Low levels of foot-and-mouth disease virus 3C protease expression are required to achieve optimal capsid protein expression and processing in mammalian cells.
The foot-and-mouth disease virus (FMDV) capsid protein precursor (P1-2A) is processed by the virus-encoded 3C protease (3C(pro)) to produce VP0, VP3, VP1 and 2A. Within the virus-encoded polyprotein, the P1-2A and 3C(pro) can be expected to be produced at equivalent concentrations. However, using transient-expression assays, within mammalian cells, it is possible to modify the relative amounts of the substrate and protease. It has now been shown that optimal production of the processed capsid proteins from P1-2A is achieved with reduced levels of 3C(pro) expression, relative to the P1-2A, compared with that achieved with a single P1-2A-3C polyprotein. Expression of the FMDV 3C(pro) is poorly tolerated by mammalian cells and higher levels of the 3C(pro) greatly inhibit protein expression. In addition, it is demonstrated that both the intact P1-2A precursor and the processed capsid proteins can be efficiently detected by FMDV antigen detection assays. Furthermore, the P1-2A and the processed forms each bind to the integrin αvβ6, the major FMDV receptor. These results contribute to the development of systems which efficiently express the components of empty capsid particles and may represent the basis for safer production of diagnostic reagents and improved vaccines against foot-and-mouth disease.
National Veterinary Institute, Technical University of Denmark, Lindholm, 4771 Kalvehave, Denmark.
Charlotta
C
Polacek
National Veterinary Institute, Technical University of Denmark, Lindholm, 4771 Kalvehave, Denmark.
Maria
M
Gullberg
National Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu-730046, China.|National Veterinary Institute, Technical University of Denmark, Lindholm, 4771 Kalvehave, Denmark.
Jiong
J
Li
National Veterinary Institute, Technical University of Denmark, Lindholm, 4771 Kalvehave, Denmark.
Graham J
GJ
Belsham
D000086042:3C Viral Proteases; D000818:Animals; D002213:Capsid / Q000378:metabolism; D036022:Capsid Proteins / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D006224:Cricetinae; D003546:Cysteine Endopeptidases / Q000235:genetics* / Q000378:metabolism; D005536:Foot-and-Mouth Disease / Q000821:virology*; D029544:Foot-and-Mouth Disease Virus / Q000201:enzymology* / Q000235:genetics; D015967:Gene Expression Regulation, Viral; D011499:Protein Processing, Post-Translational; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism
D036022:Capsid Proteins; D014764:Viral Proteins; D003546:Cysteine Endopeptidases; D000086042:3C Viral Proteases