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a 3' splice site mutation in a nuclear gene encoding a mitochondrial ribosomal protein in neurospora crassa.we showed previously that the cyt-21+ gene of neurospora crassa encodes a mitochondrial ribosomal protein homologous to escherichia coli ribosomal protein s-16 (kuiper, m. t. r., akins, r. a., holtrop, m., de vries, h., and lambowitz, a. m. (1988) j. biol. chem. 263, 2840-2847). a mutation in this gene, cyt-21-1, results in deficiency of mitochondrial small ribosomal subunits and small rrna (collins, r. a., bertrand, h., lapolla, r. j., and lambowitz, a. m. (1979) mol. gen. genet. 177, 73-84). i ...19882830267
an endo-exonuclease activity of yeast that requires a functional rad52 gene.extracts of rad+ and radiation-sensitive (rad) mutants of the yeast saccharomyces cerevisiae were examined for total mg2+-dependent alkaline deoxyribonuclease activity and the presence of a nuclease that crossreacts immunologically with an antiserum raised against an endo-exonuclease from neurospora crassa, an enzyme exhibiting both deoxyribo- and ribonuclease activities. no significant differences were observed in total deoxyribonuclease activity between rad+ and rad mutants. the antibody preci ...19882830467
purification of integral plasma membrane proteins by reverse-phase high performance liquid chromatography.following dissolution in anhydrous trifluoroacetic acid, plasma membrane isolated from two eukaryotic species was directly injected onto a reverse-phase high performance liquid chromatograph column. upon development with a 60 to 100% (v/v) linear gradient of ethanol containing 0.1% trifluoroacetic acid, most of the polypeptides eluted without retention. only the lipids and very hydrophobic proteins were retained and resolved. most noticeable among retained proteins was the mr 100,000 catalytic p ...19882454596
sequence analysis of the ddpyr5-6 gene coding for ump synthase in dictyostelium discoideum and comparison with orotate phosphoribosyl transferases and omp decarboxylases.a dictyostelium discoideum dna fragment that complements the ura3 and the ura5 mutants of saccharomyces cerevisiae has been sequenced. it contains an open reading frame of 478 codons capable of encoding a polypeptide of molecular weight 52475. this gene, named ddpyr5-6, encodes a bifunctional protein composed of the orotate phosphoribosyl transferase (oprtase) and the orotidine-5'-phosphate decarboxylase (ompdecase) domains described for ump synthase in mammals. the existence of separate domains ...19882835631
nucleotide sequence of the aspergillus niger trpc gene: structural relationship with analogous genes of other organisms.the nucleotide sequence of the aspergillus niger tryptophan c (trpc) gene was determined. northern hybridization and s1-mapping experiments showed the presence of a 2.6 kb trpc poly(a)+ rna with two very short (5 and 6 nucleotides) noncoding 5'-regions. comparison of the predicted amino acid sequence with that of trp gene proteins of pro- and eukaryotic organisms revealed three functional domains (g, c, f) in the a. niger trpc protein which catalyse the glutamine amidotransferase reaction (gat), ...19882836085
dna methylation and control of genome organization in neurospora crassa. 19882977770
the fluorescein isothiocyanate-binding site of the plasma-membrane h+-atpase of neurospora crassa.the mammalian (na+,k+), ca2+-, and (h+,k+)-atpases contain a well-characterized lysine residue that reacts with fluorescein 5'-isothiocyanate (fitc); enzymatic activity is protected by atp, suggesting that the residue is located in or near the nucleotide-binding domain. in this study, the plasma-membrane h+-atpase of neurospora crassa is also shown to be sensitive to fitc. the reaction occurs with pseudo first-order kinetics, has a pka of 8.0, and is stimulated by mg2+. enzymatic activity is pro ...19882904434
transcellular ionic currents studied by intracellular potential recordings in neurospora crassa hyphae. transfer of energy from proximal to apical cells.membrane potentials, input resistances, and electric coupling in the apical parts of n. crassa growing hyphae were recorded with the aid of intracellular microelectrodes. it was revealed that the apical cells were always depolarized by 10 to 30 mv as compared to the adjacent proximal cells. the septal pore maintained an electrical resistance of 4 to 6 m omega. the calculated values of the endogenous electrical current passing through the septal pore varied between 0.5 and 1 na. electrical isolat ...19882973993
cyclic nucleotide phosphodiesterase activity in neurospora crassa. purification by immunoaffinity chromatography and characterization.monoclonal antibodies to neurospora crassa cyclic nucleotide phosphodiesterase (pde i) were selected by their capacity to inhibit the enzyme activity. the monoclonal immunoglobulin, coupled to sepharose 4b, was used for the affinity purification of pde i activity. after sds-polyacrylamide gel electrophoresis the affinity purified pde i fractions showed a single polypeptide band of about 41 kda. this band reacted in western blots with the above mentioned monoclonal immunoglobulin.19882848723
molecular characterization of the mitochondrial dna of a new stopper mutant er-3 of neurospora crassa.an ethidium bromide-induced stopper mutant of neurospora crassa is characterized at the molecular level. the mutant has two populations of mitochondrial dna: a defective predominant mutant molecule and a basal level of the wild-type molecule. the aberrant dna resulted after a 25-kbp deletion from the wild-type mitochondrial chromosome, which included major genes such as cytb, co1 and oli2. the deletion endpoints are located in the second intron of the nd5 gene, and in a sequence 250 nucleotides ...19882976009
luminescence from the carbon monoxide derivative of agaricus bispora tyrosinase.the luminescence of the co adduct of two isozymic tyrosinases isolated from agaricus bispora, an edible white mushroom, has been studied. at room temperature the emission appears as a single smooth peak centered at 530 nm with fwhm of 2700 cm-1 and a lifetime of 36 microseconds. the lifetime and wavelength of the emission are virtually unchanged on lowering the temperature from 298 to 77 degrees k. solvent composition affects the wavelength of emission minimally. the emission is quenched by oxyg ...19882975158
polyamine transport in neurospora crassa.polyamine transport in neurospora crassa is concentrative and energy dependent in a dilute buffer. the saturable systems governing the uptake of putrescine (km = 0.6 mm), spermidine (km = ca. 0.24 mm), and spermine (km = 0.07 mm) share components, as indicated by mutual inhibition among the polyamines. in addition, nonsaturable components prevail for putrescine and spermidine, particularly the former. radiolabeled substrates, once in the cell, are released only slowly, even if unlabeled polyamin ...19882975157
metabolism of d-glucose in a wall-less mutant of neurospora crassa examined by 13c and 31p nuclear magnetic resonances: effects of insulin.13c nmr and 31p nmr have been used to investigate the metabolism of glucose by a wall-less strain of neurospora crassa (slime), grown in a supplemented nutritionally defined medium and harvested in the early stationary stage of growth. with d-[1-13c]- or d-[6-13c]glucose as substrates, the major metabolic products identified from 13c nmr spectra were [2-13c]ethanol, [3-13c]alanine, and c1- and c6-labeled trehalose. several observations suggested the existence of a substantial hexose monophosphat ...19882975509
the heat shock response of neurospora crassa: stress-induced thermotolerance in relation to peroxidase and superoxide dismutase levels.heat shock and other treatments, including cadmium chloride, hydrogen peroxide and sodium arsenite, led to the induction of high levels of peroxidase activity as well as thermotolerance in neurospora crassa. no correlation was apparent between superoxide dismutase levels and development of thermotolerance following exposure to these stress conditions. a prominent role for peroxidase in protection against damage by toxic products of oxygen is suggested.19882847725
the plasma membrane h+-atpase of neurospora crassa. properties of two reactive sulfhydryl groups.previous work with n-ethylmaleimide (nem) has defined two sites on the neurospora plasma membrane h+-atpase. modification of one (the "fast" site) by nem is rapid but does not affect atpase activity, while modification of the other (the "slow" site) inactivates the enzyme and is protectable by mgatp or mgadp. in the present study, a wider array of sulfhydryl reagents have been used to examine the properties of both sites. the results show the following. (a) both fast and slow sites react prefere ...19882903147
translocation of a fragment of invertase across microsomal vesicles isolated from neurospora crassa requires the hydrolysis of a nucleoside triphosphate.the step which requires the hydrolysis of a nucleoside triphosphate for translocation of a protein across microsome was investigated by studying translocation uncoupled from translation using two truncated products of invertase: one product contains the first 262 amino acids of the secreted invertase (inv262); the other, the first 104 amino acids (inv104). the truncated products were translated from rna transcripts without a stop codon. it is demonstrated that the translated products contain an ...19882971655
isolation of genes encoding the neurospora vacuolar atpase. analysis of vma-1 encoding the 67-kda subunit reveals homology to other atpases.the vacuolar membrane of neurospora crassa contains a h+-translocating atpase composed of at least three subunits with approximate molecular weights of 70,000, 60,000, and 15,000. both genomic and cdna clones encoding the largest subunit, which appears to contain the active site of the enzyme, have been isolated and sequenced. the gene for this subunit, designated vma-1, contains six small introns (60-131 base pairs) and encodes a hydrophilic protein of 607 amino acids, mr 67,121. within the seq ...19882971651
isolation of genes encoding the neurospora vacuolar atpase. analysis of vma-2 encoding the 57-kda polypeptide and comparison to vma-1.in partially purified preparations of the vacuolar atpase from neurospora crassa, the two most prominent components are polypeptides of mr = 70,000 and 60,000. we previously reported the isolation of the gene vma-1, which encodes the mr = 70,000 polypeptide, and presented evidence that the polypeptide contains the site of atp hydrolysis (bowman, e. j., tenney, k., and bowman, b. j. (1988) j. biol. chem. 263, 13994-14001). we now report the isolation of a gene (designated vma-2), that encodes the ...19882844751
presence of abnormal synaptonemal complexes in heterothallic species of neurospora.synaptonemal complex abnormalities are frequent in reconstructed meiotic prophase nuclei of neurospora crassa and neurospora intermedia. three kinds of synaptonemal complex anomalies were seen: lateral component splits, lateral component junctions, and multiple complexes. the anomalies apparently are formed during or after the pairing process, as they were not seen in the largely unpaired early zygotene chromosomes. their presence at all the other substages from mid-zygotene to late pachytene in ...19882974436
dual roles for calcium ions in apical growth of neurospora crassa.we report initial attempts to define the role of ca2+ in the polarized extension of neurospora crassa. growth of the organism was diminished in media containing less than 1 mm-ca2+; extension was more severely impaired than biomass synthesis, resulting in the formation of stubby, bulbous hyphae, even of spherical cells. reduced extension and abnormal morphology were correlated with the loss of surface-bound ca2+, probably associated with the cell wall. intracellular ca2+ may be represented by ma ...19882978297
binding of a 30-kda protein to the pyruvate kinase gene of neurospora crassa.extracts of a wild-type strain of neurospora crassa, electrophoresed on sds-polyacrylamide gels and electroblotted onto nitrocellulose sheets, were hybridized to an end-labelled pyruvate kinase (pk) gene fragment containing the 5' noncoding sequence and a large part of the coding region. a 30-kda protein was found to bind strongly to the pk gene dna, while binding weakly to plasmid puc12 dna and to total n. crassa dna. probing of blots with individual restriction fragments derived from the pk ge ...19882973333
molecular cloning and characterization of a negative-acting nitrogen regulatory gene of neurospora crassa.expression of the structural genes of the nitrogen control circuit of neurospora crassa is regulated by the positive-acting nit-2 control gene and by the negative-acting nmr control gene. nitrate reductase is expressed in a constitutive fashion in nmr mutant strains, which appear to be largely insensitive to nitrogen catabolite repression. thus, nmr mutants are sensitive to chlorate in the presence of ammonia or glutamine, whereas the wild type is chlorate resistant under these conditions. a cos ...19882906403
method for identification of intracellular free flavin species in the photosensitive fungus neurospora crassa.establishing the relative intracellular proportions of flavins in neurospora crassa (and in other organisms) in vivo may be hampered by degradation of flavins after homogenization of the cells. the system described here allows separation and identification of intracellular free and bound flavins under conditions restrictive for the fad-degrading enzyme(s). a "protective buffer" containing 0.1 m citrate adjusted to ph 4.0 with k2hpo4, 5 mm atp, and 0.5 mm edta prevents fad from rapid enzymatic cl ...19882973261
growth regulation by gtp. regulation of nucleotide pools in neurospora by nitrogen and sulfur control systems.purine nucleotide pools in the fungus neurospora crassa decline in response to carbon, nitrogen, or sulfur deprivation. there is, in addition, a decline in gtp/atp ratios on nitrogen or sulfur deprivation in wild type. the gtp/atp decline is missing on nitrogen deprivation of the nitrogen control mutant, nit-2, and on sulfur deprivation of the sulfur control mutant, cys-3. the nit-2 mutant also shows elevated utp pools on nitrogen deprivation when compared with similarly treated wild type. six-h ...19882969890
molybdenum cofactor deficiency in a patient previously characterized as deficient in sulfite oxidase.the metabolic status of a patient previously characterized as deficient in sulfite oxidase was reexamined applying new methodology which has been developed to distinguish between a defect specific to the sulfite oxidase protein and sulfite oxidase deficiency which arises as a result of molybdenum cofactor deficiency. urothione, the metabolic degradation product of the molybdenum cofactor, was undetectable in urine samples from the patient. analysis of molybdenum cofactor levels in fibroblasts by ...19883219233
cytoplasmic leucyl-trna synthetase of neurospora crassa is not specified by the leu-5 locus.we generated a lambda gt11 neurospora crassa cdna library and screened the library for the cytoplasmic leucyl-trna synthetase (cyto leurs) clones using cyto leurs specific antibody. two clones, lambda nclrsc1 and lambda nclrsc2, were obtained which have inserts of approximately 2 kbp and approximately 1.3 kbp, and which overlap by about 0.6 kbp. the following lines of evidence indicate that lambda nclrsc1 and lambda nclrsc2 encode parts of cyto leurs. (1) antibodies affinity purified using eithe ...19882842224
putrescine and spermidine control degradation and synthesis of ornithine decarboxylase in neurospora crassa.neurospora crassa mycelia, when starved for polyamines, have 50-70-fold more ornithine decarboxylase activity and enzyme protein than unstarved mycelia. using isotopic labeling and immunoprecipitation, we determined the half-life and the synthetic rate of the enzyme in mycelia differing in the rates of synthesis of putrescine, the product of ornithine decarboxylase, and spermidine, the main end-product of the polyamine pathway. when the pathway was blocked between putrescine and spermidine, orni ...19882968340
a mutant of neurospora crassa deficient in cytochrome c heme lyase activity cannot import cytochrome c into mitochondria.the nuclear cyt-2-1 mutant of neurospora crassa is characterized by a gross deficiency of cytochrome c (bertrand, h., and collins, r. a. (1978) mol. gen. genet. 166, 1-13). the mutant produces mrna that can be translated into apocytochrome c in vitro. apocytochrome c is also synthesized in vivo in cyt-2-1, but it is rapidly degraded and thus does not accumulate in the cytosol. mitochondria from wild-type cells bind apocytochrome c made in vitro from either wild-type or cyt-2-1 mrna and convert i ...19882454235
factors associated with the instability of nitrate-insensitive proton transport by maize root microsomes.proton transport catalyzed by the nitrate-insensitive, vanadate-sensitive h(+)-atpase in microsomes from maize (zea mays l.) roots washed with 0.25 molar ki decreased as a function of time at 0 to 4 degrees c. the rate of proton transport was approximately one-half of that by freshly isolated microsomes after 6 to 18 hours of cold storage. the decrease in proton transport coincided with losses in membrane phosphatidylcholine and was not associated with a change in vanadate-sensitive atp hydrolys ...198816666192
blue light induces circadian rhythms in the bd mutant of neurospora: double mutants bd,wc-1 and bd,wc-2 are blind.this paper describes a new blue light effect for neurospora crassa, the photoinduction of circadian rhythms in the bd mutant. the wc-1 and wc-2 genes are necessary for this effect.19882977186
characterization of a mutation that causes overproduction of inositol in neurospora crassa.slow-growing (inl+/-) spontaneous mutants have been isolated from an inositol requiring (inl) strain of neurospora crassa that produces defective myo-inositol-1-phosphate synthase (mips), the enzyme responsible for the production of inositol-1-phosphate from glucose-6-phosphate. the defective enzyme has some residual activity. in the inl+/- strain the synthesis of the defective enzyme is enhanced, which enables the strain to grow slowly on minimal medium. the mutation (opi1) responsible for the ...19882975749
mitochondrial protein import: identification of processing peptidase and of pep, a processing enhancing protein.transport of nuclear-encoded precursor proteins into mitochondria includes proteolytic cleavage of amino-terminal targeting sequences in the mitochondrial matrix. we have isolated the processing activity from neurospora crassa. the final preparation (enriched ca. 10,000-fold over cell extracts) consists of two proteins, the matrix processing peptidase (mpp, 57 kd) and a processing enhancing protein (pep, 52 kd). the two components were isolated as monomers. pep is about 15-fold more abundant in ...19882967109
molecular analysis of a neurospora crassa gene expressed during conidiation.the asexual developmental pathway in the life cycle of the filamentous fungus neurospora crassa culminates in the formation of spores called conidia. several clones of genomic neurospora dna have been isolated that correspond to mrna species expressed during conidiation and not during mycelial growth (v. berlin and c. yanofsky, mol. cell. biol. 5:849-855, 1985). in this paper we describe the characterization of one of these clones, named pcon-10a. this clone contains two genes, con-10 and con-13 ...19882970007
relationship of histidine sensitivity to dna damage and stress induced responses in mutagen sensitive mutants of neurospora crassa.previous work in other laboratories has shown that several mutagen sensitive mutants of neurospora crassa are extremely sensitive to low levels of histidine in the culture medium. we have shown that wild type neurospora accumulates nicks or breaks in the dna in the presence of histidine. the number of nicks accumulating in histidine sensitive mutants is found to increase in relation to their sensitivity to histidine. although these nicks can be repaired by both wild type and histidine sensitive ...19882969780
ly121019 inhibits neurospora crassa growth and (1-3)-beta-d-glucan synthase. 19882968332
cyclic amp-dependent, constitutive thermotolerance in the adenylate cyclase-deficient cr-1 (crisp) mutant of neurospora crassa.we investigated the heat shock response of the adenylate cyclase deficient mutant cr-1 (crisp) of neurospora crassa. this strain was observed to be much more resistant to a lethal temperature of 50 degrees c than the wild type. this constitutive thermotolerance was absent in cr-1 conidiospores raised on cyclic amp (camp, 2.5 mm) supplemented solid medium, but was partially restored when the conidiospores were germinated at 30 degrees c, a temperature which fails to induce thermotolerance in the ...19882841035
neurospora mitochondria contain an acyl-carrier protein.mitochondria of neurospora crassa were found to contain a protein which was labelled with [14c]pantothenic acid and which carried an acyl group. this protein, when purified 6000-fold, closely resembled the bacterial and chloroplast acyl-carrier protein(s) [acp(s)] in its physical and chemical properties. the predominant acyl group esterified to the purified protein was 3-hydroxytetradecanoate, as determined by gas chromatographic mass spectrometry. the amino acid sequence of the tryptic peptide ...19883360014
neurospora crassa pyruvate dehydrogenase complex: component characterization, catalytic properties and location of translation.we propose a simplified procedure for the purification of the neurospora crassa pyruvate dehydrogenase complex. the purified complex showed four protein bands with apparent mr values of 53,400, 52,900, 49,000 and 36,900 upon sds-polyacrylamide gel electrophoresis. components, e2 and e3, of n. crassa pyruvate dehydrogenase complex were identified, respectively, as polypeptides 49,000 and 53,400. it can be deduced that component e1 is constituted of two subunits with mr values of 52,900 and 36,900 ...19882965602
preparation of a cell-free translation system from a wild-type strain of neurospora crassa.we describe the preparation of an in vitro translation system from a wild-type strain of neurospora crassa. the system is capable of supporting efficient and faithful translation of native and in vitro transcribed eukaryotic messages. the translation products have minimal background and can be clearly analyzed by sds-polyacrylamide gel electrophoresis. the method of preparation of the lysate is simple, fast and reproducible. the procedure should be readily applicable to other filamentous fungi.19882968852
an electrophoretic karyotype of neurospora crassa.a molecular karyotype of neurospora crassa was obtained by using an alternating-field gel electrophoresis system which employs contour-clamped homogeneous electric fields. the migration of all seven n. crassa chromosomal dnas was defined, and five of the seven molecules were separated from one another. the estimated sizes of these molecules, based on their migration relative to schizosaccharomyces pombe chromosomal dna molecules, are 4 to 12.6 megabases. the seven linkage groups were correlated ...19882967910
molecular cloning and analysis of the regulation of cys-14+, a structural gene of the sulfur regulatory circuit of neurospora crassa.the cys-14+ gene encodes sulfate permease ii, which is primarily expressed in mycelia. cys-14+ is one of a set of sulfur-related structural genes under the control of cys-3+ and scon+, the regulatory genes of the sulfur control circuit. we have cloned cys-14+ from a cosmid library of neurospora crassa dna. a restriction fragment length polymorphism analysis showed that this clone maps to the region of chromosome iv corresponding to the cys-14+ locus. northern blot analyses were used to examine t ...19882898097
cloning of mtr, an amino acid transport gene of neurospora crassa.translocation of neutral aliphatic and aromatic amino acids across the plasma membrane of the ascomycete neurospora crassa requires a functional gene product of the mtr locus. mutations at this locus are defective in transport of those amino acids. we have cloned the mtr+ gene of neurospora crassa from an ordered cosmid library of genomic dna and produced a preliminary restriction map of 2.9 kilobases of genomic dna that encompasses the mtr coding region. we have confirmed that the cloned dna re ...19882843424
secondary structure of the neurospora crassa plasma membrane h+-atpase as estimated by circular dichroism.in a previous communication, a water-soluble, hexameric form of the neurospora crassa plasma membrane h+-atpase was described (chadwick, c. c., goormaghtigh, e., and scarborough, g. a. (1987) arch. biochem. biophys. 252, 348-356). to facilitate physical studies of the hexamers, the h+-atpase isolation procedure has been improved, resulting in a structurally and functionally stable hexamer preparation that contains only 5 to 10% non-atpase protein, approximately 12 mol of enzyme-bound lysophospha ...19882893796
the structural gene for a phosphorus-repressible phosphate permease in neurospora crassa can complement a mutation in positive regulatory gene nuc-1.van+, a gene encoding a phosphorus-repressible phosphate permease, was isolated by its ability to complement nuc-1, a positive regulatory locus that normally regulates van+ expression. this was unexpected because the nuc-1 host already contained a resident van+ gene. plasmids carrying van+ complemented a nuc-2 mutation as well. probing of rna from untransformed wild-type (nuc-1+) and constitutive (nuc-1c) strains by van+ probes indicated that levels of the van+ transcript were subject to control ...19882966896
ribosomal dna inheritance and recombination in neurospora crassa.the genetic segregation of ribosomal dna (rdna) in neurospora crassa was analyzed by exploiting restriction fragment length polymorphisms in the nontranscribed spacer (nts) sequences of nine laboratory wild-type strains and wild-collected strains. in an analysis of random spore progeny from seven crosses, and of ordered tetrads from two of those crosses the rdna was shown to be inherited in a simple, stable mendelian fashion, exhibiting an approximately 1:1 ratio of the two parental rdna types. ...19882966889
ethanol and carbon-source starvation enhance the accumulation of hsp80 in neurospora crassa.in neurospora crassa, heat shock results in the induction of 9 to 11 heat shock proteins (hsp), of which hsp80 is the most abundant and the first to be synthesized. the induction of hsp80 was investigated during normal growth (2% sucrose) and under sucrose starvation. transfer of mycelium to a medium supplemented with ethanol stimulated the synthesis of hsp80, even at the normal growth temperature of 28 degrees c. it was also synthesized under carbon starvation conditions, where the medium was s ...19882969770
xanthine dehydrogenase expression in neurospora crassa does not require a functional nit-2 regulatory gene.xanthine dehydrogenase (xdh) is the initial enzyme in the purine catabolic pathway of n. crassa. secondary nitrogen sources such as purines are metabolized when preferred sources of reduced nitrogen (ammonium or glutamine) are unavailable. xdh synthesis is regulated by glutamine repression and uric acid induction. the nit-2 locus is believed to encode a trans-acting positive regulator essential for the expression of genes encoding enzymes involved in secondary pathways of nitrogen acquisition, s ...19882967694
lateral segregation of sterol and channel proteins in the mitochondrial outer membrane induced by phospholipase a2: evidence from negative-stain electron microscopy using filipin.the channel protein in the mitochondrial outer membrane of neurospora crassa aggregates laterally into crystalline arrays by the action of phospholipase a2. when mitochondrial outer membranes are reacted with filipin and examined by negative-stain electron microscopy, filipin-sterol complexes are found everywhere on the membranes except on the crystalline channel arrays. this suggests that the channel-rich membrane domains may have a relatively low content of accessible sterol. it is proposed th ...19882967338
on the role of protein synthesis in the circadian clock of neurospora crassa.inhibitors of protein synthesis reset the biological clocks of many organisms. this has been interpreted to mean either that the synthesis per se of proteins is a step in the oscillatory feedback loop or merely that certain unstable protein(s) are required at certain times of the cycle to complete the feedback loop. we report here that neurospora strains bearing the clock mutation frq-7 are relatively insensitive to the resetting action of the protein-synthesis-inhibitor cycloheximide. protein s ...19882963337
metabolic control and autogenous regulation of nit-3, the nitrate reductase structural gene of neurospora crassa.in neurospora crassa, the expression of nit-3, the structural gene which encodes nitrate reductase, is highly regulated and requires both nitrate induction and nitrogen catabolite derepression. the major nitrogen regulatory gene, nit-2, acts in a positive fashion to turn on the expression of nit-3 and other nitrogen-related genes during nitrogen derepression. a second regulatory gene, designated nmr, acts in a negative fashion to repress the expression of nitrate reductase and related enzymes, a ...19882962990
characterization of two allelic forms of neurospora crassa laccase. amino- and carboxyl-terminal processing of a precursor.the complete structures of the laccase genes isolated from two different neurospora crassa wild-type strains are described. the genes were cloned by screening partial genomic dna libraries with a nick-translated laccase-specified 1.36-kilobase sali fragment (germann, u. a., and lerch, k. (1986) proc. natl. acad. sci. u.s.a. 83, 8854-8858) as a hybridization probe. nucleotide sequence analysis revealed the presence of two different allelic forms. they conform to the same structural organization, ...19882961749
regulation of lactate/pyruvate ratios by cyclic amp in neurospora crassa.cyclic amp is thought to have a general role in stimulating the breakdown of carbohydrate reserves and subsequent glycolytic activity. this would be expected to increase the availability of reducing equivalents in the form of cytoplasmic nadh. the current study examines another potential reaction controlling cytoplasmic nadh in the fungus neurospora crassa, that of lactate dehydrogenase, to determine whether it is also regulated by cyclic amp. the cr-1, adenylate cyclase and cyclic amp-deficient ...19882827675
ferricrocin functions as the main intracellular iron-storage compound in mycelia of neurospora crassa.neurospora crassa produces several structurally distinct siderophores: coprogen, ferricrocin, ferrichrome c and some minor unknown compounds. under conditions of iron starvation, desferricoprogen is the major extracellular siderophore whereas desferriferricrocin and desferriferichrome c are predominantly found intracellularly. mössbauer spectroscopic analyses revealed that coprogen-bound iron is rapidly released after uptake in mycelia of the wild-type n. crassa 74a. the major intracellular targ ...19882978956
defective myo-inositol-1-phosphate synthase production in an inositolless double mutant neurospora crassa strain.a slow growing inl+/- mutant was isolated from an inositol dependent (inl) neurospora crassa strain. the latter strain produces defective myo-inositol-1-phosphate synthase which has residual activity. inositol, similarly to that found in wild and inl mutant strains, represses the enzyme production in the inl+/- strain as well. withdrawing inositol from the medium results in derepression of the enzyme synthesis. derepression is hindered by cycloheximide. inl+/- character in the double mutant is b ...19882977674
mating type response in neurospora crassa. early and transient changes in the patterns of protein synthesis in sexually stimulated mycelia.1. pulse labeling with [35s]-methionine, one-dimensional sds-polyacrylamide gel electrophoresis and fluorography were used to study the pattern of protein synthesis in neurospora crassa mycelia undergoing sexual development. 2. contact of sexually-competent mycelium with cells of the opposite mating type elicited a rapid and transient increase in the synthesis of two predominant proteins of 58 kda and 40 kda localized in the cytosol fraction. 3. marked changes in the pattern of protein synthesis ...19882977101
[mechanism of photoregulation of carotenogenesis in neurospora crassa: the use of mutants]. 19882973407
transcellular ion currents and extension of neurospora crassa hyphae.hyphae of neurospora crassa, like many other tip-growing organisms, drive endogenous electric currents through themselves such that positive charges flow into the apical region and exit from the trunk. in order to identify the ions that carry the current, the complete growth medium was replaced by media lacking various constituents. omission of k+ or of phosphate diminished the zone of inward current, effectively shifting the current pattern towards the apex. omission of glucose markedly reduced ...19882966862
nitrate assimilation in neurospora crassa: enzymatic and immunoblot analysis of wild-type and nit mutant protein products in nitrate-induced and glutamine-repressed cultures.the nitrate assimilatory pathway in neurospora crassa is composed of two enzymes, nitrate reductase and nitrite reductase. both are alpha 2 type homodimers. enzyme-bound prosthetic groups mediate the electron transfer reactions which reduce inorganic nitrate to an organically utilizable form, ammonium. one, a molybdenum-containing cofactor, is required by nitrate reductase for both enzyme activity and holoenzyme assembly. three modes of regulation are imposed on the expression of nitrate assimil ...19882963944
large-scale purification of plasma membrane h+-atpase from a cell wall-less mutant of neurospora crassa. 19882906720
transformation of neurospora crassa with the trp-1 gene and the effect of host strain upon the fate of the transforming dna.neurospora trp-1+ transformants, obtained by transforming a trp-1 inl strain with plasmid dna containing the wild type trp1+ gene, were characterized by genetic and southern blot analyses. the transforming trp-1 gene integrated at or near the resident site in all of the trp-1+ transformants obtained with circular dna or dna cut within the trp-1 coding region. the frequency of homologous integration decreased substantially when the donor dna was cleaved outside the trp-1 coding region. the transf ...19882834105
control of nucleotide and erythroascorbic acid pools by cyclic amp in neurospora crassa.udpglucuronic acid and erythroascorbic acid were identified in extracts of the fungus neurospora crassa. the concentrations of these two compounds are estimated, in growing wild type n. crassa, to be about 0.10 and 0.28 mumol/ml of cell water, respectively. the pools of these two compounds are regulated by cyclic amp in neurospora, both being elevated in the cr-1, adenylate cyclase deficient mutant and both being lowered by exogenous cyclic amp. the pools of these two compounds are also elevated ...19872825802
rearrangement of duplicated dna in specialized cells of neurospora.introduction of dna into neurospora crassa can lead to sequence instability in the sexual phase of the life cycle. sequence instability was investigated by using a set of strains transformed with single copies of a plasmid including host sequences, neurospora sequences deleted from the host genome, and foreign sequences. the sequences already represented in the host were rearranged at high frequency in a cross. in general, both elements of the duplication, that from the plasmid and that from the ...19872960455
molecular cloning and analysis of the regulation of nit-3, the structural gene for nitrate reductase in neurospora crassa.the nit-3 gene of neurospora crassa encodes the enzyme nitrate reductase and is regulated by nitrogen catabolite repression and by specific induction with nitrate. the nit-3 gene was isolated from a cosmid-based genomic library by dual selection for benomyl resistance and for the ability to complement a nit-3 mutant strain using the sibling-selection procedure. the nit-3 gene was subcloned as a 3.8-kilobase dna fragment from a cosmid that carried an approximately 40-kilobase n. crassa dna insert ...19872891138
relationship between two major immunoreactive forms of arginase in neurospora crassa.two major immunoreactive proteins of mr 41,700 and 36,100 have been detected in crude mycelial extracts with polyclonal antibodies raised against arginase purified from neurospora crassa. the latter corresponded to the protein used to obtain the antibodies. both polypeptides were either missing or present in very low amounts in mutant strains having little or no detectable arginase activity. the relative proportion of the two species was altered in strains containing the nitrogen catabolite regu ...19872890621
circadian rhythms in neurospora crassa: a clock mutant, prd-1, is altered in membrane fatty acid composition.the fatty acid compositions of the phospholipids of neurospora crassa mutants with altered periods were determined to test the possibility that some of these mutants might have altered membrane composition. in liquid shaker culture in constant light the bd (band) strain, which has a normal period (21.6 h), exhibited a growth-dependent increase in linoleic acid content and a decrease in linolenic acid content during early log phase growth. by late log phase, fatty acid composition was essentially ...19872889471
antibiotic-induced derepression of the nad-specific glutamate dehydrogenase of neurospora crassa.the catabolic, nad-specific glutamate dehydrogenase (nad-gdh) of neurospora crassa is under carbon catabolite repression. cells grown on a glycolytic carbon source, such as sucrose, have low basal levels of enzyme activity. treatment of repressed cells with either polymyxin b or amphotericin b resulted in derepression of nad-gdh. derepression at the transcriptional level occurred very rapidly (within 30 min) in response to polymyxin b addition but reached a plateau within 2 h. amphotericin b-ind ...19872822659
carboxyl-terminal sequences influence the import of mitochondrial protein precursors in vivo.the large subunit of carbamoyl phosphate synthase a [carbon-dioxide: l-glutamine amido-ligase (adp-forming, carbamate-phosphorylating), ec 6.3.5.5] from neurospora crassa is encoded by a nuclear gene but is localized in the mitochondrial matrix. we have utilized n. crassa strains that produce both normal and carboxyl-terminal-truncated forms of carbamoyl phosphate synthase a to ask whether the carboxyl terminus affects import of the carbamoyl phosphate synthase a precursor. we found that carboxy ...19872958846
characterization of pi-repressible enzymes secreted in culture media by neurospora crassa wild-type cells and null-type mutants.in wild-type mycelial cultures of neurospora crassa under pi-limited conditions, alkaline phosphatase, cyclic phosphodiesterases i, ii, iii, and iv, 5'-nucleotidase, acid and alkaline nucleases, rnase n1, and a newly detected endonuclease were secreted into the culture media. these enzymes were either not produced or were produced in very reduced levels in mutants nuc-1, -2, -3, -4, -5, -6, and -7 and cpd-4. the proteins were examined by polyacrylamide gel electrophoresis in a manner which allow ...19872820943
heat shock induces peroxidase activity in neurospora crassa and confers tolerance toward oxidative stress.heat shock treatment of 14-h-old neurospora crassa mycelium, for 1 h at 48 degrees c, led to the induction of high levels of peroxidase (ec. 1.11.1.7) activity. no significant change was observed in the superoxide dismutase content. colonies formed by plating conidial suspensions on sorbose-medium also exhibited high peroxidase activity following exposure to hyperthermia and were found to be resistant to normally toxic doses of h2o2. thus one of the heat shock proteins of n. crassa has the funct ...19872959286
a eukaryotic repressor protein, the qa-1s gene product of neurospora crassa, is homologous to part of the arom multifunctional enzyme.little is known about the proteins involved in the control of gene expression in eukaryotes. although some of these proteins have been sequenced, their biochemical functions are not well understood and the identification of homologies to proteins of known activities may give useful clues to the functions of these regulatory proteins. we report here that the qa-1s repressor protein of the fungus neurospora crassa is strongly homologous to the pentafunctional arom enzyme found in many lower eukary ...19872960822
a novel stimulator of protein phosphorylation in neurospora crassa.an endogenous thermostable activator of protein kinase iii (pkiii) was purified from 100,000 x g supernatants of neurospora crassa mycelial extracts. this 38,000 dalton polypeptide, clearly separable from calmodulin on p-60 gel filtration, specifically stimulated n. crassa pkiii activity on casein or phosvitin "in vitro" phosphorylation. the factor was only present in the initial growth phase of the fungus. the mechanism of pkiii activation and its possible regulatory role are discussed.19872961977
two developmental stages of neurospora crassa utilize similar mechanisms for responding to heat shock but contrasting mechanisms for recovery.at the heat shock temperature of 45 degrees c, there is a transient induction of the synthesis of heat shock proteins and repression of normal protein synthesis in cells of neurospora crassa. both conidiospores and mycelial cells resume normal protein synthesis after 60 min at high temperature. at the rna level, however, these two developmental stages responded with different kinetics to elevated temperature. heat shock rnas (for hsp30 and hsp83) accumulated and declined more rapidly in spores t ...19872959857
isolation of telomere dna from neurospora crassa.the most distal known gene on neurospora crassa linkage group vr, his-6, was cloned. a genomic walk resulted in isolation of the telomere at vr. it was obtained from a library in which the endmost nucleotides of the chromosome had not been removed by nuclease treatment before being cloned, and mapping indicates that the entire chromosome end has probably been cloned. sequences homologous to the terminal 2.5 kilobases of dna from vr from these oak ridge n. crassa strains are found at other sites ...19872890097
transcription of neurospora crassa 5 s rrna genes requires a tata box and three internal elements.the sequences required for transcription of neurospora crassa 5s rrna genes have been defined using a comprehensive set of deletion and substitution mutations introduced into two cloned genes. an upstream tata box (consensus tcataga) located at -29 to -24, and three internal regions (d, a and c) localized to +19 to +30, +44 to +57 and +73 to +103, respectively, are absolutely required for transcription in vitro. the tata box fixes the start point of transcription. the a and c regions correspond ...19872960818
partial characterization of gtp-binding proteins in neurospora.six fractions of gtp-binding proteins separated by gel filtration of a mycelial extract containing membrane components of neurospora crassa were partially characterized. [35s]gtp gamma s bound to gtp-binding protein was assayed by repeated treatments with a norit solution and centrifugation. the binding of [35s]gtp gamma s to gtp-binding proteins was competitively prevented in the presence of 0.1 to 1 mm gtp but not in the presence of atp. these gtp-binding proteins fractionated by the gel colum ...19872956953
electron microscopy and image analysis of the mitochondrial outer membrane channel, vdac.the channel protein in the outer membrane of neurospora crassa mitochondria, vdac, forms extended planar crystals on the membrane. the arrays, which are induced by phospholipase a2, are polymorphic, varying from parallelogram (p) to near-rectangular (r) geometry with increased phospholipase treatment. computer-based analysis of projection images of negatively stained vdac arrays indicates that the protein forms a transmembrane channel in the p array. comparison of average images of arrays embedd ...19872442147
a protein required for splicing group i introns in neurospora mitochondria is mitochondrial tyrosyl-trna synthetase or a derivative thereof.the nuclear cyt-18 mutants of neurospora crassa are defective in splicing a number of group i introns in mitochondria. here, cloning and sequencing of the cyt-18 gene show that it contains an open reading frame having significant homology to bacterial tyrosyl-trna synthetases. biochemical and genetic experiments lead to the conclusions that the cyt-18 gene encodes mitochondrial tyrosyl-trna synthetase, that mutations in this gene inhibit splicing directly, and that mitochondrial tyrosyl-trna syn ...19873607872
the influence of copper on the induction of tyrosinase and laccase in neurospora crassa.the influence of copper on the cycloheximide-induced synthesis of the copper-containing enzymes tyrosinase and laccase in neurospora crassa was studied by enzyme activity measurements and immunological means. the amount of active enzyme molecules is far higher when the culture medium is copper-supplemented before cycloheximide induction. the synthesis of the apoproteins is not dependent on the presence of copper. this suggests the existence of a copper-storage protein for which metallothionein i ...19872956123
copper accumulation in the cell-wall-deficient slime variant of neurospora crassa. comparison with a wild-type strain.the copper-uptake process in the cell-wall-deficient slime variant of the fungus neurospora crassa was compared with that in a wild-type strain. in both organisms investigated most of the copper is taken up from the culture medium during the exponential growth period. the wild-type strain, however, accumulates much more copper than does the slime variant. the influence of the copper concentration in the culture medium on the amounts of copper accumulated intracellularly suggests separate ways of ...19872959274
isolation and characterization of non-neuronal enolase (nne) from neurospora crassa and comparison with neuron specific enolase isolated from neuroblastoma cell line ng108.enolase is a vital enzyme of the glycolytic pathway. it exists mainly in two forms, non-neuronal enolase (nne) and neuron specific enolase (nse). neurospora crassa, a filamentous fungus, was used as the source of pure nne, and by using deae-cellulose and a sephadex g-150 column chromatography highly purified enzyme (20.4 fold purification with 54.7 percent recovery) was obtained. the development profile of the enzyme shows a peak value after 90 hours of mycelial growth from conidia of n. crassa. ...19872969242
regulation of carbon and nitrogen flow by glutamate synthase in neurospora crassa.a glycine-resistant neurospora crassa mutant (am-132;glyr), derived from the am-132 mutant, was isolated and characterized. [am-132 itself has a deletion in the structural gene for nadp-dependent glutamate dehydrogenase (gdh).] this new mutation also conferred resistance to serine and methionine sulphoximine (ms), which are inhibitors of glutamine synthetase (gs). in addition, the mutant obtained grew better on ammonium than the am-132 parental strain. resistance to glycine was not due to increa ...19872959749
molecular cloning and characterization of the cys-3 regulatory gene of neurospora crassa.the regulatory gene cys-3+ controls the synthesis of a number of enzymes involved in sulfur metabolism. cys-3 mutants show a multiple loss of enzymes in different pathways of sulfur metabolism. the cys-3+ gene was isolated by transformation of an aro-9 qa-2 cys-3 inl strain with a clone bank followed by screening with the "sib selection" method. the library used (pral1) contained inserts of sau3a partial digest fragments of about 9 kilobases as well as the neurospora qa-2+ gene. double selection ...19872886908
deficiency in mrna splicing in a cytochrome c mutant of neurospora crassa: importance of carboxy terminus for import of apocytochrome c into mitochondria.molecular cloning and characterization of cytochrome c cdna clones of neurospora crassa wild-type (74a) and a cytochrome c-deficient mutant (cyc1-1) are described. southern blot analysis of genomic dna indicates that only one cytochrome c gene exists in the n. crassa genome. the cdna sequence of the wild-type cytochrome c confirmed the previously determined protein sequence. sequence analysis of the cyc1-1 cdna for cytochrome c revealed the presence of a larger open reading frame, owing to the p ...19872820723
differential dna methylation during the vegetative life cycle of neurospora crassa.isotope dilution gas chromatography-mass spectrometry analysis of genomic dnas isolated from the different growth phases of neurospora crassa revealed significant differences in the amounts of 5-methylcytosine; the mol % of 5-methylcytosine was 0.36 in conidia (asexual spores), 0.40 in conidial germlings cultured for 3 h, 0.24 in mycelial cells that had grown exponentially for 6 and 12 h, and 0.40 in stationary-phase mycelial cells. these results indicate an approximate inverse correlation betwe ...19872953709
arginine-specific carbamoyl phosphate metabolism in mitochondria of neurospora crassa. channeling and control by arginine.citrulline is synthesized in mitochondria of neurospora crassa from ornithine and carbamoyl phosphate. in mycelia grown in minimal medium, carbamoyl phosphate limits citrulline (and arginine) synthesis. addition of arginine to such cultures reduces the availability of intramitochondrial ornithine, and ornithine then limits citrulline synthesis. we have found that for some time after addition of excess arginine, carbamoyl phosphate synthesis continued. very little of this carbamoyl phosphate esca ...19872953716
characterization of nit-2, the major nitrogen regulatory gene of neurospora crassa.the nit-2 gene is the major nitrogen-regulatory gene of neurospora crassa, and under conditions of nitrogen limitations, it turns on the expression of various unlinked structural genes which specify nitrogen-catabolic enzymes. the nit-2 gene was subcloned as a 6-kilobase (kb) dna fragment from a cosmid that carried approximately a 40-kb n. crassa dna insert. the nit-2 gene was localized in a dna segment of approximately 3.5 kb and was shown to correspond to a unique dna sequence located on linka ...19872885741
a single precursor protein for two separable mitochondrial enzymes in neurospora crassa.the arg-6 locus of neurospora crassa encodes two early enzymes of the arginine biosynthetic pathway, acetylglutamate kinase and acetylglutamyl-phosphate reductase. previous genetic and biochemical analyses of this locus and its products showed that: 1) strains carrying polar nonsense mutations in the acetylglutamate kinase gene lacked both enzyme activities (davis, r.h., and weiss, r.l. (1983) mol. gen. genet. 192, 46-50), and 2) the proteins isolated from mitochondria were completely separable ...19873032945
gmp-stimulation of the cyanide-insensitive mitochondrial respiration in heat-shocked conidia of neurospora crassa.in mitochondria of heat-shocked conidia of neurospora exogenous nadh and succinate were oxidized mainly via the alternative, hydroxamate-sensitive pathway (70%) and only 30% via the cytochromic, cyanide-sensitive pathway which was predominant in untreated conidia; the alternative oxidase pathway was markedly stimulated by guanosine 5'-monophosphate (gmp).19873032673
location of a dicyclohexylcarbodiimide-reactive glutamate residue in the neurospora crassa plasma membrane h+-atpase.the proton pump (h+-atpase) found in the plasma membrane of the fungus neurospora crassa is inactivated by dicyclohexylcarbodiimide (dccd). kinetic and labeling experiments have suggested that inactivation at 0 degrees c results from the covalent attachment of dccd to a single site in the mr = 100,000 catalytic subunit (sussman, m. r., and slayman, c. w. (1983) j. biol. chem. 258, 1839-1843). in the present study, when [14c]dccd-labeled enzyme was treated with the cleavage reagent, n-bromosuccin ...19872881924
induced pelletized growth of neurospora crassa for tyrosinase biosynthesis in airlift fermenters. 198718576515
some aspects of the regulation of pyruvate kinase levels in neurospora crassa.pyruvate kinase levels were monitored in neurospora crassa mycelium (grown on different carbon sources for varying time intervals) by immunoprecipitation using polyclonal antibodies raised against a purified enzyme preparation. pyruvate kinase specific mrna was demonstrated by hybridization of northern and dot blots of total rna with a n. crassa pyruvate kinase gene fragment. two pyruvate kinase specific mrna species were detected in mycelia of all ages examined. an age-dependent and carbon sour ...19873036325
import of cytochrome c into mitochondria. cytochrome c heme lyase.the import of cytochrome c into mitochondria can be resolved into a number of discrete steps. here we report on the covalent attachment of heme to apocytochrome c by the enzyme cytochrome c heme lyase in mitochondria from neurospora crassa. a new method was developed to measure directly the linkage of heme to apocytochrome c. this method is independent of conformational changes in the protein accompanying heme attachment. tryptic peptides of [35s]cysteine-labelled apocytochrome c, and of enzymat ...19873030750
isolation and characterization of coated vesicles from filamentous fungi.coated vesicles have been shown to exist in neurospora crassa (ascomycetes) and uromyces phaseoli (basidiomycetes) growing germlings. separation of coated vesicles in both fungi was obtained when the high-speed (100,000g) pellet was fractioned on a sephacryl s-1000 gel filtration column, according to the procedure of mueller and branton. electron micrographs of negatively stained coated vesicles from fractions of gel filtration show the same striking lattice coated vesicles similar to vertebrate ...19872885195
circadian rhythms in neurospora crassa: membrane composition of a mutant defective in temperature compensation.the cel mutant of neurospora, partially blocked in fatty acid synthesis and lacking temperature compensation of its circadian rhythm below 22 degrees c, had a phospholipid fatty acid composition in liquid shaker culture distinctly different from that of a cel+ control strain. during growth, cel+ exhibited a reproducible increase in its linoleic acid level from about 32 to a plateau at 63 mol%, and a corresponding decrease in its linolenic acid level from about 40 to a plateau at 10 mol%. the lev ...19872950925
three-dimensional structure of nadh: ubiquinone reductase (complex i) from neurospora mitochondria determined by electron microscopy of membrane crystals.nadh: ubiquinone reductase (electron transfer complex i) has been isolated from neurospora crassa mitochondria as a monodisperse protein-phospholipid-triton x-100 complex (1:0.04:0.15, by weight). the enzyme is in the monomeric state, has a protein molecular weight of 610,000 and consists of about 25 different subunits. membrane crystals of the enzyme complex have been prepared by adding mixed phospholipid-triton x-100 micelles and then removing the triton by dialysis. diffraction patterns of th ...19872956429
h-atpase activity from storage tissue of beta vulgaris: iv. n,n'-dicyclohexylcarbodiimide binding and inhibition of the plasma membrane h-atpase.the molecular weight and isoelectric point of the plasma membrane h(+)-atpase from red beet storage tissue were determined using n,n'-dicyclohexylcarbodiimide (dccd) and a h(+)-atpase antibody. when plasma membrane vesicles were incubated with 20 micromolar [(14)c]-dccd at 0 degrees c, a single 97,000 dalton protein was visualized on a fluorograph of a sodium dodecyl sulfate polyacrylamide gel. a close correlation between [(14)c]dccd labeling of the 97,000 dalton protein and the extent of atpase ...198716665290
characterization of two abundantly expressed constitutive genes of neurospora crassa.two abundantly expressed, constitutive genes of neurospora crassa were isolated during differential screening of neurospora genomic libraries. the coding regions of these two genes, designated rlf1 and rlf3, were identified by hybridization of the cloned dna sequences with cdna probes made from polyadenylated rna. the rlf3 gene was carried on a 15-kilobase neurospora bamhi dna fragment present in a lambda 1059 recombinant; a 2-kilobase restriction fragment that contains rlf3 was subcloned into p ...19873032385
expression of qa-1f activator protein: identification of upstream binding sites in the qa gene cluster and localization of the dna-binding domain.the qa-1f regulatory gene of neurospora crassa encodes an activator protein required for quinic acid induction of transcription in the qa gene cluster. this activator protein was expressed in insect cell culture with a baculovirus expression vector. the activator binds to 13 sites in the gene cluster that are characterized by a conserved 16-base-pair sequence of partial dyad symmetry. one site is located between the divergently transcribed qa-1f and qa-1s regulatory genes, corroborating prior ev ...19872951591
nonsense mutations of the ornithine decarboxylase structural gene of neurospora crassa.ornithine decarboxylase (odc) (ec 4.1.1.17) is an early enzyme of polyamine synthesis, and its activity rises quickly at the onset of growth and differentiation in most eucaryotes. some have speculated that the enzyme protein may have a role in the synthesis of rrna in addition to its role in catalyzing the decarboxylation of ornithine (g. d. kuehn and v. j. atmar, fed. proc. 41:3078-3083, 1982; d. h. russell, proc. natl. acad. sci. usa 80:1318-1321, 1983). to test this possibility, we sought mu ...19872951589
signal for dna methylation associated with tandem duplication in neurospora crassa.most cytosine residues are subject to methylation in the zeta-eta (zeta-eta) region of neurospora crassa. the region consists of a tandem direct duplication of a 0.8-kilobase-pair element including a 5s rrna gene. the repeated elements have diverged about 15% by the occurrence of numerous cg to ta mutations, which probably resulted from deamination of methylated cytosines. most but not all common laboratory strains of n. crassa have methylated duplicated dna at the zeta-eta locus. however, many ...19872951588
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