In vitro translation of cardiovirus ribonucleic acid by mammalian cell-free extracts.

Cell-free extracts prepared from Ehrlich ascites and mouse L cells synthesize viral proteins in response to encephalomyocarditis virus, mouse Elberfeld virus, and mengovirus ribonucleic acid. Although HeLa cell extracts are inactive, their ribosomes are functional in the presence of heterologous supernatant fractions. Synthesis depends upon the addition of adenosine triphosphate, guanosine triphosphate, an energy-generating system, and 4 mm Mg(2+). Initiation is completed during the first 10 to 20 min of incubation, but chain elongation continues for 1 hr or more. The products are of higher molecular weight than virion structural proteins and resemble polypeptides formed in virus-infected cells during a short pulse. Tryptic peptides of virion proteins and in vitro products are similar for all three cardioviruses.