MOLECULAR REGULATION OF PENICILLIN BIOSYNTHESIS IN ASPERGILLUS (EMERICELLA) NIDULANS

The p-lactam antibiotic penicillin is produced as end product by only some filamentous fungi, most notably by Aspergillus nidulans and Penic illium chrysogenum. The biosynthesis of this secondary metabolite is c atalyzed by three enzymes which are encoded by the following three gen es: acvA (pcbAB), ipnA (pcbC) and aat (penDE). The genes are organized into a gene cluster. In A. nidulans, several studies have indicated t hat the genes are controlled by a complex regulatory network. The wide -domain regulatory protein PACC binds to the intergenic region between acvA and ipnA and, at alkaline pH, increases at least ipnA gene trans cription. An additional DNA binding protein (PENR1) was suggested to r epress acvA and to activate ipnA and aat expression. Furthermore, thre e recessive trans-acting mutations have been characterized (prgAl, prg Bl, npeEl) which most likely correspond to positively acting regulator y genes of the penicillin biosynthesis genes.