Membrane permeabilization by poliovirus proteins 2B and 2BC

Area of Science:

• Virology
• Molecular Biology
• Cell Biology

Background:

• Poliovirus infection causes significant changes in host cell membrane permeability, particularly in later stages.
• Understanding these alterations is crucial for comprehending viral pathogenesis and host-pathogen interactions.

Purpose of the Study:

• To identify specific poliovirus nonstructural proteins responsible for altering membrane permeability.
• To map the functional regions within these proteins involved in membrane permeabilization.

Main Methods:

• Transient expression of individual poliovirus nonstructural proteins using recombinant vaccinia virus and T7 RNA polymerase.
• Assessing membrane permeability by measuring hygromycin B resistance in HeLa cells.
• Analyzing the effects of deletions and point mutations in viral proteins 2B and 2BC.

Main Results:

• Poliovirus proteins 2B and 2BC significantly enhance membrane permeability to hygromycin B.
• Specific sequences at both ends of protein 2B are essential for membrane permeabilization.
• Deletions in 2BC, including within the 2C GTPase motifs, did not abolish the membrane-modifying capacity of 2BC.
• Expression of 2B and 2BC also increased the release of preloaded compounds like choline and uridine.

Conclusions:

• Poliovirus proteins 2B and 2BC are key mediators of increased membrane permeability during infection.
• The N-terminal and C-terminal regions of protein 2B are critical for its role in membrane permeabilization.
• The functional domains of protein 2C are not essential for the membrane-altering activity of the 2BC polyprotein.