• Title/Summary/Keyword: Gene Regulation

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Control of Acetate Production Rate in Escherichia coli by Regulating Expression of Single-Copy pta Using $lacI^Q$ in Multicopy Plasmid

  • Lee, Sun-Gu;Liao, James C
    • Journal of Microbiology and Biotechnology
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    • v.18 no.2
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    • pp.334-337
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    • 2008

  • A tightly regulated gene expression system composed of a single-copy target gene under the control of a lac promoter derivative and lacI gene in a multicopy plasmid is proposed, and its ability to control the flux of a metabolic pathway is demonstrated. A model system to control the flux of acetyl-CoA to acetyl phosphate was constructed by integrating pta, a gene encoding phosphotransacetylase, under a tac promoter into the chromosome of E. coli with a pta-negative background and transforming a multicopy plasmid containing the $lacI^Q$ gene into the strain. The production rate of acetate was shown to be tightly controlled when varying the concentration of the inducer (IPTG) in he model system.

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Fnr, NarL and NarP Regulation and Time Course Expression of Escherichia coli aeg-46.5 Gene

  • Ahn, Ju-Hyuk;Choe, Mu-Hyeon
    • BMB Reports
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    • v.29 no.1
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    • pp.88-91
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    • 1996

  • The anaerobically expressed gene aeg-46.5, which had been identified by the operon fusion technique with a hybrid bacteriophage of ${\lambda}$ and Mu, ${\lambda}$placMu53, was studied for its expression pattern and growth. The expression of aeg-46.5 was studied in the wild-type cell and mutant cells that have mutation (s) in the control gene of anaerobic respiration (fnr) and nitrate response (narL and narP). The ${\beta}$-galactosidase reporter gene showed maximum expression in narL host after two hours of aerobic to anaerobic switch in M9-Glc-nitrate medium. Both 40 mM and 100 mM concentrations of nitrate ion in the medium had little effect on expression level. We propose that aeg-46.5 is subject to multiple regulations of anaerobic activation by Fnr, nitrate activation by NarP and repression mediated by NarL.

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