Identification of direct target genes of the Neurospora crassa essential plant biomass deconstruction transcription factors CLR-1, CLR-2 and XLR-1
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ABSTRACT:
ORGANISM(S): Neurospora crassa
PROVIDER: GSE68517 | GEO | 2015/09/01
SECONDARY ACCESSION(S): PRJNA282961
REPOSITORIES: GEO
Similar Datasets
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2015-09-01 | E-GEOD-68517 | biostudies-arrayexpress
Project description:abstract: The plant cell wall is composed of many complex polymers, and its deconstruction requires an equally complex orchestration of a wide array of enzymes. In Neurospora crassa, clr-1, clr-2 and xlr-1 have been identified as the key transcription factors involved in cell wall breakdown. In order to define their regulons, we performed ChIPseq upon these three transcription factors. CLR-1, CLR-2 and XLR-1 each bind to the most highly and differentially expressed gene populations, which include the cellulases for the CLRs and the hemicellulases for XLR-1. CLR-1 also bound to its regulon under non-inducing conditions; however, this did not translate into gene expression. Motif analysis of the bound genes revealed conserved DNA binding motifs, with the CLR-2 motif matching that of its closest yeast homolog, GAL4. Co-immunoprecipitation studies were able to show that CLR-1 and CLR-2 act as homodimers. Finally, we report on a conserved XLR-1 point mutation that is sufficient to drive hemicellulase expression under non-inducing conditions. Understanding how these transcription factors work in concert to break down plant biomass can inform decisions on how to best engineer future fungal strains for decreased enzyme costs.
2015-09-01 | GSE68516 | GEO
Project description:abstract: The plant cell wall is composed of many complex polymers, and its deconstruction requires an equally complex orchestration of a wide array of enzymes. In Neurospora crassa, clr-1, clr-2 and xlr-1 have been identified as the key transcription factors involved in cell wall breakdown. In order to define their regulons, we performed ChIPseq upon these three transcription factors. CLR-1, CLR-2 and XLR-1 each bind to the most highly and differentially expressed gene populations, which include the cellulases for the CLRs and the hemicellulases for XLR-1. CLR-1 also bound to its regulon under non-inducing conditions; however, this did not translate into gene expression. Motif analysis of the bound genes revealed conserved DNA binding motifs, with the CLR-2 motif matching that of its closest yeast homolog, GAL4. Co-immunoprecipitation studies were able to show that CLR-1 and CLR-2 act as homodimers. Finally, we report on a conserved XLR-1 point mutation that is sufficient to drive hemicellulase expression under non-inducing conditions. Understanding how these transcription factors work in concert to break down plant biomass can inform decisions on how to best engineer future fungal strains for decreased enzyme costs.
2015-09-01 | GSE68514 | GEO
Project description:abstract: The plant cell wall is composed of many complex polymers, and its deconstruction requires an equally complex orchestration of a wide array of enzymes. In Neurospora crassa, clr-1, clr-2 and xlr-1 have been identified as the key transcription factors involved in cell wall breakdown. In order to define their regulons, we performed ChIPseq upon these three transcription factors. CLR-1, CLR-2 and XLR-1 each bind to the most highly and differentially expressed gene populations, which include the cellulases for the CLRs and the hemicellulases for XLR-1. CLR-1 also bound to its regulon under non-inducing conditions; however, this did not translate into gene expression. Motif analysis of the bound genes revealed conserved DNA binding motifs, with the CLR-2 motif matching that of its closest yeast homolog, GAL4. Co-immunoprecipitation studies were able to show that CLR-1 and CLR-2 act as homodimers. Finally, we report on a conserved XLR-1 point mutation that is sufficient to drive hemicellulase expression under non-inducing conditions. Understanding how these transcription factors work in concert to break down plant biomass can inform decisions on how to best engineer future fungal strains for decreased enzyme costs. RNAseq and ChIPseq was performed upon knockout mutants and wild type strains growing on various carbon sources to determin the role of the transcription factors CLR-1, CLR-2, and XLR-1 in plant cell wall degradation
2015-09-01 | E-GEOD-68514 | biostudies-arrayexpress
Project description:abstract: The plant cell wall is composed of many complex polymers, and its deconstruction requires an equally complex orchestration of a wide array of enzymes. In Neurospora crassa, clr-1, clr-2 and xlr-1 have been identified as the key transcription factors involved in cell wall breakdown. In order to define their regulons, we performed ChIPseq upon these three transcription factors. CLR-1, CLR-2 and XLR-1 each bind to the most highly and differentially expressed gene populations, which include the cellulases for the CLRs and the hemicellulases for XLR-1. CLR-1 also bound to its regulon under non-inducing conditions; however, this did not translate into gene expression. Motif analysis of the bound genes revealed conserved DNA binding motifs, with the CLR-2 motif matching that of its closest yeast homolog, GAL4. Co-immunoprecipitation studies were able to show that CLR-1 and CLR-2 act as homodimers. Finally, we report on a conserved XLR-1 point mutation that is sufficient to drive hemicellulase expression under non-inducing conditions. Understanding how these transcription factors work in concert to break down plant biomass can inform decisions on how to best engineer future fungal strains for decreased enzyme costs. RNAseq and ChIPseq upon knockout mutants and sild type growing on various carbon sources to determin the role of the transcription factors: CLR-1, CLR-2, and XLR-1 in plant cell wall degradation
2015-09-01 | E-GEOD-68516 | biostudies-arrayexpress
Project description:UnlabelledFungal deconstruction of the plant cell requires a complex orchestration of a wide array of intracellular and extracellular enzymes. In Neurospora crassa, CLR-1, CLR-2, and XLR-1 have been identified as key transcription factors regulating plant cell wall degradation in response to soluble sugars. The XLR-1 regulon was defined using a constitutively active mutant allele, resulting in hemicellulase gene expression and secretion under noninducing conditions. To define genes directly regulated by CLR-1, CLR-2, and XLR-1, we performed chromatin immunoprecipitation and next-generation sequencing (ChIPseq) on epitope-tagged constructs of these three transcription factors. When N. crassa is exposed to plant cell wall material, CLR-1, CLR-2, and XLR-1 individually bind to the promoters of the most strongly induced genes in their respective regulons. These include promoters of genes encoding cellulases for CLR-1 and CLR-2 (CLR-1/CLR-2) and promoters of genes encoding hemicellulases for XLR-1. CLR-1 bound to its regulon under noninducing conditions; however, this binding alone did not translate into gene expression and enzyme secretion. Motif analysis of the bound genes revealed conserved DNA binding motifs, with the CLR-2 motif matching that of its closest paralog in Saccharomyces cerevisiae, Gal4p. Coimmunoprecipitation studies showed that CLR-1 and CLR-2 act in a homocomplex but not as a CLR-1/CLR-2 heterocomplex.ImportanceUnderstanding fungal regulation of complex plant cell wall deconstruction pathways in response to multiple environmental signals via interconnected transcriptional circuits provides insight into fungus/plant interactions and eukaryotic nutrient sensing. Coordinated optimization of these regulatory networks is likely required for optimal microbial enzyme production.
| S-EPMC4620465 | biostudies-literature
Project description:BackgroundPlant biomass degradation by fungal-derived enzymes is rapidly expanding in economic importance as a clean and efficient source for biofuels. The ability to rationally engineer filamentous fungi would facilitate biotechnological applications for degradation of plant cell wall polysaccharides. However, incomplete knowledge of biomolecular networks responsible for plant cell wall deconstruction impedes experimental efforts in this direction.ResultsTo expand this knowledge base, a detailed network of reactions important for deconstruction of plant cell wall polysaccharides into simple sugars was constructed for the filamentous fungus Neurospora crassa. To reconstruct this network, information was integrated from five heterogeneous data types: functional genomics, transcriptomics, proteomics, genetics, and biochemical characterizations. The combined information was encapsulated into a feature matrix and the evidence weighted to assign annotation confidence scores for each gene within the network. Comparative analyses of RNA-seq and ChIP-seq data shed light on the regulation of the plant cell wall degradation network, leading to a novel hypothesis for degradation of the hemicellulose mannan. The transcription factor CLR-2 was subsequently experimentally shown to play a key role in the mannan degradation pathway of N. crassa.ConclusionsHere we built a network that serves as a scaffold for integration of diverse experimental datasets. This approach led to the elucidation of regulatory design principles for plant cell wall deconstruction by filamentous fungi and a novel function for the transcription factor CLR-2. This expanding network will aid in efforts to rationally engineer industrially relevant hyper-production strains.
| S-EPMC5609067 | biostudies-literature
Project description:The ability to rationally engineer filamentous fungi could greatly facilitate biotechnological enzyme production for the degradation of plant cell wall polysaccharides in biorefinery applications. However, an incomplete and fragmented knowledge base of the biomolecular networks responsible for plant cell wall deconstruction by filamentous fungi impedes experimental efforts in this direction. To expand this knowledge base, we have reconstructed a detailed network of those reactions occurring in the filamentous fungus Neurospora crassa that are important for the degradation of plant cell wall polysaccharides into simple sugars. To build this network, we integrated information from five heterogeneous data types: functional genomics, transcriptomics, proteomics, genetics, and biochemical characterizations. We encapsulated the combined information into a feature matrix and weighed evidence to assign annotation confidence scores for each gene within the network. Comparative analyses of next-generation transcriptome sequencing profiles for N. crassa grown on different substrates corresponding to specific plant cell wall polysaccharides revealed environment-specific modules within the network. Subsequent analyses of next-generation ChIP and RNA sequencing data within the network context shed new light on how N. crassa regulates the plant cell wall degradation network (PCWDN). Specifically, our system-level analyses led to the hypothesis-driven experimental validation of the role transcription factor CLR-2 plays in degradation of the major hemicellulose mannan. In the future, we expect the network to serve as a scaffold for integration of diverse experimental data, leading to elucidation of regulatory design principles for plant cell wall deconstruction by filamentous fungi. In turn, this will guide efforts to rationally engineer novel, industrially relevant fungal hyper-secretion strains.
2017-09-19 | GSE90611 | GEO
Project description:Many fungi produce multiple lytic polysaccharide monooxygenases (LPMOs) with seemingly similar functions, but the biological reason for this multiplicity remains unknown. To address this question, here we carried out comparative structural and functional characterizations of three cellulose-active C4-oxidizing family AA9 LPMOs from the fungus Neurospora crassa, NcLPMO9A (NCU02240), NcLPMO9C (NCU02916), and NcLPMO9D (NCU01050). We solved the three-dimensional structure of copper-bound NcLPMO9A at 1.6-Å resolution and found that NcLPMO9A and NcLPMO9C, containing a CBM1 carbohydrate-binding module, bind cellulose more strongly and were less susceptible to inactivation than NcLPMO9D, which lacks a CBM. All three LPMOs were active on tamarind xyloglucan and konjac glucomannan, generating similar products but clearly differing in activity levels. Importantly, in some cases, the addition of phosphoric acid-swollen cellulose (PASC) had a major effect on activity: NcLPMO9A was active on xyloglucan only in the presence of PASC, and PASC enhanced NcLPMO9D activity on glucomannan. Interestingly, the three enzymes also exhibited large differences in their interactions with enzymatic electron donors, which could reflect that they are optimized to act with different reducing partners. All three enzymes efficiently used H2O2 as a cosubstrate, yielding product profiles identical to those obtained in O2-driven reactions with PASC, xyloglucan, or glucomannan. Our results indicate that seemingly similar LPMOs act preferentially on different types of copolymeric substructures in the plant cell wall, possibly because these LPMOs are functionally adapted to distinct niches differing in the types of available reductants.
| S-EPMC6791328 | biostudies-literature
Project description:BackgroundFilamentous fungi are efficient degraders of plant biomass and the primary producers of commercial cellulolytic enzymes. While the transcriptional regulation mechanisms of cellulases have been continuously explored in lignocellulolytic fungi, the induction of cellulase production remains a complex multifactorial system, with several aspects still largely elusive.ResultsIn this study, we identified a Zn2Cys6 transcription factor, designated as Clr-5, which regulates the expression of cellulase genes by influencing amino acid metabolism in Neurospora crassa during growth on cellulose. The deletion of clr-5 caused a significant decrease in secreted protein and cellulolytic enzyme activity of N. crassa, which was partially alleviated by supplementing with yeast extract. Transcriptomic profiling revealed downregulation of not only the genes encoding main cellulases but also those related to nitrogen metabolism after disruption of Clr-5 under Avicel condition. Clr-5 played a crucial role in the utilization of multiple amino acids, especially leucine and histidine. When using leucine or histidine as the sole nitrogen source, the Δclr-5 mutant showed significant growth defects on both glucose and Avicel media. Comparative transcriptomic analysis revealed that the transcript levels of most genes encoding carbohydrate-active enzymes and those involved in the catabolism and uptake of histidine, branched-chain amino acids, and aromatic amino acids, were remarkably reduced in strain Δclr-5, compared with the wild-type N. crassa when grown in Avicel medium with leucine or histidine as the sole nitrogen source. These findings underscore the important role of amino acid metabolism in the regulation of cellulase production in N. crassa. Furthermore, the function of Clr-5 in regulating cellulose degradation is conserved among ascomycete fungi.ConclusionsThese findings regarding the novel transcription factor Clr-5 enhance our comprehension of the regulatory connections between amino acid metabolism and cellulase production, offering fresh prospects for the development of fungal cell factories dedicated to cellulolytic enzyme production in bio-refineries.
| S-EPMC10687990 | biostudies-literature