Effects of Time of Day on the Neurospora Metabolome
Ontology highlight
ABSTRACT: Elucidating the metabolome of the filamentous fungi Neurospora crassa to better understand the link between the circadian clock and metabolism; specifically the role that the clock plays in regulating cellulase production.
Project description:Light represents an important environmental cue, which exerts considerable influence on the metabolism of fungi. Studies with the biotechnological fungal workhorse Trichoderma reesei (Hypocrea jecorina) have revealed an interconnection between transcriptional regulation of cellulolytic enyzmes and the light response. The filamentous fungus, Neurospora crassa, has been used as a model organism to study light and circadian rhythm biology. We therefore investigated whether light also regulates transcriptional regulation of cellulolytic enzymes in N. crassa. We show that the N. crassa photoreceptor genes wc-1, wc-2 and vvd are involved in regulation of cellulase gene expression, indicating that this phenomenon is conserved among filamentous fungi. Genome wide analysis of photoreceptor mutants and evaluation of results by analysis of mutant strains identified several candidate genes likely to play a role in light modulated cellulase gene expression.
Project description:Light represents an important environmental cue, which exerts considerable influence on the metabolism of fungi. Studies with the biotechnological fungal workhorse Trichoderma reesei (Hypocrea jecorina) have revealed an interconnection between transcriptional regulation of cellulolytic enyzmes and the light response. The filamentous fungus, Neurospora crassa, has been used as a model organism to study light and circadian rhythm biology. We therefore investigated whether light also regulates transcriptional regulation of cellulolytic enzymes in N. crassa. We show that the N. crassa photoreceptor genes wc-1, wc-2 and vvd are involved in regulation of cellulase gene expression, indicating that this phenomenon is conserved among filamentous fungi. Genome wide analysis of photoreceptor mutants and evaluation of results by analysis of mutant strains identified several candidate genes likely to play a role in light modulated cellulase gene expression. Three deletion strains (delta-wc-1 (FGSC 11712), delta-wc-2 (FGSC 11124) and delta-vvd (FGSC 11556)) and the wild type strain (FGSC 2489) at two different timepoints (28h or 40h) were analyzed. Cy3 and Cy5 dye swaps were performed.
Project description:Cryptochromes were identified in plants and animals where they function as either photoreceptors or circadian clock components. In the filamentous fungus Neurospora, the biological function of cryptochrome has not yet been explored. Here, we demonstrate that Neurospora crassa cryptochrome (Nc cry) is a DASH-type of cryptochrome, capable of binding FAD and MTHF, whose transcript and protein levels are both strongly induced by blue light in a wc-1 dependent manner. Although the Nc cry transcript is circadian-regulated and antiphasic to frq, knockout strains of Nc cry appears to have a normal clock phenotype. Whole genome microarray and RT-QPCR analysis confirm that Nc cry is not involved in the signal transduction of either early or late light responses and seems to have no transcriptional regulatory activity under our laboratory conditions. Our study concludes that the only cryptochrome in Neurospora crassa is dispensable for the well-characterized blue light sensing cascade and is not part of the circadian clock system. Keywords: light response
Project description:Purpose: To explore conservation of gene regulation by the transcription factor clr-2/clrB in Neurospora crassa and Aspergillus nidulans Methods: mRNA from wild type and clr-2/clrB mutants were collected after a culture shift from sucrose/glucose to Avicel (crystaline cellulose) or no carbon media Results: We show that N. crassa and A. nidulans have similair global transcriptional responses to Avicel, with several hundred genes showing specific induction, though the induced genes are more specifically targeted at cellulose for N. crassa and more targeted at hemicellulose and pectin for A. nidulans. clr-2/clrB has a conserved fundamental function in cellulose induction, though the mechanism has diverged. Misexpression of clr-2 is sufficeint for inducer free cellulase secretion in N. crassa, but neither clrB or heterologous clr-2 is sufficient for inducer free cellulase secretion in A. nidulans. Conclusions: Our study demonstrates a conserved and essential role in cellulose utilization for the transcription factor clr-2 in filamentous ascomycetes and demonstrates that manipulation of clr-2 expression can be used to control cellulase expression in some species. Biological triplicates of liquid culture N. crassa and A. nidulans were harvested at 4 hours and 6 hours, respectively, after a switch to media of interest. Global mRNA abundances from liquid cultures of N. crassa and A. nidulans were measured by sequencing on the Illumina Genome Analyzer IIx and HiSeq2000 platforms.
Project description:Purpose: To explore conservation of gene regulation by the transcription factor clr-2/clrB in Neurospora crassa and Aspergillus nidulans Methods: mRNA from wild type and clr-2/clrB mutants were collected after a culture shift from sucrose/glucose to Avicel (crystaline cellulose) or no carbon media Results: We show that N. crassa and A. nidulans have similair global transcriptional responses to Avicel, with several hundred genes showing specific induction, though the induced genes are more specifically targeted at cellulose for N. crassa and more targeted at hemicellulose and pectin for A. nidulans. clr-2/clrB has a conserved fundamental function in cellulose induction, though the mechanism has diverged. Misexpression of clr-2 is sufficeint for inducer free cellulase secretion in N. crassa, but neither clrB or heterologous clr-2 is sufficient for inducer free cellulase secretion in A. nidulans. Conclusions: Our study demonstrates a conserved and essential role in cellulose utilization for the transcription factor clr-2 in filamentous ascomycetes and demonstrates that manipulation of clr-2 expression can be used to control cellulase expression in some species.
Project description:Cryptochromes were identified in plants and animals where they function as either photoreceptors or circadian clock components. In the filamentous fungus Neurospora, the biological function of cryptochrome has not yet been explored. Here, we demonstrate that Neurospora crassa cryptochrome (Nc cry) is a DASH-type of cryptochrome, capable of binding FAD and MTHF, whose transcript and protein levels are both strongly induced by blue light in a wc-1 dependent manner. Although the Nc cry transcript is circadian-regulated and antiphasic to frq, knockout strains of Nc cry appears to have a normal clock phenotype. Whole genome microarray and RT-QPCR analysis confirm that Nc cry is not involved in the signal transduction of either early or late light responses and seems to have no transcriptional regulatory activity under our laboratory conditions. Our study concludes that the only cryptochrome in Neurospora crassa is dispensable for the well-characterized blue light sensing cascade and is not part of the circadian clock system. Keywords: light response Two-color microarray. Alexa Fluor 555 was consistently used to label cDNA synthesized from reference RNA, which is a mixture containing equal amounts of RNA samples harvested from different circadian time points and light treatment durations. The same batch of pooled RNA was used as a reference for each array experiment. Alexa Fluor 647 was used exclusively to label cDNA representing sample RNA.
Project description:Neurospora crassa recently has become a novel system to investigate cellulase induction. Here, we discovered a novel membrane protein, CLP1 (NCU05853), a putative cellodextrin transporter-like protein, that is a critical component of the cellulase induction pathway in N. crassa. Although CLP1 protein cannot transport cellodextrin, the suppression of cellulase induction by this protein was discovered on both cellobiose and Avicel. The co-disruption of the cellodextrin transporters cdt2 and clp1 in strain M-NM-^T3M-NM-2G formed strain CPL7. With induction by cellobiose, cellulase production was enhanced 6.9-fold in CPL7 compared with M-NM-^T3M-NM-2G. We also showed that the suppression of cellulase expression by CLP1 occurred by repressing the expression of cellodextrin transporters, particularly cdt1 expression. Transcriptome analysis of the hypercellulase-producing strain CPL7 showed that the cellulase expression machinery was dramatically stimulated, as were the cellulase enzyme genes including the inducer transporters and the major transcriptional regulators. N. crassa was pregrown in sucrose and transferred to cellobiose media. Up regulated and down regulated genes expressions were compared with M-NM-^T3M-NM-2G and M-NM-^T3M-NM-2GM-NM-^Tclp1 strain.
Project description:CDT-1 and CDT-2 are two cellodextrin transporters discovered in the filamentous fungus Neurospora crassa. Previous studies focused on characterizing the role of these transporters in only a few conditions, including cellulose degradation, and the function of these two transporters is not yet completely understood. In this study, we show that deletion of cdt-2, but not cdt-1, results in growth defects not only on Avicel but also on xylan. cdt-2 can be highly induced by xylan, and this mutant has a xylodextrin consumption defect. Transcriptomic analysis of the cdt-2 deletion strain on Avicel and xylan showed that major cellulase and hemicellulase genes were significantly down-regulated in the cdt-2 deletion strain and artificial over expression of cdt-2 in N. crassa increased cellulase and hemicellulase production. Together, these data clearly show that CDT-2 plays a critical role in hemicellulose sensing and utilization. This is the first time a sugar transporter has been assigned a function in the hemicellulose degradation pathway. Furthermore, we found that the transcription factor XLR-1 is the major regulator of cdt-2, while cdt-1 is primarily regulated by CLR-1. These results deepen our understanding of the functions of both cellodextrin transporters, particularly for CDT-2. Our study also provides novel insight into the mechanisms for hemicellulose sensing and utilization in N. crassa, and may be applicable to other cellulolytic filamentous fungi. N. crassa was pregrown in Sucrose and transferred to Avicel (cellulose) or Xylan(hemicellulose) media. Up regulated and down regulated genes expressions were compared with wild type strain on two conditions (Avicel and xylan) respectively.
Project description:Neurospora crassa recently has become a novel system to investigate cellulase induction. Here, we discovered a novel membrane protein, CLP1 (NCU05853), a putative cellodextrin transporter-like protein, that is a critical component of the cellulase induction pathway in N. crassa. Although CLP1 protein cannot transport cellodextrin, the suppression of cellulase induction by this protein was discovered on both cellobiose and Avicel. The co-disruption of the cellodextrin transporters cdt2 and clp1 in strain Δ3βG formed strain CPL7. With induction by cellobiose, cellulase production was enhanced 6.9-fold in CPL7 compared with Δ3βG. We also showed that the suppression of cellulase expression by CLP1 occurred by repressing the expression of cellodextrin transporters, particularly cdt1 expression. Transcriptome analysis of the hypercellulase-producing strain CPL7 showed that the cellulase expression machinery was dramatically stimulated, as were the cellulase enzyme genes including the inducer transporters and the major transcriptional regulators.
Project description:Staurosporine induces programmed cell death in a series of organisms. Here, we analyse gene expression of the filamentous fungus Neurospora crassa following exposure to staurosporine for different time periods.