FIG. 2.

Sucrose gradient sedimentation of viral RNA extracted from unheated and heated FHV particles. Ten micrograms (100,000 cpm) of [³H]uridine-labeled FHV particles was either heated to 65°C and cooled or kept at 4°C for 10 min. Viral RNA was extracted from each aliquot, sedimented through an 11-ml 5 to 25% sucrose gradient, and fractionated on an ISCO gradient fractionator. The radioactivity in an aliquot (100 μl) of each fraction was determined by liquid scintillation counting. (A) Plot of RNA extracted from unheated FHV particles. (B) Plot of RNA extracted from heated FHV particles. The peaks corresponding to RNA1, RNA2, and the RNA complex are indicated. The arrows in the top left corners of both graphs indicate the direction of sedimentation.