TBP residence time at RNA Pol I, Pol II, and Pol III promoters as measured by the anchor-away assay. See also Supplemental Figures S4 and S5. (A) Schematic diagram of the TBP anchor-away approach (Haruki et al. 2008). Upon addition of rapamycin (+rap, red dot), TBP fused to the rapamycin-binding domain FRB is exported out of the nucleus by the flow of ribosomal subunits (ribos) through its interaction with a ribosomal protein bearing the complementary FKBP rapamycin-binding domain (for details, see Haruki et al. 2008). (B) FRB-tagged TBP occupancy at the indicated promoters was measured just before and at the indicated time points after rapamycin addition by quantitative ChIP using anti-TBP antibodies. Note that the experiment includes a 2-min time point. Because TBP occupancy varies among promoters, results are expressed relative to the T0 value, which was taken as 100, to allow for direct comparison. (C) Same as in B at other TFIID-independent RNA Pol II promoters. The results for FBA1 are from B and serve as a comparison. The individual data points are as in B and are not shown in this and the next two panels to facilitate visual comparison. (D) Same as in C at TFIID-dependent promoters. (E) Same at three genes regulated by the Rap1 activator, which is known to recruit the TBP-containing TFIID factor to the promoter (Mencia et al. 2002). FBA1 is from B.
