Regulation of two extracellular proteases of Neurospora crassa by induction and by carbon-nitrogen and sulfur-metabolite repression

Cohen, Bernard L.; Morris, James E.; Drucker, H.

doi:10.1016/0003-9861(75)90347-1

Cited by 52 publications

(33 citation statements)

References 15 publications

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“…There have been many reports of protease production being effected in fungi by exogenous protein under conditions of nutrient deprivation. Nenrospora crassa produces both neutral and acid proteases if starved of either carbon, nitrogen or sulphur when grown on a protein substrate (Drucker, 1975;Cohen e t al., 1975). Similar results have been described for several Candida species (Crandall & Edwards, 1987;Banerjee etal., 1991).…”

Section: Discussionmentioning

confidence: 99%

Specific induction of a cuticle-degrading protease of the insect pathogenic fungus Metarhizium anisopliae

et al. 1994

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~The insect pathogenic fungus Metarhizium anisopliae produces several extracellular cuticle-degrading proteases and evidence is consistent that one of these, a chymoelastase PRl, is a determinant of pathogenicity. We have shown previously that the wide-domain regulatory circuits of carbon and nitrogen derepression regulate PRI production. In the present work we have established in addition that PRI is specifically induced by insect cuticle, but not by other soluble or insoluble proteinaceous substrates. The feeding of elastin or collagen to derepressed established mycelium (starved for carbon and nitrogen) did not enhance PR1 production significantly and the soluble proteins BSA and gelatin rapidly and completely repressed PRI. The carbohydrate polymers cellulose and xylan gave derepressed basal levels of PR1. However, addition of locust cuticle enhanced PRI production to a level approximately 10-fold that of derepressed mycelium. In order to establish if the enhancing effect of insect cuticle on PRI production was due to specific induction or merely a reflection of enhanced growth on this insoluble dual carbon and nitrogen source, ergosterol was used as a measure of fungal growth. Expressing enzyme activity per mg dry weight showed that PRI production in cuticle cultures increased approximately five-and ninefold after 12 and 24 h growth compared with elastin-grown cultures. Thus, the substantial increase in PR1 production on cuticle was shown not to be a function of fungal growth and this confirms that PRI is induced by a component of insect cuticle; we believe this is the first report of induction by a specific substrate for any microbial protease.

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Section: Discussionmentioning

confidence: 99%

Specific induction of a cuticle-degrading protease of the insect pathogenic fungus Metarhizium anisopliae

et al. 1994

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“…In both N. crassa and A. nidulans, the production of extracellular proteases is subject to regulation by carbon, nitrogen, and sulfur availability and pH. In N. crassa, two or three extracellular protease types (acid proteases, an alkaline protease, and/or a neutral protease) are secreted in response to nitrogen, sulfur, or carbon starvation (14,20,48,49). Derepression of an alkaline protease (48) is blocked in N. crassa strains carrying loss-of-function mutations in nit-2 (an ortholog of A. nidulans areA) and cys-3 (33).…”

Section: Vib-1 Is a Nucleus-localized Proteinmentioning

confidence: 99%

VIB-1 Is Required for Expression of Genes Necessary for Programmed Cell Death in Neurospora crassa

2006

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Nonself recognition during somatic growth is an essential and ubiquitous phenomenon in both prokaryotic and eukaryotic species. In filamentous fungi, nonself recognition is also important during vegetative growth. Hyphal fusion between genetically dissimilar individuals results in rejection of heterokaryon formation and in programmed cell death of the fusion compartment. In filamentous fungi, such as Neurospora crassa, nonself recognition and heterokaryon incompatibility (HI) are regulated by genetic differences at het loci. In N. crassa, mutations at the vib-1 locus suppress nonself recognition and HI mediated by genetic differences at het-c/pin-c, mat, and un-24/het-6. vib-1 is a homolog of Saccharomyces cerevisiae NDT80, which is a transcriptional activator of genes during meiosis. For this study, we determined that vib-1 encodes a nuclear protein and showed that VIB-1 localization varies during asexual reproduction and during HI. vib-1 is required for the expression of genes involved in nonself recognition and HI, including pin-c, tol, and het-6; all of these genes encode proteins containing a HET domain. vib-1 is also required for the production of downstream effectors associated with HI, including the production of extracellular proteases upon carbon and nitrogen starvation. Our data support a model in which mechanisms associated with starvation and nonself recognition/HI are interconnected. VIB-1 is a major regulator of responses to nitrogen and carbon starvation and is essential for the expression of genes involved in nonself recognition and death in N. crassa.Nonself recognition during somatic growth is an essential and ubiquitous phenomenon in both prokaryotic and eukaryotic species. In vertebrate species, self/nonself recognition relies on the major histocompatibility complex (MHC), which is an array of polymorphic genetic loci that generate proteins important in pathogen recognition and the activation of defense mechanisms (37). In filamentous fungi, nonself recognition is important during vegetative growth. Hyphal fusion between genetically dissimilar individuals results in rejection of heterokaryon formation and in programmed cell death of the fusion compartment (Fig. 1), an event analogous to nonself recognition following fusion in colonial marine invertebrates, such as Hydractinia and Botryllus (32, 73), and nonself recognition and death following fusion of plasmodia in the slime mold Physarum polycephalum (9). Nonself recognition during heterokaryon formation in filamentous fungi is regulated genetically by het loci (for heterokaryon incompatibility [HI]) (29,70,86). In the filamentous fungus Neurospora crassa, 11 het loci mediate nonself recognition and HI (28, 63); each het locus has two or three alternative allelic specificities. Since these het loci are effectively unlinked, the number of possible het genotypes within a segregating population is at least 2 11 genotypes, thus forming an effective barrier to heterokaryon formation between genetically different isolates. HI in filamentous fungi...

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“…The production of proteases appeared to be subjected to control easily ei-100 SAMARNTARN, CHEEVADHANARAK, and TANTICHAROEN Vol. 45 ther by metabolites repression/derepression or proteinaceous induction, or by the combination of both in several fungi (Cohen, 1973;Cohen et al, 1975;Farley and Ikasari, 1992;Lasure, 1980;North, 1982). Thus it is likely that the high production of alkaline protease in BDS medium involved the slow hydrolyzation and/or the proteinaceous component(s) of defatted soybean.…”

Section: Defatted Soybean As Substrate For Alkaline Protease Productionmentioning

confidence: 99%

Production of alkaline protease by a genetically engineered Aspergillus oryzae U1521.

Samarntarn

Cheevadhanarak

Tanticharoen

1999

J. Gen. Appl. Microbiol.

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Regulation of two extracellular proteases of Neurospora crassa by induction and by carbon-nitrogen and sulfur-metabolite repression

Cited by 52 publications

References 15 publications

Specific induction of a cuticle-degrading protease of the insect pathogenic fungus Metarhizium anisopliae

Specific induction of a cuticle-degrading protease of the insect pathogenic fungus Metarhizium anisopliae

VIB-1 Is Required for Expression of Genes Necessary for Programmed Cell Death in Neurospora crassa

Production of alkaline protease by a genetically engineered Aspergillus oryzae U1521.

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