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photomorphogenetic characteristics are severely affected in nucleoside diphosphate kinase-1 (ndk-1)-disrupted mutants in neurospora crassa.we previously demonstrated that the ndk-1 (nucleoside diphosphate kinase-1) point mutant, ndk-1(p72h), displays a defective phenotype in light-induced perithecial polarity in neurospora crassa. to investigate the biological function of ndk-1 in detail, we isolated two ndk-1 mutants, ndk-1(rip-1) and ndk-1(rip-2), using the riping (repeat induced point mutation) method. notably, we detected no accumulation of ndk-1(rip-1) mrna and truncated ndk-1(rip-2) protein. the ndk-1(rip) mutants exhibited a ...200616307287
proteome analysis of mitochondrial outer membrane from neurospora crassa.the mitochondrial outer membrane mediates numerous interactions between the metabolic and genetic systems of mitochondria and the rest of the eukaryotic cell. we performed a proteomic study to discover novel functions of components of the mitochondrial outer membrane. proteins of highly pure outer membrane vesicles (omv) from neurospora crassa were identified by a combination of lc-ms/ms of tryptic peptide digests and gel electrophoresis of solubilized omv proteins, followed by their identificat ...200616294304
molecular mechanism of light responses in neurospora: from light-induced transcription to photoadaptation.blue light regulates many molecular and physiological activities in a large number of organisms. in neurospora crassa, a eukaryotic model system for studying blue-light responses, the transcription factor and blue-light photoreceptor white collar-1 (wc-1) and its partner wc-2 are central to blue-light sensing. neurospora's light responses are transient, that is, following an initial acute phase of induction, light-regulated processes are down-regulated under continuous illumination, a phenomenon ...200516287715
a rho-type gtpase, rho-4, is required for septation in neurospora crassa.proteins in the rho family are small monomeric gtpases primarily involved in polarization, control of cell division, and reorganization of cytoskeletal elements. phylogenetic analysis of predicted fungal rho proteins suggests that a new rho-type gtpase family, whose founding member is rho4 from the archiascomycete schizosaccharomyces pombe, is involved in septation. s. pombe rho4delta mutants have multiple, abnormal septa. in contrast to s. pombe rho4delta mutants, we show that strains containin ...200516278458
[study on xylose fermentation by neurospora crassa].the influence of oxygen limitation and medium initial ph on xylose fermentation by neurospora crassa as 3.1602 was investigated. n. crassa as 3.1602 has high ability of xylose fermentation producing ethanol and xylitol. oxygen limitation has big influence on ethanol and xylitol production. the maximum conversion rate of ethanol was 63.2% obtained under semi-aerobic conditions. the maximum conversion rate of xylitol was 31.8% obtained under micro-aerobic conditions. xylitol accumulation is behind ...200316276921
the gene for a lectin-like protein is transcriptionally activated during sexual development, but is not essential for fruiting body formation in the filamentous fungus sordaria macrospora.the filamentous fungus sordaria macrospora forms complex three-dimensional fruiting bodies called perithecia that protect the developing ascospores and ensure their proper discharge. in previous microarray analyses, several genes have been identified that are downregulated in sterile mutants compared to the wild type. among these genes was tap1 (transcript associated with perithecial development), a gene encoding a putative lectin homolog.200516266439
the pas/lov protein vivid supports a rapidly dampened daytime oscillator that facilitates entrainment of the neurospora circadian clock.a light-entrainable circadian clock controls development and physiology in neurospora crassa. existing simple models for resetting based on light pulses (so-called nonparametric entrainment) predict that constant light should quickly send the clock to an arrhythmic state; however, such a clock would be of little use to an organism in changing photoperiods in the wild, and we confirm that true, albeit dampened, rhythmicity can be observed in extended light. this rhythmicity requires the pas/lov p ...200516264193
synchronizing the neurospora crassa circadian clock with the rhythmic environment.the metronomic predictability of the environment has elicited strong selection pressures for the evolution of endogenous circadian clocks. circadian clocks drive molecular and behavioural rhythms that approximate the 24 h periodicity of our environment. found almost ubiquitously among phyla, circadian clocks allow preadaptation to rhythms concomitant with the natural cycles of the earth. cycles in light intensity and temperature for example act as important cues that couple circadian clocks to t ...200516246018
temperature-modulated alternative splicing and promoter use in the circadian clock gene frequency.the expression of frequency, a central component of the circadian clock in neurospora crassa, shows daily cycles that are exquisitely sensitive to the environment. two forms of frq that differ in length by 99 amino acids, lfrq and sfrq, are synthesized from alternative initiation codons and the change in their ratio as a function of temperature contributes to robust rhythmicity across a range of temperatures. we have found frq expression to be surprisingly complex, despite our earlier prediction ...200516195340
rna silencing in fungi: mechanisms and applications.two rna silencing-related phenomena, quelling and meiotic silencing by unpaired dna (msud) have been identified in the fungus neurospora crassa. similar to the case with the sirna and mirna pathways in drosophila, different sets of protein components including rna-dependent rna polymerase, argonaute and dicer, are used in the quelling and msud pathways. orthologs of the rna silencing components are found in most, but not all, fungal genomes currently available in the public databases, indicating ...200516137680
biotransformation of racemic diisophorone by cephalosporium aphidicola and neurospora crassa.racemic diisophorone (500 mg) was converted by cephalosporium aphidicola and neurospora crassa over 10 days at 25 degrees c to 8beta-hydroxydiisophorone in yields of 10% (52 mg) and 20% (103 mg), respectively. the structure was established by ir, specific rotation, mass spectral, 1d and 2d-nmr studies.200516132845
transcripts and transcript-binding proteins in mitochondria of neurospora crassa.we analyzed expression elements of three disparate groups of mitochondrial genes in neurospora crassa, apocytochrome b (cob), cytochrome c oxidase 1 (cox1), and the clustered atp8-atp6-mtatp9-cox2. to identify promoter sequences we employed the published n. crassa consensus sequence for cob and rrna genes, and we found closely related sequences within the 5'-regions of both cox1 and the atp8-cox2 transcriptional units. we determined that the mature cox1 rna includes two flanking unassigned readi ...200316120332
molecular mechanism of temperature sensing by the circadian clock of neurospora crassa.expression levels and ratios of the long (l) and short (s) isoforms of the neurospora circadian clock protein frequency (frq) are crucial for temperature compensation of circadian rhythms. we show that the ratio of l-frq versus s-frq is regulated by thermosensitive splicing of intron 6 of frq, a process removing the translation initiation site of l-frq. thermosensitivity is due to inefficient recognition of nonconsensus splice sites at elevated temperature. the temperature-dependent accumulation ...200516107616
[photoreceptor apparatus of a fungus neurospora crassa].light governs living functions of ascomycete fungus neurospora crassa by controlling expression of the genes responsible for differentiation of reproductive structures, synthesis of secondary metabolites and the circadian oscillator activity. illumination also influences electrogenic processes in cell membrane and the activity and molecular organization of some enzymes. the major but, probably, not the sole photoreceptor pigment in neurospora cells is wcc, a heterodimeric complex formed by pas-d ...200616083009
mass flow and pressure-driven hyphal extension in neurospora crassa.mass flow of cytoplasm in neurospora crassa trunk hyphae was directly confirmed by injecting oil droplets into the hyphae. the droplets move in a manner similar to cytoplasmic particles and vacuoles within the hyphae. the direction of mass flow is towards the growing hyphal tips at the colony edge. based on flow velocities (about 5 microm s(-1)), hyphal radius and estimates of cytoplasm viscosity, the reynolds number is about 10(-4), indicating that mass flow is laminar. therefore, the poiseulle ...200516079346
the 29.9 kda subunit of mitochondrial complex i is involved in the enzyme active/de-active transitions.mitochondrial respiratory chain complex i undergoes transitions from active to de-activated forms. we have investigated the phenomenon in sub-mitochondrial particles from neurospora crassa wild-type and a null-mutant lacking the 29.9 kda nuclear-coded subunit of complex i. based on enzymatic activities, genetic crosses and analysis of mitochondrial proteins in sucrose gradients, we found that about one-fifth of complex i with catalytic properties similar to the wild-type enzyme is assembled in t ...200516005890
oxygen and hydrogen peroxide enhance light-induced carotenoid synthesis in neurospora crassa.previously, we found that intracellular reactive oxygen species (ros) affect photomorphogenesis in neurospora crassa. in this study, we investigated the physiological roles of ros in the response to light and found that the exposure of mycelia to air was important for the light-induced carotenogenesis. mycelia treated with a high concentration of o(2) gas and h(2)o(2) to release ros showed an enhancement of light-induced carotenoid accumulation and the expression of gene related to light-inducib ...200516004990
evaluation of phenylaminopyrimidines as antifungal protein kinase inhibitors.the effects of diverse phenylaminopyrimidines (pap), namely pap-pyridines (type a), pap-pyrazoles (type b) and pap-thiazoles (type c), on neurospora crassa shear & dodge has been investigated. the results revealed that type a strongly inhibit the in vitro growth of n crassa, whereas types b and c are much less active. a significant correlation was observed between the neurospora growth inhibition and the intrinsic activity of type a compounds on the cyclin-dependent protein kinase p34(cdc2) of s ...200515952247
hyperbranching induced by cold-shock or snow-flake mutation in neurospora crassa is prevented by addition of exogenous calcium.hyphal tip growth is a highly polarized process of cell extension, which may be affected by chemical and physical stress. neurospora crassa exposed to cold-shock lost its polarized growth and dichotomous branches were detected. these effects were not observed in the presence of 500 mm ca2+. we compared here the morphological pattern of a snow-flake mutant (sn) and the wild-type (wt) exposed to 4 degrees c. hyphal morphology, nuclei, actin and microtubule distribution were analyzed. no effects on ...200515900541
identification and distribution of sequences having similarity to mitochondrial plasmids in mitochondrial genomes of filamentous fungi.mitochondrial plasmids are autonomously replicating genetic elements commonly associated with fungal and plant species. analysis of several plant and fungal mitochondrial genomes has revealed regions that show significant homology to mitochondrial plasmids, suggesting that plasmids have had a long-term association with their mitochondrial hosts. to assess the degree to which plasmids have invaded fungal mitochondrial genomes, blast search parameters were modified to identify plasmid sequences wi ...200515891911
molecular and functional analyses of poi-2, a novel gene highly expressed in sexual and perithecial tissues of neurospora crassa.the poi-2 gene is highly and specifically expressed in starved and sexual tissues of the filamentous fungus neurospora crassa. it encodes a 27-kda protein, as shown by in vitro transcription and translation. the poi2 protein contains a hydrophobic signal sequence at the amino terminus followed by novel 16 tandem repeats of 13 to 14 amino acid residues; all repeats are separated by kex2 processing sites. repeat-induced point mutation (rip)-mediated gene disruption was used to generate poi-2 mutan ...200515879524
small interfering rnas that trigger posttranscriptional gene silencing are not required for the histone h3 lys9 methylation necessary for transgenic tandem repeat stabilization in neurospora crassa.in neurospora crassa, the introduction of a transgene can lead to small interfering rna (sirna)-mediated posttranscriptional gene silencing (ptgs) of homologous genes. sirnas can also guide locus-specific methylation of lys9 of histone h3 (lys9h3) in schizosaccharomyces pombe. here we tested the hypothesis that transgenically derived sirnas may contemporaneously both activate the ptgs mechanism and induce chromatin modifications at the transgene and the homologous endogenous gene. we carried out ...200515831483
a catalytic subunit of cyclic amp-dependent protein kinase, pkac-1, regulates asexual differentiation in neurospora crassa.a cyclic amp (camp)-dependent protein kinase pathway has been shown to regulate growth, morphogenesis and virulence in filamentous fungi. however, the precise mechanisms of regulation through the pathway remain poorly understood. in neurospora crassa, the cr-1 adenylate cyclase mutant exhibits colonial growth with short aerial hyphae bearing conidia, and the mcb mutant, a mutant of the regulatory subunit of camp-dependent protein kinase (pka), shows the loss of growth polarity at the restrictive ...200515824453
collateral damage: spread of repeat-induced point mutation from a duplicated dna sequence into an adjoining single-copy gene in neurospora crassa.repeat-induced point mutation (rip) is an unusual genome defense mechanism that was discovered in neurospora crassa. rip occurs during a sexual cross and induces numerous g : c to a : t mutations in duplicated dna sequences and also methylates many of the remaining cytosine residues. we measured the susceptibility of the erg-3 gene, present in single copy, to the spread of rip from duplications of adjoining sequences. genomic segments of defined length (1, 1.5 or 2 kb) and located at defined dis ...200515824437
analysis of circadian rhythms in neurospora: overview of assays and genetic and molecular biological manipulation.the eukaryotic filamentous fungus neurospora crassa is a tractable model system that has provided numerous insights into the molecular basis of circadian rhythms. in the core circadian clock feedback loop, wc-1 and wc-2 interact via pas domains to heterodimerize, and this complex acts both as the circadian photoreceptor and, in the dark, as a transcription factor that promotes the expression of the frq gene. in the negative step of the loop, dimers of frq feed back to block the activity of the w ...200515817284
a kinase for light and time.the eukaryotic filamentous fungus neurospora crassa has proven to be a dependable model system for the analysis of light-regulated gene expression and circadian rhythmicity. the molecular basis of the core circadian clock is a transcription/translation-based feedback loop in which a heterodimer of the white-collar 1 (wc-1) and white-collar 2 (wc-2) proteins act as a transcription factor to promote expression of the negative elements in the clock, frq mrna and frq protein. additionally, wc-1 is a ...200515813724
cross-species microarray hybridization to identify developmentally regulated genes in the filamentous fungus sordaria macrospora.the filamentous fungus sordaria macrospora forms complex three-dimensional fruiting bodies that protect the developing ascospores and ensure their proper discharge. several regulatory genes essential for fruiting body development were previously isolated by complementation of the sterile mutants pro1, pro11 and pro22. to establish the genetic relationships between these genes and to identify downstream targets, we have conducted cross-species microarray hybridizations using cdna arrays derived f ...200515778868
the post-transcriptional gene silencing machinery functions independently of dna methylation to repress a line1-like retrotransposon in neurospora crassa.post-transcriptional gene silencing (ptgs) involving small interfering rna (sirna)-directed degradation of rna transcripts and transcriptional silencing via dna methylation have each been proposed as mechanisms of genome defence against invading nucleic acids, such as transposons and viruses. furthermore, recent data from plants indicates that many transposons are silenced via a combination of the two mechanisms, and sirnas can direct methylation of transposon sequences. we investigated the cont ...200515767281
possible role of ionic gradients in the apical growth of neurospora crassa.the effects of the ca2+/h+ exchanger a23187 and the k+/h+ exchanger nigericin on the growth of neurospora crassa were analyzed. both ionophores had the same effects on the fungus. they both inhibited growth in liquid media, apical extension being more affected than protein synthesis. a sudden challenge to either ionophore on solid media rapidly stopped hyphal extension. additionally, both ionophores induced profuse mycelium branching and upward hyphal growth. hyphae growing on nigericin-containi ...200415702382
a tyrosyl-trna synthetase adapted to function in group i intron splicing by acquiring a new rna binding surface.we determined a 1.95 a x-ray crystal structure of a c-terminally truncated neurospora crassa mitochondrial tyrosyl-trna synthetase (cyt-18 protein) that functions in splicing group i introns. cyt-18's nucleotide binding fold and intermediate alpha-helical domains superimpose on those of bacterial tyrrss, except for an n-terminal extension and two small insertions not found in nonsplicing bacterial enzymes. these additions surround the cyt-18-1 mutation site and are sites of suppressor mutations ...200515694342
intramolecular recombination and deletions in mitochondrial dna of senescent, a nuclear-gene mutant of neurospora crassa exhibiting "death" phenotype.in neurospora crassa, a nuclear-gene mutant, senescent, derived from a phenotypically normal wild isolate of neurospora intermedia exhibits a 'death' phenotype. regardless of the composition of the culture medium, the mycelium ceases to grow in 2-6 subcultures at 26 degrees c and 1 or 2 subcultures at 34 degrees c. senescence of vegetative mycelium is associated with deficiencies in cytochromes aa3 and b and reduced oxygen uptake. the restriction fragment analysis of mitochondrial dna from senes ...200515670715
the neurospora crassa gene responsible for the cut and ovc phenotypes encodes a protein of the haloacid dehalogenase family.light stimulation of carotenogenesis in neurospora crassa, mediated by the white collar proteins, is enhanced in some regulatory mutants, such as vivid and ovc. the gene responsible for the vivid mutation has been identified, but not the one responsible for the ovc phenotype. the ovc mutant is sensitive to high osmotic conditions and allelic with another mutant, cut, also osmosensitive but not affected in carotenogenesis. a phenotypic characterization of both strains is presented. light inductio ...200515661007
neutral glycolipids of the filamentous fungus neurospora crassa: altered expression in plant defensin-resistant mutants.to defend themselves against fungal pathogens, plants produce numerous antifungal proteins and peptides, including defensins, some of which have been proposed to interact with fungal cell surface glycosphingolipid components. although not known as a phytopathogen, the filamentous fungus neurospora crassa possesses numerous genes similar to those required for plant pathogenesis identified in fungal pathogens (galagan, j. e., et al. 2003. nature 422: 859-868), and it has been used as a model for s ...200515654124
a model for the neurospora circadian clock.circadian clocks are important biological oscillators that generally involve two feedback loops. here, we propose a new model for the neurospora crassa circadian clock. first, we model its main negative feedback loop, including only experimentally well-documented reactions, the transcriptional activation of frequency (frq) by the white-collar complex (wcc), and the post-transcriptional dimerization of frq with wcc. this main loop is sufficient for oscillations and a similar one lies at the core ...200515653726
[a simple method to correct genetic distance between linked genes and a correction of calculating data in tetrad analysis in neurospora crassa].the present paper is dealing with a simple method to correct the distance of linked genes in tetrad analysis in neurospora crassa. it is suggested that the data of 4-thread double crossing over should be added in two single crossing over respectively in centromere maping when calculating crossover value of the two genes locating across the centromere.200315639882
[new approach in the explaining of the morgan law in genetics teaching].using the model of broad and narrow way, the paper introduces a new approach in the explaining of a few basic concepts in the morgan law. the paper introduces a thorough inquiry into the applying condition of the three-factor crosses, and finds the source of the difference between the crossover frequency (f(c)) and recombination frequency (f(r)) of the non-adjacent factors in the three-factor crosses in neurospora crassa.200415626673
copper alone, but not oxidative stress, induces copper-metallothionein gene in neurospora crassa.two metal response elements, flanking an antioxidant response element, were identified in regions upstream (-3730 bp) to copper metallothionein (cumt) gene of neurospora crassa. presence of copper in culture media, but not of pro-oxidants like h2o2 or menadione, induced cumt gene expression that could not be completely abolished by antioxidants such as n-acetyl cysteine and ascorbic acid. gel shift assays revealed the ability of nuclear extracts from copper induced cultures to bind pcr-amplified ...200515621418
mechanism of nickel resistance in a cobalt-resistant wall-less mutant of neurospora crassa (fz; sg; os-1).a cobalt-resistant wall-less mutant of n. crassa (cor-sl) characterized previously was also found to be 3-fold more resistant to nickel when compared to the parent wall-less mutant (w-sl). the cor-sl strain accumulates relatively lower amounts of nickel when compared to w-sl. sub-cellular fractionation showed significant quantities of nickel to be associated with nuclear and mitochondrial fractions in both the wall-less mutants. however significant differences were observed in vacuolar fractions ...200415587120
genomic organization of the neurospora crassa gsn gene: possible involvement of the stre and hse elements in the modulation of transcription during heat shock.glycogen synthase, an enzyme involved in glycogen biosynthesis, is regulated by phosphorylation and by the allosteric ligand glucose-6-phosphate (g6p). in addition, enzyme levels can be regulated by changes in gene expression. we recently cloned a cdna for glycogen synthase ( gsn) from neurospora crassa, and showed that gsn transcription decreased when cells were exposed to heat shock (shifted from 30 degrees c to 45 degrees c). in order to understand the mechanisms that control gsn expression, ...200415558319
the neurospora circadian system.the eukaryotic filamentous fungus neurospora crassa has proven to be a durable and dependable model system for the analysis of the cellular and molecular bases of circadian rhythms. pioneering genetic analyses identified clock genes, and beginning with the cloning of frequency (frq), work over the past 2 decades has revealed the molecular basis of a core circadian clock feedback loop that has illuminated our understanding of circadian oscillators in microbes, plants, and animals. in this transcr ...200415534321
the control of mating type heterokaryon incompatibility by vib-1, a locus involved in het-c heterokaryon incompatibility in neurospora crassa.the mating-type (mat) locus of neurospora crassa has a dual function. it is required for mating during sexual development, but it also mediates heterokaryon incompatibility following hyphal fusion during vegetative growth. previously, it was determined that mutations in vib-1, which encodes a putative transcriptional regulator, suppress het-c heterokaryon incompatibility. this study showed that mutations in vib-1 suppress mat heterokaryon incompatibility in a/a partial diploids; suppression in ( ...200415531211
chitosan as a macroaffinity ligand purification of chitinases by affinity precipitation and aqueous two-phase extractions.(1) chitosan was found to be a suitable macroaffinity ligand for affinity precipitation of chitinase from neurospora crassa, cabbage and puffballs. (2) the activity recoveries of 85, 82 and 90% with concomitant fold purifications in terms of specific activities were 27, 15 and 30 with n. crassa, cabbage and puffballs and were obtained with affinity precipitation. these results were obtained with clarified extracts/homogenates as the starting materials. (3) the incorporation of chitosan in poly(e ...200415527124
time-lapse analysis of the circadian rhythms of conidiation and growth rate in neurospora.the filamentous fungus neurospora crassa has frequently served as a model organism for the study of circadian rhythms through its ability to form conidial spores on a daily basis. this phenomenon leaves a spatial pattern of conidiation bands along a solid surface of agar after several days of growth. using time-lapse video, the authors have quantified the rate of conidiation. they have found that conidia do not form at a specified lag time after the growth front is laid down, but rather the band ...200415523111
role of unc104/kif1-related motor proteins in mitochondrial transport in neurospora crassa.eukaryotic cells use diverse cytoskeleton-dependent machineries to control inheritance and intracellular positioning of mitochondria. in particular, microtubules play a major role in mitochondrial motility in the filamentous fungus neurospora crassa and in mammalian cells. we examined the role of two novel unc104/kif1-related members of the kinesin family, nkin2 and nkin3, in mitochondrial motility in neurospora. the nkin2 protein is required for mitochondrial interactions with microtubules in v ...200515483054
genetic evidence for a regulatory pathway controlling alternative oxidase production in neurospora crassa.when the cytochrome-mediated mitochondrial electron transport chain of neurospora crassa is disrupted, an alternative oxidase encoded by the nuclear aod-1 gene is induced. the alternative oxidase donates electrons directly to oxygen from the ubiquininol pool and is insensitive to chemicals such as antimycin a and kcn that affect the standard electron transport chain. to facilitate isolation of mutants affecting regulation of aod-1, a reporter system containing the region upstream of the aod-1 co ...200515466423
efficient gene silencing by expression of double stranded rna in neurospora crassa.in neurospora crassa, sequence-specific inhibition of endogenous genes can be induced by the introduction of transgenic dna homologous to the target gene, through the mechanism of post-transcriptional gene silencing (ptgs) known as quelling. the application of this strategy to inactivate genes in n. crassa has, to date, been restricted by a limited silencing efficiency and instability of the silenced phenotype. in this study we show that the use of constructs that express hairpin double stranded ...200415465390
[effect of 5-azacytidine on the light-sensitive formation of sexual and asexual reproductive structures in wc-1 and wc-2 mutants of neurospora crassa].under the conditions of nitrogen starvation, illumination by blue light of wc-1 and wc-2 mutants of the ascomycete neurospora crassa failed to stimulate the formation of protoperithecia and inhibit conidiation (contrary to what was observed in the mycelium of the wild-type fungus). the data obtained indicate that wc-1 and wc-2 genes of n. crassa are involved in light-dependent formation of protoperithecia and conidia. the effects of 5-azacytidine (an inhibitor of dna methylation) under the same ...201315455721
characterization of pco-1, a newly identified gene which regulates purine catabolism in neurospora.a new gene of neurospora crassa, designated pco-1, was characterized and shown to regulate the expression of several genes which encode enzymes required for the catabolism of purines. unlike the wild type, a pco-1 mutant created by repeat-induced point mutation cannot utilize purines as a nitrogen source. the pco1 protein contains a zn(ii)2cys6 binuclear cluster motif near its n-terminus, followed by a putative coiled-coil motif. a chemical crosslinking experiment demonstrated that pco1 forms ho ...200415378267
a two variable delay model for the circadian rhythm of neurospora crassa.a two variable model with delay in both the variables, is proposed for the circadian oscillations of protein concentrations in the fungal species neurospora crassa. the dynamical variables chosen are the concentrations of frq and wc-1 proteins. our model is a two variable simplification of the detailed model of smolen et al. (j. neurosci. 21 (2001) 6644) modeling circadian oscillations with interlocking positive and negative feedback loops, containing 23 variables. in our model, as in the case o ...200415363927
unusual cys-tyr covalent bond in a large catalase.catalase-1, one of four catalase activities of neurospora crassa, is associated with non-growing cells and accumulates in asexual spores. it is a large, tetrameric, highly efficient, and durable enzyme that is active even at molar concentrations of hydrogen peroxide. catalase-1 is oxidized at the heme by singlet oxygen without significant effects on enzyme activity. here we present the crystal structure of catalase-1 at 1.75a resolution. compared to structures of other catalases of the large cla ...200415342250
gfp as a tool to analyze the organization, dynamics and function of nuclei and microtubules in neurospora crassa.we report the construction of a versatile gfp expression plasmid and demonstrate its utility in neurospora crassa. to visualize nuclei and microtubules, we generated carboxy-terminal fusions of sgfp to neurospora histone h1 (hh1) and beta-tubulin (bml). strong expression of gfp fusion proteins was achieved with the inducible neurospora ccg-1 promoter. nuclear and microtubule organization and dynamics were observed in live vegetative hyphae, developing asci, and ascospores by conventional and con ...200415341912
rip: the evolutionary cost of genome defense.repeat-induced point mutation (rip) is a homology-based process that mutates repetitive dna and frequently leads to epigenetic silencing of the mutated sequences through dna methylation. consistent with the hypothesis that rip serves to control selfish dna, an analysis of the neurospora crassa genome sequence reveals a complete absence of intact mobile elements. as in most eukaryotes, the centromeric regions of n. crassa are rich in sequences that are related to transposable elements; however, i ...200415313550
rnai-dependent and rnai-independent mechanisms contribute to the silencing of riped sequences in neurospora crassa.rna interference (rnai) can silence genes at the transcriptional level by targeting locus-specific lys9h3 methylation or at the post-transcriptional level by targeting mrna degradation. here we have cloned and sequenced genomic regions methylated in lys9h3 in neurospora crassa to test the requirements for components of the rnai pathway in this modification. we find that 90% of clones map to repeated sequences and relics of transposons that have undergone repeat-induced point mutations (rip). we ...200415302921
key differences between lateral and apical branching in hyphae of neurospora crassa.we examined in fine detail growth kinetics and intracellular events during lateral and apical branching in hyphae of neurospora crassa. by high-resolution video-enhanced light microscopy, we found remarkable differences in the events preceding lateral vs apical branching. while apical branching involved a significant disturbance in the apical growth of the parental hypha, lateral branching occurred without any detectable alterations in the growth of the parental hypha. prior to the emergence of ...200415288020
interaction of mushroom tyrosinase with aromatic amines, o-diamines and o-aminophenols.3-amino-l-tyrosine was found to be a substrate of mushroom tyrosinase, contrary to what had previously been reported in the literature. a series of amino derivatives of benzoic acid were tested as substrates and inhibitors of the enzyme. 3-amino-4-hydroxybenzoic acid, 4-amino-3-hydroxybenzoic acid and 3,4-diaminobenzoic acid were oxidized by this enzyme, as previously reported for neurospora crassa tyrosinase, but 4-aminobenzoic acid and 3-aminobenzoic acid were not. interestingly, 3-amino-4-hyd ...200415279888
photomorphogenesis in the hypogeous fungus tuber borchii: isolation and characterization of tbwc-1, the homologue of the blue-light photoreceptor of neurospora crassa.truffles form a group of plant-symbiotic ascomycetes whose hypogeous life cycle is poorly understood. here we present initial evidence for the influence of light on tuber borchii mycelial growth and the identification and cloning of a gene, tbwc-1, homologous to a blue-light photoreceptor of neurospora crassa. blue-light irradiation of t. borchii colonies inhibits their apical growth. it also alters apical growth in n. crassa. in neurospora, the response is controlled by a nuclear photoreceptor, ...200415275664
a nitrate-induced frq-less oscillator in neurospora crassa.when nitrate is the only nitrogen source, neurospora crassa's nitrate reductase (nr) shows endogenous oscillations in its nitrate reductase activity (nra) on a circadian time scale. these nra oscillations can be observed in darkness or continuous light conditions and also in a frq(9) mutant in which no functional frq protein is formed. even in a white-collar-1 knockout mutant, nra oscillations have been observed, although with a highly reduced amplitude. this indicates that the nra oscillations ...200415245647
the wild-type circadian period of neurospora is encoded in the residual network of the null frq mutants.we model theoretically the response of the widely studied circadian oscillator of neurospora crassa to inactivation of the frq gene. the resulting organism has been termed "arrhythmic" under constant conditions. under entrainment to periodic temperature cycles roenneberg, merrow and coworkers have shown that the phase angle at which spore formation occurs depends on the entrainment period, curiously even in the null frq mutants (frq9 and frq10). we show that such a response does not imply the pr ...200415234207
a pheromone receptor gene, pre-1, is essential for mating type-specific directional growth and fusion of trichogynes and female fertility in neurospora crassa.neurospora crassa is a heterothallic filamentous fungus with two mating types, mat a and mat a. its mating involves differentiation of female reproductive structures (protoperithecia) and chemotropic growth of female-specific hyphae (trichogynes) towards a cell of the opposite mating type in a pheromone-mediated process. in this study, we characterize the pre-1 gene, encoding a predicted g-protein-coupled receptor with sequence similarity to fungal pheromone receptors. pre-1 is most highly expre ...200415186425
properties of unpaired dna required for efficient silencing in neurospora crassa.the presence of unpaired copies of a gene during meiosis triggers silencing of all copies of the gene in the diploid ascus cell of neurospora. this phenomenon is called meiotic silencing and on the basis of genetic studies appears to be a post-transcriptional gene silencing (ptgs) mechanism. previously, meiotic silencing was defined to be induced by the presence of a dna region lacking an identical segment in the homologous chromosome. however, the determinants of unpaired dna remained a mystery ...200415166142
a genetic selection for circadian output pathway mutations in neurospora crassa.in most organisms, circadian oscillators regulate the daily rhythmic expression of clock-controlled genes (ccgs). however, little is known about the pathways between the circadian oscillator(s) and the ccgs. in neurospora crassa, the frq, wc-1, and wc-2 genes encode components of the frq-oscillator. a functional frq-oscillator is required for rhythmic expression of the morning-specific ccg-1 and ccg-2 genes. in frq-null or wc-1 mutant strains, ccg-1 mrna levels fluctuate near peak levels over th ...200415166141
gadolinium effects on gigaseal formation and the adhesive properties of a fungal amoeboid cell, the slime mutant of neurospora crassa.low gadolinium concentrations induce rapid gigaseal formation and cell adhesion to glass and plastic (polystyrene) substrates in the slime mutant of neurospora crassa. cellular adhesion is independent of an integrin-mediated mechanism, because pretreatment with the oligopeptide arg-gly-asp-ser (rgds) did not inhibit it, and there was no spatial correlation between integrin and adhesions. in contrast, concanavalin a and beta-galactosidase both inhibit adhesion, suggesting that adhesion is mediate ...200415138747
the fluffy gene of neurospora crassa is necessary and sufficient to induce conidiophore development.the fl (fluffy) gene of neurospora crassa encodes a binuclear zinc cluster protein that regulates the production of asexual spores called macroconidia. two other genes, acon-2 and acon-3, play major roles in controlling development. fl is induced specifically in differentiating tissue during conidiation and acon-2 plays a role in this induction. we examined the function of fl by manipulating its level of expression in wild-type and developmental mutant strains. increasing expression of fl from a ...200415126394
the rna-dependent rna polymerase, qde-1, is a rate-limiting factor in post-transcriptional gene silencing in neurospora crassa.the rna-dependent rna polymerase (rdrp) qde-1 is an essential component of post-transcriptional gene silencing (ptgs), termed 'quelling' in the fungus neurospora crassa. here we show that the overexpression of qde-1 results in a dramatic increase in the efficiency of quelling, with a concomitant net increase in the quantity of al-1 sirnas. moreover, in overexpressed strains there is a significant reduction in the number of transgenes required to induce quelling, and an increase in the phenotypic ...200415090622
severe impairment of growth and differentiation in a neurospora crassa mutant lacking all heterotrimeric g alpha proteins.heterotrimeric g alpha proteins play a critical role in regulating growth and differentiation in filamentous fungi. no systematic analysis of functional relationships between subunits has been investigated. this study explores the relative contributions of neurospora crassa g alpha subunits, gna-1, gna-2, and gna-3, in directing development by analyzing strains deleted for various combinations of these genes. although viable, mutants lacking all g alpha subunits or gna-1 and gna-3 are severely r ...200415082543
oxygen flux magnitude and location along growing hyphae of neurospora crassa.oxygen fluxes were mapped at the growing apices and along mycelial hyphal segments of the ascomycete neurospora crassa. high spatial resolution was obtained using micro-oxygen probes (2-3 microm tip diameters) and the self-referencing technique to maximize the sensitivity of oxygen flux measurements. as expected, oxygen influx was inhibited by cyanide, although oxygen influx (and hyphal growth) resumed with the induction of an alternate oxidase activity. along hyphal segments, variations in oxyg ...200415043878
photoperiodism in neurospora crassa.plants and animals use day or night length for seasonal control of reproduction and other biological functions. overwhelming evidence suggests that this photoperiodic mechanism relies on a functional circadian system. recent progress has defined how flowering time in plants is regulated by photoperiodic control of output pathways, but the underlying mechanisms of photoperiodism remain to be described. the authors investigate photoperiodism in a genetic model system for circadian rhythms research ...200415038853
entrainment dissociates transcription and translation of a circadian clock gene in neurospora.circadian systems coordinate the daily sequence of events in cells, tissues, and organisms. in constant conditions, the biological clock oscillates with its endogenous period, whereas it is synchronized to the 24 hr light:dark cycle in nature. here, we investigate light entrainment of neurospora crassa to photoperiods that mimic seasonal changes. clock gene (frequency, or frq) rna levels directly reflect the light environment in all photoperiods, whereas the frq protein follows neither rna level ...200415028220
redundancy of the two dicer genes in transgene-induced posttranscriptional gene silencing in neurospora crassa.rna interference (rnai) in animals, cosuppression in plants, and quelling in fungi are homology-dependent gene silencing mechanisms in which the introduction of either double-stranded rna (dsrna) or transgenes induces sequence-specific mrna degradation. these phenomena share a common genetic and mechanistic basis. the accumulation of short interfering rna (sirna) molecules that guide sequence-specific mrna degradation is a common feature in both silencing mechanisms, as is the component of the r ...200414993290
hp1 is essential for dna methylation in neurospora.methylation of cytosines silences transposable elements and selected cellular genes in mammals, plants, and some fungi. recent findings have revealed mechanistic connections between dna methylation and features of specialized condensed chromatin, "heterochromatin." in neurospora crassa, dna methylation depends on trimethylation of lys9 in histone h3 by dim-5. heterochromatin protein hp1 binds methylated lys9 in vitro. we therefore investigated the possibility that a neurospora hp1 homolog reads ...200414967149
comparative sequence analysis of sordaria macrospora and neurospora crassa as a means to improve genome annotation.one of the most challenging parts of large scale sequencing projects is the identification of functional elements encoded in a genome. recently, studies of genomes of up to six different saccharomyces species have demonstrated that a comparative analysis of genome sequences from closely related species is a powerful approach to identify open reading frames and other functional regions within genomes [science 301 (2003) 71, nature 423 (2003) 241]. here, we present a comparison of selected sequenc ...200414761789
the main external alternative nad(p)h dehydrogenase of neurospora crassa mitochondria.a dna sequence homologous to non-proton-pumping nadh dehydrogenase genes was found in the genome of neurospora crassa encoding a polypeptide of 577 amino acid residues, molecular mass of 64,656 da, with a putative transmembrane domain. analysis of fungal mitochondria fractionated with digitonin indicates that the protein is located at the outer face of the inner membrane of the organelle (external enzyme). the corresponding gene was inactivated by the generation of repeat-induced point mutations ...200414741584
a mutation in the neurospora crassa actin gene results in multiple defects in tip growth and branching.actin has a pivotal function in hyphal morphogenesis in filamentous fungi, but it is not certain whether its function is equivalent to that of a morphogen, or if it is simply part of a mechanism that executes orders given by another regulatory entity. to address this question we selected for cytochalasin a resistance and isolated act1, the first actin mutant in neurospora crassa. this mutant branches apically and shows an altered distribution of actin at the tip. based on the properties of this ...200414732267
reduced models of the circadian oscillators in neurospora crassa and drosophila melanogaster illustrate mechanistic similarities.we have developed a reduced model representing feedback loops of transcriptional regulation underlying circadian rhythms in neurospora crassa. the model contains two delay differential equations that describe the dynamics of two core gene products, frq and wcc. in a negative feedback loop, frq protein represses frq transcription by binding the white-collar complex (wcc), which consists of the wc-1 and wc-2 proteins. in a positive feedback loop, wcc indirectly enhances its own formation. the mode ...200314683608
guest, a transposable element belonging to the tc1/mariner superfamily is an ancient invader of neurospora genomes.guest is a transposable element of the tc1/mariner superfamily with 30-40bp terminal inverted repeats and a ta dinucleotide target site duplication. guest was originally discovered in the st. lawrence 74a laboratory strain of the filamentous fungus neurospora crassa. in this report, guest iterations subcloned from a cosmid library of the oakridge 74a strain were used to design pcr primers that permitted the detection of guest in wild isolates of n. crassa. guest is present in n. crassa as multip ...200414643259
extreme nuclear disproportion and constancy of enzyme activity in a heterokaryon of neurospora crassa.heterokaryons of neurospora crassa were generated by transformation of multinucleate conidia of a histidine-3 auxotroph with his-3(+) plasmid. in one of the transformants, propagated on a medium with histidine supplementation, a gradual but drastic reduction occurred in the proportion of prototrophic nuclei that contained an ectopically integrated his-3(+) allele. this response was specific to histidine. the reduction in prototrophic nuclei was confirmed by several criteria: inoculum size test, ...200614631094
reactive oxygen species affect photomorphogenesis in neurospora crassa.in neurospora crassa, several biological phenomena such as the synthesis of carotenoids in the mycelia and polarity of perithecia are regulated by light. we found that a sod-1 mutant, with a defective cu,zn-type superoxide dismutase (sod), showed accelerated light-dependent induction of carotenoid accumulation in the mycelia compared with the wild type. the initial rate of light-induced carotenoid accumulation in the sod-1 mutant was faster than that in the vvd mutant known to accumulate high co ...200414625272
photoreception in neurospora: a tale of two white collar proteins.neurospora crassa is the best-understood fungal organism in terms of the mechanism of light responses. all known neurospora photoresponses are mediated by blue light. two per-arnt-simdomain containing transcription factors, white collar-1 (wc-1) and wc-2, are essential components for almost all light responses. recently, wc-1was shown to be a blue-light photoreceptor. how light affects the dna binding of the wc proteins to the promoter of the circadian clock gene frequency was also demonstrated. ...200314618260
interaction of mutations affecting tip growth and branching in neurospora.there are at least 100 loci encoding products that influence tip growth and branching in neurospora crassa. the functional relationships between 38 of these loci were examined by an analysis of gene interaction in double mutants. a complex range of interactions was revealed. these have been grouped into full and partial epistasis, costasis, novel phenotypes, and synthetic lethality and sublethality. epistasis was used to construct the simplest "pathway" that accommodated the results; this pathwa ...200314599894
analysis of nutrient-dependent transcript variations in neurospora crassa.nutrient-dependent variations in transcript levels of the filamentous fungus neurospora crassa were studied on a microarray containing some 4700 cdnas. cells were grown in minimal and acetate medium. the isolated rna was analyzed in comparison to the results obtained upon the hybridization of samples prepared from the rna of cells grown in full medium. altogether, 160 cdna clones exhibited significant variations, falling into five distinct subgroups of very similar transcription profiles. this i ...200314599890
multiple oscillators regulate circadian gene expression in neurospora.high-density microarrays were used to profile circadian gene expression in neurospora crassa cultures grown in constant darkness. we identified 145 clock-controlled genes (ccgs). the ccgs peaked in mrna accumulation at all phases of the day, with the majority peaking in the late night to early morning. the predicted or known functions of the ccgs demonstrate that the clock contributes to a wide range of cellular processes, including cell signaling, development, metabolism, and stress responses. ...200314597725
identification of a type-d feruloyl esterase from neurospora crassa.feruloyl esterases constitute an interesting group of enzymes that have the potential for use over a broad range of applications in the agri-food industries. in order to expand the range of available enzymes, we have examined the presence of feruoyl esterase genes present in the genome sequence of the filamentous fungus neurospora crassa. we have identified an orphan gene (contig 3.544), the translation of which shows sequence identity with known feruloyl esterases. this gene was cloned and the ...200414595525
the neurospora crassa mus-19 gene is identical to the qde-3 gene, which encodes a recq homologue and is involved in recombination repair and postreplication repair.an allele called mus-19 was identified by screening temperature-sensitive and mutagen-sensitive mutants of neurospora crassa. the mus-19 gene was genetically mapped to a region near the end of the right arm of linkage group i, where a recq homologue called qde-3 had been physically mapped in the neurospora database. complementation tests between the mus-19 mutant and the qde-3(rip) mutant showed that mus-19 and qde-3 were the same gene. the qde-3 genes of both mutants were cloned and sequenced; ...200414595518
silencing of hygromycin phosphotransferase (hph) gene during sexual cycle and its reversible inactivation in heterokaryon of neurospora crassa.we transformed wild-type neurospora crassa with hph gene encoding hygromycin phosphotransferase to obtain hygromycin-resistant (hygr) transformants and studied their behavior in the vegetative and sexual phases of growth. during vegetative growth in the absence of hygromycin, the hph gene was stable for at least three successive transfers with conidia. on the other hand, the behavior of the transformants in the sexual phase was different. the segregation of hph gene in the meiotic progeny was in ...200314570273
isolation and characterization of neurospora crassa mutants resistant to antifungal plant defensins.twenty-five neurospora crassa mutants obtained by chemical mutagenesis were screened for increased resistance to various antifungal plant defensins. plant defensin-resistant n. crassa mutants were further tested for their cross-resistance towards other families of structurally different antimicrobial peptides. two n. crassa mutants, termed mut16 and mut24, displaying resistance towards all plant defensins tested but not to structurally different antimicrobial peptides were selected for further c ...200314516770
nuclear dna degradation during heterokaryon incompatibility in neurospora crassa.many filamentous fungi are capable of undergoing conspecific hyphal fusion with a genetically different individual to form a heterokaryon. however, the viability of such heterokaryons is dependent upon vegetative (heterokaryon) incompatibility (het) loci. if two individuals undergo hyphal anastomosis, but differ in allelic specificity at one or more het loci, the fusion cell is usually compartmentalized and self-destructs. many of the microscopic features associated with vegetative incompatibili ...200314516765
the genetic basis of cellular morphogenesis in the filamentous fungus neurospora crassa.cellular polarity is a fundamental property of every cell. due to their extremely fast growth rate (>/=1 microm/s) and their highly elongated form, filamentous fungi represent a prime example of polarized growth and are an attractive model for the analysis of fundamental mechanisms underlying cellular polarity. to identify the critical components that contribute to polarized growth, we developed a large-scale genetic screen for the isolation of conditional mutants defective in this process in th ...200312960438
calcium gradient dependence of neurospora crassa hyphal growth.a tip-high cytoplasmic calcium gradient has been identified as a requirement for hyphal growth in the fungus neurospora crassa. the ca2+ gradient is less steep compared to wall vesicle, wall incorporation and vesicular ca2+ gradients, but this can be explained by ca2+ diffusion. analysis of the relation between the rate of hyphal growth and the spatial distribution of tip-localized calcium indicates that hyphal growth rates depend upon the tip-localized calcium concentration. it is not the steep ...200312949173
circadian rhythms in neurospora crassa: farnesol or geraniol allow expression of rhythmicity in the otherwise arrhythmic strains frq10, wc-1, and wc-2.in neurospora crassa, the circadian rhythm can be seen in the bd (band) strain as a series of "bands" or conidiation (spore-forming) regions on the surface of an agar medium. certain mutations at 3 different genes (frq, wc-1, or wc-2) lead to the loss of the circadian rhythm. in this study, it was found that the addition of 10(-4) to 10(-5) m of geraniol or farnesol restored rhythmic banding to strains that lack a circadian rhythm due to mutations in any 1 of these 3 genes. these 3 conditionally ...200312932081
a comparison of physical mapping algorithms based on the maximum likelihood model.physical mapping of chromosomes using the maximum likelihood (ml) model is a problem of high computational complexity entailing both discrete optimization to recover the optimal probe order as well as continuous optimization to recover the optimal inter-probe spacings. in this paper, two versions of the genetic algorithm (ga) are proposed, one with heuristic crossover and deterministic replacement and the other with heuristic crossover and stochastic replacement, for the physical mapping problem ...200312874040
genetic analysis of wild-isolated neurospora crassa strains identified as dominant suppressors of repeat-induced point mutation.repeat-induced point mutation (rip) in neurospora results in inactivation of duplicated dna sequences. rip is thought to provide protection against foreign elements such as retrotransposons, only one of which has been found in n. crassa. to examine the role of rip in nature, we have examined seven n. crassa strains, identified among 446 wild isolates scored for dominant suppression of rip. the test system involved a small duplication that targets rip to the easily scorable gene erg-3. we previou ...200312871906
the frequency gene is required for temperature-dependent regulation of many clock-controlled genes in neurospora crassa.the circadian clock of neurospora broadly regulates gene expression and is synchronized with the environment through molecular responses to changes in ambient light and temperature. it is generally understood that light entrainment of the clock depends on a functional circadian oscillator comprising the products of the wc-1 and wc-2 genes as well as those of the frq gene (the frq/wcc oscillator). however, various models have been advanced to explain temperature regulation. in nature, light and t ...200312871904
genome sequencing: the ripping yarn of the frozen genome.the completion of the genome sequence of the filamentous fungus neurospora crassa reveals a gene number very much higher than those of yeasts. of particular interest in this species are the effects of the repeat-induced point mutation (rip) process, which appears to have prevented recent evolution through gene duplication in this lineage.200312867046
putative functions of nucleoside diphosphate kinase in plants and fungi.the putative functions of ndp (nucleoside diaphosphate) kinases from various organisms focusing to fungi and plants are described. the biochemical reactions catalyzed by ndp kinase are as follows. (i) phosphotransferring activity from mainly atp to cognate ndps generating nucleoside triphosphates (ntps). (ii) autophosphorylation activity from atp and gtp. (iii) protein kinase (phosphotransferring) activity phosphorylating such as myelin basic protein. ndp kinase could function to provide ntps as ...200312848342
the neurospora crassa genome opens up the world of filamentous fungi.the filamentous fungus neurospora crassa, which has played an important role in the development of modern genetics, has several unique genome-defense mechanisms, including a process called repeat-induced point mutation. the draft genome sequence has revealed several unusual features, which suggest that the evolution of n. crassa has been greatly influenced by these defense mechanisms.200312801405
analysis of two additional loci in neurospora crassa related to spore killer-2.two new loci found in one strain of neurospora crassa (p2604) collected in malaya are related to the meiotic drive system spore killer sk-2. sk-2 was found in neurospora intermedia and introgressed into n. crassa. p2604 showed high resistance to killing when crossed to sk-2. this resistance was found to be linked to, but not allelic to, resistance locus r(sk-2) on lgiiil. analysis showed that the high resistance phenotype of p2604 requires resistance alleles at two different loci on lgiiir. stra ...200312781673
cobalt-resistance in wall-less mutant (fz; sg; os-1) of neurospora crassa.a cobalt-resistant wall-less mutant (slime) of neurospora crassa was obtained by repeated sub-culturing of the sensitive wall-less mutant (w-sl) on agar medium containing toxic concentrations of cobalt. resistance was stable on culturing cor-sl on cobalt-free medium up to 15 weekly subcultures. cor-sl is 10-fold more resistant to cobalt when compared to w-sl. it is also cross-resistant to cu (10-fold) and ni (3-fold). cobalt accumulated by cor-sl during growth and in short-term uptake experiment ...200312779238
protonation of the neurospora crassa plasma membrane h+-atpase as a function of ph monitored by atr-ftir. 200312763847
synthesis and conformational characterization of peptides related to the neck domain of a fungal kinesin.the y362k mutation in the neck domain of conventional kinesin from neurospora crassa provokes a significant reduction of the rate of movement along microtubules. since the alpha-helical coiled-coil structure of the neck region is implicated in the mechanism of the processive movement of kinesins, a series of peptides related to the heptad region 338-379 of the wild-type and the variant fungal kinesinswere synthesized as monomers and as n-terminal disulfide dimers, crosslinked to favour self-asso ...200312725241
rhythmic binding of a white collar-containing complex to the frequency promoter is inhibited by frequency.the biological clock of neurospora crassa includes interconnected transcriptional and translational feedback loops that cause both the transcript and protein encoded by the frequency gene (frq) to undergo the robust daily oscillations in abundance, which are essential for clock function. to understand better the mechanism generating rhythmic frq transcript, reporter constructs were used to show that the oscillation in frq message is transcriptionally regulated, and a single cis-acting element in ...200312714686
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