Carbon Regulation of Ribosomal Genes in Neurospora crassa Occurs by a Mechanism Which Does Not Require Cre-1, the Homologue of the Aspergillus Carbon Catabolite Repressor, CreA

Serna, Ivana de la; Ng, Dean; Tyler, Brett M.

doi:10.1006/fgbi.1999.1121

Cited by 30 publications

(19 citation statements)

References 51 publications

(78 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This decrease in ribosome biogenesis suggests that during conidiation there is an overall metabolic switch from active vegetative growth to a lower energetic state. These findings are consistent with the existing view that starvation provides an important signal for reducing vegetative growth and the induction of sporulation to enhance escape from unfavorable environmental conditions such as growth in nutrient-poor RPMI medium (5,12,13,15,27). As would be expected, the ⌬brlA mutant strain was defective in sporulation in RPMI medium, consistent with its known role in governing the core program of conidiation.…”

supporting

confidence: 91%

Transcriptional Profiling Identifies a Role for BrlA in the Response to Nitrogen Depletion and for StuA in the Regulation of Secondary Metabolite Clusters in Aspergillus fumigatus

et al. 2009

View full text Add to dashboard Cite

Conidiation (asexual sporulation) is a key developmental process in filamentous fungi. We examined the gene regulatory roles of the Aspergillus fumigatus developmental transcription factors StuAp and BrlAp during conidiation. Conidiation was completely abrogated in an A. fumigatus ⌬brlA mutant and was severely impaired in a ⌬stuA mutant. We determined the full genome conidiation transcriptomes of wild-type and ⌬brlA and ⌬stuA mutant A. fumigatus and found that BrlAp and StuAp governed overlapping but distinct transcriptional programs. Six secondary metabolite biosynthetic clusters were found to be regulated by StuAp, while only one cluster exhibited BrlAp-dependent expression. The ⌬brlA mutant, but not the ⌬stuA mutant, had impaired downregulation of genes encoding ribosomal proteins under nitrogen-limiting, but not carbon-limiting, conditions. Interestingly, inhibition of the target of rapamycin (TOR) pathway also caused downregulation of ribosomal protein genes in both the wild-type strain and the ⌬brlA mutant. Downregulation of these genes by TOR inhibition was associated with conidiation in the wild-type strain but not in the ⌬brlA mutant. Therefore, BrlAp-mediated repression of ribosomal protein gene expression is not downstream of the TOR pathway. Furthermore, inhibition of ribosomal protein gene expression is not sufficient to induce conidiation in the absence of BrlAp.Aspergillus species are filamentous fungi with a complex life cycle that is characterized by distinct developmental stages. Development is a highly regulated process that has been studied extensively in the model organism Aspergillus nidulans (3), a minimally pathogenic Aspergillus species. Little is known, however, about the role of these stages of development in the more virulent species Aspergillus fumigatus, which can cause invasive pneumonia and disseminated disease in immunocompromised patients. The asexual life cycle of Aspergillus spp. can be divided into two broad stages. First, conidia (asexual spores) undergo germination to produce filamentous hyphae that grow by elongation. As these hyphae mature, they gain the ability to respond to a variety of stimuli such as nutrient starvation by forming multicellular structures (conidiophores) that produce single cellular conidia and thus begin the cycle again. This stage is termed conidiation, and hyphae that have the capacity to form conidiophores are called developmentally competent.The process of conidiation is under complex genetic control. In A. nidulans, Timberlake demonstrated that there are in excess of 1,000 distinct mRNAs that are found at increased concentrations during conidiation (33). Despite this staggering number, which was derived from subtractive hybridization experiments, brlA is one of very few genes that have been shown through genetic analysis to be absolutely required for conidiation (1, 7). Further, overexpression of brlA can induce conidiation at times and under conditions in which conidiation does not normally occur (1, 2).In both A. fumigatus and A. nidulans, the...

show abstract

supporting

confidence: 91%

Transcriptional Profiling Identifies a Role for BrlA in the Response to Nitrogen Depletion and for StuA in the Regulation of Secondary Metabolite Clusters in Aspergillus fumigatus

et al. 2009

View full text Add to dashboard Cite

show abstract

“…The situation in Neurospora crassa is also interesting. A creA homologue has been identified in Neurospora, but since a deletion has not been obtained it is not possible to assess whether this gene has a major role in carbon catabolite repression (de la Serna et al, 1999). However, the developmentally regulated conidiation-specific gene in Neurospora, ccg1, is induced by starvation stress and is subject to carbon catabolite repression (Wang et al, 1994).…”

Section: Discussionmentioning

confidence: 98%

ADHII in Aspergillus nidulans Is Induced by Carbon Starvation Stress

Jones

Fairhurst

Sealy-Lewis

2001

Fungal Genetics and Biology

View full text Add to dashboard Cite

“…One of the genes in the os-2 starvation regulon was cre-1, which encodes a transcription factor that is a regulator of carbon catabolite repression (Fig. 5A and Dataset S3) (13). Deletion of cre-1 increases activation of the cellulolytic response when preferred carbon sources, such as sugars released during the breakdown of cellulose, are present (11).…”

Section: The Os Pathway Exhibits Tunable Regulation Of Cellulase Exprmentioning

confidence: 99%

“…There are several transcription factors involved in carbon catabolite repression (3). The best studied is the zinc finger transcription factor cre-1 (NCU08807), the N. crassa ortholog of Saccharomyces cerevisiae MIG1 (12,13). CRE-1 represses the expression of cellulase genes in response to a range of simple sugars, including glucose, and products of cellulose degradation, such as the disaccharide cellobiose (14).…”

mentioning

confidence: 99%

Network of nutrient-sensing pathways and a conserved kinase cascade integrate osmolarity and carbon sensing in Neurospora crassa

Huberman

Coradetti

Glass

2017

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Identifying nutrients available in the environment and utilizing them in the most efficient manner is a challenge common to all organisms. The model filamentous fungus Neurospora crassa is capable of utilizing a variety of carbohydrates, from simple sugars to the complex carbohydrates found in plant cell walls. The zinc binuclear cluster transcription factor CLR-1 is necessary for utilization of cellulose, a major, recalcitrant component of the plant cell wall; however, expression of clr-1 in the absence of an inducer is not sufficient to induce cellulase gene expression. We performed a screen for unidentified actors in the cellulose-response pathway and identified a gene encoding a hypothetical protein (clr-3) that is required for repression of CLR-1 activity in the absence of an inducer. Using clr-3 mutants, we implicated the hyperosmotic-response pathway in the tunable regulation of glycosyl hydrolase production in response to changes in osmolarity. The role of the hyperosmotic-response pathway in nutrient sensing may indicate that cells use osmolarity as a proxy for the presence of free sugar in their environment. These signaling pathways form a nutrient-sensing network that allows N. crassa cells to tightly regulate gene expression in response to environmental conditions. MAP kinase cascade | carbon metabolism | hyperosmotic response | carbon catabolite repression | plant biomass degradation

show abstract

Carbon Regulation of Ribosomal Genes in Neurospora crassa Occurs by a Mechanism Which Does Not Require Cre-1, the Homologue of the Aspergillus Carbon Catabolite Repressor, CreA

Cited by 30 publications

References 51 publications

Transcriptional Profiling Identifies a Role for BrlA in the Response to Nitrogen Depletion and for StuA in the Regulation of Secondary Metabolite Clusters in Aspergillus fumigatus

Transcriptional Profiling Identifies a Role for BrlA in the Response to Nitrogen Depletion and for StuA in the Regulation of Secondary Metabolite Clusters in Aspergillus fumigatus

ADHII in Aspergillus nidulans Is Induced by Carbon Starvation Stress

Network of nutrient-sensing pathways and a conserved kinase cascade integrate osmolarity and carbon sensing in Neurospora crassa

Contact Info

Product

Resources

About