Figure 5.

The suppressor effect of the U1–7U snRNA and selected prp8 alleles on splicing of U+2A pre-mRNA reporters. (A) Copper growth phenotypes of the wild-type and selected prp8 suppressor strains (as indicated at right) in the presence of the wild-type or U+2A ACT1–CUP1 reporter (as indicated at left). Strains containing no additional copy, a wild-type, or U1–7U snRNA, as indicated, were plated in the presence of 0.1 mm (left) and 0.2 mm (right) CuSO₄ in the media. (B) Primer extension analysis of total RNA isolated from strains containing a wild-type (lanes 1–6) or suppressor prp8 alleles (lanes 7–13), as well as an additional copy of the wild-type (lanes 1,4), U1–7U (lanes 2,6–13), or no U1 snRNA (lanes 3,5). Positions of U14, pre-mRNA, mRNA and lariat intermediates are indicated.