Abstract
Anisomycin stabilized ribosome initiation complexes containing mRNA and .**GRAPHIC**. to high salt conditions. Extracts from [human cervical carcinoma] HeLa cells treated with 5 .times. 10-7 M-anisomycin for 15 min accumulate 80S initiation complexes which can be detected by their absorbance in sucrose gradients. Poliovirus-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. The step in protein synthesis inhibited by poliovirus precedes the entry of components into the 80S initiation complex.