Promoter domain mediates guanosine tetraphosphate activation of the histidine operon.
AUTOR(ES)
Riggs, D L
RESUMO
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 E sigma 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.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=387132Documentos Relacionados
- Promoter- and attenuator-related metabolic regulation of the Salmonella typhimurium histidine operon.
- Structure and function of the internal promoter (hisBp) of the Escherichia coli K-12 histidine operon.
- Specific binding of the first enzyme for histidine biosynthesis to the DNA of histidine operon.
- The promoter of the Streptomyces glaucescens mel operon.
- Promoter of the Mycoplasma pneumoniae rRNA operon.