Interaction of cellular proteins with the poliovirus 5' noncoding region

Area of Science:

• Virology
• Molecular Biology
• Genetics

Background:

• The 5' noncoding region (NCR) of poliovirus RNA possesses a complex secondary structure essential for viral infectivity.
• Mutations within the 5' NCR significantly impact poliovirus neurovirulence.
• Known viral proteins interact with the 5' NCR to regulate translation.

Purpose of the Study:

• To identify novel proteins that bind to the 5' NCR of poliovirus.
• To investigate the role of these protein-RNA interactions in viral translation and neurovirulence.
• To characterize the molecular basis for differential protein binding between neurovirulent and attenuated poliovirus strains.

Main Methods:

• Crosslinking of proteins to specific stem-loop domains of the poliovirus 5' NCR using Hela cell ribosomal salt wash.
• In vitro translation assays to assess the inhibitory effect of RNA segments on protein binding.
• Comparative analysis of RNA binding affinities between wild-type and Sabin vaccine strains.

Main Results:

• Three novel proteins were identified that specifically bind to stem-loop structures within the poliovirus 5' NCR.
• These RNA segments, when bound by proteins, inhibit in vitro translation, suggesting a competitive binding mechanism.
• The Sabin vaccine strain demonstrated a reduced binding affinity for specific viral proteins compared to neurovirulent strains.

Conclusions:

• The 5' NCR of poliovirus interacts with multiple cellular proteins that are critical for viral translation and neurovirulence.
• A single nucleotide difference at position 480 is identified as the determinant for reduced protein binding in the attenuated Sabin vaccine strain.
• These findings provide insights into the molecular mechanisms underlying poliovirus attenuation and neurovirulence.