FIG. 2.

Microinjection of poliovirus, HRV 14, and mengovirus RNAs yields infectious viral particles in Xenopus oocytes. Ten nanograms of viral RNA was injected into oocytes in the presence or absence of 100 ng of HeLa cell cytoplasmic proteins. The presence of infectious viral particles in filter-sterilized oocyte extracts obtained after 40 h of incubation at 30°C was determined by plaque assays. For comparison of plaque phenotype, plaque assays using viruses maintained in cell culture were also included, as indicated on the top (From Stock).