Biologically active protease of foot and mouth disease virus is expressed from cloned viral cDNA in Escherichia coli.

Foot and mouth disease virus O1K cDNA had been cloned in Escherichia coli. Here we report on in vitro recombination of cDNA fragments according to the cDNA restriction map and on expression of viral proteins in E. coli. Use was made of the expression vector pPLVP1 , which is known to express the virus capsid protein VP1. Recombined cDNAs of various sizes were inserted downstream from the VP1 gene. The constructed plasmids differ from each other in the number of virus genes coding for nonstructural proteins. The effects caused by their expression in E. coli are compared. It is shown that the virus protease is expressed in E. coli as an active enzyme that recognizes the simultaneously produced virus-specific polyprotein as substrate. The virus protease gene was mapped 5'-adjacent to the virus replicase gene.