Promoter Domain Mediates Guanosine Tetraphosphate Activation of the Histidine Operon

• Published in: Proceedings of the National Academy of Sciences - PNAS 1986-12, Vol.83 (24), p.9333-9337
• Main Authors: Riggs, Daniel L., Mueller, Reinhold D., Kwan, Hoi-Shan, Artz, Stanley W.
• Format: Article
• Language: English
• Subjects: Bacteriophages; Biological and medical sciences; DNA; DNA, Bacterial - genetics; DNA, Superhelical - genetics; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation; Genes; Genetic mutation; Guanine Nucleotides - pharmacology; Guanosine Tetraphosphate - pharmacology; Histidine - genetics; Molecular and cellular biology; Molecular genetics; Operator regions; Operon; Operons; Plasmids; Promoter regions; Promoter Regions, Genetic; RNA; Salmonella typhimurium; Salmonella typhimurium - genetics; Transcription, Genetic - drug effects; Transcription. Transcription factor. Splicing. Rna processing; Transcriptional regulatory elements
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.83.24.9333

We have analyzed the effects of the ``alarmone'' guanosine 5′-diphosphate 3′-diphosphate (ppGpp) on regulation of the Salmonella typhimurium histidine operon in vitro. Expression of the wild-type promoter, measured in a DNA-dependent transcription-translation system, was strongly dependent on ppGpp; addition of ppGpp stimulated his expression 22-fold with plasmid DNA templates. Oligonucleotide-directed, site-specific mutations that increase the homology of the -10 hexamer to the consensus sequence of the Eσ 70 promoters dramatically increased his expression in the absence of ppGpp and reduced the stimulation to less than a factor of 2. A deletion mutation that alters the sequence between the -10 hexamer and the start point of transcription, generated by BAL-31 nuclease, affected ppGpp regulation in a similar manner. We propose that the -10 hexamer sequence and the adjacent downstream region are both important in regulating transcription by ppGpp. Mechanisms to account for activation and repression of transcription by ppGpp are discussed.