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Inhibition of 80S initiation complex formation by infection with poliovirus
Abstract:
Anisomycin has been shown to stabilize ribosome initiation complexes containing messenger RNA and met-tRNAf 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. 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. Thus, the step in protein synthesis inhibited by poliovirus precedes the entry of components into the 80S initiation complex.
Insights
Anisomycin stabilizes ribosome initiation complexes. Poliovirus infection initially inhibits these complexes, which re-form later, indicating protein synthesis inhibition occurs before complex formation.
Area of Science:
- Molecular Biology
- Virology
- Biochemistry
Background:
- Anisomycin is known to stabilize ribosome initiation complexes.
- Ribosome initiation complexes are crucial for protein synthesis.
- Poliovirus infection inhibits host cell protein synthesis.
Purpose of the Study:
- To investigate the effect of anisomycin on ribosome initiation complexes in HeLa cells.
- To determine the stage of protein synthesis inhibited by poliovirus infection.
- To understand the role of ribosome initiation complexes in poliovirus replication.
Main Methods:
- Treatment of HeLa cells with anisomycin.
- Analysis of ribosome initiation complexes using sucrose gradient centrifugation.
- Monitoring complex formation in poliovirus-infected cells at different stages of infection.
Main Results:
- Anisomycin treatment leads to the accumulation of 80S initiation complexes.
- Poliovirus-infected cells show a failure to form 80S initiation complexes early in infection.
- These complexes re-form later in infection, correlating with viral RNA synthesis and replication.
Conclusions:
- The inhibition of host cell protein synthesis by poliovirus occurs prior to the formation of the 80S initiation complex.
- Re-formation of 80S initiation complexes is dependent on viral replication.
- Poliovirus targets a step in protein synthesis that precedes the assembly of the 80S initiation complex.