Parameters of RNA-dependent RNA polymerase activity in a mengovirus-infected Ehrlich ascites carcinoma cell-free system.

Virus-specific RNA polymerase activity of mengovirus-infected Ehrlich ascites carcinoma (EAC) cells was maximal 7 hours after infection in a one-step growth cycle. In a cell-free system with the mitochondrial-microsomal fraction (MMF) derived from mengovirus-infected EAC cells in a nucleoside-triphosphate medium, polymerase activity increased up to 60 min (when MMF was obtained by a homogenizer) or 120 min (when MMF was prepared by sodium deoxycholate disruption). Subsequently RNA polymerase activity decreased between 150-180 min of incubation at 37 degrees C and then formed a plateau up to 300 min. The cell-free system used is able to give valuable information as regards testing of RNA polymerase inhibitors in an antiviral screening programme.