Translational competition between related virus RNA species in cell-free systems

The competition between the RNAs from two tobacco mosaic virus (TMV) strains for translation in rabbit reticulocyte lysate and wheat germ cell-free systems was investigated. The virus translational products were distinguished by the size difference of the I2 polypeptides. The RNAs of the two strains were translated simultaneously if added to the translation system together at the beginning of the reaction. Each of the TMV RNAs could inhibit translation of the other when the reaction was initiated by the RNA of one strain and that of the other strain was added after active translation had commenced. In contrast, translation of alfalfa mosaic virus (AMV) RNA was not appreciably inhibited when its RNA was added after the start of translation of TMV RNA; the addition of TMV RNA to an AMV RNA-initiated reaction also resulted in independent synthesis of the products of both virus RNAs.