FIG. 5.

Effect of dr1 mutations on cytoplasmic RNA stability. QT6 cells transfected with the indicated mutant DNAs were treated with 2 μg of actinomycin D per ml at 40 h posttransfection for the indicated times, when cytoplasmic RNA was harvested and subjected to analysis by RNase protection as described above. (A) Representative RNase protection assay performed as described above. (B) Amounts of unspliced viral RNAs remaining at 6, 12, and 24 h as a fraction of that amount present at the time of actinomycin D addition. Error bars indicate the standard deviations computed from three separate experiments.