PMID:7527789
| Citation |
Liu, C, Heath, LS and Turnbough, CL Jr (1994) Regulation of pyrBI operon expression in Escherichia coli by UTP-sensitive reiterative RNA synthesis during transcriptional initiation. Genes Dev. 8:2904-12 |
|---|---|
| Abstract |
Pyrimidine-mediated regulation of pyrBI operon expression in Escherichia coli K-12 occurs through UTP-sensitive transcriptional attenuation and through a second mechanism that functions at the level of transcriptional initiation. In this study we demonstrate that this second control mechanism is based on UTP-sensitive reiterative RNA synthesis within a run of three T-A base pairs in the pyrBI initially transcribed region. Our results show that high UTP levels induce the synthesis in vitro of nascent transcripts with the sequence AAUUUUn (where n = 1 to > 30), which are not extended downstream to include pyrBI sequences. Synthesis of these transcripts, which are initiated at the predominant in vivo transcriptional start site, inhibits the production of full-length pyrBI transcripts. A TTT to GTA mutation in the pyrBI initially transcribed region eliminates reiterative transcription and stimulates productive transcription in vitro. When introduced into the E. coli chromosome, this mutation causes a sevenfold increase in pyrBI expression in cells grown under conditions of pyrimidine excess and nearly abolishes pyrimidine-mediated regulation of pyrBI expression when coupled with a mutation that eliminates attenuation control. Additional experiments indicate that the context of the three T-A base pairs within the pyrBI initially transcribed region is important for reiterative transcription. A possible mechanism for reiterative transcription and the likely involvement of this process in the regulation of other genes are discussed. |
| Links | |
| Keywords |
Base Composition; Base Sequence; Codon; DNA-Directed RNA Polymerases/metabolism; Escherichia coli/genetics; Escherichia coli/metabolism; Gene Expression Regulation, Bacterial; Genotype; Kinetics; Mutagenesis; Operon; Plasmids; Promoter Regions, Genetic; RNA, Bacterial/biosynthesis; Recombination, Genetic; Templates, Genetic; Transcription, Genetic; Uridine Triphosphate/metabolism |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.