Dec 12, 2001

Homogeneous expression of the P(BAD) promoter in Escherichia coli by constitutive expression of the low-affinity high-capacity AraE transporter

Microbiology
A KhlebnikovJay D Keasling

Abstract

Genes placed under the control of the arabinose-inducible araBAD promoter (P(BAD)) of Escherichia coli are expressed in an all-or-none fashion, in which the percentage of induced cells in the population, rather than the degree of induction in individual cells, varies with the concentration of arabinose in the culture medium. Previous work showed that all-or-none gene expression from P(BAD) was due to the arabinose-dependent expression of the gene encoding the low-affinity high-capacity transporter (araE), and that expression of heterologous genes from P(BAD) in individual cells could be regulated by placing the araE gene under control of an arabinose-independent promoter. Based on these results, two expression systems were developed to allow regulatable control of genes under control of P(BAD). In one system, the native araE promoter on the chromosome was replaced by constitutive promoters of different strengths. In the second system, the araE gene under control of the same constitutive promoters was placed on a medium-copy plasmid. Both systems allow regulatable expression of a plasmid-borne P(BAD)-controlled heterologous gene and a homogeneous population of cells over a wide range of arabinose concentrations. While the degree...Continue Reading

Mentioned in this Paper

Gene Expression Regulation, Bacterial
Arabinose
Bacterial Proteins
Alkalescens-Dispar Group
Promoter
Gene Expression
Hexose Transporter
Chromosomes, Bacterial
Chromosomes
Membrane Transport Proteins

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