FIG. 1.

Kinetics of FHV RNA1 replication in RNA-transfected cells. (Lower panel) EcR-CHO cells were transfected with FHV RNA1 and incubated at 28°C. At 24-h intervals, cells were pulse-labeled for 2 h with [³H]uridine in the presence of actinomycin D. Total cellular RNAs were isolated. Labeled RNAs were then acid precipitated and quantitated by scintillation spectrometry. The rate of RNA replication (counts per minute per 1.7 × 10⁵ cells) was expressed as a function of incubation time. Results were normalized to the amount of rRNA present in each sample as described in Materials and Methods. (Middle panel) The relative abundance of FHV RNA1 in the total RNA pool isolated at each time point was determined by primer extension with an RNA1-specific primer and quantitated by densitometric analysis as described in Materials and Methods. The amounts are expressed as percentages of the maximum (day 2) value. (Upper panel) A portion (4%) of the total cellular RNAs isolated at each time point shown in the lower panel were transfected into a fresh monolayer of EcR-CHO cells and incubated at 28°C. At 24 h posttransfection, RNAs were labeled, isolated, and analyzed as described for the lower panel.