IDENTIFICATION OF A MAJOR CIS-ACTING DNA ELEMENT CONTROLLING THE BIDIRECTIONALLY TRANSCRIBED PENICILLIN BIOSYNTHESIS GENES ACVA (PCBAB) ANDIPNA (PCBC) OF ASPERGILLUS-NIDULANS

The beta-lactam antibiotic penicillin is produced as a secondary metab olite by some filamentous fungi. In this study, the molecular regulati on of the Aspergillus (Emericella) nidulans penicillin biosynthesis ge nes acvA (pcbAB) and ipnA (pcbC) was analyzed. acvA and ipnA are diver gently oriented and separated by an intergenic region of 872 bp. Trans lational fusions of acvA and ipnA with the two Escherichia coli report er genes lacZ and uidA enabled us to measure the regulation of both ge nes simultaneously. A moving-window analysis of the 872-bp intergenic region indicated that the divergently oriented promoters are, at least in part, overlapping and share common regulatory elements. Removal of nucleotides -353 to -432 upstream of the acvA gent! led to a 10-fold increase of acvA-uidA expression and simultaneously to a reduction of ipnA-lacZ expression to about 30%. Band shift assays and methyl interf erence analysis using partially purified protein extracts revealed tha t a CCAAT-containing DNA element within this region mas specifically b ound by a protein (complex), which we designated PENRI, for penicillin regulator. Deletion of 4 bp within the identified protein binding sit e caused the same contrary effects on acvA and ipnA expression as obse rved for all of the deletion clones which lacked nucleotides -353 to - 432. The PENR1 binding site thus represents a major cis-acting DNA ele ment. The intergenic regions of the corresponding genes of the beta-la ctam-producing fungi Penicillium chrysogenum and Acremonium chrysogenu m also diluted the complex formed between the A. nidulans probe and PE NR1 in vitro, suggesting that these beta-lactam biosynthesis genes are regulated by analogous DNA elements and proteins.