Arabinose-inducible promoter from Escherichia coli. Its cloning from chromosomal DNA, identification as the araFG promoter and sequence.

An arabinose-inducible promoter was cloned from Escherichia coli DNA, identified as the promoter of the aruFG genes and sequenced. The cloning used a plasmid containing a tetracycline resistance gene lacking a functional promoter. Tetracycline resistance could be expressed from this plasmid by inserting a functional promoter in an EcoRI site that is located just in front of the tet gene. E. coli DNA digested with EcoRI* and ligated into the plasmid yielded 20/2000 transformants that were tetracycline resistant only in the presence of arabinose. Two different promoters were identified, the well-characterized psao promoter, and a new one. DNA containing the new promoter hybridized to a segment of DNA carrying the araFG genes, thus identifying the cloned promoter as pFG. Transcription directed by pFG is stimulated in vitro by uruC protein and cyclic AMP receptor protein as it is in V&J. Despite the functional similarities between pBAo and pFG, they lack extended sequence homology.