In vivo selection of protease cleavage sites by using chimeric Sindbis virus libraries

Area of Science:

• Virology
• Molecular Biology
• Enzymology

Background:

• Identifying protease cleavage sites is crucial for understanding enzyme specificity and designing inhibitors.
• Current methods often rely on in vitro screening of synthetic or phage-displayed libraries, which can be limited by enzyme purification and assay conditions.

Purpose of the Study:

• To develop a novel in vivo system for identifying protease cleavage sites using recombinant Sindbis virus.
• To demonstrate the system's efficacy using the serine protease of hepatitis C virus (HCV).

Main Methods:

• Engineered Sindbis virus genomes encoding the HCV protease and specific cleavage sites.
• Constructed viral libraries with random sequences at cleavage sites.
• Selected for viable viruses, indicating successful protease cleavage of viral genomes.

Main Results:

• The Sindbis virus system successfully identified cleavage sites in vivo.
• Selected viral sequences mirrored natural HCV protease substrates.
• Cleavage efficiencies were comparable to natural substrates.

Conclusions:

• The recombinant Sindbis virus system provides an efficient in vivo method for identifying protease cleavage sites.
• This approach eliminates the need for purified enzymes and in vitro conditions, simplifying the process.
• The system is valuable for studying protease specificity and developing targeted inhibitors, particularly for viruses like HCV.