Cloning and expression of two genes of Streptomyces pilosus involved in the biosynthesis of the siderophore desferrioxamine B.

Genes involved in biosynthesis of the siderophore desferrioxamine B have been cloned from Streptomyces pilosus using a self-cloning approach with the low-copy plasmid pIJ943. Mutants in two steps of the pathway can be complemented by a 4.5-kb DNA fragment. One of these mutants is defective for the first step, lysine decarboxylation. Expression of lysine decarboxylase by the cloned DNA was found to be regulated by iron. S1 mapping and Northern blotting experiments show that iron regulation of desferrioxamine B production is exerted at the transcriptional level, and also that genes involved specify a long message, which determines at least two steps in the biosynthetic pathway.