Temperature-mediated regulation and downstream inducible selection for controlling gene expression from the...

Area of Science:

• Molecular Biology
• Biotechnology
• Microbial Genetics

Background:

• Bacteriophage lambda PL promoter is a powerful tool for controlled gene expression in Escherichia coli.
• Heat-inducible expression systems offer temporal control over protein production.
• The CIts857 repressor is commonly used for temperature-inducible systems.

Purpose of the Study:

• To investigate the impact of various induction temperatures on heterologous gene expression.
• To determine optimal temperature conditions for maximizing protein yield in E. coli.
• To evaluate the utility of a chloramphenicol acetyltransferase (cat) reporter gene for monitoring transcription.

Main Methods:

• Utilized a heat-inducible E. coli expression system with the lambda PL promoter and CIts857 repressor.
• Performed experiments across a temperature range of 29-42°C.
• Cloned the cat reporter gene downstream of a heterologous gene to monitor transcription.

Main Results:

• Full repression of CI857-controlled transcription from PL required temperatures as low as 29°C.
• Highest protein yields were achieved after induction at 36°C for 6 hours.
• cat gene expression at low induction temperatures facilitated the selection of transformants capable of producing the heterologous protein.

Conclusions:

• Precise temperature control is critical for optimizing heat-inducible gene expression in E. coli.
• The cat reporter gene is effective for monitoring transcription and selecting successful transformants.
• This study provides valuable insights for maximizing protein yields in E. coli expression systems.