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quelling: post-transcriptional gene silencing guided by small rnas in neurospora crassa.the filamentous fungus neurospora crassa is a model organism for the study of gene silencing. the most characterized gene silencing mechanism in this ascomycete is quelling, which occurs at the post-transcriptional level. quelling is triggered by the introduction of transgenes and results in silencing of both transgenes and cognate endogenous mrnas. quelling is related to co-suppression, observed in plants, and rna interference in animals; it requires an argonaute protein and acts by generating ...200717395524
molecular cloning and biochemical characterization of a cu,zn-superoxide dismutase from scedosporium apiospermum.a cu,zn-superoxide dismutase has been characterized from scedosporium apiospermum, a fungus which often colonizes the respiratory tract of patients with cystic fibrosis. enzyme production was stimulated by iron starvation. purification was achieved from mycelial extract from 7-day-old cultures on amberlite xad-16. the purified enzyme presented a relative molecular mass of 16.4 kda under reducing conditions and was inhibited by potassium cyanide and diethyldithiocarbamate, which are two known inh ...200717395518
the response regulator rrg-1 functions upstream of a mitogen-activated protein kinase pathway impacting asexual development, female fertility, osmotic stress, and fungicide resistance in neurospora crassa.two-component systems, consisting of proteins with histidine kinase and/or response regulator domains, regulate environmental responses in bacteria, archaea, fungi, slime molds, and plants. here, we characterize rrg-1, a response regulator protein from the filamentous fungus neurospora crassa. the cell lysis phenotype of delta rrg-1 mutants is reminiscent of osmotic-sensitive (os) mutants, including nik-1/os-1 (a histidine kinase) and strains defective in components of a mitogen-activated protei ...200717392518
the external alternative nad(p)h dehydrogenase nde3 is localized both in the mitochondria and in the cytoplasm of neurospora crassa.the filamentous fungus neurospora crassa has a branched respiratory chain. several alternative dehydrogenases, aside from the canonical complex i enzyme, are involved in the oxidation of nad(p)h substrates. based on homology searches in the fungal genome, we have tentatively identified one of these proteins. the corresponding gene was inactivated by the generation of repeat-induced point mutations and a null-mutant strain was isolated. this mutant is deficient in the oxidation of cytosolic nadh, ...200717379240
pentaketide resorcylic acid synthesis by type iii polyketide synthase from neurospora crassa.type iii polyketide synthases (pkss) are responsible for aromatic polyketide synthesis in plants and bacteria. genome analysis of filamentous fungi has predicted the presence of fungal type iii pkss, although none have thus far been functionally characterized. in the genome of neurospora crassa, a single open reading frame, ncu04801.1, annotated as a type iii pks was found. in this report, we demonstrate that ncu04801.1 is a novel type iii pks catalyzing the synthesis of pentaketide alkylresorcy ...200717374612
a double-stranded-rna response program important for rna interference efficiency.when recognized by the rna interference (rnai) pathway, double-stranded rna (dsrna) produced in eukaryotic cells results in posttranscriptional gene silencing. in addition, dsrna can trigger the interferon response as part of the immune response in vertebrates. in this study, we show that dsrna, but not short interfering rna (sirna), induces the expression of qde-2 (an argonaute gene) and dcl-2 (a dicer gene), two central components of the rnai pathway in the filamentous fungus neurospora crassa ...200717371837
efficient recursive linking algorithm for computing the likelihood of an order of a large number of genetic markers.assuming no interference, a multi-locus genetic likelihood is implemented based on a mathematical model of the recombination process in meiosis that accounts for events up to double crossovers in the genetic interval for any specified order of genetic markers. the mathematical model is realized with a straightforward algorithm that implements the likelihood computation process. the time complexity of the straightforward algorithm is exponential without bound in the number of genetic markers and ...200617369637
enabling a community to dissect an organism: overview of the neurospora functional genomics project.a consortium of investigators is engaged in a functional genomics project centered on the filamentous fungus neurospora, with an eye to opening up the functional genomic analysis of all the filamentous fungi. the overall goal of the four interdependent projects in this effort is to accomplish functional genomics, annotation, and expression analyses of neurospora crassa, a filamentous fungus that is an established model for the assemblage of over 250,000 species of non yeast fungi. building from ...200717352902
the ww domain protein pro40 is required for fungal fertility and associates with woronin bodies.fruiting body formation in ascomycetes is a highly complex process that is under polygenic control and is a fundamental part of the fungal sexual life cycle. however, the molecular determinants regulating this cellular process are largely unknown. here we show that the sterile pro40 mutant is defective in a 120-kda ww domain protein that plays a pivotal role in fruiting body maturation of the homothallic ascomycete sordaria macrospora. although ww domains occur in many eukaryotic proteins, homol ...200717351077
genomics of aspergillus oryzae.the genome sequence of aspergillus oryzae, a fungus used in the production of the traditional japanese fermentation foods sake (rice wine), shoyu (soy sauce), and miso (soybean paste), has revealed prominent features in its gene composition as compared to those of saccharomyces cerevisiae and neurospora crassa. the a. oryzae genome is extremely enriched with genes involved in biomass degradation, primary and secondary metabolism, transcriptional regulation, and cell signaling. even compared to t ...200717341818
neurospora spore killers sk-2 and sk-3 suppress meiotic silencing by unpaired dna.in neurospora crassa, pairing of homologous dna segments is monitored during meiotic prophase i. any genes not paired with a homolog, as well as any paired homologs of that gene, are silenced during the sexual phase by a mechanism known as meiotic silencing by unpaired dna (msud). two genes required for msud have been described previously: sad-1 (suppressor of ascus dominance), encoding an rna-directed rna polymerase, and sad-2, encoding a protein that controls the perinuclear localization of sa ...200717339226
kinetics of circadian band development in neurospora crassa.the circadian rhythm of neurospora crassa can be seen as a conidiation rhythm that produces concentric rings of bands (conidiating regions) alternating with interbands (non-conidiating regions) on the surface of an agar medium. to follow quantitatively this rhythm, densitometric analysis, gravimetric procedures, and video microscopy were employed. the circadian behavior of n. crassa is commonly monitored by cultivation in race tubes; in this work we report different growth kinetics during cultiv ...200717329132
mutagenic analysis of an invariant aspartate residue in chorismate synthase supports its role as an active site base.chorismate synthase catalyzes the anti-1,4-elimination of the 3-phosphate and the c(6pror) hydrogen from 5-enolpyruvylshikimate 3-phosphate (epsp) to generate chorismate, the final product of the common shikimate pathway and a precursor for the biosynthesis of aromatic compounds. the enzyme has an absolute requirement for reduced fmn, which is thought to facilitate cleavage of c-o bonds by transiently donating an electron to the substrate. the crystal structure of the enzyme revealed that epsp i ...200717326665
the evolutionary history of cytochrome p450 genes in four filamentous ascomycetes.the cytochrome p450 system is important in fungal evolution for adapting to novel ecological niches. to elucidate the evolutionary process of cytochrome p450 genes in fungi with different life styles, we studied the patterns of gene gains and losses in the genomes of four filamentous ascomycetes, including two saprotrophs (aspergillus nidulans (an) and neurospora crassa (nc)) and two plant pathogens (fusarium graminearum (fg) and magnaporthe grisea (mg)).200717324274
cyclosporin a-resistance based gene placement system for neurospora crassa.dna introduced into neurospora crassa are usually inserted at random ectopic sites of the genome, often in multiple copies. to facilitate the study of gene expression and function, transformation by a single-copy of a gene at a defined locus is desired. although several targeted gene placement methods are available for n. crassa, they all require a specific genetic background in the recipient. we describe here the development of a new locus for targeted gene placement that does not require any p ...200717320431
translesion dna polymerases pol zeta, pol eta, pol iota, pol kappa and rev1 are not essential for repeat-induced point mutation in neurospora crassa.pol zeta, pol eta, pol iota, pol kappa and rev1 are specialized dna polymerases that are able to synthesize dna across a damaged template. dna synthesis by such translesion polymerases can be mutagenic due to the miscoding nature of most damaged nucleotides. in fact, many mutational and hypermutational processes in systems ranging from yeast to mammals have been traced to the activity of such polymerases. we show however, that the translesion polymerases are dispensable for repeat-induced point ...200617301493
a genetic network for the clock of neurospora crassa.a diverse array of organisms from bacteria to humans may have evolved the ability to tell time in the presence or absence of external environmental cues. in the lowly bread mould, neurospora crassa, biomolecular reactions involving the white-collar-1 (wc-1), white-collar-2 (wc-2), and frequency (frq) genes and their products constitute building blocks of a biological clock. here we use genetic network models to explain quantitatively, from a systems perspective, how these building blocks interac ...200717301235
cloning and sequence analysis of ornithine decarboxylase gene fragments from the ascomycota.ornithine decarboxylase (odc; ec 4.1.1.17) catalyzes the initial step in the biosynthesis of polyamines, the conversion of ornithine to putrescine. based on the most conserved regions of fungal odcs, we designed and synthesized oligonucleotides to amplify homologous fragments of three important plant pathogenic pyrenomycete fungi (ascomycota), magnaporthe grisea, colletotrichum lindemuthianum and fusarium solani, and one insect pathogenic fungus metarhizium anisopliae. cloning and sequencing of ...200617286052
role of the conserved cysteine residues of the 11.5 kda subunit in complex i catalytic properties.mitochondrial complex i exists as a mixture of two inter-convertible forms: active (a) and de-activated (d), the latter being sensitive to sh-modifying compounds. to investigate if the conserved cysteine-rich 11.5 kda subunit of neurospora crassa complex i is involved in this process, we subjected the corresponding genomic dna to site-directed mutagenesis. the four cysteine residues of the subunit were separately substituted with serine residues and the resulting proteins were independently expr ...200717261544
biochemical characterization of an l-xylulose reductase from neurospora crassa.an l-xylulose reductase identified from the genome sequence of the filamentous fungus neurospora crassa was heterologously expressed in escherichia coli as a his(6) tag fusion protein, purified, and characterized. the enzyme may be used in the production of xylitol from the major pentose components of hemicellulosic waste, d-xylose and l-arabinose.200717261518
a neurospora mutation that arrests perithecial development as either male or female parent.a mutant of neurospora crassa fails to produce perithecia when crossed as either the male (fertilizing) parent or the female (protoperithecial) parent. this mutant is unique in that it appears to be due to a single mutation that blocks sexual development when crossed as either parent. as either a male or female parent, the mutant, fmf-1, produces perithecia blocked at a diameter of 120 microns and containing no meiotic figures; normal perithecia are over 400 microns in diameter. the mutant maps ...197917248941
the relationship between synaptinemal complexes, recombination nodules and crossing over in neurospora crassa bivalents and translocation quadrivalents.reconstruction of serially sectioned zygotene and pachytene nuclei has allowed the estimation of both the number and position of central component recombination nodules in the synaptinemal complexes of two chromosomally different strains of neurospora crassa. in both strains the number of nodules is that expected if each nodule represents one crossover event (50 map units). the distribution of nodules within the arms of bivalents shows evidence of centromeric repulsion and telomeric localization ...197917248878
a meiotic uv-sensitive mutant that causes deletion of duplications in neurospora.the meiotic-3 (mei-3) mutant of neurospora crassa has several effects: (1) when homozygous, it almost completely blocks meiosis and ascospore formation, (2) it is sensitive to uv, (3) its growth is inhibited by histidine and, (4) it increases the instability of nontandem duplications. this was shown for duplications produced by five different rearrangements and was demonstrated by two different criteria. the effects on meiosis and duplication instability are expressed strongly at 25 degrees ; th ...197817248837
mutations of the a mating-type gene in neurospora crassa.in neurospora, the mating-type locus controls both mating ( a + a is fertile) and heterokaryosis (a + a is incompatible). the two alleles appear stable: no novel fertility reactions have ever been reported, and attempts to separate fertility and heterokaryon incompatibility functions by recombination have been unsuccessful. in the present approach the locus was studied through a mutational analysis of heterokaryon incompatibility function. a selection system was used that detects vigorous (a + a ...197817248797
isolation and characterization of perithecial development mutants in neurospora.the isolation and characterization of mutants that block perithecial development in neurospora crassa are described. several classes of mutants have been isolated after uv mutagenesis, and those that block perithecial development when used as the female (protoperithecial) component of a cross have been further characterized. these mutants fall into 29 complementation groups. twelve of the 33 mutants block development at the protoperithecial stage; no other clustering of block points is observed. ...197817248793
heteromorphism for heterokaryon incompatibility genes in natural populations of neurospora crassa.five neurospora crassa isolates from each of three sites in louisiana were compared for genotype at five heterokaryon incompatibility (het) loci. the comparisons were made using duplications (partial diploids), based on the fact that duplications heterozygous for het loci have strikingly abnormal phenotypes which greatly facilitate the study of such genes. duplications were synthesized in crosses between the wild strains (normal chromosome sequence) and testers of defined het genotype and having ...197617248714
complementation analysis of metabolite-resistant mutations with forced heterokaryons of neurospora crassa.the double mutant strain pyr-3 arg-12(s) is a prototroph because a common precursor of arginine and pyrimidine is supplied by the arginine pathway. growth of this strain is inhibited by exogenous citrulline or arginine. citrulline-resistant mutants of this strain were selected, and they resulted from modifier mutations at other loci. forced heterokaryons were used to study complementation among these modifiers. since the complementation test requires the scoring of non-growth as the positive res ...197317248629
mutants of neurospora crassa permeable to histidinol. 196917248455
cytoplasmic mutants selected from continuously growing cultures of neurospora crassa. 196917248432
phenylalanine-tyrosine biosynthesis in neurospora crassa. 196817248403
interactions between an extrachromosomal factor, poky, and nuclear genes in neurospora crassa. 196517248272
chromatid interference in neurospora crassa. 196417248216
induction of ad-3 mutants of neurospora crassa by 2-aminopurine. 196317248163
complementation studies with isoleucine-valine mutants of neurospora crassa. 196117248057
genetical and biochemical studies of histidine-requiring mutants of neurospora crassa. ii. evidence concerning heterogeneity among hist-3 mutants. 196017248025
genetical and biochemical studies of histidine-requiring mutants of neurospora crassa. i. classification of mutants and characterization of mutant groups. 196017248024
evidence of non random distribution of ascus classes in fruiting bodies of neurospora crassa. 196017247996
high negative interference at the am locus in neurospora crassa. 196017247968
mitosis in vegetative nuclei of neurospora crassa. 196017247965
studies with purple adenine mutants in neurospora crassa. iv. lack of complementation between different ad-3a mutants in heterokaryons and pseudowild types. 196017247943
studies of adenylosuccinase in mutants and revertants of neurospora crassa. 196017247942
ascus formation and recombinant frequencies in neurospora crassa. 196017247940
asexual selection in neurospora crassa. 195917247894
studies with purple adenine mutants in neurospora crassa. iii. reversion of x-ray-induced mutants. 195817247749
the correlation effect for a histidine locus of neurospora crassa. 195717247726
studies with purple adenine mutants in neurospora crassa. ii. tetrad analyses from a cross of an ad-3a mutant with an ad-3b mutant. 195717247720
heterocaryons between strains of neurospora crassa with different cytoplasms. 195617247662
studies with purple adenine mutants in neurospora crassa. i. structural and functional complexity in the ad-3 region. 195617247654
crossing over and nuclear passing in neurospora crassa. 195617247652
a map of linkage group vi of neurospora crassa. 195617247646
genetic mechanisms governing the effect of canavanine on neurospora crassa. 195517247584
genetic control of heterocaryosis in neurospora crassa. 195517247532
the general incidence of pseudo-wild types in neurospora crassa. 195417247487
genetic and non-genetic factors in pigmentation of neurospora crassa. 195217247390
a series of histidineless mutants of neurospora crassa. 195217247387
linkage studies with biochemical mutants of neurospora crassa. 194917247329
genetics of a colonial microconidiating mutant strain of neurospora crassa. 194917247320
heterocaryosis in neurospora crassa. 194417247122
non-random crossing over in the second chromosome of neurospora crassa. 193917246907
epistatic grouping of repair-deficient mutants in neurospora: comparative analysis of two uvs-3 alleles, uvs-6 and their mus double mutant strains.the nuclease halo mutant, nuh-4, of neurospora crassa was identified conclusively as an allele of uvs-3, a gene involved in error-prone dna repair. like uvs-3, nuh-4 showed spontaneous mutator effects, and any previous contradictory findings were found to be due to newly arisen mutants. in normal strains the two alleles are noncomplementing and indistinguishable for sensitivity to uv and methyl methanesulfonate (mms). like uvs-3, nuh-4 lacked secretion of the extracellular enzyme, dnase a, a ca( ...198317246153
antifungal pisum sativum defensin 1 interacts with neurospora crassa cyclin f related to the cell cycle.plant defensins, components of the plant innate immune system, are cationic cysteine-rich antifungal peptides. evidence from the literature [thevissen, k., et al. (2003) peptides 24, 1705-1712] has demonstrated that patches of fungi membrane containing mannosyldiinositolphosphorylceramide and glucosylceramides are selective binding sites for the plant defensins isolated from dahlia merckii and raphanus sativus, respectively. whether plant defensins interact directly or indirectly with fungus int ...200717240982
circadian rhythms in neurospora crassa: clock mutant effects in the absence of a frq-based oscillator.in neurospora, the circadian rhythm is expressed as rhythmic conidiation driven by a feedback loop involving the protein products of frq (frequency), wc-1 (white collar-1), and wc-2, known as the frq/wc (fwc) oscillator. although strains carrying null mutations such as frq(10) or wc-2delta lack a functional fwc oscillator and do not show a rhythm under most conditions, a rhythm can be observed in them by the addition of geraniol or farnesol to the media. employing this altered media as an assay, ...200717237512
identification of an alternative oxidase induction motif in the promoter region of the aod-1 gene in neurospora crassa.the nuclear aod-1 gene of neurospora crassa encodes the alternative oxidase and is induced when the standard cytochrome-mediated respiratory chain of mitochondria is inhibited. to study elements of the pathway responsible for alternative oxidase induction, we generated a series of mutations in the region upstream from the aod-1 structural gene and transformed the constructs into an aod-1 mutant strain. transformed conidia were plated on media containing antimycin a, which inhibits the cytochrome ...200717237510
characterization of the blr1 gene encoding a putative blue-light regulator in the phytopathogenic fungus bipolaris oryzae.bipolaris oryzae is a filamentous ascomycetous fungus that causes brown leaf spot disease in rice. we isolated and characterized blr1, a gene that encodes a putative blue-light regulator similar to neurospora crassa white-collar 1 (wc-1). the deduced amino acid sequence of blr1 showed high degrees of similarity to other fungal blue-light regulator protein. disruption of the blr1 gene demonstrated that this gene is essential for conidial development after conidiophore formation and for near-uv ra ...200717233721
identification of genes displaying differential expression in the nuc-2 mutant strain of the mold neurospora crassa grown under phosphate starvation.subtractive hybridization was used to isolate transcripts up-regulated in the nuc-2 mutant strain of neurospora crassa grown under phosphate starvation. following differential screening, 66 cdna clones of the total enriched were screened in a second round by reverse northern hybridization. the 17 cdna candidates displaying visual positive differential expression were sequenced, and functional grouping identified putative proteins possibly involved in diverse cellular processes as, for example, p ...200717229059
hydrophobin genes and their expression in conidial and aconidial neurospora species.homologs of the gene encoding the hydrophobin eas from neurospora crassa have been identified both in the other conidial species of neurospora (n. discreta, n. intermedia, n. sitophila, and n. tetrasperma) and selected aconidial species (n. africana, n. dodgei, n. lineolata, n. pannonica, and n. terricola). southern blot analysis indicated the presence of a single gene in all species examined. eas-like proteins were purified from the conidial species and each was shown to be the proteolytically ...200717218129
roles of putative his-to-asp signaling modules hpt-1 and rrg-2, on viability and sensitivity to osmotic and oxidative stresses in neurospora crassa.neurospora crassa has a putative histidine phosphotransfer protein (hpt-1) that transfers signals from 11 histidine kinases to two putative response regulators (rrg-1 and rrg-2) in its histidine-to-aspartate phosphorelay system. the hpt-1 gene was successfully disrupted in the os-2 (map kinase gene) mutant, but not in the wild-type strain in this study. crossing the resultant hpt-1; os-2 mutants with the wild-type or os-1 (histidine kinase gene) mutant strains produced no progeny with hpt-1 or o ...200717211673
circadian rhythmicity during prolonged chemostat cultivation of neurospora crassa.following exposure to light and attainment of steady-state in the chemostat, neurospora was grown in constant conditions of darkness at 25 degrees c for 6 days. biomass samples were taken every 4h for the extraction of rna and protein, and the state of the circadian clock was assessed by assaying the levels of three rhythmically expressed mrnas; frequency (frq), antisense frq (qrf) and clock-controlled gene-14 (ccg-14), and by monitoring the clock-controlled rhythm of sporulation. our results in ...200717196855
structural and kinetic alterations of constitutive conidial alkaline phosphatase from the osmotically-sensitive mutant of neurospora crassa.the osmotically-sensitive os-1 mutant of neurospora crassa overproduced conidial alkaline phosphatase. the enzyme was purified by phenyl-sepharose cl-4b chromatography and sephadex g-200 gel filtration. page analysis of the purified enzyme suggested the occurrence of aggregation and/or disaggregation phenomena. the enzyme is a glycoprotein containing 16% saccharide, with apparent molar mass of 137 kda. two protein bands (36 and 62 kda) were observed in sds-page, suggesting that the native enzyme ...200617176763
functional expression of a drosophila antifungal peptide in escherichia coli.drosomycin is a key effector molecule involved in drosophila innate immunity against fungal infection. this peptide is composed of 44 residues stabilized by four disulfide bridges. as the first step towards the understanding of the molecular basis for its specific antifungal activity, rapid and efficient production of the wild-type peptide and its mutants is needed. here, we report a pgex system for high-level expression of recombinant drosomycin. the fusion drosomycin protein with a carrier of ...200717169573
mutation and divergence of the phospholipase c gene in neurospora crassa.in the fungus neurospora crassa we have used rip to obtain a presumptive null mutation of the phospholipase c-1 gene, thought to be important in intracellular calcium signaling, notably maintenance of the tip-high calcium gradient. the mutant is viable but has slow, aberrant growth and branching. hence plc-1 is not required for polar growth at the tip, but is necessary to modulate growth to give normal form. the mutant has residual plc activity suggesting that this enzyme function can be provide ...200717157541
the structure of an rnai polymerase links rna silencing and transcription.rna silencing refers to a group of rna-induced gene-silencing mechanisms that developed early in the eukaryotic lineage, probably for defence against pathogens and regulation of gene expression. in plants, protozoa, fungi, and nematodes, but apparently not insects and vertebrates, it involves a cell-encoded rna-dependent rna polymerase (crdrp) that produces double-stranded rna triggers from aberrant single-stranded rna. we report the 2.3-a resolution crystal structure of qde-1, a crdrp from neur ...200617147473
substrate-inducible versions of internal alternative nadh: ubiquinone oxidoreductase from yarrowia lipolytica.in standard laboratory strains of the obligate aerobic yeast yarrowia lipolytica, respiratory chain complex i (proton-translocating nadh : ubiquinone oxidoreductase) is an essential enzyme, since alternative nadh dehydrogenase activity is located exclusively at the external face of the mitochondrial inner membrane. deletions and other loss-of-function mutations in genes for nuclear coded subunits of complex i can be obtained only when an internal version of the latter enzyme, termed ndh2i, is in ...200617133620
ontogeny of the spitzenkörper in germlings of neurospora crassa.the spitzenkörper (spk) is a highly dynamic and pleomorphic complex located at the hyphal apex of filamentous fungi. most studies revealing the structure and behavior of the spk have been conducted on mature vegetative hyphae of filamentous fungi, including both main leading hyphae and branches. however, these reports do not address whether the observations can be extended to germ tubes. by enhanced phase-contrast video-microscopy and laser scanning confocal microscopy we have analyzed the intra ...200717127085
identification of non-specific alkaline phosphatases in hyphal cells of the fungus neurospora crassa by in situ histochemistry.the present study was designed to identify alkaline phosphatases in non-permeabilized hyphal cells of the fungus neurospora crassa by staining these enzymatic activities with a modified azo dye coupling method. our strategy allowed the identification of three non-specific alkaline phosphatase activities, one of them possibly being a novel putative enzyme, which is not responsive to either mg(2+) or edta. another alkaline phosphatase activity, whose location in the hyphal cell is regulated by pho ...200617117363
the rhythms of life: circadian output pathways in neurospora.research in neurospora crassa pioneered the isolation of clock-controlled genes (ccgs), and more than 180 ccgs have been identified that function in various aspects of the fungal life cycle. many clock-controlled genes are associated with damage repair, stress responses, intermediary metabolism, protein synthesis, and development. the expression of most of these genes peaks just before dawn and appears to prepare the cells for the desiccation, mutagenesis, and stress caused by sunlight. progress ...200617107934
so, a protein involved in hyphal fusion in neurospora crassa, localizes to septal plugs.the colony of a filamentous ascomycete fungus typically grows as a multinucleate syncytium. while this syncytial organization has developmental advantages, it bears the risk of extensive damage caused by local injury of hyphae. loss of cytoplasm in injured hyphae is restricted by the fast and efficient sealing of the central pores of hyphal crosswalls, or septa, by a peroxisome-derived organelle called the woronin body. the formation of septal plugs is also associated with development and leads ...200717099082
multiple layers of temporal and spatial control regulate accumulation of the fruiting body-specific protein app in sordaria macrospora and neurospora crassa.during fungal fruiting body development, specialized cell types differentiate from vegetative mycelium. we have isolated a protein from the ascomycete sordaria macrospora that is not present during vegetative growth but accumulates in perithecia. the protein was sequenced by mass spectrometry and the corresponding gene was termed app (abundant perithecial protein). app transcript occurs only after the onset of sexual development; however, the formation of ascospores is not a prerequisite for app ...200717092746
genetic basis of the ovc phenotype of neurospora: identification and analysis of a 77 kb deletion.the ovc mutant of neurospora crassa accumulates more carotenoids than the wild type in the light, is sensitive to high osmotic pressure and exhibits an altered aerial development. the three traits are complemented by a single gene, cut-1, but only the two latter are exhibited by a mutant of this gene carrying a premature stop mutation. targeted cut-1 deletion results in a normal carotenoid content, confirming the involvement of at least a second gene in the carotenoid-overproducing phenotype of ...200717082948
cloning and characterization of a thioredoxin gene, cptrx1, from the chestnut blight fungus cryphonectria parasitica.a differential display for the expression profiles of wild-type cryphonectria parasitica and its virally-infected isogenic hypovirulent strain revealed several transcripts of interest, which evidenced significant matches with fungal genes of known function. among which, we have further analyzed an amplified pcr product with significant sequence similarity to the known fungal stress-responsive thioredoxin gene from neurospora crassa. the product of the cloned thioredoxin gene, cptrx1, consists of ...200617082750
involvement of dead-box proteins in group i and group ii intron splicing. biochemical characterization of mss116p, atp hydrolysis-dependent and -independent mechanisms, and general rna chaperone activity.the rna-catalyzed splicing of group i and group ii introns is facilitated by proteins that stabilize the active rna structure or act as rna chaperones to disrupt stable inactive structures that are kinetic traps in rna folding. in neurospora crassa and saccharomyces cerevisiae, the latter function is fulfilled by specific dead-box proteins, denoted cyt-19 and mss116p, respectively. previous studies showed that purified cyt-19 stimulates the in vitro splicing of structurally diverse group i and g ...200717081564
loss of catalase-1 (cat-1) results in decreased conidial viability enhanced by exposure to light in neurospora crassa.light is one of the most important factors inducing morphogenesis in neurospora crassa. the reception of light triggers the generation of reactive oxygen species (ros) including hydrogen peroxide (h(2)o(2)). catalase-1 (cat-1) is one of three catalases known to detoxify h(2)o(2) into water and oxygen. we reported that the photomorphogenetic characteristics of mutants in nucleoside diphosphate kinase-1 (ndk-1), a light signal transducer, are severely affected, and ndk-1 interacted with cat-1 in a ...200717077971
nps6, encoding a nonribosomal peptide synthetase involved in siderophore-mediated iron metabolism, is a conserved virulence determinant of plant pathogenic ascomycetes.nps6, encoding a nonribosomal peptide synthetase, is a virulence determinant in the maize (zea mays) pathogen cochliobolus heterostrophus and is involved in tolerance to h(2)o(2). deletion of nps6 orthologs in the rice (oryza sativa) pathogen, cochliobolus miyabeanus, the wheat (triticum aestivum) pathogen, fusarium graminearum, and the arabidopsis thaliana pathogen, alternaria brassicicola, resulted in reduced virulence and hypersensitivity to h(2)o(2). introduction of the nps6 ortholog from th ...200617056706
rapid genetic mapping in neurospora crassa.forward genetic analysis is the most broadly applicable approach to discern gene functions. however, for some organisms like the filamentous ascomycete neurospora crassa, genetic mapping frequently represents a limiting step in forward genetic approaches. we describe an efficient method for genetic mapping in n. crassa that makes use of a modified bulked segregant analysis and pcr-based molecular markers. this method enables mapping with progeny from a single cross and requires only 90 pcr ampli ...200717056287
her-2 upstream open reading frame effects on the use of downstream initiation codons.the her-2 (neu, erbb-2) oncogene encodes a 185-kda transmembrane receptor tyrosine kinase. her2 overexpression occurs in numerous primary human tumors and contributes to 25-30% of breast and ovarian carcinomas. synthesis of her2 is controlled in part by an upstream open reading frame (uorf) present in the transcript. we used synthetic capped and polyadenylated mrnas containing sequences derived from the 5' region of the her-2 transcript fused to a firefly luciferase (luc) reporter to examine thi ...200617045969
[oxidative stress and cell differentiation in neurospora crassa].environmental stress factors induce oxidative stress in fungi by increasing the intracellular concentrations of reactive oxygen species (ros). in the mycelium, ros act as signal molecules needed for cytodifferentiation at certain stages of the development of fungi. generation of ros in cells induces the activation of antioxidant protective mechanisms. the purpose of this communication is to analyze the role of ros in light signal transduction, mediated in neurospora crassa cells by the white col ...200617025175
the homologue of het-c of neurospora crassa lacks vegetative compatibility function in fusarium proliferatum.for two fungal strains to be vegetatively compatible and capable of forming a stable vegetative heterokaryon they must carry matching alleles at a series of loci variously termed het or vic genes. cloned het/vic genes from neurospora crassa and podospora anserina have no obvious functional similarity and have various cellular functions. our objective was to identify the homologue of the neurospora het-c gene in fusarium proliferatum and to determine if this gene has a vegetative compatibility fu ...200617021201
vib-1 is required for expression of genes necessary for programmed cell death in neurospora crassa.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 ge ...200617012538
a ste12 homologue of the homothallic ascomycete sordaria macrospora interacts with the mads box protein mcm1 and is required for ascosporogenesis.the mads box protein mcm1 controls diverse developmental processes and is essential for fruiting body formation in the homothallic ascomycete sordaria macrospora. mads box proteins derive their regulatory specificity from a wide range of different protein interactions. we have recently shown that the s. macrospora mcm1 is able to interact with the alpha-domain mating-type protein smta-1. to further evaluate the functional roles of mcm1, we used the yeast two-hybrid approach to identify mcm1-inte ...200616999832
lithium leads to an increased frq protein stability and to a partial loss of temperature compensation in the neurospora circadian clock.in many organisms, the presence of lithium leads to an increase of the circadian period length. in neurospora crassa, it was earlier found that lithium results in a decrease of overall growth and increased circadian periods. in this article, the authors show that lithium leads to a reduction of frq degradation with elevated frq levels and to a partial loss of temperature compensation. at a concentration of 13 mm lithium, frq degradation is reduced by about 60% while, surprisingly, the activity o ...200616998153
identification of os-2 map kinase-dependent genes induced in response to osmotic stress, antifungal agent fludioxonil, and heat shock in neurospora crassa.two-component signal transduction comprising of os-1 (histidine kinase), os-4 (mapkk kinase), os-5 (mapk kinase), and os-2 (map kinase) plays an important role in osmotic regulation in neurospora crassa. to identify the genes regulated downstream of os-2 map kinase, quantitative real-time rt-pcr analysis was conducted in selected genes based on hog1 map kinase regulated genes in yeast. in response to osmotic stress and fludioxonil, expression of six genes that for glycerol synthesis (gcy-1, gcy- ...200716990038
evolutionary changes in the fungal carbamoyl-phosphate synthetase small subunit gene and its associated upstream open reading frame.the neurospora crassa arg-2 and the saccharomyces cerevisiae ortholog cpa1 encode the arginine-specific carbamoyl-phosphate synthetase (cps-a) small subunit. arginine decreases synthesis of this subunit through the action of a 5' upstream open reading frame in the mrna that encodes a cis-regulatory element, the arginine attenuator peptide (aap), which stalls ribosomes in response to arginine. we performed a comparative analysis of the genomic structure and predicted peptide sequence of the aap a ...200716979358
proteolytic cleavage of a spectrin-related protein by calcium-dependent protease in neurospora crassa.to investigate the functional significance of a cytoskeletal spectrin-like protein, we studied its localization pattern in neurospora crassa and sought the answer to whether it is a substrate for another apically localized protein, the calcium-dependent protease (cdp ii). immunoblots of crude extracts from exponentially growing mycelia, separated by one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis using antichicken alpha/beta-spectrin antibodies, revealed a sing ...200616972126
the predicted g-protein-coupled receptor gpr-1 is required for female sexual development in the multicellular fungus neurospora crassa.g-protein-coupled receptors (gpcrs) control important aspects of asexual and sexual development in eukaryotic organisms. we have identified a predicted gpcr in the filamentous fungus neurospora crassa with similarity to cyclic amp-receptor like gpcrs from dictyostelium discoideum and gcr1 from arabidopsis thaliana. expression of gpr-1 is highest in female reproductive structures, and deletion of gpr-1 leads to defects during sexual development. unfertilized female structures (protoperithecia) fr ...200616963633
a eukaryote without catalase-containing microbodies: neurospora crassa exhibits a unique cellular distribution of its four catalases.microbodies usually house catalase to decompose hydrogen peroxide generated within the organelle by the action of various oxidases. here we have analyzed whether peroxisomes (i.e., catalase-containing microbodies) exist in neurospora crassa. three distinct catalase isoforms were identified by native catalase activity gels under various peroxisome-inducing conditions. subcellular fractionation by density gradient centrifugation revealed that most of the spectrophotometrically measured activity wa ...200616963632
biotransformations of ent-18-acetoxy-6-ketomanoyl oxides epimers at c-13 with filamentous fungi.two ent-18-acetoxy-6-oxomanoyl oxides, epimers at c-13, have been prepared from ent-6alpha,8alpha,18-trihydroxylabda-13(16),14-diene (andalusol), isolated from sideritis foetens, by means of several chemical pathways and a regioselective acylation with candida cylindracea lipase (ccl). biotransformation of these 13-epimeric ent-manoyl oxides by fusarium moniliforme and neurospora crassa produced mainly ent-1beta- or ent-11alpha-hydroxylations, as well as their deacetylated derivatives, in both e ...200616956632
karyotyping of neurospora crassa using synaptonemal complex spreads of translocation quadrivalents.the purposes of the present research are (i) to establish the karyotype of neursopora crassa using visualization of kinetochores in the synaptonemal complex (sc) spreads, (ii) to assign each chromosome to a linkage group, and (iii) to examine chromosome pairing and recombination nodules in quadrivalents. two strains containing reciprocal translocations were used: t(i;ii)4637, which involves linkage groups i and ii, and alcoy, which contains 3 independent translocations involving i and ii, iv and ...200616936840
the biotechnological potential of the al-2 gene from neurospora [correction of neurospra] crassa for the production of monocyclic keto hydroxy carotenoids.the al-2 cdna from neurospora crassa was cloned, expressed and functionally characterized. the enzyme comprised the two catalytic activities of a phytoene synthase and a lycopene cyclase. in contrast to most other lycopene cyclases, single cyclizations were preferentially catalyzed. this n. crassa enzyme is the first crtyb-type monocyclic-acting lycopene cyclase. therefore, this cdna has been evaluated for the heterologous synthesis of monocyclic hydroxy-keto carotenoids by combination with othe ...200616928467
purification and characterization of a novel thermostable extracellular protein tyrosine phosphatase from metarhizium anisopliae strain cqma102.an extracellular phosphatase was purified to homogeneity from the entomopathogenic fungus metarhizium anisopliae with a 41.0% yield. the molecular mass and isoelectric point of the purified enzyme were about 82.5 kda and 9.5 respectively. the optimum ph and temperature were about 5.5 and 75 degrees c when using o-phospho-l-tyrosine as substrate. the protein displayed high stability in a ph range 3.0-9.5 at 30 degrees c and was remarkably thermostable at 70 degrees c. the purified enzyme showed h ...200616926509
metal transportome of neurospora crassa.neurospora crassa has been the model filamentous fungus for the study of many fundamental cellular mechanisms of transport and metabolism. the recently completed genome sequence of n. crassa has over 10,000 genes without significant matches for a large number of genes (41%) in the sequence databases, indeed presents many challenges for new discoveries. using transporter database and blast searches a total of 65 open reading frames for putative cation transporter genes have been identified in n. ...200616922681
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