Interaction of poly(A) and mRNA with eukaryotic initiator met-tRNA-f binding factor: identification of this activity on reticulocyte ribonucleic acid protein particles.

Abstract

Messenger ribonucleoprotein particles (mRNPs) have been isolated from rabbit reticulocyte polysomes. One of the proteins of the mRNP complex has many properties of a specific eukaryotic initiation factor, the soluble Met-tRNA-f binding protein. A purified preparation of this factor, in addition to binding Met-tRNA-f, binds poly(A) and globin mRNA. The binding of these substrates is greater than that obtained with other natural or artificial polyribonucleotides. The mRNP fraction also binds poly(A) and Met-tRNA-f. Since the factor which binds initiator tRNA also binds poly(A) and mRNA, and this activity can be found on mRNPs, there may be a relationship between initiator tRNA binding and messenger binding in early events of eukaryotic initiation.