The Aspergillus nidulans npeA locus consists of three contiguous genes required for penicillin biosynthesis.

MacCabe, Andrew; Riach, M.B.R.; Unkles, Shiela E.; Kinghorn, James R.

doi:10.1002/j.1460-2075.1990.tb08106.x

Cited by 134 publications

(68 citation statements)

References 25 publications

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“…The transcriptional start sites of both genes appear to be located in the intergenic region (18,25,26,33), which could thus be expected to contain recognition sequences for trans-acting factors. Our data suggest that the glucose effect is mediated by the ipnA promoter region.…”

Section: Discussionmentioning

confidence: 99%

“…1 kb) (25,26,39,47,48). The nucleotide sequence of the 872-bp intergenic region of A. nidulans between acvA and ipnA contains the transcription start point of acvA and presumably of ipnA (26,33).…”

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confidence: 99%

“…This is particularly true for the acvA gene, which produces a transcript of about 11.5 kb (25). Both translational fusions of acvA and ipnA with different reporter genes were constructed, and the expression of both genes was monitored simultaneously within one strain during the course of a standard fermentation.…”

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Regulation of Aspergillus nidulans penicillin biosynthesis and penicillin biosynthesis genes acvA and ipnA by glucose

1992

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Expression of the Aspergilus nidulans penicillin biosynthesis genes acvA and ipnA, encoding 8-(L-aaminoadipyl)-L-cysteinyl-D-valine synthetase and isopenicillin N synthetase, respectively, was analyzed. The intergenic region carrying the divergently oriented promoters was fused in frame in both orientations to Escherichia coli lacZ and E. coli uidA4 reporter genes. Each construct permits simultaneous expression studies of both genes. Transformants of A. nidulans carrying a single copy of either plasmid integrated at the chromosomal argB locus were selected for further investigations. Expression of both genes was directed by the 872-bp intergenic region. ipnA-and acvA-derived gene fusions were expressed from this region at different levels. ipnA had significantly higher expression than did acvA. Glucose specifically reduced the production of penicillin and significantly repressed the expression of ipnA but not of acvA gene fusions. The specific activities of isopenicillin N synthetase, the gene product of ipnA, and acyl coenzyme A:6-aminopenicillanic acid acyltransferase were also reduced in glucose-grown cultures.The P-lactam antibiotic penicillin is synthesized by filamentous fungi of the genera Penicillium and Aspergillus (17, 32). It has been produced industrially by Penicillium chrysogenum for 50 years (20). Despite the worldwide usage of this antibiotic over a long period of time, little is known about the genetic regulation of its biosynthesis. This is in part because P. chrysogenum lacks a sexual cycle, and hence the genetics of this organism is poorly developed. In contrast, although producing only modest amounts of penicillin, Aspergillus nidulans, because of its sexual cycle, is well characterized genetically (12). A wide variety of genetic techniques are available, making identification of regulatory mechanisms feasible (2, 13, 51). The genetic system of A. nidulans permits manipulation of the genome with a high precision, providing an attractive model system in which to investigate genetic control of the biosynthesis of the secondary metabolite penicillin.In the first step of the penicillin biosynthetic pathway, the (5, 6, 11, 26, 31,

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Section: Discussionmentioning

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Regulation of Aspergillus nidulans penicillin biosynthesis and penicillin biosynthesis genes acvA and ipnA by glucose

1992

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“…The production of secondary metabolites by the opportunistic pathogen Aspergillus fumigatus is associated with its virulence (23). Aspergillus nidulans is a classical model eukaryote, and it produces the antibiotic penicillin G as well as toxic and carcinogenic sterigmatocystin, which is related to the agricultural contaminant aflatoxin (9,20). Secondary metabolite production is regulated by cyclic AMP (cAMP) and light through the activities of protein kinase A and the transcription factor LaeA (3, 8).…”

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Hydrolase Controls Cellular NAD, Sirtuin, and Secondary Metabolites

Shimizu

Masuo

Fujita

et al. 2012

Molecular and Cellular Biology

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Cellular levels of NAD؉ and NADH are thought to be controlled by de novo and salvage mechanisms, although evidence has not yet indicated that they are regulated by NAD ؉ degradation. Here we show that the conserved nudix hydrolase isozyme NdxA hydrolyzes and decreases cellular NAD ؉ and NADH in Aspergillus nidulans. The NdxA-deficient fungus accumulated more NAD ؉ during the stationary growth phase, indicating that NdxA maintains cellular NAD ؉ /NADH homeostasis. The deficient strain also generated less of the secondary metabolites sterigmatocystin and penicillin G and of their gene transcripts than did the wild type. These defects were associated with a reduction in acetylated histone H4 on the gene promoters of aflR and ipnA that are involved in synthesizing secondary metabolites. Thus, NdxA increases acetylation levels of histone H4. We discovered that the novel fungal sirtuin isozyme SirA uses NAD ؉ as a cosubstrate to deacetylate the lysine 16 residue of histone H4 on the gene promoter and represses gene expression. The impaired acetylation of histone and secondary metabolite synthesis in the NdxA-deficient strain were restored by eliminating functional SirA, indicating that SirA mediates NdxA-dependent regulation. These results indicated that NdxA controls total levels of NAD ؉ /NADH and negatively regulates sirtuin function and chromatin structure. N udix (nucleoside diphosphates linked to moiety X) hydrolases are ubiquitous in viruses, bacteria, and eukaryotes, and they hydrolyze NADH, NAD ϩ , ADP-ribose, and other nucleotide sugars, which allows their classification into subfamilies (6,22). One important function of nudix hydrolases is the hydrolytic degradation of oxidatively damaged nucleotides to prevent spontaneous mutations (39). Saccharomyces cerevisiae Ysa1p and Arabidopsis thaliana AtNUDX2 and AtNUDX7 hydrolyze ADP-ribose and respond to oxidative stress (17,43). Nudix hydrolases that hydrolyze NAD ϩ and NADH [NAD(H)] exist throughout the biological kingdom and include A. thaliana AtNUDX1 (12) and yeast peroxisomal Npy1p (1). The physiological role of NAD(H) hydrolases is unknown, especially that in epigenetic gene regulation.Gene expression is regulated by specific transcription regulators and by posttranslational modifications of nucleosomal histones. Acetylation is this type of modification that correlates with conformational changes in chromatin. Two groups of histone deacetylases (HDAC) deacetylate acetylated histones. One is classical HDAC, and the other is sirtuin, which deacetylates lysine residues of histones H3 and/or H4 using NAD ϩ as a cosubstrate (10,16,45). Yeast Sir2p is the prototype sirtuin, and it silences genes at mating type, ribosomal DNA (rDNA), and subtelomeric loci (14, 37). Its mammalian counterparts control aging, stress responses, and circadian rhythms (15, 25). Sirtuin activity is controlled by cellular NAD ϩ production (4, 19) that links cellular metabolic status and gene regulation, since NAD ϩ is a crucial coenzyme for biological redox reactions and energy conservat...

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“…The enzyme catalyzing this reaction, acyl-coenzyme A: isopenicillin N acyltransferase (AT), was purified and found to be an a&heterodimer containing subunits of 11 and 29 kDa [5]. In both P. chrysogenum and A. nidulans, the gene encoding AT, penDE, is located immediately adjacent to the pcbAB (b(L-ol-aminoadipoyl)-L-cysteinyl-o-valine synthetase (ACVS)) and pcbC (IPN synthase) genes [6,7]. Cloning and sequencing of the P. chrysogenum [g-10] and A. nidulans penDE gene [lO,l l] revealed that they are colinear, and are -73% identical at the amino acid level.…”

Section: Introductionmentioning

confidence: 99%

On the production of α,β‐heterodimeric acyl‐coenzyme A: isopenicillin N‐acyltransferase of Penicillium chrysogenum

Aplin¹,

Baldwin²,

Cole³

et al. 1993

FEBS Letters

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A high level E coli expression system has been constructed for the Penicillium chrq'sogenum penDE gene, which encodes the acyl-coenzyme A: isopenicilhn N-acyltransferase (AT) enzyme. Induction of overexpression of recombinant AT (recAT) by increasing the growth temperature of the host adversely affected solubility and activity of the AT enzyme. Addition of isopropylthio-/?-o-galactopyranoside (IPTG) at decreased growth temperatures (less than 32°C) resulted in the overproduction of soluble. active recAT. When purified to homogeneity, recAT was an a$-heterodimer, comprised of 11 kDa (ar) and 29 kDa @) subunits, derived from a 40 kDa precursor polypeptide by a posttranslational cleavage. The recAT enzyme contained both the acyl-coenzyme A: isopenicillin N-acyltransferase and the acyl-coenzyme A: 6-aminopenicillanic acid acyltransferase activities. The processing event that generated the two subunits of recAT from the 40 kDa precursor polypeptide occurred between Gly'02/Cys'03. This expression system produced a large amount of soluble, active recAT that is identical to native AT, making it a suitable source of AT enzyme for further characterization.

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The Aspergillus nidulans npeA locus consists of three contiguous genes required for penicillin biosynthesis.

Cited by 134 publications

References 25 publications

Regulation of Aspergillus nidulans penicillin biosynthesis and penicillin biosynthesis genes acvA and ipnA by glucose

Regulation of Aspergillus nidulans penicillin biosynthesis and penicillin biosynthesis genes acvA and ipnA by glucose

Hydrolase Controls Cellular NAD, Sirtuin, and Secondary Metabolites

On the production of α,β‐heterodimeric acyl‐coenzyme A: isopenicillin N‐acyltransferase of Penicillium chrysogenum

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