FIG. 7.
TBP is essential for SL RNA gene transcription. (A) Western blot analysis of preimmune-depleted (PreIm) and anti-TBP-depleted (α-TBP) nuclear extracts. A small amount of tSNAPc was depleted by anti-TBP; TBP was efficiently removed. (B) Anti-TBP-depleted extracts lost their transcription activity (compare lanes 2 and 6 with 1 and 5). Addition of either TAP-purified tSNAPc, containing TBP (lanes 3 and 4), or sucrose velocity-sedimented tSNAPc, containing TBP (lanes 7 to 9), complemented SL RNA transcription. (C) Quantification, in arbitrary units, of transcription activities shown in panel B. (D) Addition of a purified Ty-tagged TBP (amounts shown above each lane) restored SL RNA gene transcription (lanes 3 to 6).