Iron chelator-inducible expression system for Escherichia coli

Area of Science:

• Microbiology
• Molecular Biology
• Biotechnology

Background:

• The PentC promoter in E. coli regulates enterobactin biosynthesis genes.
• Iron availability tightly controls PentC promoter activity via the Fur (ferric uptake regulator) protein.
• Fur represses transcription by binding to the Fur box under iron-rich conditions.

Purpose of the Study:

• To construct and characterize an expression vector (pOS2) utilizing the PentC promoter.
• To evaluate the repression, induction, and modulation of the PentC promoter.
• To assess the utility of this system for recombinant protein production.

Main Methods:

• Construction of the pOS2 expression vector containing the PentC promoter.
• Quantification of lacZ reporter gene expression (beta-galactosidase activity) in E. coli transformants.
• Treatment with iron chelators (2,2'-dipyridyl, EDTA) and excess iron to assess promoter activity.
• Introduction of the fur gene into the expression vector to study its effect.

Main Results:

• Beta-galactosidase activity was significantly induced by iron chelators.
• Beta-galactosidase activity was strongly repressed by excess iron.
• Incorporating the fur gene drastically decreased basal beta-galactosidase expression.
• The PentC promoter demonstrates efficient iron-dependent regulation.

Conclusions:

• The developed PentC promoter-based system is an effective iron chelator-inducible expression system.
• This system offers efficient and cost-effective control for gene expression.
• It holds significant potential for applications in recombinant protein production.