Multiple proteases in foot-and-mouth disease virus replication

Area of Science:

• Molecular Biology
• Virology
• Biochemistry

Background:

• Foot-and-mouth disease virus (FMDV) RNA translation produces a polyprotein precursor.
• This polyprotein undergoes proteolytic cleavage to yield functional viral proteins.
• Understanding FMDV polyprotein processing is crucial for viral replication studies.

Purpose of the Study:

• To investigate the mechanisms of FMDV polyprotein cleavage.
• To differentiate between primary and secondary cleavage events.
• To identify host proteases involved in FMDV polyprotein processing.

Main Methods:

• In vitro translation of FMDV RNA in rabbit reticulocyte lysate.
• Analysis of peptide products at short and prolonged incubation times.
• Treatment of infected cells with a specific protease inhibitor (D-valyl phenylalanyl lysyl chloromethyl ketone).

Main Results:

• Short-term translation produced peptides P20a, P16, and P88.
• P88 cleavage was prevented under conditions inhibiting further translation, indicating distinct mechanisms for primary and secondary cleavages.
• Protease inhibitor treatment blocked cleavage between P20a-P16 and P88, but not other cleavages, suggesting specific host protease involvement.

Conclusions:

• The cleavage of FMDV polyprotein involves at least two distinct mechanisms.
• Primary cleavages (P20a-P16 and P88) are mediated by specific host proteases.
• Secondary cleavages utilize different enzymatic machinery.