Journal of Industrial Microbiology and Biotechnology

, Volume 29, Issue 1, pp 34-37

Modulation of gene expression from the arabinose-inducible araBAD promoter

  • A KhlebnikovAffiliated withDepartment of Chemical Engineering, University of California, Berkeley, CA 94720-1462, USA
  • , T SkaugAffiliated withDepartment of Chemical Engineering, University of California, Berkeley, CA 94720-1462, USA
  • , J D KeaslingAffiliated withDepartment of Chemical Engineering, University of California, Berkeley, CA 94720-1462, USA

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The arabinose-inducible PBAD promoter suffers from all-or-none gene expression in which cells harboring the natively controlled arabinose transport gene (araE) are either induced or uninduced, the relative fraction of which is controlled by the concentration of arabinose. The population-averaged variation in expression from PBAD as a function of inducer concentration is proportional to the percentage of cells that are fully induced (vs. uninduced) rather than the level of expression in individual cells. Because of its undesirable effects on the expression of heterologous genes, the all-or-none phenomenon was eliminated in Escherichia coli by expression of araE from arabinose-independent (either the Lactococcus lactis constitutive or IPTG-inducible lac) promoters. In these arabinose-transport engineered cells, variation in PBAD expression with arabinose concentration was a result of variation of the expression level in individual cells with all cells in the population having approximately the same induction level. Journal of Industrial Microbiology & Biotechnology (2002) 29, 34–37 doi:10.1038/sj.jim.7000259

Keywords: arabinose; constitutive promoter; Escherichia coli; regulatable control; arabinose transport