Autocatalytic synthesis of a viral RNA in vitro.

Experiments with an RNA-dependent RNA polymerase ("replicase") purified from Escherichia coli infected with an RNA bacteriophage (Qbeta) demonstrate that the enzyme generates a polynucleotide of the same molecular weight as viral RNA; the "replicase" cannot distinguish the polynucleotide from its own RNA genome. By starting reactions at input ratios below the saturation levels of template to enzyme, autocatalytic kinetics of RNA increase are observed. The data are consistent with the conclusion that self-propagation of complete viral genomes is occurring in this simple system.