Fig. 1.
Characterization of the S. cerevisiae TFC6 promoter suggests autoregulation by the TFIIIC complex. (A) Transcriptional start sites upstream of TFC6 were mapped by 5′-RACE analysis and are detailed in Fig. S1. TFC6 promoter regions of highest homology among five budding yeast species are designated as promoter boxes 1–7 and are also detailed in Fig. S1. (B) Mutant promoters were reintegrated into the yeast chromosome, and relative TFC6 mRNA levels were determined by Northern blotting. Expression was determined from three independently isolated strains for each mutation; one each is shown here. (C) Temperature-sensitive mutation in TFC3, but not in other Pol III mutations, results in increased TFC6 transcript levels. Strains containing mutant alleles of TFIIIC, TFIIIB, and Pol III components were grown at permissive temperature (30 °C) and then pulsed for 1 h at the nonpermissive temperature (37 °C) before RNA extraction and Northern analysis.