INHIBITION OF 80S INITIATION COMPLEX-FORMATION BY INFECTION WITH POLIOVIRUS

Anisomycin has been shown to stabilize ribosome initiation complexes containing messenger RNA and met-tRNA(f)(met) to high salt conditions. Extracts from HeLa cells treated with 5 x 10-7 M-anisomycin for 15 min accumulate 80S initiation complexes which can be detected by their absorbance in sucrose gradients. Polio-virus-infected cells fail to form the 80S initiation complex early after infection, when inhibition of host cell protein synthesis occurs. These complexes re-form later in infection after virus RNA is synthesized. No re-formation occurs in the absence of virus replication. Thus, the step in protein synthesis inhibited by poliovirus precedes the entry of components into the 80S initiation complex.