The promoters of vertebrate and yeast U6 small nuclear RNA genes are structurally dissimilar, although both are recognized by RNA polymerase III. Vertebrate U6 RNA genes have exclusively upstream promoters, while the U6 RNA gene from the yeast Saccharomyces cerevisiae (SNR6) has internal and downstream promoter elements that match the tRNA gene intragenic A- and B-block elements, respectively. Substitution of the SNR6 A or B block greatly diminished U6 RNA accumulation in vivo, and a subcellular extract competent for RNA polymerase III transcription generated nearly identical DNase I protection patterns over the SNR6 downstream B block and a tRNA gene intragenic B block. We conclude that the SNR6 promoter is functionally similar to tRNA gene promoters, although the effects of extragenic deletion mutations suggest that the downstream location of the SNR6 B block imposes unique positional constraints on its function. Both vertebrate and yeast U6 RNA genes have an upstream TATA box element not normally found in tRNA genes. Substitution of the SNR6 TATA box altered the site of transcription initiation in vivo, while substitution of sequences further upstream had no effect on SNR6 transcription. We present a model for the SNR6 transcription complex that explains these results in terms of their effects on the binding of transcription initiation factor TFIIIB.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|