Crude initiation factors from poliovirus-infected cells failed to stimulate translation of host cell mRNA but successfully stimulated translation of viral mRNA, indicating an mRNA-specific activity.
The study demonstrates an mRNA-specific activity in crude initiation factor preparations from poliovirus-infected cells, providing insights into mechanisms of poliovirus-induced host cell shutoff.
By using cell-free systems prepared from uninfected and poliovirus-infected cells, we have been able to demonstrate that crude preparations of initiation factors from infected cells do not stimulate the initiation of translation by polyribosomes containing endogenous host cell mRNA. When tested with polysomes containing endogenous viral mRNA, however, they were able to stimulate initiation of translation nearly as well as uninfected cell initiation factors. The uninfected cell initiation factor preparations were able to stimulate initiation of translation of both cell and viral mRNA. The results indicate an mRNA-specific activity present in crude initiation factor preparations from infected cells. Furthermore, the ability of eIF2 from infected cells to form a ternary complex with GTP and formyl 35Smethionine-tRNAfmet, an mRNA-independent step in initiation, was found not to be deficient. Implications of these data for proposed mechanisms of poliovirus-induced host cell shutoff are discussed.
Helentjaris et al. (1978) studied Poliovirus infection (in vitro). Crude initiation factors from poliovirus-infected cells vs. Initiation factors from uninfected cells was evaluated on Stimulation of translation initiation by polyribosomes. Crude initiation factors from poliovirus-infected cells failed to stimulate translation of host cell mRNA but successfully stimulated translation of viral mRNA, indicating an mRNA-specific activity.