Preferential stimulation of rabbit alpha globin mRNA translation by a cap-binding protein complex

A cap-binding protein complex (Edery et al. (1983) J. Biol. Chem. 258, 11398-11403) is shown here to stimulate preferentially the translation of endogenous alpha versus beta globin mRNA in a rabbit reticulocyte lysate. Several initiation factors (eIF-2, eIF-3, eIF-4A, eIF-4B, eIF-4C, eIF-4E and eIF-5) and elongation factor 1 were found to have no such discriminatory effect. These results are in contrast to several previous reports and demonstrate that the only factor capable of relieving translational competition between alpha and beta globin mRNAs is the cap-binding protein complex.