IDENTIFICATION OF A MAJOR CIS-ACTING DNA ELEMENT CONTROLLING THE BIDIRECTIONALLY TRANSCRIBED PENICILLIN BIOSYNTHESIS GENES ACVA (PCBAB) ANDIPNA (PCBC) OF ASPERGILLUS-NIDULANS
Kt. Bergh et al., IDENTIFICATION OF A MAJOR CIS-ACTING DNA ELEMENT CONTROLLING THE BIDIRECTIONALLY TRANSCRIBED PENICILLIN BIOSYNTHESIS GENES ACVA (PCBAB) ANDIPNA (PCBC) OF ASPERGILLUS-NIDULANS, Journal of bacteriology, 178(13), 1996, pp. 3908-3916
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.