FIG. 6.

Steady-state level of the global poly(A)⁺ mRNA during mild and severe HS: effect of RPB4 deletion and overexpression of RPB7. SUB62 (wild-type), MC11-1 (rpb4Δ), and AS1 (rpb4Δ GAL1p-RPB7) strains were grown at 22°C on galactose-containing medium as described in Materials and Methods. In mid-log phase (at 10⁷ cells/ml), cells were shifted to either 34 or 39°C and harvested at the indicated time points after the shift. RNA was extracted, and 1 μg of the RNA samples was dot blotted onto nitrocellulose filter in duplicate. One set of dots was hybridized with ³²P-labeled poly(dT) to detect the poly(A)-containing mRNA (designated mRNA at the left or right of the figure) and the other set was hybridized with ³²P-labeled rDNA to detect the rRNA (designated rRNA at the left or right of the figure). This procedure was described in detail previously (5). The absence of a gene (−), the presence of one copy of a gene (+), and the overexpression of a gene (+++) are indicated.