Specificity of mRNA binding factor in eukaryotes.

It has been shown previously that ribosomal factors removed from chick muscle ribosomes by a high salt wash are required for both the binding of muscle mRNA to ribosomes and mRNA-directed synthesis of myosin on reticulocyte ribosomes. These factors can be separated into several components on DEAE-cellulose. A factor eluting between 0.18 and 0.25 M KCl is responsible for binding mRNA to the ribosome. This binding factor shows specificity in the recognition of mRNA, as has been demonstrated by the preferential binding of muscle and globin mRNA to ribosomes which contain their respective binding factors. Similarly, globin mRNA is preferentially translated when reticulocyte factors are present on the ribosome.