Development of Sindbis viruses encoding nsP2/GFP chimeric proteins and their application for studying nsP2...

Area of Science:

• Virology
• Molecular Biology
• Protein Biochemistry

Background:

• Sindbis virus (SINV) is a significant alphavirus known for its replication proteins and interference with host antiviral responses.
• The viral nonstructural protein nsP2 possesses protease and RNA helicase activities crucial for viral RNA replication and host cell shutoff.
• The complex functions and structure of nsP2 present challenges for detailed investigation.

Purpose of the Study:

• To develop a novel method for studying Sindbis virus nsP2 protein functions and interactions.
• To identify nsP2-specific protein complexes within infected cells.
• To explore the utility of a transposon-based approach for viral protein analysis.

Main Methods:

• Generation of a Sindbis virus cDNA library with random green fluorescent protein (GFP) insertions into the nsP2 gene using a transposon-based system.
• Selection and characterization of viable recombinant SIN viruses expressing nsP2/GFP chimeric proteins.
• Isolation and analysis of nsP2-specific protein complexes from infected cell cytoplasm using the GFP tag.

Main Results:

• Identified specific sites for GFP insertion in nsP2 without significantly impacting viral replication.
• Recombinant SIN viruses expressing nsP2/GFP were viable and capable of cellular interference.
• Isolated nsP2-specific protein complexes containing viral nonstructural proteins (nsPs) and previously unidentified cellular factors.

Conclusions:

• The transposon-based random insertion library approach is effective for mapping viral protein domains and isolating protein complexes.
• This method facilitates the study of protein complex formation using live-cell imaging.
• The approach holds potential for antigen presentation and viral retargeting applications.