Osmoregulated TAQ polymerase gene expression in Escherichia coli

• Published in: Revista latinoamericana de microbiología (1970) Vol. 44; no. 1; p. 14
• Main Authors: Cabrera Artiles, Yeosvany, Martínez García, Duniesky, Pérez Cruz, Enrique R, Márquez Perera, Gabriel J, Feble, Manuel Luis
• Format: Journal Article
• Language: English
• Published: Mexico 01.01.2002
• Subjects: Biotechnology; Culture Media - pharmacology; Dose-Response Relationship, Drug; Enzyme Induction - drug effects; Escherichia coli - drug effects; Escherichia coli - enzymology; Escherichia coli - growth & development; Gene Expression Regulation, Bacterial - drug effects; Genetic Vectors - genetics; Industrial Microbiology; Osmolar Concentration; Osmosis; Promoter Regions, Genetic - genetics; Recombinant Fusion Proteins - biosynthesis; Recombinant Fusion Proteins - genetics; Saline Solution, Hypertonic; Taq Polymerase - biosynthesis; Taq Polymerase - genetics
• ISSN: 0187-4640

The Thermus aquaticus DNA Polymerase I (Taq Pol I) gene was cloned into the pOSEX4 plasmid under the osmo-inducible promoter proU and subsequently expressed into the Escherichia coli MKH13 strain. The suitability of the enzyme in polymerase assays was determined in standard 35S dATP incorporation tests and by PCR. The Taq Pol I expression in this system, which is under the control of the osmotic pressure in the growth medium, was analyzed in different media and in different sodium chloride concentrations. A study of the osmolarity effects in the growth of the strain and in Taq Pol I expression shows that an increase in sodium chloride concentration limits the growth. At 0.25 M of NaCl maximum activity was observed; at higher values of osmolarity, we found an unexpected decline of activity. This is the first report of using the pOSEX vector for the expression of an heterologous protein and it is very advantageous to make a regulated, non toxic, simple and cost-effective manner of induction in a biotechnology process using just NaCl or other non-permeable osmolyte.