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identification of yeast mas17 encoding the functional counterpart of the mitochondrial receptor complex protein mom22 of neurospora crassa.mom22 of neurospora crassa was suggested to be required for the transfer of mitochondrial precursor proteins from the receptors to the protein translocation machinery. we isolated a yeast mutant the viability of which depended on the expression of the introduced n. crassa mom22 gene. the mutant cells showed defects in protein import into mitochondria when the cells were depleted of mom22. by screening for suppressor genes for the mutant, we could identify the yeast gene mas17 encoding the functi ...19957805891
chromium toxicity in neurospora crassa.a comparative study has been made on the mechanisms of toxicities of trivalent and hexavalent forms of chromium in neurospora crassa. of the two forms, cr6+ is more toxic than cr3+. the toxicity of cr3+ was found to be due to its specific antagonism with iron uptake. fe3+ was found to be very effective in reversing the toxicity of cr3+ by concomitantly suppressing its uptake. that the cr3+ toxicity caused a conditional intracellular iron deficiency was indicated by the decrease in the activities ...19947798896
reconstitution of import-competent outer membrane vesicles from mammalian mitochondria.protein insertion into mitochondrial outer membrane (om) vesicles isolated from neurospora crassa has recently been reported. the n. crassa om vesicles retained the features of the intact mitochondria concerning the dependency of insertion on the receptor protein [a. mayer et al. (1993) j. cell biol. 121, 1233-1243]. in this study, om vesicles were purified from bovine adrenal cortex mitochondria, and unilamellar proteoliposomes were reconstituted from om vesicles using heptyl beta-thioglucoside ...19947798173
the hsp70 gene family of neurospora crassa: cloning, sequence analysis, expression, and genetic mapping of the major stress-inducible member.the gene encoding the major heat shock-inducible member of the hsp70 family of neurospora crassa was cloned and characterized. the 5' nontranscribed region shows the presence of consensus sequence motifs resembling the classical heat shock elements found in many heat shock-responsive eukaryotic promoters, as well as metal-responsive-element sequences. the coding region of the gene contains four introns with boundaries and internal consensus motifs typical of genes of filamentous fungi. none of t ...19957798134
reconstitution of the neurospora crassa plasma membrane h(+)-adenosine triphosphatase.the purified h(+)-atpase of the neurospora crassa plasma membrane has been reconstituted by a gel filtration method into lipidic vesicles using sodium deoxycholate as the detergent. reconstitution was performed for lipid/atpase ratios ranging from 1000:1 to 5:1 (w/w). whatever the lipid/atpase ratio, the atpase molecules completely associate with the lipid vesicles. the atpase specific activity is identical for all proteoliposomes regardless of the lipid/atpase ratio, but the h+ transport decrea ...19957794959
laccase component of the ceriporiopsis subvermispora lignin-degrading system.laccase activity in the lignin-degrading fungus ceriporiopsis subvermispora was associated with several proteins in the broth of cultures grown in a defined medium. activity was not increased significantly by adding 2,5-xylidine or supplemental copper to the medium. higher activity, associated with two major isoenzymes, developed in cultures grown on a wheat bran medium. these two isoenzymes were purified to homogeneity. l1 and l2 had isoelectric points of 3.4 and 4.8, molecular masses of 71 and ...19957793921
some property of the nucleus determines the competence of neurospora crassa for transformation.in neurospora, transformation of spheroplasts is quite efficient and usually occurs with the transforming dna integrated at ectopic sites in the chromosome. however, only a small fraction of the spheroplasts is actually competent for transformation. to distinguish whether the limitation to competence is at the level of the plasma membrane or at the level of the nucleus, we performed experiments in which heterocaryotic spheroplasts were required to integrate two different plasmids in one transfor ...19957789759
ectopic integration of transforming dna is rare among neurospora transformants selected for gene replacement.in a variety of organisms, dna-mediated transformation experiments commonly produce transformants with multiple copies of the transforming dna, including both selected and unselected molecules. such "cotransformants" are much more common than expected from the individual transformation frequencies, suggesting that subpopulations of cells, or nuclei, are particularly competent for transformation. we found that neurospora crassa transformants selected for gene replacement at the am gene had not ef ...19957789758
molecular cloning and analysis of nre, the major nitrogen regulatory gene of penicillium chrysogenum.we have isolated the penicillium chrysogenum nre gene which is homologous to the major nitrogen regulatory genes area from aspergillus nidulans and nit-2 from neurospora crassa. overall, nre shows 60% identity to area and 30% identity to nit-2 at the amino-acid level. the gene encodes a protein of 835 amino-acid residues and contains a single cys2/cys2-type zinc finger with an adjacent basic region and a putative acidic activation region. in the dna-binding domain, 98% of the amino-acid residues ...19957788718
redox imbalance at the start of each morphogenetic step of neurospora crassa conidiation.the conidiation process of neurospora crassa is characterized by three morphogenetic steps: hyphal adhesion, aerial hyphal formation, and production of conidia. total protein oxidation and specific enzyme oxidation coincided with an increased oxygen-dependent chemiluminescence and indicated the occurrence of a hyperoxidant state at the onset of all three morphogenetic steps. oxidation of nad(p)h and excretion of glutathione disulfide was detected at the start of hyphae adhesion. here we show tha ...19957786037
isolation and identification of adenosine triphosphoribosyl nicotinamide adenine dinucleotidephosphate from azotobacter vinelandii.a novel type of pyridine nucleotide, containing two adenosine triphosphate ribose residues rather than one, was isolated from azotobacter vinelandii strain o. the nucleotide was shown to be 2"- or 3"-(2'-phosphoadenosine-5'-diphosphoribosyl)nicotinamide adenine dinucleotide phosphate, in which 2'-phospho-5'-diphosphoadenosylribose was glycosidically linked to the nadp at position 2' or 3' of the nicotinamide mononucleotide moiety. the atpribosylnadp did not show coenzyme activity for yeast gluco ...19957775384
a eukaryotic gene encoding an endonuclease that specifically repairs dna damaged by ultraviolet light.many eukaryotic organisms, including humans, remove ultraviolet (uv) damage from their genomes by the nucleotide excision repair pathway, which requires more than 10 separate protein factors. however, no nucleotide excision repair pathway has been found in the filamentous fungus neurospora crassa. we have isolated a new eukaryotic dna repair gene from n.crassa by its ability to complement uv-sensitive escherichia coli cells. the gene is altered in a n.crassa mus-18 mutant and responsible for the ...19957774597
isolation of dihydrofolate and folylpolyglutamate synthetase activities from neurospora.the possible association of dihydrofolate synthetase (dhfs) and folylpolyglutamate synthetase (fpgs) in neurospora crassa (fgsc 853, wild type) has been examined using mycelial extracts prepared and fractionated in the presence of protease inhibitors. dhfs and fpgs were assayed by following the incorporation of labelled glutamate into dihydrofolate and methylenetetrahydrofolate polyglutamate, respectively. both of these activities were predominately cytosolic in mycelia that were harvested 24 hr ...19957772303
isolation and characterization of genes expressed uniquely during appressorium formation by colletotrichum gloeosporioides conidia induced by the host surface wax.appressorium formation in germinating colletotrichum gloeosporioides is induced by the surface wax of the host, the avocado fruit. to elucidate the mechanism by which differentiation of appressorium formation is induced, the fungal genes specifically activated by this host signal were sought. from a cdna library of the transcripts present in appressorium-forming conidia, the clones representing nongerminating conidia were removed by hybridization with cdnas synthesized from the nongerminating co ...19957770033
inactivation of genes encoding subunits of the peripheral and membrane arms of neurospora mitochondrial complex i and effects on enzyme assembly.we have isolated and characterized the nuclear genes encoding the 12.3-kd subunit of the membrane arm and the 29.9-kd subunit of the peripheral arm of complex i from neurospora crassa. the former gene was known to be located in linkage group i and the latter is now assigned to linkage group iv of the fungal genome. the genes were separately transformed into different n. crassa strains and transformants with duplicated dna sequences were isolated. selected transformants were then mated with other ...19957768434
folylpolyglutamate synthesis in neurospora crassa: transformation of polyglutamate-deficient mutants.the methionine auxotrophy of neurospora crassa met-6 and mac mutants is related to an inability to synthesize long-chained folylpolyglutamates. both of these lesions affect folylpolyglutamate synthetase activity, but it is not clear whether these mutations occur in different genes or in functional domains of the same gene. to address this question, copies of the met-6+ gene have been introduced into both mutants using plasmid and cosmid vectors. transformation to prototrophy was achieved in both ...19957766162
development of a new transformant selection system for penicillium chrysogenum: isolation and characterization of the p. chrysogenum acetyl-coenzyme a synthetase gene (faca) and its use as a homologous selection marker.a new transformation system for the filamentous fungus penicillium chrysogenum is described, based on the use of the homologous acetyl-coenzyme a synthetase (faca) gene as a selection marker. acetate-non-utilizing (fac-) strains of p. chrysogenum were obtained by positive selection for spontaneous resistance to fluoroacetate. among these fac mutants putative faca strains were selected for a loss of acetyl-coenzyme a (coa) synthetase activity. the faca gene, coding for the enzyme acetyl-coa synth ...19937765289
identification of three chitin synthase genes in the dimorphic fungal pathogen sporothrix schenckii.degenerate pcr primers were used to amplify a 600-bp conserved gene region for chitin synthases from genomic dna of sporothrix schenckii, a dimorphic fungal pathogen of humans and animals. three chitin synthase gene homologs were amplified as shown by dna sequence analysis and by southern blotting experiments. based on differences among the predicted amino acid sequences of these homologs, each was placed within one of three different chitin synthase classes. phylogenies constructed with the seq ...19947765092
use of aspergillus overproducing mutants, cured for integrated plasmid, to overproduce heterologous proteins.aspergillus niger var. awamori was previously transformed with a vector designed to express a fused glucoamylase-prochymosin gene and bearing the neurospora crassa pyr4 gene as a selectable marker. mutant strains that overproduced the glucoamylase-prochymosin fusion protein were derived from one of the transformants. despite the fact that the expression vector was integrated into the genome of these strains it was possible to obtain strains from which the vector sequences had been removed. this ...19937764120
disruption of the gene for hsp30, an alpha-crystallin-related heat shock protein of neurospora crassa, causes defects in thermotolerance.the alpha-crystallin-related heat shock proteins are produced by all eukaryotes, but the role of these proteins in thermoprotection remains unclear. to investigate the function of one of these proteins, we disrupted expression of the single-copy hsp30 gene of neurospora crassa, using repeat-induced point mutagenesis, and we generated and characterized mutant strains that were deficient in hsp30 synthesis. these strains could grow at high temperature and they acquired thermotolerance from a heat ...19957761443
translocation of apocytochrome c across the outer membrane of mitochondria.apocytochrome c follows a unique pathway into mitochondria. import does not require the general protein translocation machinery, protease-sensitive components of the outer membrane, or a membrane potential across the inner membrane. we investigated the membrane binding and translocation steps of the import reaction using purified outer membrane vesicles (omv) from neurospora crassa mitochondria. omv specifically bound, but did not import apocytochrome c. if, however, specific antibodies were enc ...19957759479
cloning and identification of arp1, an actin-related protein from pneumocystis carinii.the complete pneumocystis carinii arp1 gene has been sequenced from two cdna clones. the gene encodes a protein 385 bp in length with an estimated size of 45,000 kd. the a + t% for the arp1 gene and a 900-bp sequence upstream of the gene were 63.7% and 70.3%, respectively. these values are consistent with a + t codon preference displayed by p. carinii and are similar to values reported for other p. carinii genes. the predicted amino acid sequence of the p. carinii arp1 protein had a similarity o ...19957757056
light induction of the clock-controlled gene ccg-1 is not transduced through the circadian clock in neurospora crassa.ambient light and the circadian clock have been shown to be capable of acting either independently or in an interrelated fashion to regulate the expression of conidiation in the ascomycete fungus neurospora crassa. recently several molecular correlates of the circadian clock have been identified in the form of the morning-specific clock-controlled genes ccg-1 and ccg-2. in this paper we report studies on the regulation of ccg-1, an abundantly expressed gene displaying complex regulation. consist ...19957753024
developmental and photoregulation of al-1 and al-2, structural genes for two enzymes essential for carotenoid biosynthesis in neurospora.the levels of al-1 and al-2 transcripts change dramatically in response to light and development during the formation of neurospora crassa asexual spores (conidia). al-1 and al-2 mrnas accumulate throughout conidiation irrespective of lighting conditions initially at low levels. as conidiation proceeds, two increases in albino message accumulation are observed. this developmentally induced photoindependent message accumulation was not observed in neurospora mutants blocked at relevant stages of ...19957750660
development of primer sets designed for use with the pcr to amplify conserved genes from filamentous ascomycetes.we constructed nine sets of oligonucleotide primers on the basis of the results of dna hybridization of cloned genes from neurospora crassa and aspergillus nidulans to the genomes of select filamentous ascomycetes and deuteromycetes (with filamentous ascomycete affiliations). nine sets of primers were designed to amplify segments of dna that span one or more introns in conserved genes. pcr dna amplification with the nine primer sets with genomic dna from ascomycetes, deuteromycetes, basidiomycet ...19957747954
cloning and expression of cdna encoding a protein that binds a palindromic promoter element essential for induction of fungal cutinase by plant cutin.previous studies showed that a palindromic sequence located at -159 base pairs is essential for induction of cutinase gene in fusarium solani f. sp. pisi (nectria haematococca mating type vi) by the hydroxy fatty acids from plant cutin and that a 50-kda nuclear protein binds to a promoter that contains this element. screening of a phage lambda gt11 expression library with the concatenated palindromic sequence as the probe identified a cdna encoding a palindrome-binding protein (pbp). nucleotide ...19957744822
2-d structure of the neurospora crassa plasma membrane atpase as determined by electron cryomicroscopy.large, well-ordered 2-d crystals of the dodecylmaltoside complex of the neurospora crassa plasma membrane h(+)-atpase grow rapidly on the surface of a polyethylene glycol-containing mixture similar to that originally developed for growing 3-d crystals of this integral membrane transport protein. negative stain electron microscopy of the crystals shows that many are single layers. cryoelectron microscopy of unstained specimens indicates that the crystals have a p6 layer group with unit cell dimen ...19957743992
comparison of the mutagenicity and mutagen specificity of ethylenimine with triethylenemelamine in the ad-3 region of heterokaryon 12 of neurospora crassa.studies have been performed to compare the mutagenicity and mutagenic specificity of the trifunctional alkylating agent, triethylenemelamine (tem), and a closely related monofunctional agent, ethylenimine (ei), in the adenine-3 (ad-3) region of a 2-component heterokaryon (h-12) of neurospora crassa. the primary objective of our studies was to characterize the genetic damage produced by each agent with regard to (1) mutagenic potency, and (2) the spectrum of specific-locus mutations induced in a ...19957739603
cyclophilin 20 is involved in mitochondrial protein folding in cooperation with molecular chaperones hsp70 and hsp60.we studied the role of mitochondrial cyclophilin 20 (cyp20), a peptidyl-prolyl cis-trans isomerase, in preprotein translocation across the mitochondrial membranes and protein folding inside the organelle. the inhibitory drug cyclosporin a did not impair membrane translocation of preproteins, but it delayed the folding of an imported protein in wild-type mitochondria. similarly, neurospora crassa mitochondria lacking cyp20 efficiently imported preproteins into the matrix, but folding of an import ...19957739545
limitations to in vivo import of hydrophobic proteins into yeast mitochondria. the case of a cytoplasmically synthesized apocytochrome b.the apocytochrome b gene, exclusively encoded by the mitochondrial genome, was engineered so that it could be expressed in the yeast cytoplasm. different combinations of the apocytochrome b transmembrane domains were produced in the form of hybrid proteins fused to both the n-terminal mitochondrial targeting sequence of the atpase subunit 9 from neurospora crassa and to a cytoplasmic version of the bi4 rna maturase, localised on the n-terminal and c-terminal sides, respectively, of the hydrophob ...19957737175
a kluyveromyces lactis gene homologue to aac2 complements the saccaromyces cerevisiae op1 mutation.a mutation (op1) in the saccharomyces cerevisiae aac2 gene, which codes for the most abundant adp/atp carrier isoform, results in lack of mitochondrial-dependent growth and in an as yet unexplained petite-negative phenotype. a gene from the petite-negative yeast kluyveromyces lactis has been isolated by complementing in multicopy the op1 mutation of s. cerevisiae. this gene, designated kiaac, can complement the petite-negative phenotype of op1 as well as its inability to grow on nonfermentable c ...19957736606
purification of arginase from aspergillus nidulans.arginase (ec 3.5.3.1) of aspergillus nidulans, the enzyme which enables the fungus to use arginine as the sole nitrogen source was purified to homogeneity. molecular mass of the purified arginase subunit is 40 kda and is similar to that reported for the neurospora crassa (38.3 kda) and saccharomyces cerevisiae (39 kda) enzymes. the native molecular mass of arginase is 125 kda. the subunit/native molecular mass ratio suggests a trimeric form of the protein. the arginase protein was cleaved and pa ...19947732765
repressible cation-phosphate symporters in neurospora crassa.the filamentous fungus neurospora crassa possesses two nonhomologous high-affinity phosphate permeases, pho-4 and pho-5. we have isolated separate null mutants of these permeases, allowing us to study the remaining active transporter in vivo in terms of phosphate uptake and sensitivity to inhibitors. the specificity for the cotransported cation differs for pho-4 and pho-5, suggesting that these permeases employ different mechanisms for phosphate translocation. phosphate uptake by pho-4 is stimul ...19957732001
analysis of cys3 regulator function in neurospora crassa by modification of leucine zipper dimerization specificity.the cys3 positive regulator is a basic region-leucine zipper (bzip) dna-binding protein that is essential for the expression of sulfur-controlled structural genes in neurospora crassa. an approach of modifying the dimerization specificity of the cys3 leucine zipper was used to determine whether the in vivo regulatory function of cys3 requires the formation of homodimeric or heterodimeric complexes. two altered versions of cys3 with coiled coil elecrostatic interactions favorable to heterodimeriz ...19957731792
yeast phylogenetic relationships based on cytochrome c sequences.the availability of the kicyc1 sequence was used to establish homologies with other cytochrome c genes from yeasts and the fungus neurospora crassa. in terms of nucleotide composition, the cytochrome c gene from kluyveromyces lactis showed a higher homology with schwanniomyces occidentalis than with saccharomyces cerevisiae, and this point is discussed in regard to the differences found in the codon usage of these yeasts. the deduced amino acidic composition of the protein facilitated comparison ...19957731389
the sulfur controller-2 negative regulatory gene of neurospora crassa encodes a protein with beta-transducin repeats.the sulfur regulatory system of neurospora crassa is composed of a set of structural genes involved in sulfur catabolism controlled by a genetically defined set of trans-acting regulatory genes. these sulfur regulatory genes include cys-3+, which encodes a basic region-leucine zipper transcriptional activator, and the negative regulatory gene scon-2+. we report here that the scon-2+ gene encodes a polypeptide of 650 amino acids belonging to the expanding beta-transducin family of eukaryotic regu ...19957724564
'sheltered disruption' of neurospora crassa mom22, an essential component of the mitochondrial protein import complex.mom22 is a component of the protein import complex of the mitochondrial outer membrane of neurospora crassa. using the newly developed procedure of 'sheltered disruption', we created a heterokaryotic strain harboring two nuclei, one with a null allele of the mom-22 gene and the other with a wild-type allele. homokaryons bearing the mom-22 disruption could not be isolated, suggesting that mom-22 is an essential gene. the mutant nucleus can be forced to predominate in the heterokaryon through the ...19957720701
molecular cloning, sequencing and sequence analysis of the fox-2 gene of neurospora crassa encoding the multifunctional beta-oxidation protein.we present the molecular cloning and sequencing of genomic and cdna clones of the fox-2 gene of neurospora crassa, encoding the multifunctional beta-oxidation protein (mfp). the coding region of the fox-2 gene is interrupted by three introns, one of which appears to be inefficiently spliced out. the encoded protein comprises 894 amino acid residues and exhibits 45% and 47% sequence identity with the mfps of candida tropicalis and saccharomyces cerevisiae, respectively. sequence analysis identifi ...19957715608
guest: a 98 bp inverted repeat transposable element in neurospora crassa.the region immediately 3' of histidine-3 has been cloned and sequenced from two laboratory strains of the ascomycete fungus neurospora crassa; st lawrence 74a and lindegren, which have different derivations from wild collections. amongst the differences distinguishing these sequences are insertions ranging in size from 20 to 101 bp present only in st lawrence. the largest of these is flanked by a 3 bp direct repeat, has terminal inverted repeats (tir) and shares features with several known trans ...19957715596
spontaneous mutation during the sexual cycle of neurospora crassa.the dna sequences of 42 spontaneous mutations of the mtr gene in neurospora crassa have been determined. the mutants were selected among sexual spores to represent mutations arising in the sexual cycle. three sexual-cycle-specific mutational classes are described: hotspot mutants, spontaneous repeat-induced point mutation (rips) and mutations occurring during a mutagenic phase of the sexual cycle. together, these three sexual-cycle-specific mutational classes account for 50% of the mutations in ...19957705619
zero-current potentials in a large membrane channel: a simple theory accounts for complex behavior.flow of ions through large channels is complex because both cations and anions can penetrate and multiple ions can be in the channel at the same time. a modification of the fixed-charge membrane theory of teorell was reported (peng, s., e. blachly-dyson, m. forte, and m. colombini. 1992. biophys. j. 62:123-135) in which the channel is divided into two compartments: a relatively charged cylindrical shell of solution adjacent to the wall of the pore and a relatively neutral central cylinder of sol ...19937694668
mei-3, a recombination and repair gene of neurospora crassa, encodes a reca-like protein.neurospora crassa mei-3 is a mutant which exhibits meiotic and mitotic defects and mutagen sensitivity. its defect is believed to be in recombination and repair. we have cloned the mei-3 gene from a n. crassa cosmid library of genomic dna. restriction fragment length polymorphism analysis determined the location of the cloned fragment was on chromosome one in approximately the same position that was previously reported for mei-3 by classical genetic methods. deletion analysis showed the approxim ...19937692262
nucleotide sequence of the large mitochondrial rrna gene of penicillium chrysogenum.the nucleotide sequence of a large rrna (1-rrna) gene and its flanking regions in the cloned fragments of mitochondrial (mt) dna from penicillium chrysogenum nrrl1951 (sekiguchi j., ohsaki, t., yamamoto, h., koichi, k. and shida, t. (1990) j. gen. microbiol. 136, 535-543) was determined and compared with those in aspergillus nidulans and neurospora crassa mitochondrial dnas. the p. chrysogenum mt 1-rrna gene has a 1678 bp intron which intervenes between a 2835 bp 5' exon and a 581 bp 3' exon, an ...19937680578
fk506-binding protein of neurospora crassa (ncfkbp) mediates sensitivity to the immunosuppressant fk506; resistant mutants identify two loci.growth of neurospora crassa wild-type is inhibited by micromolar concentrations of the immunosuppressive macrolide fk506. spontaneous and induced mutations that confer resistance to fk506 identified two loci, fkr-1 and fkr-2. they map on the right arm of linkage group v on either side of inl with fkr-1 being centromere proximal. allele fb (fkr-2) lacks immunodetectable n. crassa fk506-binding protein (ncfkbp). this demonstrates that the sensitivity of n. crassa towards fk506 is mediated by ncfkb ...19937679056
comparison of the spectra of genetic damage in n4-hydroxycytidine-induced ad-3 mutations between nucleotide excision repair-proficient and -deficient heterokaryons of neurospora crassa.a comparison has been made of the mutagenic effects of n4-hydroxycytidine (hc) in the adenine-3 (ad-3) region of two-component heterokaryons of neurospora crassa: nucleotide excision repair-proficient (uvs-2+/uvs-2+) heterokaryon 12 (h-12) and nucleotide excision repair-deficient (uvs-2/uvs-2) heterokaryon 59 (h-59). hc was found to produce mutations predominantly, if not exclusively, by at to gc base-pair transitions in escherichia coli strain k12 by janion and glickman (1980, mutation res., 72 ...19937678887
characterization of sfp2, a putative sulfate permease gene of saccharomyces cerevisiae.the sfp2 gene of saccharomyces cerevisiae has been characterized. the deduced amino acid sequence contained twelve highly hydrophobic domains and showed 50, 47, 44 and 48% homologies to neurospora crassa sulfate permease ii (cys14), soybean gmak170 nodulin, human colon mucosa protein (dra) and a putative open reading frame (orf) downstream of escherichia coli prs (phosphoribosyl pyrophosphatate synthetase) gene, respectively, in the aligned regions. cells lacking sfp2 were viable and displayed n ...19957677785
purification and characterization of mitochondrial processing peptidase of neurospora crassa. 19957674958
cloning and expression of human deoxyhypusine synthase cdna. structure-function studies with the recombinant enzyme and mutant proteins.deoxyhypusine synthase catalyzes the first step in the post-translational formation of hypusine (n epsilon-(4-amino-2-hydroxybutyl)lysine). cdna clones encoding deoxyhypusine synthase were isolated from a human hela cell library. full-length cdna clones encoding a 369-amino acid protein (calculated molecular mass of 40,970 da) and a shorter cdna clone that would potentially encode a protein with an internal deletion of 56 amino acids (asp262-ser317) were isolated. the deduced amino acid sequence ...19957673224
three-to-one segregation from reciprocal translocation quadrivalents in neurospora and its bearing on the interpretation of spore-abortion patterns in unordered asci.in neurospora, viable ascospores become black (b) when mature, whereas ascospores that are deficient for a chromosome segment are inviable and usually fail to blacken. the presence of a chromosome rearrangement can be recognized and the type of rearrangement can usually be inferred by visual inspection of asci. when a cross is heterozygous for a reciprocal translocation, asci with eight black ascospores (8b:0w) and asci with eight abortive unpigmented ("white" (w)) ascospores (0b:8w) are theoret ...19957672602
genetic nomenclature guide. neurospora crassa. 19957660461
cloning and characterization of a heterologously expressed bifunctional chorismate synthase/flavin reductase from neurospora crassa.activities of all chorismate synthases (cs) so far analyzed are absolutely dependent upon reduced flavin. for monofunctional css, which represent the only class of css that have yet been cloned, the flavin must be reduced either (photo-)chemically or by a separable flavin reductase (fr) for in vitro activity. neurospora crassa cs, in contrast, possesses an intrinsic fr activity and represents the only firmly established member of a bifunctional class of css. to better understand this bifunctiona ...19957657620
the effects of temperature change on the circadian clock of neurospora.the phase resetting of the circadian oscillatory system by pulses of increased temperature (zeitgebers) and the temperature compensation of its period length during longer exposures are major features of the system, but are not well understood in molecular terms. in neurospora crassa, the effects of pulses of increased temperature on the circadian rhythm of conidiation were determined and possible inputs to the oscillatory system tested, including changes in cyclic 3',5'-adenosine monophosphate ...19957656690
the fusarium solani gene encoding kievitone hydratase, a secreted enzyme that catalyzes detoxification of a bean phytoalexin.among the antimicrobial phytoalexins produced by phaseolus vulgaris (french bean) is the prenylated isoflavonoid, kievitone. the bean pathogen, fusarium solani f. sp. phaseoli, secretes a glycoenzyme, kievitone hydratase (ec 4.2.1.95), which catalyzes conversion of kievitone to a less toxic metabolite. among f. solani strains, those that are highly virulent to p. vulgaris also produce kievitone hydratase constitutively, suggesting that the enzyme is a virulence factor. based on the n-terminal am ...19957655061
the aspergillus uvsh gene encodes a product homologous to yeast rad18 and neurospora uvs-2.the uvsh dna repair gene of aspergillus nidulans has been cloned by complementation of the uvsh77 mutation with a cosmid library containing genomic dna inserts from a wild-type strain. methylmethane sulfonate (mms)-resistant transformants were obtained on medium containing 0.01% mms, to which uvsh mutants exhibit high sensitivity. retransformation of uvsh77 mutants with the rescued cosmids from the mms-resistant transformants resulted in restoration of both uv and mms resistance to wild-type lev ...19957651340
the cpc-2 gene of neurospora crassa encodes a protein entirely composed of wd-repeat segments that is involved in general amino acid control and female fertility.phenotypic and molecular studies of the mutation u142 indicate that the cpc-2+ gene is required to activate general amino acid control under conditions of amino acid limitation in the vegetative growth phase, and for formation of protoperithecia in preparation for the sexual phase of the life cycle of neurospora crassa. the cpc-2 gene was cloned by complementation of the cpc-2 mutation in a his-2ts bradytrophic background. genomic and cdna sequence analysis indicated a 1636 bp long open reading ...19957651339
characterization of the promoter region of a cell-adhesion protein gene derived from the basidiomycete lentinus edodes.an analysis of the 2 kb nucleotide sequence including the 5'-flanking region of a cell-adhesion protein-encoding gene (mfba) isolated from the basidiomycete lentinus edodes revealed that the promoter region contains a tata box, a gc box, a caat box, a ct-rich sequence element, a tata box, two ct-rich sequences, and a caat box, in the order, from upstream to downstream. three major and three alternative transcriptional initiation sites were located 127, 129 and 131 nucleotides and 96, 193 and 197 ...19957649440
light and development regulate the expression of the albino-3 gene in neurospora crassa.the albino-3 gene of neurospora crassa codes for geranylgeranyl pyrophosphate synthase, an enzyme involved in the biosynthesis of carotenoids. the albino-3 locus encodes two overlapping transcription units that give rise to two mrnas of 2.2 kb (al-3(c)) and 1>6 kb (al-3(m)), with the promoter of the latter residing in the transcribed region of the former. the 1.6-kb transcript was transiently expressed in the mycelium after light induction, while the 2.2-kb mrna appeared in conidiating cultures ...19957649389
the cellulase complex of neurospora crassa: cbh-1 cloning, sequencing and homologies.we describe the isolation, cloning and sequencing of the cellobiohydrolase 1 (ec 3.2.1.91)-encoding gene (cbh-1) of neurospora crassa. the nucleotide and amino-acid sequences have high homology with the cbh-1 of trichoderma reesei, humicola grisea and phanerochaete chrysosporium, with clear signal, catalytic, hinge and substrate-binding domains in that order.19957642129
purification, n-terminal amino acid sequence and partial characterization of a cu,zn superoxide dismutase from the pathogenic fungus aspergillus fumigatus.a superoxide dismutase (sod) has been purified to homogeneity from the fungal pathogen aspergillus fumigatus using a combination of cell homogenization, isoelectric focusing and gel filtration fplc. the n-terminal amino acid sequence of the purified enzyme demonstrated substantial homology to known cu,zn superoxide dismutases for a range of organisms, including neurospora crassa and saccharomyces cerevisiae. the enzyme subunit has a pi of 5.9, a relative molecular mass of 19 kda and a spectral a ...19957633574
isolation of a functional homolog of the cell cycle-specific nima protein kinase of aspergillus nidulans and functional analysis of conserved residues.to investigate the degree of conservation of the cell cycle-specific nima protein kinase of aspergillus nidulans, and to help direct its functional analysis, we cloned a homolog (designated nim-1) from neurospora crassa. over the catalytic domain nim-1 is 75% identical to nima, but overall the identity drops to 52%. nim-1 was able to functionally complement nima5 in a. nidulans. mutational analysis of potential activating phosphorylation sites found in nima, nim-1, and related protein kinases wa ...19957629122
fourier transform infrared spectroscopy study of the secondary structure of the reconstituted neurospora crassa plasma membrane h(+)-atpase and of its membrane-associated proteolytic peptides.we reconstituted purified plasma membrane h(+)-atpase from neurospora crassa into soybean phospholipid vesicles (lipid/atpase ratio of 5:1 w/w). the proteoliposomes contained an active atpase, oriented inside-out. they were subjected to proteolysis by using pronase, proteinase k, trypsin, and carboxypeptidase y. fourier transform infrared attenuated total reflection spectroscopy indicates that the amount of protein remaining after hydrolysis and elimination of the extramembrane domain of atpase ...19957629067
conservative sorting of f0-atpase subunit 9: export from matrix requires delta ph across inner membrane and matrix atp.in an attempt to understand the mechanisms of sorting of mitochondrial inner membrane proteins, we have analyzed the import of subunit 9 of the mitochondrial f1f0-atpase (su9) from neurospora crassa, an integral inner membrane protein. a chimeric protein was used consisting of the presequence and the first transmembrane domain of su9 fused to mouse dihydrofolate reductase (presu9(1-112)-dhfr). this protein attains the correct topology across the inner membrane (nout-cin) following import. the tr ...19957628445
isolation of the vma-4 gene encoding the 26 kda subunit of the neurospora crassa vacuolar atpase.we have isolated the vma-4 gene, which encodes a 25,746 dalton subunit of the vacuolar atpase, from neurospora crassa. the gene contains two introns and was mapped to the left arm of linkage group i. comparison of the predicted amino acid sequence with homologous proteins from saccharomyces cerevisiae, manduca sexta, and bos taurus showed only 25% sequence identity. however, computer-assisted predictions of secondary structures gave similar results for all four proteins. analysis of the sequence ...19957619848
[cyclic nucleotides and membrane electrogenesis in cell differentiation in neurospora crassa].significance of membrane electrogenic system and cyclic nucleotides for developmental regulation in lower eukaryotes was studied in neurospora crassa. despite of their morphological uniformity, hyphal cells were differentiated by their electrophysiological parameters--membrane potential and input resistance. the cells maintained regulated electric communication through septal pores. such electric communication allowed the apical "cell" to compensate the energy requirements for membrane transport ...20137618293
nuclear dna-binding proteins which recognize the intergenic control region of penicillin biosynthetic genes.the biosynthesis of penicillin, a secondary metabolite produced by penicillium chrysogenum, is subject to sophisticated genetic and metabolic regulation. the structural genes, pcbc and pcbab, which encode two of the penicillin biosynthetic enzymes are separated by a 1.16-kb intergenic region and transcribed divergently from one another. to identify and characterize nuclear proteins which interact with the pcbab-pcbc intergenic promoter region, crude and partially purified nuclear extracts were u ...19957614558
disruption of the gene encoding the 78-kilodalton subunit of the peripheral arm of complex i in neurospora crassa by repeat induced point mutation (rip).we have used the procedure of sheltered rip to generate mutants of the 78-kda protein of the peripheral arm of neurospora crassa complex i. the nuclei containing the mutations were initially isolated as one component of a heterokaryon but subsequent analysis showed that nuclei containing null alleles of the gene could be propagated as homokaryons. this demonstrates that the gene does not serve an essential function. sequence analysis of one allele shows that 61 transition mutations were created ...19957614557
solubilization of neurospora crassa rodlet proteins and identification of the predominant protein as the proteolytically processed eas (ccg-2) gene product.proteins from conidial rodlet preparations of neurospora crassa were solubilized in trifluoroacetic acid. sodium dodecyl sulfate-polyacrylamide gel electrophoresis of solubilized rodlets revealed a predominant protein of approximately 7 kda. this protein was absent from preparations of n. crassa cultures carrying the eas mutation. the protein was purified by reverse-phase high-performance liquid chromatography and the n-terminal amino acid sequence of the purified protein was found to be identic ...19957614378
resistance to azole drugs in neurospora crassa.neurospora crassa was susceptible to azole drugs: ketoconazole (mic 1 microgram/ml), fluconazole (mic 5 micrograms/ml), and sch39304 (mic 5 micrograms/ml). mutants of n. crassa resistant to ketoconazole were selected and genetically characterized. the seven characterized resistance mutations represented at least four genetic loci. some mutants, but not all, were also resistant to fluconazole and to sch39304.19957614377
(1,3)-beta-d-glucan synthase activity in mycelial and cell wall-less phenotypes of the fz, sg, os-1 ("slime") mutant strain of neurospora crassa.the cell wall-less fz, sg, os-1 ("slime") triple mutant of neurospora crassa lacks (1,3)-beta-d-glucan synthase activity. fz, sg, os-1 segregants from slime x wild-type crosses initially germinate as a plasmodium (slime-like), but develop hyphae in a few hours and acquire a stable mycelial phenotype (mycelial intermediate). the cell wall-less phenotype (stable slime) can be reisolated from mycelial intermediates by filtration-enrichment selection in medium of high osmolarity. pairs of mycelial i ...19957614368
the negative-acting nmr regulatory protein of neurospora crassa binds to and inhibits the dna-binding activity of the positive-acting nitrogen regulatory protein nit2.structural genes of the nitrogen regulatory circuit of the filamentous fungus neurospora crassa are under the control of both positive and negative regulatory proteins. nit2, the major positive-acting nitrogen regulatory protein, activates the expression of structural genes within the nitrogen circuit. nit2 binds to upstream activation sites which contain at least two gata core elements in the promoter regions of the nitrogen-controlled structural genes, and activates their transcription, possib ...19957612627
[analysis of light signal transmission through the phosphorylation of proteins in neurospora crassa]. 19957610259
cloning, nucleotide sequence, and expression of tef-1, the gene encoding translation elongation factor 1 alpha (ef-1 alpha) of neurospora crassa.the tef-1 gene encoding translation elongation factor 1 alpha was cloned from the ascomycete fungus neurospora crassa. the sequences of genomic dna and cdna clones showed that the tef-1 gene contained one orf of 1380 bp length that is interrupted by three short introns. the deduced polypeptide contained 460 amino acid residues, and the sequence had a high similarity with those of ef-1 alpha polypeptides from other species. the level of tef-1 mrna was low in conidia but high in growing cells. whe ...19957605676
a chimeric light-regulated amino acid transport system allows the isolation of blue light regulator (blr) mutants of neurospora crassa.we have developed a system for the isolation of neurospora crassa mutants that shows altered responses to blue light. to this end we have used the light-regulated promoter of the albino-3 gene fused to the neutral amino acid permease gene mtr. the product of the mtr gene is required for the uptake of neutral aliphatic and aromatic amino acids, as well as toxic analogs such as p-flurophenylalanine or 4-methyltryptophan. mtr trp-2-carrying cells were transformed with the al-3 promoter-mtr wild-typ ...19957604041
a fungal actin-related protein involved in nuclear migration.the ro-4 mutant of the filamentous fungus neurospora crassa forms distinctive colonies in which hyphae grow into rope-like aggregates. this unusual morphology coincides with a defect in hyphal nuclear migration. the ro-4 gene was cloned from a cosmid library by complementation of the closely linked pab-2 gene. the deduced 380 amino acid protein is most similar to the vertebrate actin-related protein/centractin. the ro4 protein is not essential for cell viability, and new strains created by induc ...19957603438
analysis of the iron-sulfur clusters within the complex i (nadh:ubiquinone oxidoreductase) isolated from potato tuber mitochondria.the mitochondrial complex i (nadh:ubiquinone oxidoreductase) isolated from potato (solanum tuberosum) has been investigated for the presence of iron-sulfur clusters. epr spectroscopic analysis detected signals arising from clusters n1, n2, n3 and n4. quantitation of the content of iron and sulfur within the isolated complex i showed the preparation to contain 22.6 mol acid-labile sulfide and 30.4 mol iron/mol complex i. the iron-sulfur cluster composition of the plant complex i appears to be sim ...19957601133
assembly of the preprotein receptor mom72/mas70 into the protein import complex of the outer membrane of mitochondria.membrane integration and assembly of mom72 from neurospora crassa and its yeast homolog mas70 was studied with isolated mitochondria. after synthesis in vitro, the precursors of mom72/mas70 are tightly folded and expose only their n-terminal amino acid residues comprising the targeting and the membrane anchor domain. insertion of the protein into the mitochondrial outer membrane (mom) occurs in a time- and temperature-dependent manner and is stimulated by atp. mom72/mas70 is then assembled into ...19957592965
molecular cloning and functional expression of neurospora deoxyhypusine synthase cdna and identification of yeast deoxyhypusine synthase cdna.deoxyhypusine synthase catalyzes the formation of deoxyhypusine residue on the eif-5a precursor using spermidine as the substrate. we have purified deoxyhypusine synthase from neurospora crassa to apparent homogeneity (tao, y., and chen, k. y. (1995) j. biol. chem. 270, 383-386). we have now cloned and characterized the deoxyhypusine synthase cdna using a reverse genetic approach. conceptual translation of the nucleotide sequence of the cloned 1258-base pair cdna revealed an open reading frame c ...19957592594
nucleotide sequence and characterization of the large mitochondrial rrna gene of penicillium urticae, and its comparison with those of other filamentous fungi.the nucleotide sequence of a large rrna gene and its flanking regions in cloned fragments of mitochondrial dna from a patulin producer, penicillium urticae nrrl2159a, was determined by dideoxy sequencing, and the 5' end and intron-exon border of the 1-rrna gene were determined by primer extension analysis and rna sequencing, respectively. in addition to the extensive sequence homology of the 3' end of the p. urticae mt 1-rrna gene with those of aspergillus nidulans and neurospora crassa, the p. ...19957592555
binding affinity and functional significance of nit2 and nit4 binding sites in the promoter of the highly regulated nit-3 gene, which encodes nitrate reductase in neurospora crassa.in the filamentous fungus neurospora crassa, both the global-acting regulatory protein nit2 and the pathway-specific regulatory protein nit4 are required to turn on the expression of the nit-3 gene, which encodes nitrate reductase, the first enzyme in the nitrate assimilatory pathway. three nit2 binding sites and two nit4 binding sites have been identified in the 1.3-kb nit-3 promoter region via mobility shift and footprinting experiments with nit2-beta-galactosidase and nit4-beta-gactosidase fu ...19957592372
design of an object-oriented database for reverse genetics.we present the design of an object-oriented database system for reverse genetics applications. such a database will encapsulate not only the data in the genetic and physical maps, but also the methods used to create the maps as well as methods to link them to other databases, such as genbank, pir, and medline. the purpose of this database is to provide the fungal genetics community with an electronic tool for identifying the biochemical function of any dna fragment in the database--electronic re ...19937584341
immunological evidence for accumulation of two high-molecular-weight (104 and 90 kda) hsps in response to different stresses in rice and in response to high temperature stress in diverse plant genera.rice seedlings accumulate stainable amounts of the 104 and 90 kda polypeptides in response to high temperature stress. we have purified and raised highly specific polyclonal antisera against both of these polypeptides. in western blotting experiments, we find that these proteins are accumulated to different extents in rice seedlings subjected to salinity (nacl), water stress, low-temperature stress and exogenous abscisic acid application. these proteins also accumulated when rice seedlings grown ...19957579180
mechanism of pyrithione-induced membrane depolarization in neurospora crassa.pyrithione is a general inhibitor of membrane transport in fungi and is widely used in antidandruff shampoos as an antifungal agent. an electrophysiological approach has been used to determine the mode of action of pyrithione on the plasma membrane of the model ascomycete, neurospora crassa. at ph 5.8, pyrithione induces a dramatic dose-dependent electrical depolarization of the membrane which is complete within 4 min, amounts to 110 mv at saturating pyrithione concentrations, and is half maxima ...19957574648
cytochrome c oxidase in neurospora crassa contains myristic acid covalently linked to subunit 1.radiolabel from [3h]myristic acid was incorporated by neurospora crassa into the core catalytic subunit 1 of cytochrome c oxidase (ec 1.9.3.1), as indicated by immunoprecipitation. this modification of the subunit, which was specific for myristic acid, represents an uncommon type of myristoylation through an amide linkage at an internal lysine, rather than an n-terminal glycine. the [3h]myristate, which was chemically recovered from the radiolabeled subunit peptide, modified an invariant lys-324 ...19957567996
dna methylation associated with repeat-induced point mutation in neurospora crassa.repeat-induced point mutation (rip) is a process that efficiently detects dna duplications prior to meiosis in neurospora crassa and peppers them with g:c to a:t mutations. cytosine methylation is typically associated with sequences affected by rip, and methylated cytosines are not limited to cpg dinucleotides. we generated and characterized a collection of methylated and unmethylated amrip alleles to investigate the connection(s) between dna methylation and mutations by rip. alleles of am harbo ...19957565710
translational regulation in response to changes in amino acid availability in neurospora crassa.we examined the regulation of neurospora crassa arg-2 and cpc-1 in response to amino acid availability.arg-2 encodes the small subunit of arginine-specific carbamoyl phosphate synthetase; it is subject to unique negative regulation by arg and is positively regulated in response to limitation for many different amino acids through a mechanism known as cross-pathway control. cpc-1 specifies a transcriptional activator important for crosspathway control. expression of these genes was compared with ...19957565672
molecular characterization of the proline-1 (pro-1) locus of neurospora crassa, which encodes delta 1-pyrroline-5-carboxylate reductase.delta 1-pyrroline-5-carboxylate reductase (p5cr; [l-proline: nad(p+) 5-oxidoreductase]; ec 1.5.1.2) catalyzes the final step in proline biosynthesis. we have shown that the proline-1 (pro-1) locus of neurospora crassa encodes p5cr. the pro-1 gene was localized to a 3.2 kb region by complementation of (restoration of proline-independent growth to) a proline auxotroph carrying a recessive mutation at the pro-1 locus. the nucleotide sequence of this 3.2 kb region contains an open reading frame with ...19957565596
escherichia coli chorismate synthase catalyzes the conversion of (6s)-6-fluoro-5-enolpyruvylshikimate-3-phosphate to 6-fluorochorismate. implications for the enzyme mechanism and the antimicrobial action of (6s)-6-fluoroshikimate.chorismate synthase catalyzes the conversion of 5-enolpyruvylshikimate-3-phosphate to chorismate. it is the seventh enzyme of the shikimate pathway, which is responsible for the biosynthesis of aromatic metabolites from glucose. the chorismate synthase reaction involves a 1,4-elimination with unusual anti-stereochemistry and requires a reduced flavin cofactor. the substrate analogue (6s)-6-fluoro-5-enolpyruvylshikimate-3-phosphate is a competitive inhibitor of neurospora crassa chorismate syntha ...19957559411
sequence of the met-10+ locus of neurospora crassa: homology to a sequence of unknown function in saccharomyces cerevisiae chromosome 8.we have determined the sequence of the neurospora crassa met-10+ gene and its flanking regions, and have isolated and analyzed cdna clones for this region. we have identified two closely linked genes transcribed in the same orientation. the met-10+ gene is the downstream gene; an open reading frame (orf) derived from five exons encodes a 475-amino-acid protein. the deduced protein lacks similarity to other characterized proteins. however, it exhibits a strong similarity to the product of an orf ...19957557397
phylogenetic ordinal placement based on rdna sequences of the freshwater genera ophioceras and pseudohalonectria.the ordinal placement of two closely related freshwater genera, ophioceras and pseudohalonectria, was assessed by using phylogenetic analysis of morphological characters, partial sequences of the large subunit ribosomal dna and restriction site variations in the internal transcribed spacer (its). the two genera have some morphological features that are used to define taxa in both the sordariales and diaporthales, and, hence, their phylogenetic relationships are unclear. equally weighted analyses ...19957553269
cell wall deficiency in "slime" strains of neurospora crassa: osmotic inhibition of cell wall synthesis and beta-d-glucan synthase activity.1. the rcp-3 s/h mutant of neurospora crassa was obtained by vegetative selection in medium of high osmolarity of a mycelial form of an fz, sg, os-1 ("slime"-like) segregant. the mutant exhibits spheroplast-hyphal dimorphism conditioned by the osmolarity of the culture medium (pietro et al. (1990). journal of general microbiology, 136: 121-129). the carbohydrate composition of the cell wall of the mutant was different from that of the wild type in the absence of an alkali-soluble galactosaminogl ...19947550004
homology cloning of gtp-cyclohydrolase i from various unrelated eukaryotes by reverse-transcription polymerase chain reaction using a general set of degenerate primers.gtp-cyclohydrolase i is the primary enzyme of tetrahydrobiopterin and folic acid biosynthesis. cdna fragments of gtp-cyclohydrolase i were obtained from rainbow trout, chicken, the fungi neurospora crassa, phycomyces blakesleeanus and saccharomyces cerevisiae, the cellular slime mold dictyostelium discoideum, the phytoflagellate euglena gracilis and the higher plant mucuna hassjo using primers specific for conserved regions of the open reading frame and the reverse transcription polymerase chain ...19957542887
peptide-specific antibodies as probes of the topography of the voltage-gated channel in the mitochondrial outer membrane of neurospora crassa.the voltage-dependent anion-selective channel (vdac) in mitochondrial outer membranes is formed by a polypeptide (m(r) 31,000) coded by a nuclear gene whose cdna sequence is known for several organisms. antibodies have been raised against synthetic peptides corresponding to four different regions in the predicted sequence of the vdac polypeptide of the fungus neurospora crassa (residues 1-20, amino terminus; 195-210, 251-268, and 272-283, carboxyl terminus). specificity of the antibodies has bee ...19957542652
nuclear actin and rna export in conidial cells of neurospora crassa. 19957542118
forward-mutation tests on the antitumor agent icr-170 in neurospora crassa demonstrate that it induces gene/point mutations in the ad-3 region and an exceptionally high frequency of multiple-locus ad-3 mutations with closely linked sites of recessive lethal damage.the mutagenicity of the antitumor agent icr-170 (2-methoxy-6-chloro-9-[(ethyl-2-chloroethyl)amino propylamino] acridine dihydrochloride) in the adenine-3 (ad-3) region was studied with a two-component heterokaryon (h-12) of neurospora crassa. the objective was to characterize the genetic damage produced by this acridine nitrogen mustard derivative to determine in a lower eukaryotic organism the basis for its potent activity against ascites tumors in mice. as in higher eukaryotes, specific-locus ...19947523879
molecular evolution. unlocking the secrets of retroviral evolution.studies of a small circular plasmid found in the mitochondria of the fungus neurospora crassa shed unexpected light on the evolution of rna viruses into retroviruses.19947522918
x-ray-induced specific-locus mutations in the ad-3 region of two-component heterokaryons of neurospora crassa. xii. analysis of multiple-locus ad-3 mutations reveals a nonrandom distribution of the separate sites of recessive lethal damage throughout the genome.previous studies on x-ray-induced adenine-3 mutations induced in heterokaryon 12 of neurospora crassa showed that they consisted of gene/point mutations, multilocus deletion mutations, and 3 different genotypic classes of multiple-locus mutations (designated [-3]ir + rlcl, ad-3r + rlcl, and ad-3r + rl). in the present paper, multiple-locus mutations consisting of gene/point mutations at the ad-3a or the ad-3b locus with sites of recessive lethal damage closely linked to the ad-3 region (designat ...19947513795
tad1-1, an active line-like element of neurospora crassa.tad is a line-like retrotransposon of neurospora crassa. the element was originally detected and cloned using the am gene as a transposon trap in hybrid strains derived from a cross of adiopodoume (a wild collected strain) and a laboratory strain devoid of tad elements. we report the cloning and sequencing of an active tad element, tad1-1, which is capable of independent transposition. transposition was demonstrated by screening for transfer of the element from a donor nucleus that contained the ...19947512193
palindromic repeated sequences (prss) in the mitochondrial genome of rice: evidence for their insertion after divergence of the genus oryza from the other gramineae.we have identified a family of small repeated sequences (from 60 to 66 bp in length) in the mitochondrial genome of rice (oryza sativa cv. nipponbare). there are at least ten copies of these sequences and they are distributed throughout the mitochondrial genome. each is potentially capable of forming a stem-and-loop structure and we have designated them prss (palindromic repeated sequences). their features are reminiscent of the small dispersed repeats in the mitochondrial dna (mtdna) of some lo ...19947509206
abnormal chromosome behavior in neurospora mutants defective in dna methylation.the function and regulation of dna methylation in eukaryotes remain unclear. genes affecting methylation were identified in the fungus neurospora crassa. a mutation in one gene, dim-2, resulted in the loss of all detectable dna methylation. abnormal segregation of the methylation defects in crosses led to the discovery that the methylation mutants frequently generate strains with extra chromosomes or chromosomal parts. starvation for s-adenosylmethionine, the presumed methyl group donor for dna ...19937505062
quantitative and qualitative aspects of spontaneous specific-locus mutation in the ad-3 region of heterokaryon 12 of neurospora crassa.the data from forward-mutation experiments to obtain specific-locus mutations at 2 closely linked loci in the adenine-3 (ad-3) region of heterokaryon 12 (h-12) of neurospora crassa have been tabulated to determine the frequency of spontaneous ad-3 mutations and to determine the percentages resulting from each of the 2 major genotypic classes: gene/point mutations and multilocus deletion mutations. gene/point mutations at the ad-3b locus (ad-3br) have been characterized to determine the percentag ...19957500991
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