A RECOMBINANT FOOT-AND-MOUTH-DISEASE VIRUS-ANTIGEN INHIBITS DNA-REPLICATION AND TRIGGERS THE SOS RESPONSE IN ESCHERICHIA-COLI

The 3D gene of foot-and-mouth disease virus encodes the viral RNA depe ndent RNA polymerase, also called virus infection associated (VIA) ant igen, which is the most important serological marker of virus infectio n. This 3D gene from a serotype C1 virus has been cloned and overexpre ssed in Escherichia coli under the control of the strong lambda lytic promoters. The resulting 51 kDa recombinant protein has been shown to be immunoreactive with sera from infected animals. After induction of gene expression, an immediate and dramatic arrest of cell DNA synthesi s occurs, similar to that produced by genotoxic doses of the drug mito mycin C. This effect does not occur during the production of either a truncated VIA antigen or other related and non-related viral proteins. The inhibition of DNA replication results in a subsequent induction o f the host SOS DNA-repair response and in an increase of the mutation frequency in the surviving cells.