Proteins induced by infection with caliciviruses

Area of Science:

• Virology
• Molecular Biology
• Protein Biochemistry

Background:

• Caliciviruses are a significant genus of viruses causing various diseases in humans and animals.
• Understanding calicivirus replication, particularly protein synthesis, is crucial for developing antiviral strategies.
• Previous studies have identified viral proteins, but their synthesis and processing pathways remain incompletely understood.

Purpose of the Study:

• To investigate the polypeptides produced during calicivirus infection.
• To determine the precursor-product relationships among these viral polypeptides.
• To explore potential mechanisms of translation utilized by caliciviruses.

Main Methods:

• Analysis of infected cell lysates to identify viral polypeptides using molecular weight determination.
• Pulse-chase experiments to trace protein synthesis and processing.
• Use of selective inhibitors for protein synthesis and proteases to elucidate pathways.
• Identification of a precursor polypeptide (P120) in the presence of protease inhibitors.

Main Results:

• Three major polypeptides, P100, P80, and P65 (molecular weights 100, 80, and 65 x 10^3 Da, respectively), were detected in calicivirus-infected cells.
• P100 and P80 were found in sub-molar quantities relative to P65.
• No direct precursor-product relationship was established between P100, P80, and P65 under normal conditions.
• A 120 x 10^3 Da polypeptide (P120) was identified as a likely precursor to P100, particularly when protease activity was inhibited.

Conclusions:

• Calicivirus infection involves the synthesis of distinct polypeptides, with P65 being the most abundant.
• The identification of P120 as a P100 precursor suggests a complex proteolytic processing pathway.
• These findings provide insights into the translational mechanisms and protein maturation of caliciviruses, warranting further investigation.