FIGURE 5.

Effects of SKI1 on 20S RNA virus. A, wild-type 20S RNA virus is quite insensitive to SKI1 overexpression. ski1Δ strain carrying wild-type 20S RNA virus was transformed with a SKI1 centromeric vector (lane 2) or with a SKI1 multicopy vector (lane 3). Lane 1, 20S RNA virus-carrying ski1Δ strain without plasmid as control. B, 20S RNA with the 69GG69 mutation becomes sensitive to SKI1 suppression. ski1Δ strain carrying wild-type 20S RNA virus (lanes 1–4) or virus with the 68GG69 mutation (lanes 5–8) was transformed with a SKI1-overexpressing multicopy vector (lanes 3, 4, 7, and 8) or the vector alone (lanes 1, 2, 5, and 6). Two transformants from each experiment were analyzed. 20S RNA was detected as described in the legend to Fig. 2B. The lower panel shows 25S and 18S rRNAs stained with ethidium bromide as loading control. The photograph was taken before blotting. The strains used in A and B have no L-A virus.