Fig. 5. The C-terminal motif restores processing of transcripts made by pol II with heptads 1–25 but not 1–15 or 27–42. RNase protection of pSVβ128Rpbex5 transcripts from α-amanitin-treated cells expressing Rpb1 mutants. +WT indicates the presence of the wild-type C-terminus with the indicated hepad repeats. 27-Cter has heptads 27–52 plus the C-terminus, and 27–52ΔC has the C-terminus deleted. Corrected ratios of spliced:unspliced and cleaved:uncleaved transcripts are shown below the lanes. The asterisk marks an irrelevant undigested probe.