Characterization of vesicular stomatitis virus mutants by partial proteolysis

Area of Science:

• Virology
• Molecular Biology
• Protein Chemistry

Background:

• Vesicular stomatitis virus (VSV) is a model system for studying RNA virus replication.
• Temperature-sensitive (ts) mutants are crucial for dissecting viral protein function.
• Understanding protein structure-function relationships aids in viral pathogenesis research.

Purpose of the Study:

• To compare structural proteins of VSV Indiana serotype ts mutants with wild-type and revertant virions.
• To identify specific viral proteins affected by mutations in different complementation groups.
• To pinpoint the exact location of mutations within viral proteins.

Main Methods:

• Electrophoresis on polyacrylamide gels was used to analyze protein digests.
• Partial digestion of viral structural proteins with Staphylococcus aureus V8 protease.
• Comparison of peptide profiles between wild-type, mutant, and revertant VSV strains.

Main Results:

• Mutants tsG31 and tsG33 (Group III) showed altered peptide profiles in M protein.
• Mutant tsG22 (Group II) exhibited changes in the NS protein peptide profile.
• Mutant tsG41 (Group IV) displayed differences in the N protein peptide profile.
• Revertants generally restored the wild-type peptide pattern, except for a partial reversion in tsG22's NS protein.

Conclusions:

• Lesions in VSV complementation groups III and IV are located in the M and N proteins, respectively.
• The mutation site for VSV complementation group II was definitively identified as the NS protein cistron.
• Partial reversion in tsG22 suggests potential silent mutations or complex reversion pathways.