Widespread use of TATA elements in the core promoters for RNA polymerases III, II, and I in fission yeast

In addition to directing transcription initiation, core promoters integrate input from distal regulatory elements. Except for rare exceptions, it has been generally found that eukaryotic tRNA and rRNA genes do not contain TAT A promoter elements and instead use protein-protein interactions to bring t he TATA-binding protein (TBP), to the core promoter. Genomewide analysis re vealed TATA elements in the core promoters of tRNA and 5S rRNA (Pol III), U 1 to U5 snRNA (Pol II), and 37S rRNA (Pol I) genes in Schizosaccharomyces p ombe. Using tRNA-dependent suppression and other in vivo assays, as well as in vitro transcription, we demonstrated an obligatory requirement for upst ream TATA elements for tRNA and 5S rRNA expression in S. pombe. The Pol III initiation factor Brf is found in complexes with TFIIIC and Pol III in S. pombe, while TBP is not, consistent with independent recruitment of TBP by TATA. Template commitment assays are consistent with this and confirm that the mechanisms of transcription complex assembly and initiation by Pol III in S. pombe differ substantially from those in other model organisms. The r esults were extended to large-rRNA synthesis, as mutation of the TATA eleme nt in the Pol I promoter also abolishes rRNA expression in fission yeast. A survey of other organisms' genomes reveals that a substantial number of eu karyotes may use,widespread TATAs for transcription. These results indicate the presence of TATA-unified transcription systems in contemporary eukaryo tes and provide insight into the residual need for TBP by all three Pols in other eukaryotes despite a lack of TATA elements in their promoters.