FIG. 6.

The tpa1Δ mutation does not significantly inhibit mRNA export from the nucleus. The indicated strains were grown at 37°C, HAC1 gene expression was induced from the CUP1 promoter, and DTT was added to induce the UPR. Samples were harvested at the indicated times after induction of the UPR to prepare RNA for Northern blot analysis using a HAC1-specific probe. (Upper panel) Northern blot showing HAC1 mRNA splicing in wild-type, tpa1Δ, and mex67-5 strains following induction of the UPR. (Lower panel) Graph showing the percentage of total HAC1 mRNA spliced as a function of time after UPR induction.