Citrinin, a secondary fungal metabolite of polyketide origin, is moderately nephrotoxic to vertebrates, including humans. From the red-pigment producer Monascus purpureus, a 21-kbp region flanking pksCT, which encodes citrinin polyketide synthase, was cloned. Four open reading frames (ORFs) (orf1, orf2, orf3, and orf4) in the 5'-flanking region and one ORF (orf5) in the 3'-flanking region were ...