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J. Bacteriol., Jul 1996, 3908-3916, Vol 178, No. 13
KT Bergh, O Litzka and AA Brakhage
The beta-lactam antibiotic penicillin is produced as a secondary metabolite
by some filamentous fungi. In this study, the molecular regulation of the
Aspergillus (Emericella) nidulans penicillin biosynthesis genes acvA
(pcbAB) and ipnA (pcbC) was analyzed. acvA and ipnA are divergently
oriented and separated by an intergenic region of 872 bp. Translational
fusions of acvA and ipnA with the two Escherichia coli reporter genes lacZ
and uidA enabled us to measure the regulation of both genes 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 gene 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 interference analysis using partially purified
protein extracts revealed that a CCAAT-containing DNA element within this
region was specifically bound by a protein (complex), which we designated
PENR1, for penicillin regulator. Deletion of 4 bp within the identified
protein binding site caused the same contrary effects on acvA and ipnA
expression as observed for all of the deletion clones which lacked
nucleotides -353 to -432. The PENR1 binding site thus represents a major
cis-acting DNA element. The intergenic regions of the corresponding genes
of the beta-lactam-producing fungi Penicillium chrysogenum and Acremonium
chrysogenum also diluted the complex formed between the A. nidulans probe
and PENR1 in vitro, suggesting that these beta-lactam biosynthesis genes
are regulated by analogous DNA elements and proteins.
Copyright © 1996, American Society for Microbiology
Identification of a major cis-acting DNA element controlling the bidirectionally transcribed penicillin biosynthesis genes acvA (pcbAB) and ipnA (pcbC) of Aspergillus nidulans
Lehrstuhl fur Mikrobiologie, Universitat Munchen, Germany.
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