Abstract
The kinetics of appearance of an RNA-dependent RNA polymerase activity obtained from human embryo lung cells infected with rhinovirus type 2 have been followed by analysis of the RNA synthesized by the polymerase preparation in vitro. Little single-stranded RNA was synthesized and the proportion of replicative intermediate to replicative form was over threefold greater than obtained in vivo. The polymerase activity in vivo declined in the presence of cycloheximide showing that continued protein synthesis was necessary to maintain RNA replication.