translationally active and inactive mRNPs in rabbit reticulocytes

Abstract
Translation of free mRNPs and polyribosomal mRNPs from rabbit reticulocytes was studied in a rabbit reticulocyte and wheat germ cell-free systems. It has been shown that the translation efficiency of polyribosomal mRNPs and the mRNA isolated from the particles is nearly the same in both systems. At the same time, free mRNPs' translatability, which is high in the homologous cell-free system, is very low in the system from wheat germs. Translation efficiency of free mRNPs in the wheat germ system can be restored by addition of 0.5 M KCl-wash of rabbit reticulocyte ribosomes. These results testify to the existence of some special repressor/activator system which controls the distribution of mRNA between free mRNPs and polyribosomes in rabbit reticulocytes.