FIG. 4.

Positive-strand viral RNA production. ICAM-L cells (A) or HeLa cells (B) were infected with virus at 10 PFU/cell. At the indicated times after infection, total RNA was extracted and immobilized on a membrane. Plus-strand viral RNA was detected by hybridization with a ³²P-labeled RNA probe. RNA levels were quantified by using a PhosphorImager and ImageQuant software. At each time point, viral RNA levels were normalized to levels at time zero and to amounts of wild-type HRV16 RNA.