Transcription reinitiation rate: a special role for the TATA box.
Promoters need to specify both the timing of transcriptional induction and the amount of transcript synthesized. In order to explore each of these effects separately, in vitro assays for the level of active preinitiation complex formation and for the rate of continuous RNA production were done. The effects were found to be influenced differently by different promoter elements. A consensus TATA element had a very strong effect on the rate of continuous RNA production, whereas two types of activators were important primarily in forming active transcription preinitiation complexes. Consensus TATA promoters exhibited high rates of continuous transcription; they assembled active preinitiation transcription complexes slowly but then produced transcripts continuously at an approximately fivefold-higher rate. Initiator-containing TATA-less promoters produced continuous transcripts slowly. Point mutations in the TATA element led to lower levels of transcription by reducing the number of preinitiation complexes and amplifying this reduction by lowering the apparent reinitiation rate. The results allow understanding of the sequence diversity of promoter elements in terms of specifying separate controls over the sensitivity of gene induction and over the strength of the induced promoter.
Yean
D
D
Department of Chemistry & Biochemistry and Molecular Biology Institute, University of California, Los Angeles 90095-1569, USA.
Gralla
J
J
D002474:Cell-Free System; D016384:Consensus Sequence; D006367:HeLa Cells; D006801:Humans; D011401:Promoter Regions, Genetic; D012319:RNA Polymerase II / Q000378:metabolism; D016329:Sp1 Transcription Factor / Q000378:metabolism; D016385:TATA Box; D013698:Templates, Genetic; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D016329:Sp1 Transcription Factor; D014157:Transcription Factors; D012319:RNA Polymerase II