Analysis of two chromosomal regions adjacent to a type II polyketide synthase involved in the biosynthesis of the antitumor polyketide mithramycin in Streptomyces argillaceus - Prado, L; Lombó, F; Braña, A F; Méndez, C; Rohr, J; Salas, J A (Mol Gen Genet, 1999)