Possible involvement of messenger RNA-associated proteins in protein synthesis.

Abstract

Two distinct forms of globin mRNA were isolated from mouse spleen cells infected with Friend erythroleukemia virus: polyribosomal messenger ribonucleoprotein particles (15S mRNP), and their corresponding protein-free mRNA obtained by chemical deproteinization. The translation efficiencies of both messenger forms were assayed in a [mouse] Krebs II ascites cell-free system. Selective removal of RNA-binding proteins from the ascites cell lysate did not affect globin synthesis when the mRNA was supplied as 15S mRNP; deproteinized mRNA was not translated. Only in the presence of 2 fractions of RNA-binding proteins was the protein-free mRNA translated. Some of the RNA-binding proteins have the same MW and isoelectric points as the principal proteins of 15S mRNP.