A novel phosphate-regulated expression vector in Escherichia coli

Ti Zhi Su, Herbert Schweizer, Dale L. Oxender

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


The ugp promoter (pugp) responsible for expression of the binding-protein-dependent sn-glycerol-3-phosphate transport system in Escherichia coli was cloned into a small multicopy plasmid pTER5, a derivative of pBR322, between the transcription terminators rpoCt and tL1. The resulting expression vector, pPH3, permits convenient insertion of structural genes containing their own translational-initiation regions, into the multiple-cloning site derived from the pUC19 plasmid. The efficiency and regulatory properties of pugp were measured using xylE and lacZ as reporter genes, which code for the corresponding enzymes catechol-2,3-dioxygenase (C23O) and β-galactosidase (βGal), respectively. Enzyme activities were virtually completely repressed in the presencee of excess inorganic phosphates (Pi) and high concentrations of glucose. Maximal induction was observed at limiting Pi (<0.1 mM) and normal levels of glucose (0.2-0.4%). The maximum expression of the pugp -directed βGal synthesis was approx. 80% of that directed by directed by strong ptac. When the xylE gene was maximally expressed, the induced enzyme constituted approx. 50% of total cellular protein as judged by laser densitometry following sodium dodecyl sulfate-polyacrylamide-gel electrophoresis. These results suggest the usefulness of the pugp in expression vectors for strong, but controlled, expression of cloned genes in E. coli. This Pi controlled vector can be adapted to large-scale fermentation by using Pi-limiting growth conditions.

Original languageEnglish (US)
Pages (from-to)129-133
Number of pages5
Issue number1
StatePublished - May 31 1990
Externally publishedYes


  • Prokaryotic expression vector
  • pho regulon
  • phosphate regulation
  • recombinant DNA
  • ugp promoter

ASJC Scopus subject areas

  • Genetics


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