Analysis of a polyketide synthesis-encoding gene cluster of Streptomyces curacoi

A gene cluster homologous to the beta-ketoacyl synthase-encoding gene, actl, was cloned by Southern blot hybridization from Streptomyces curacoi, and a 5469-bp fragment was sequenced. Analysis of the sequence revealed seven open reading frames (ORFs). A striking similarity to the whiE locus (encoding spore pigment synthesis) of Streptomyces coelicolor was found throughout the whole cluster, with conservation of the size and position of the seven ORFs. The structure of these two gene clusters suggests that they have a common origin, although the lower similarity in the noncoding regions suggests that the regulatory regions have diverged through evolution.