Poliovirus-specific primer-dependent RNA polymerase able to copy poly(A)

Area of Science:

• Virology
• Molecular Biology
• Biochemistry

Background:

• Poliovirus replication relies on RNA-dependent RNA polymerase (RdRp).
• Understanding the specific components of poliovirus RdRp is crucial for comprehending viral replication strategies.

Purpose of the Study:

• To isolate and characterize a template-dependent RNA polymerase from poliovirus-infected cells.
• To investigate the enzymatic activity and properties of the isolated polymerase.

Main Methods:

• Isolation of RNA polymerase from poliovirus-infected HeLa cells using detergent solubilization and LiCl precipitation.
• Assay for polymerase activity using poly(A) template and oligo(U) primer.
• Analysis of polymerase properties, including cofactor requirements (Mg2+, Mn2+) and sedimentation behavior via glycerol gradient centrifugation.

Main Results:

• A poly(A)-oligo(U)-dependent poly(U) polymerase activity was detected in poliovirus-infected cells, appearing 2 hours post-infection and increasing linearly until 5 hours.
• The polymerase activity was stimulated by Mg2+ and inhibited by Mn2+.
• Glycerol gradient centrifugation indicated the active polymerase sedimented at approximately 4 S, suggesting it was not associated with high-molecular-weight RNA or cellular membranes.

Conclusions:

• The isolated poly(A)-oligo(U)-dependent polymerase activity represents a significant component of the poliovirus RNA-dependent RNA polymerase.
• This finding contributes to understanding the molecular mechanisms of poliovirus RNA synthesis.