| structure of the recombinant full-length hamster prion protein prp(29-231): the n terminus is highly flexible. | the prion diseases seem to be caused by a conformational change of the prion protein (prp) from the benign cellular form prpc to the infectious scrapie form prpsc; thus, detailed information about prp structure may provide essential insights into the mechanism by which these diseases develop. in this study, the secondary structure of the recombinant syrian hamster prp of residues 29-231 [prp(29-231)] is investigated by multidimensional heteronuclear nmr. chemical shift index analysis and nuclear ... | 1997 | 9391046 |
| the proofreading domain of escherichia coli dna polymerase i and other dna and/or rna exonuclease domains. | prior sequence analysis studies have suggested that bacterial ribonuclease (rnase) ds comprise a complete domain that is found also in homo sapiens polymyositis-scleroderma overlap syndrome 100 kda autoantigen and werner syndrome protein. this rnase d 3'-->5' exoribonuclease domain was predicted to have a structure and mechanism of action similar to the 3'-->5' exodeoxyibonuclease (proofreading) domain of dna polymerases. here, hidden markov model (hmm) and phylogenetic studies have been used to ... | 1997 | 9396823 |
| identification of a novel, non-snrnp protein complex containing u1a protein. | mouse monoclonal antibodies (mabs) were generated against escherichia coli-produced u1snrnp-a (u1a) protein. u1a-specific mabs as well as mabs that reacted with both u1a and u2snrnp-b" (u2b") were isolated. mab 12e12 was unique among the characterized mabs because it failed to immunoprecipitate u1a protein produced by in vitro transcription and translation using rabbit reticulocyte lysates. however, when u1a protein was made using a wheat germ extract, mab 12e12 could immunoprecipitate u1a quite ... | 1997 | 9404895 |
| control of expression of plcbeta1 by lac repressor system: relationship between nuclear plcbeta1 overexpression and growth factor stimulation. | swiss 3t3 cells have a nuclear phosphoinositide signalling system which is under the control of insulin-like growth factor i (igf-i) and acts separately from that at the plasma membrane. by using the lac repressor system we were able both to obtain the inducible overexpression of phospholipase c beta1 (plc beta1) and to determine its subcellular localisation and partitioning. moreover, by comparing the level of expression at the nucleus and the percentage of cells actively incorporating bromodeo ... | 1997 | 9405244 |
| the 1.25 a crystal structure of sepiapterin reductase reveals its binding mode to pterins and brain neurotransmitters. | sepiapterin reductase catalyses the last steps in the biosynthesis of tetrahydrobiopterin, the essential co-factor of aromatic amino acid hydroxylases and nitric oxide synthases. we have determined the crystal structure of mouse sepiapterin reductase by multiple isomorphous replacement at a resolution of 1.25 a in its ternary complex with oxaloacetate and nadp. the homodimeric structure reveals a single-domain alpha/beta-fold with a central four-helix bundle connecting two seven-stranded paralle ... | 1997 | 9405351 |
| spatio-temporally controlled site-specific somatic mutagenesis in the mouse. | the efficient introduction of somatic mutations in a given gene, at a given time, in a specific cell type will facilitate studies of gene function and the generation of animal models for human diseases. we have shown previously that conditional recombination-excision between two loxp sites can be achieved in mice by using the cre recombinase fused to a mutated ligand binding domain of the human estrogen receptor (cre-ert), which binds tamoxifen but not estrogens. dna excision was induced in a nu ... | 1997 | 9405652 |
| cloning and mutagenesis of a herpesvirus genome as an infectious bacterial artificial chromosome. | a strategy for cloning and mutagenesis of an infectious herpesvirus genome is described. the mouse cytomegalovirus genome was cloned and maintained as a 230 kb bacterial artificial chromosome (bac) in e. coli. transfection of the bac plasmid into eukaryotic cells led to a productive virus infection. the feasibility to introduce targeted mutations into the bac cloned virus genome was shown by mutation of the immediate-early 1 gene and generation of a mutant virus. thus, the complete construction ... | 1997 | 9405686 |
| a functional cftr protein is required for mouse intestinal camp-, cgmp- and ca(2+)-dependent hco3- secretion. | 1. most segments of the gastrointestinal tract secrete hco3-, but the molecular nature of the secretory mechanisms has not been identified. we had previously speculated that the regulator for intestinal electrogenic hco3- secretion is the cystic fibrosis transmembrane regulator (cftr) channel. to prove this hypothesis, we have now measured hco3- secretion by ph-stat titration, and recorded the electrical parameters of in vitro duodenum, jejunum and ileum of mice deficient in the gene for the cft ... | 1997 | 9423183 |
| genomic organization, cdna sequence, bacterial expression, and purification of human seryl-trna synthase. | in this paper, we report the cdna sequence and deduced primary sequence for human cytosolic seryl-trna synthetase, and its expression in escherichia coli. two human brain cdna clones of different origin, containing overlapping fragments coding for human seryl-trna synthetase were sequenced: hfbdn14 (fetal brain clone); and ib48 (infant brain clone). for both clones the 5' region of the cdna was missing. this 5' region was obtained via pcr methods using a human brain 5' race-ready cdna library. t ... | 1997 | 9431993 |
| urea inhibits inducible nitric oxide synthase in macrophage cell line. | macrophage dysfunction is considered an important contributory factor for increased propensity of infections in uremia. because nitric oxide (no) is believed to be an effector molecule of macrophage cytotoxicity, we propose that the dysfunction may be related to impaired no synthesis. to verify this hypothesis, we evaluated macrophage no synthesis in the presence of urea, a compound that accumulates in renal failure and is believed by some to be a uremic toxin. macrophages (raw 264.7 cells) were ... | 1997 | 9435493 |
| developmental regulation of 14-3-3 epsilon isoform in rat heart. | human heart cdna sequencing yielded a cdna clone that is similar in dna and amino acid sequences to that of mouse 14-3-3 epsilon isoform. the 6xhis-tagged h1433 epsilon recombinant protein was expressed in escherichia coli and its size was approximately 30 kda. from northern blot results with human multiple tissues, human skeletal muscle was found to have the highest level of h1433 epsilon mrna expression, whereas northern blots of human cancer cell lines detected the highest mrna level of h1433 ... | 1998 | 9443075 |
| intramolecular repression of mouse heat shock factor 1. | the pathway leading to transcriptional activation of heat shock genes involves a step of heat shock factor 1 (hsf1) trimerization required for high-affinity binding of this activator protein to heat shock elements (hses) in the promoters. previous studies have shown that in vivo the trimerization is negatively regulated at physiological temperatures by a mechanism that requires multiple hydrophobic heptad repeats (hrs) which may form a coiled coil in the monomer. to investigate the minimal requi ... | 1998 | 9447987 |
| the yersiniabactin biosynthetic gene cluster of yersinia enterocolitica: organization and siderophore-dependent regulation. | the ability to synthesize and uptake the yersinia siderophore yersiniabactin is a hallmark of the highly pathogenic, mouse-lethal species yersinia pestis, y. pseudotuberculosis, and y. enterocolitica 1b. we have identified four genes, irp1, irp3, irp4, and irp5, on a 13-kb chromosomal dna fragment of y. enterocolitica 08, wa-314. these genes constitute the yersiniabactin biosynthetic gene cluster together with the previously defined irp2. the irp1 gene consists of 9,486 bp capable of encoding a ... | 1998 | 9457855 |
| curli fibers are highly conserved between salmonella typhimurium and escherichia coli with respect to operon structure and regulation. | mouse-virulent salmonella typhimurium strains sr-11 and atcc 14028-1s express curli fibers, thin aggregative fibers, at ambient temperature on plates as judged by western blot analysis and electron microscopy. concomitantly with curli expression, cells develop a rough and dry colony morphology and bind the dye congo red (called the rdar morphotype). cloning and characterization of the two divergently transcribed operons required for curli biogenesis, csgba(c) and csgdefg, from s. typhimurium sr- ... | 1998 | 9457880 |
| a previously unidentified host protein protects retroviral dna from autointegration. | integration of a dna copy of the viral genome into a host chromosome is an essential step in the retrovirus life cycle. the machinery that carries out the integration reaction is a nucleoprotein complex derived from the core of the infecting virion. to successfully integrate into host dna, the viral dna within this complex must avoid self-destructive integration into itself, a reaction termed autointegration. we have previously shown [lee, m. s. and craigie, r. (1994) proc. natl. acad. sci. usa ... | 1998 | 9465049 |
| mouse steroid sulfotransferases: substrate specificity and preliminary x-ray crystallographic analysis. | three mouse cytosolic sulfotransferases were expressed in escherichia coli cells in order to study their substrate specificities toward natural as well as synthetic steroid hormones. the km and vmax values confirmed the high substrate specificity of estrogen and hydroxysteroid sulfotransferases toward estradiol and dehydroepiandrosterone, respectively. in sharp contrast, the synthetic estrogen diethylstilbestrol was metabolized efficiently by both enzymes to its disulfate ester. these sulfotrans ... | 1998 | 9484797 |
| bone marrow and liver mutagenesis in lacz transgenic mice treated with hexavalent chromium. | the mutagenic effects of the hexavalent chromium compound k2cro4 in lacz transgenic mice (muta mouse) were investigated at two sampling times. k2cro4 was administered intraperitoneally to five male mice per treatment group at a single dose of 40 mg/kg. the animals were sacrificed on days 1 and 7 after the treatment. mutant frequencies in the bone marrow and liver were analyzed by the positive selection method using escherichia coli c (gale-) strain and phenyl beta-d-galactoside. k2cro4 induced a ... | 1998 | 9508365 |
| mutations in either nucleotide-binding site of p-glycoprotein (mdr3) prevent vanadate trapping of nucleotide at both sites. | vanadate trapping of nucleotide and site-directed mutagenesis were used to investigate the role of the two nucleotide-binding (nb) sites in the regulation of atp hydrolysis by p-glycoprotein (mouse mdr3). mdr3, tagged with a hexahistidine tail, was overexpressed in the yeast pichia pastoris and purified to about 90% homogeneity by ni-affinity chromatography. this protocol yielded purified, reconstituted mdr3 which exhibited high verapamil stimulation of atpase activity with a vmax of 4.2 micromo ... | 1998 | 9521779 |
| the largest subunit of mouse rna polymerase ii (rpb1) functionally substituted for its yeast counterpart in vivo. | the full-length mouse rna polymerase ii (pol ii) largest subunit (rpb1) gene was used to replace 5070 bp of the yeast saccharomyces cerevisiae rpb1 gene via homologous recombination and gene replacement in vivo. transcription of the mouse rpb1 gene using the yeast promoter in the haploid state was confirmed by northern analysis. this strain of yeast is viable, indicating that mouse rpb1 is able to interact functionally with the other yeast rna pol ii subunits in vivo. | 1998 | 9524248 |
| in-vitro and in-vivo antibacterial activity of cfc-222, a new fluoroquinolone. | cfc-222 is a novel fluoroquinolone with potent and broad-spectrum antibacterial activity. the in-vitro and in-vivo activities of cfc-222 were compared with those of ciprofloxacin, ofloxacin, lomefloxacin and sparfloxacin. against gram-positive bacteria such as staphylococcus aureus (quinolone-susceptible and quinolone-resistant), staphylococcus epidermidis, streptococcus pneumoniae and enterococcus faecalis, cfc-222 was more active than ciprofloxacin and similar to sparfloxacin. against gram-neg ... | 1998 | 9533464 |
| statistical modelling and phylogenetic analysis of a deaminase domain. | deamination reactions are catalyzed by a variety of enzymes including those involved in nucleoside/nucleotide metabolism and cytosine to uracil (c-->u) and adenosine to inosine (a-->i) mrna editing. the active site of the deaminase (dm) domain in these enzymes contains a conserved histidine (or rarely cysteine), two cysteines and a glutamate proposed to act as a proton shuttle during deamination. here, a statistical model, a hidden markov model (hmm), of the dm domain has been created which iden ... | 1998 | 9541871 |
| determinants of the substrate specificity of human cytochrome p-450 cyp2d6: design and construction of a mutant with testosterone hydroxylase activity. | cytochrome p-450 cyp2d6, human debrisoquine hydroxylase, metabolizes more than 30 prescribed drugs, the vast majority of which are small molecules containing a basic nitrogen atom. in contrast, the similar mouse protein cyp2d-9 was first characterized as a testosterone 16alpha-hydroxylase. no common substrates have been reported for the two enzymes. here we investigate the structural basis of this difference in substrate specificity. we have earlier used a combination of nmr data and homology mo ... | 1998 | 9560305 |
| molecular cloning and expression of a cdna encoding an olfactory-specific mouse phenol sulphotransferase. | previously we demonstrated the presence of phenol sulphotransferase (p-st) in mouse nasal cytosols and identified its zonal location in mouse nasal cavity by staining with an antiserum raised against a rat liver p-st isoenzyme, pstg. in the present study a cdna was isolated from a mouse olfactory cdna library by immunological screening with the antiserum. the isolated cdna consisted of 1347 bp with a 912 bp open reading frame encoding a 304-residue polypeptide. both the nucleotide and deduced am ... | 1998 | 9560327 |
| differential expression of ifn-gamma, il-4, il-10, and il-1beta mrnas in decalcified tissue sections of mouse lipopolysaccharide-induced periodontitis mandibles assessed by in situ hybridization. | to examine the role of t cell subgroups, th1 and th2, in the development of periodontitis, the expression of various cytokines was investigated in a mouse model of alveolar bone resorption using in situ hybridization (ish) with digoxigenin-labeled oligonucleotides. when mice received repetitive injections with escherichia coli lipopolysaccharide into the gingiva every 48 h, alveolar bone resorption was detectable after the fourth injection, reaching a maximum after the 13th injection. for the be ... | 1998 | 9562383 |
| type specific and genotype cross reactive b epitopes of the l1 protein of hpv16 defined by a panel of monoclonal antibodies. | mouse monoclonal antibodies (mabs) were raised against the major capsid protein, l1, of human papillomavirus type 16 (hpv16), produced in escherichia coli with the expression plasmid ptrcl1. epitope specificity could be assigned to 11 of these 12 antibodies using a series of linear peptides and fusion proteins from hpv16. one mab (mc53) recognized a novel linear epitope that appears to be unique to the hpv16 genotype. a further 11 mabs were characterized as recognizing novel and previously defin ... | 1998 | 9568027 |
| purification and characterization of a recombinant human cripto-1 protein. | cripto-1 (cr-1) is a novel protein that contains a modified egf-like motif and that does not directly bind to any of the known erb b type-1 receptor tyrosine kinase receptors. to more clearly define the biological effects of cr-1 and to more adequately compare the structure-function relationships of cr-1 with other members of the egf family of growth factors, we have expressed a modified, full-length recombinant human cr-1 protein (rhcr-1) in e. coli and have devised a procedure for the solubili ... | 1998 | 9570042 |
| time course and host responses to escherichia coli urinary tract infection in genetically distinct mouse strains. | recurrent urinary tract infections (utis) are a significant clinical problem for many women; however, host susceptibility factors have not been completely defined. the mouse model of induced uti provides an experimental environment in which to identify specific host characteristics that are important in initial bacterial colonization of the urinary tract and in resolution of an infection. this study examined initial susceptibility, bacterial clearance, and host defense mechanisms during inductio ... | 1998 | 9596750 |
| effect of mouse intestinal bacteria on incidence of colorectal tumors induced by 1,2-dimethylhydrazine injection in gnotobiotic transgenic mice harboring human prototype c-ha-ras genes. | we produced transgenic (tg) gnotobiotic (gb) mice carrying human prototype c-ha-ras genes and compared the incidence of colorectal tumors induced by 1,2-dimethylhydrazine (dmh) injection. at 7 to 11 weeks of age, germfree (gf) cb6f1-tg hras2 mice were inoculated with various mouse fecal suspensions or mixtures of bacteria isolated from mouse feces. three weeks after bacterial inoculation, dmh was administered by subcutaneous injection at 20 mg per kg body weight for 20 weeks. mice were euthanize ... | 1998 | 9606421 |
| cloning, expression, and biochemical characterization of a functionally novel alpha class glutathione s-transferase with exceptional activity in the glutathione conjugation of (+)-anti-7,8-dihydroxy-9,10-oxy-7,8,9,10-tetrahydrobenzo(a)pyrene. | the present study describes cdna cloning, expression, and kinetic characterization of the two subunits of a murine alpha-class glutathione (gsh) s-transferase (gst) isoenzyme (previously designated as gst 9.5), which, unlike other alpha-class mammalian gsts, is exceptionally efficient in the gsh conjugation of (+)-anti-7,8-dihydroxy-9,10-oxy-7,8,9,10-tetrahydrobenzo(a)pyrene [(+)-anti-bpde] [x. hu, s. k. srivastava, h. xia, y. c. awasthi, and s. v. singh (1996) j. biol. chem. 271, 32684-32688]. ... | 1998 | 9606968 |
| immunisation with recombinant ama-1 protects mice against infection with plasmodium chabaudi. | the plasmodium merozoite surface antigen apical membrane antigen-1 (ama-1) has previously been shown to provide partial protection to saimiri and rhesus monkeys immunised with recombinant plasmodium fragile or parasite-derived plasmodium knowlesi ama-1, respectively. in the study reported here we have used the plasmodium chabaudi/mouse model system to extend our pre-clinical assessment of an ama-1 vaccine. we describe here the expression of the full-length plasmodium chabaudi adami ama-1 and the ... | 1998 | 9607037 |
| cloning and characterization of the mouse and rat type ii arginase genes. | two forms of arginase, both catalyzing the hydrolysis of arginine to ornithine and urea, are found in animals ranging from amphibians to mammals. in humans, inherited deficiency of hepatic or type i arginase results in hyperargininemia, a syndrome characterized by periodic episodes of hyperammonemia, spasticity, and neurological deterioration. in these patients, a second extrahepatic or type ii arginase activity is significantly increased, an induction that may partially compensate for the lack ... | 1998 | 9608538 |
| endotoxin-induced alteration in the expression of leptin and beta3-adrenergic receptor in adipose tissue. | cytokines, such as tumor necrosis factor (tnf) and interleukin-6, may contribute to the anorexia and cachexia of infection, cancer, and aids. the present study tests the hypothesis that endotoxin alters the expression of two key fat cell proteins, leptin and beta3-adrenergic receptor (beta3-ar), through a mechanism involving tnf-alpha. increasing doses of escherichia coli endotoxin (lipopolysaccharide, lps) resulted in dose-dependent elevations of plasma leptin (maximal response approximately 7- ... | 1998 | 9611147 |
| chimeric small subunit inhibitors of mammalian ribonucleotide reductase: a dual function for the r2 c-terminus? | here we report on the formation and activity of complexes between the large subunit (mr1) dimer of mouse ribonucleotide reductase (mrr) and small subunit chimeric dimers (cr2) derived from escherichia coli and mouse small subunits. cr2 subunits were constructed by substituting mouse c-terminal gene sequences, coding for either 7 or 33 amino acid residues, for the corresponding e.coli r2 (er2) sequences, with the remainder of the gene corresponding to er2. the purified cr2s contained the micro-ox ... | 1998 | 9613846 |
| lipofection of cultured mouse muscle cells: a direct comparison of lipofectamine and dosper. | cationic lipid-dna complexes (lipoplexes) have been widely used as gene transfer vectors which avoid the adverse immunogenicity and potential for viraemia of viral vectors. with the long-term aim of gene transfer into skeletal muscle in vivo, we describe a direct in vitro comparison of two commercially available cationic lipid formulations, lipofectamine and dosper. optimisation of transfection was performed in the c2c12 mouse muscle cell line, before further studies in primary mouse myoblasts a ... | 1998 | 9614580 |
| nucleolar localization of the werner syndrome protein in human cells. | werner syndrome (ws) is a human genetic disorder with many features of premature aging. the gene defective in ws (wrn) has been cloned and encodes a protein homologous to several helicases, including escherichia coli recq, the human bloom syndrome protein (blm), and saccharomyces cerevisiae sgs1p. to better define the function of wrn protein we have determined its subcellular localization. indirect immunofluorescence using polyclonal anti-human wrn shows a predominant nucleolar localization. stu ... | 1998 | 9618508 |
| new monoclonal antibodies to the t cell antigens cd4 and cd8. production and characterization in formalin-fixed paraffin-embedded tissue. | we have generated a recombinant protein representing part of the cd4 molecule and a peptide representing an epitope of predicted high antigenicity on the cd8 molecule and employed these to generate mouse monoclonal antibodies using standard hybridoma protocols. the extracellular domain of the cd4 molecule was obtained by reverse transcription of mrna from peripheral blood lymphocytes followed by polymerase chain reaction. the amplified gene fragment was cloned into an expression vector to allow ... | 1998 | 9626046 |
| purification, characterization, and cloning of a cytosolic aspartyl aminopeptidase. | an aminopeptidase with a preference for n-terminal aspartyl and glutamyl residues but distinct from glutamyl aminopeptidase (ec 3.4. 11.7) was purified to near homogeneity from rabbit brain cytosol. its properties were similar to an enzyme described previously (kelly, j. a., neidle, e. l., and neidle, a. (1983) j. neurochem. 40, 1727-1734). aspartyl aminopeptidase had barely detectable activity toward simple aminoacyl-naphthylamide substrates. its activity was determined with the substrate asp-a ... | 1998 | 9632644 |
| leukocystatin, a new class ii cystatin expressed selectively by hematopoietic cells. | we describe a new cystatin in both mice and humans, which we termed leukocystatin. this protein has all the features of a class ii secreted inhibitory cystatin but contains lysine residues in the normally hydrophobic binding regions. as determined by cdna library southern blots, this cystatin is expressed selectively in hematopoietic cells, although fine details of the distribution among these cell types differ between the human and mouse mrnas. in addition, we have determined the genomic organi ... | 1998 | 9632704 |
| aberrant expression and potential function for parotid secretory protein (psp) in the nod (non-obese diabetic) mouse. | | 1998 | 9634989 |
| mutations in the nucleotide-binding sites of p-glycoprotein that affect substrate specificity modulate substrate-induced adenosine triphosphatase activity. | the amino- and carboxy-terminal nucleotide-binding domains (nbd1 and nbd2) of p-glycoprotein (p-gp) share over 80% sequence identity. almost all of nbd1 can be exchanged by corresponding nbd2 segments with no significant loss of function, except for a small segment around the walker b motif. within this segment, we identified two sets of residues [erga --> dkgt (522-525) and t578c] that, when replaced by their nbd2 counterparts, cause dramatic alterations of the substrate specificity of the prot ... | 1998 | 9636053 |
| the fragile-x-related gene fxr1 is a human autoantigen processed during apoptosis. | we describe a new human autoimmune antigen in a patient suffering from scleroderma with high levels of antibodies to nucleolus and cytoplasmic antigens. using a chinese hamster ovary cell expression library, we have shown that this antigen corresponds to the autosomal fragile-x-related gene fxr1. the deduced amino acid sequence from the hamster cdna is 97, 98, and 58% homologous to the human, mouse, and xenopus laevis fxr1 genes, respectively. expression of the hamster cdna clone in escherichia ... | 1998 | 9642279 |
| efficient introduction of alkene functionality into proteins in vivo. | the methionine analogue 2-amino-5-hexenoic acid (homoallylglycine, hag) can be utilized by escherichia coli in the initiation and elongation steps of protein biosynthesis. use of an e. coli methionine auxotroph and hag-supplemented medium resulted in replacement of ca. 85% of the methionine residues in mouse dihydrofolate reductase expressed under control of a bacteriophage t5 promoter. n-terminal sequencing indicated 92+/-5% occupancy of the initiator site by hag. the vinyl function of hag rema ... | 1998 | 9645477 |
| construction and expression of a bifunctional single-chain antibody against bacillus cereus p6ores. | the variable-region genes of monoclonal antibody against bacillus cereus spores were cloned from mouse hybridoma cells by reverse transcription-pcr. the heavy- and light-chain variable-region genes were connected by a 45-base linker dna to allow folding of the fusion protein into a functional tertiary structure. for detection of protein expression, a 10-amino-acid strep tag (biotin-like peptide) was attached to the c terminus of recombinant antibody as the reporter peptide. the single-chain anti ... | 1998 | 9647820 |
| sequence analysis and expression of a novel mouse homolog of escherichia coli reca gene. | escherichia coli reca and its yeast homologs rad51 and dmc1 play crucial roles in mitotic and/or meiotic recombination and in repair of double-strand dna breaks. we have identified a murine novel reca-like gene (mmtrad). the predicted 329 amino acid protein showed significant homology to mouse rec2, rad51, dmc1 (or lim15) and e. coli reca. northern blot analysis revealed that mmtrad was ubiquitously transcribed in various tissues. | 1998 | 9655934 |
| molecular characterization of the human carbonic anhydrase-related protein (hca-rp viii). | the very evolutionarily conserved human carbonic anhydrase-related polypeptide (ca-rp viii) lacks the carbon-dioxide hydration-activity, characteristic of the enzymatically active carbonic anhydrases. we have expressed hca-rp viii as a glutathione-s-transferase fusion protein (gst-hca-rp viii). the purified hca-rp viii showed a substantially higher apparent molecular weight by gel-filtration compared to the molecular weight calculated from the amino acid sequence, indicating a larger than expect ... | 1998 | 9659390 |
| improved properties of flp recombinase evolved by cycling mutagenesis. | the site-specific recombinases flp and cre are useful for genomic engineering in many living systems. manipulation of their enzymatic properties offers a means to improve their applicability in different host organisms. we chose to manipulate the thermolability of flp recombinase. a lacz-based recombination assay in escherichia coli was used for selection in a protein evolution strategy that relied on error-prone pcr and dna shuffling. improved flp recombinases were identified through cycles of ... | 1998 | 9661200 |
| displacement of platelets from blood to spleen following intravenous injection of liposomes encapsulating dichloromethylene bisphosphonate. | liposomes encapsulating dichloromethylene bisphosphonate (cl2mbp-liposomes) have been shown to cause selective depletion of phagocytic macrophages. we have shown that intravenous injection of cl2mbp-liposomes into mice induces an almost complete depletion of f4/80-positive cells (mature macrophages) in the liver and in the splenic red pulp, but not in the lung. platelets in the mouse contain a large amount of 5-hydroxytryptamine (5ht; serotonin) and so, by measuring 5ht, it is possible to assess ... | 1998 | 9667418 |
| selective activation of oncogenic ha-ras-induced apoptosis in nih/3t3 cells. | a ha-ras transformant '7-4', derived from mouse nih/3t3 fibroblasts, was used to study the relationship between overexpression of activated ha-ras and cell apoptosis. this cell line contains an inducible ha-rasval12 oncogene, which was under the regulation of the escherichia coli (e. coli) lac operator/repressor system. we demonstrate that overexpression of activated ha-ras oncogene by exogenous isopropyl-beta-d-thiogalactoside (iptg) under serum-depleted conditions can stimulate cell apoptosis. ... | 1998 | 9667646 |
| pathogenic adaptation of escherichia coli by natural variation of the fimh adhesin. | conventional wisdom regarding mechanisms of bacterial pathogenesis holds that pathogens arise by external acquisition of distinct virulence factors, whereas determinants shared by pathogens and commensals are considered to be functionally equivalent and have been ignored as genes that could become adapted specifically for virulence. it is shown here, however, that genetic variation in an originally commensal trait, the fimh lectin of type 1 fimbriae, can change the tropism of escherichia coli, s ... | 1998 | 9671780 |
| molecular cloning of a cdna encoding human calumenin, expression in escherichia coli and analysis of its ca2+-binding activity. | by microsequencing and cdna cloning we have identified the transformation-sensitive protein no. ief ssp 9302 as the human homologue of calumenin. the nucleotide sequence predicts a 315 amino acid protein with high identity to murine and rat calumenin. the deduced protein contains a 19 amino acid n-terminal signal sequence, 7 ef-hand domains and, at the c-terminus, a hdef sequence which has been reported to function as retrieval signal to the er. the calumenin transcript is ubiquitously expressed ... | 1998 | 9675259 |
| isolation and characterization of an allelic cdna for human muscle fructose-1,6-bisphosphatase. | by applying a newly developed method, cdnas for the human muscle isoform of fructose-1,6-bisphosphatase were isolated from phage- and plasmid-derived libraries. from these cdnas and an est clone, a composite sequence (1302 bp) was deduced that contains an open reading frame encoding a polypeptide of 339 amino acids with an estimated molecular weight of 36 755. after overexpression in e. coli, recombinant human muscle fructose 2,6-bisphosphatase was found to be active in cel-free extracts and cou ... | 1998 | 9678974 |
| molecular cloning of cdna and tissue-specific expression of the gene for sii-k1, a novel transcription elongation factor sii. | transcription elongation factor sii has been shown to promote read-through by rna polymerase ii of pausing sites within various eukaryotic genes in vitro by inducing cleavage of the 3'-end of the nascent transcript in the ternary elongation complex. recently, we showed that various mouse tissues contain multiple sii-related proteins. of these, 'general sii' was ubiquitously expressed, whereas the others were expressed in a tissue-specific manner. we have identified testis-specific sii (sii-t1) a ... | 1998 | 9685180 |
| kinetic evidence that a radical transfer pathway in protein r2 of mouse ribonucleotide reductase is involved in generation of the tyrosyl free radical. | class i ribonucleotide reductases consist of two subunits, r1 and r2. the active site is located in r1; active r2 contains a diferric center and a tyrosyl free radical (tyr.), both essential for enzymatic activity. the proposed mechanism for the enzymatic reaction includes the transport of a reducing equivalent, i.e. electron or hydrogen radical, across a 35-a distance between tyr. in r2 and the active site in r1, which are connected by a hydrogen-bonded chain of conserved, catalytically essenti ... | 1998 | 9705274 |
| identification and characterization of hu protein from mycoplasma gallisepticum. | a hypothetical orf of mycoplasma gallisepticum with a putative 99-amino-acid product (orf99) was noted previously in the upstream region from the type ii topoisomerase gene. the amino acid sequence shows weak homology with the escherichia coli histone-like protein hu. to identify and characterize the protein product of orf99, we prepared mouse antiserum against recombinant gst-orf99 fusion protein. the antiserum reacted with an 11-kda peptide in the crude cell extract of m. gallisepticum, indica ... | 1998 | 9705829 |
| mutagenicity of p-aminophenol in e. coli wp2uvra/pkm101 and its relevance to oxidative dna damage. | it was recently reported that p-aminophenol (p-ap) induces dna cleavage in mouse lymphoma cells, cho cells and human lymphoblastoid cells. the mutagenicity of p-ap has not, however, been detected by reverse mutation assays. the purpose of this study was to assess the mutagenicity of p-ap by reverse mutation assay using escherichia coli wp2uvra/pkm101, which has a spectrum for detecting mutations different from those of other strains in the family with an at base pair at the mutation site and has ... | 1998 | 9711270 |
| chlamydial heat shock protein 60 localizes in human atheroma and regulates macrophage tumor necrosis factor-alpha and matrix metalloproteinase expression. | recent evidence has implicated chlamydia pneumoniae in the aggravation of atherosclerosis. however, the mechanisms by which this agent affects atherogenesis remain poorly understood. chlamydiae produce large amounts of heat shock protein 60 (hsp 60) during chronic, persistent infections, and c pneumoniae localizes predominantly within plaque macrophages. several studies have furnished evidence that endogenous (human) hsp 60 may play a role in atherogenesis. we tested here the hypothesis that ath ... | 1998 | 9711934 |
| bovine herpesvirus type 1 glycoprotein h is essential for penetration and propagation in cell culture. | bovine herpesvirus type 1 (bhv-1) glycoprotein h (gh) is a structural component of the virion which forms a complex with glycoprotein gl. to study the role of bhv-1 gh in the virus infectious cycle, a gh null mutant was constructed in which the gh coding sequences were deleted and replaced by the escherichia coli lacz cassette. the bhv-1 gh null mutant was propagated in trans-complementing mdbk cells, stably transfected with plasmid pmep4 containing the bhv-1 gh gene under the control of the ind ... | 1998 | 9714247 |
| the escherichia coli chaperonin 60 (groel) is a potent stimulator of osteoclast formation. | chaperonins (cpns) are intracellular oligomeric protein complexes that fold and refold proteins in a catalytic manner and aid in the transmembrane transport of cellular proteins. we reported previously that the lipopolysaccharide-free recombinant cpn60 of escherichia coli (groel) is able to stimulate the breakdown of murine calvarial bone in culture and showed that such resorption is potently inhibited by an inhibitor of the enzyme cyclo-oxygenase and to a lesser extent by inhibitors of 5-lipoxy ... | 1998 | 9718194 |
| the lim domains of hic-5 protein recognize specific dna fragments in a zinc-dependent manner in vitro. | hic-5 protein is a member of the lim protein family, containing four lim domains in its c-terminal region. it is mainly localized in focal adhesions and shows striking similarity to paxillin in its lim domains, although the function of these lim domains has remained elusive. in the present study, we found that full-length and the c-terminal half of hic-5 protein, including four lim domains, bound to dna in a zinc-dependent manner in vitro . mouse genomic fragments that specifically bound to the ... | 1998 | 9722648 |
| mapping of cholecystokinin transcription in transgenic mouse brain using escherichia coli beta-galactosidase reporter gene. | cholecystokinin (cck), a neuro-gut peptide, occurs not only in the nervous but also in the digestive system. as a first step in elucidating whether cck gene expression and its physiological functions co-operate in these separate organs, transgenic mice were produced using cck promoter that directs bacterial beta-galactosidase as a reporter gene. a new transgenic vector was constructed, inserting the sv40 poly a signal 5' to the cck promoter to impede any transcription upstream of the transgene. ... | 1998 | 9727353 |
| thermodynamics and kinetics of the reaction of a single-chain antibody fragment (scfv) with the leucine zipper domain of transcription factor gcn4. | single-chain fv (scfv) fragments of antibodies have become important analytical and therapeutic tools in biology and medicine. the reaction of scfv fragments has not been well-characterized with respect to the energetics and kinetics of antigen binding. this paper describes the thermodynamic and kinetic behavior of the high-affinity scfv fragment sw1 directed against the dimeric leucine zipper domain of the yeast transcription factor gcn4. the scfv fragment was selected by the phage display tech ... | 1998 | 9737882 |
| anchoring antibodies to membranes using a diphtheria toxin t domain-zz fusion protein as a ph sensitive membrane anchor. | we have constructed a fusion protein, t-zz, in which the igg-fc binding protein zz was fused to the c-terminus of the diphtheria toxin transmembrane domain (t domain). while soluble at neutral ph, t-zz retained the capacity of the t domain to bind to phospholipid membranes at acidic ph. once anchored to the membrane, the zz part of the protein was capable of binding mouse monoclonal or rabbit polyclonal igg. our results show that the t-zz protein can function as a ph sensitive membrane anchor fo ... | 1998 | 9738938 |
| cdna cloning and characterization of mouse nifs-like protein, m-nfs1: mitochondrial localization of eukaryotic nifs-like proteins. | we have isolated a mouse cdna which shows significant sequence similarity to the yeast nifs-like gene (y-nfs1), and termed it m-nfs1. the deduced protein sequence (459 amino acids long) has several characteristic features common to those of bacterial nifs proteins, but distinct from them by its amino-terminal extension which contains a typical mitochondrial targeting presequence. m-nfs1 was found to be a soluble 47-kda protein in the matrix fraction of mouse liver mitochondria. the m-nfs1 gene w ... | 1998 | 9738949 |
| characterization of hematopoietic progenitor cells that express the transcription factor scl, using a lacz "knock-in" strategy. | gene targeting experiments have demonstrated that the transcription factor scl is essential for primitive and definitive hematopoiesis in the mouse. to study the functional properties of hematopoietic cells expressing scl, we have generated mutant mice (scllacz/w) in which the escherichia coli lacz reporter gene has been "knocked in" to the scl locus, thereby linking beta-galactosidase expression to transcription from the scl promoter. bone marrow cells from heterozygous scllacz/w mice were sort ... | 1998 | 9751762 |
| cdna cloning and escherichia coli expression of uk114 tumor antigen. | experimental evidence indicates that the antineoplastic effects of uk101, a goat liver perchloric acid extract, is likely due to one of its constituent proteins: the 14 kda protein named uk114. the cdna encoding uk114, obtained by pcr methodologies, contains an open reading frame coding for a protein of 137 amino acids with a theoretical molecular mass of 14298 da. it shows high sequence homology with a 14 kda protein identified in human, rat and mus musculus tissues which is likely involved in ... | 1998 | 9767104 |
| unmyristoylated marcks-related protein (mrp) binds to supported planar phosphatidylcholine membranes. | we have recently shown that unmyristoylated marcks-related protein (mrp) does not bind to neutral phospholipid vesicles, unless negatively charged phospholipids are present. similar behaviour has also been reported for marcks itself. here we have compared the binding of mrp to neutral and negatively charged supported planar lipid bilayer membranes (splm) using two-mode waveguide spectroscopy. we find appreciable binding of unmyristoylated mrp to neutral splm. we propose that hydrophobic residues ... | 1998 | 9767142 |
| a stomatin-like protein encoded by the slp gene of rhizobium etli is required for nodulation competitiveness on the common bean. | rhizobium etli strain tal182 is a competitive strain for effective nodulation of beans. from this strain, a novel gene was isolated, slp, which is 669 bp in size and required for nodulation competition on the common bean. the slp knockout mutant of tal182 is defective in nodulation competition, shows reduced growth in the presence of 200 mm nacl, kcl or licl and is complemented by the cloned slp gene. the deduced amino acid sequence of slp shows 66-72% similarity to stomatin proteins of homo sap ... | 1998 | 9782511 |
| protective immunity against equine herpesvirus type-1 (ehv-1) infection in mice induced by recombinant ehv-1 gd. | the ability of recombinant preparations of equine herpesvirus type 1 (ehv-1) glycoprotein d (gd) to elicit specific antibody and t lymphocyte responses in the balb/c mouse model of respiratory infection was investigated. recombinant gd (rgd) expressed as a glutathione-s-transferase (gst) fusion protein in escherichia coli elicited both high titer neutralizing antibody (nab) and cd4 t cell proliferative responses following subcutaneous or intranasal immunization, but elicited only a weak antibody ... | 1998 | 9784062 |
| ambiguus nucleus neurons innervating the abdominal esophagus are malpositioned in the reeler mouse. | to examine whether the migration of ambiguus nucleus (na) neurons is affected in the reeler mouse, recombinant replication-deficient adenoviral vector carrying e. coli-galactosidase gene (lacz) was injected into the abdominal esophagus of the reeler mouse and normal control at two months of age prior to 5 days of sacrifice of the animals. in the normal control, lacz-positive neurons were found in the compact formation of the na, whereas, in the reeler, they were scattered from the base of the fo ... | 1998 | 9804938 |
| the reductase domain of the human inducible nitric oxide synthase is fully active in the absence of bound calmodulin. | nitric oxide synthases (noss) are composed of a flavin-containing reductase domain and a heme-containing oxygenase domain. each nos enzyme also contains a calmodulin (cam) binding domain and requires bound calmodulin for enzymatic activity. the cam binding properties of the different nos isozymes differ in the need for free calcium ions (ca2+). we investigated cam binding using reductase domains from the human and mouse inducible as well as the rat neuronal isoforms of nos. an escherichia coli e ... | 1998 | 9808767 |
| cloning of murine low molecular weight phosphotyrosine protein phosphatase cdna: identification of a new isoform. | the low molecular weight phosphotyrosine protein phosphatase (lmw-ptp) is a 18 kda cytosolic enzyme, involved in the negative regulation of cell proliferation. in different mammalian species lmw-ptps are expressed in two molecular forms produced from a single primary transcript through an alternative splicing mechanism. in this paper we report the cloning, expression and characterization of mouse isoforms of lmw-ptps (called m-if1 and m-if2), very similar to the corresponding rat and human isoen ... | 1998 | 9824304 |
| a functional homolog of a yeast trna splicing enzyme is conserved in higher eukaryotes and in escherichia coli. | trna splicing in the yeast saccharomyces cerevisiae requires an endonuclease to excise the intron, trna ligase to join the trna half-molecules, and 2'-phosphotransferase to transfer the splice junction 2'-phosphate from ligated trna to nad, producing adp ribose 1"-2" cyclic phosphate (appr>p). we show here that functional 2'-phosphotransferases are found throughout eukaryotes, occurring in two widely divergent yeasts (candida albicans and schizosaccharomyces pombe), a plant (arabidopsis thaliana ... | 1998 | 9826666 |
| susceptibility of three strains of conventional adult mice to intestinal colonization by an isolate of escherichia coli o157:h7. | three mouse strains were assessed for their susceptibility to intestinal colonization by a strain of the enteric bacterial pathogen escherichia coli o157:h7. following intragastric inoculation of e. coli o157:h7, the intestines of young adult female cd1, balb/c, and c57bl/6 mice became colonized, as evidenced by faecal shedding of the pathogen for periods of up to 5 weeks. none of the three mouse strains examined developed overt disease in response to colonization by the organism. following clea ... | 1998 | 9830109 |
| methylation of cpg dinucleotides in the laci gene of the big blue transgenic mouse. | cytosine residues at cpg dinucleotides can be methylated by endogenous methyltransferases in mammalian cells. the resulting 5-methylcytosine base may undergo spontaneous deamination to form thymine causing g/c to a/t transition mutations. methylated cpgs also can form preferential targets for environmental mutagens and carcinogens. the big blue(r) transgenic mouse has been used to investigate tissue and organ specificity of mutations and to deduce mutational mechanisms in a mammal in vivo. the t ... | 1998 | 9838042 |
| antigen mimicry by an anti-idiotypic antibody single chain variable fragment. | for the therapy of cancer patients whose disease is positive for carcinoembryonic antigen (cea), we developed an active specific immunotherapy based on the idiotypic network. the anti-idiotype monoclonal antibody (mab), 3h1 was generated by immunization of mice with the anti-cea mab, 8019. 3h1 mimics cea both functionally and structurally and acts as a surrogate for cea. to define the minimum structural requirements for antigen mimicry by 3h1, we constructed plasmid vectors for expression of sin ... | 1998 | 9839554 |
| role of inducible nitric oxide synthase in endotoxin-induced acute lung injury. | the role of nitric oxide (no) in lung injury remains unclear. both beneficial and detrimental roles have been proposed. in this study, we used mutant mice lacking the inducible nitric oxide synthase (inos) to assess the role of this isoform in sepsis-associated lung injury. wild-type and inos knockout mice were injected with either saline or escherichia coli endotoxin (lps) 25 mg/kg and killed 6, 12, and 24 h later. lung injury was evaluated by measuring lactate dehydrogenase activity in the bro ... | 1998 | 9847282 |
| effect of dietary insulin on the response of suckling mice enterocytes to escherichia coli heat-stable enterotoxin. | effect of insulin on the response of suckling mice to the enterotoxigenic escherichia coli heat-stable enterotoxin (sta) was studied. four groups (8-10 in each group) of 2-day-old swiss webster suckling mice were used. for this study, 5, 10, 25 and 50 micrograms of insulin was given orally to half the mice in each group for 7 days. the rest of the mice in each group were given normal saline as intra-litter controls. after 7 days, a suckling mouse assay in which 1 microgram of sta was given to al ... | 1998 | 9851009 |
| mutation studies in laci transgenic mice after exposure to radiation or cyclophosphamide. | we have used the big blue laci transgenic mouse reporter system to investigate mutation induction in the testes, spleen and liver after exposure to an internally incorporated radionuclide, 114min, whole body irradiation with 60co gamma-rays and systemically administered cyclophosphamide. spontaneous mutation frequencies were 6-17x10(-6). no statistically significant mutation induction was observed in testes or spleen at 35 days after exposure to any test agent, although mutation frequencies tend ... | 1998 | 9862192 |
| specific mutational spectrum of dimethylnitrosamine in the laci transgene of big blue c57bl/6 mice. | dimethylnitrosamine (dmn) produces tumors in mice predominantly in the liver, but also in the kidney and lung. it forms o6-methylguanine adducts in dna, which induce g:c-->a:t transitions. we have analyzed the spectra of spontaneous and dmn-induced mutations in the laci transgene of the big blue mouse (c57bl/6). in both cases, mutations in the liver, kidney and lung were predominantly base substitutions, among which g:c-->a:t transitions were the most frequent. in contrast, a high incidence of s ... | 1998 | 9862195 |
| interaction of nk lysin, a peptide produced by cytolytic lymphocytes, with endotoxin. | nk lysin is a 9-kda polypeptide that was originally isolated from porcine intestinal tissue based on its antibacterial activity. it is produced by cytolytic lymphocytes and is cytolytic against a number of different types of tumor cells. here we report the binding of nk lysin to lipopolysaccharide (lps) and its anti-lps activity. nk lysin binds to matrix-coated lps from escherichia coli, pseudomonas aeruginosa, and different strains of salmonella enterica. lipid a and polymyxin b inhibited the b ... | 1999 | 9864216 |
| detection of live trypanosoma cruzi in tissues of infected mice by using histochemical stain for beta-galactosidase. | the pathogenesis of tissue damage in chronic trypanosoma cruzi infection has been a subject of long-standing debate. conventional staining methods reveal a paucity of parasites in tissues from chronically infected individuals, which has led to the theory that the pathologic findings may be primarily autoimmune in origin. immunostaining for t. cruzi antigens or in situ pcr methods show evidence for parasite components in chronic tissues; however, these methods do not address whether the stained m ... | 1999 | 9864242 |
| cooperative formation of the ligand-binding site of the inositol 1,4, 5-trisphosphate receptor by two separable domains. | limited trypsin digestion of mouse cerebellar membrane fractions leads to fragmentation of the type 1 inositol 1,4,5-trisphosphate receptor (ip3r1) into five major components (yoshikawa, f., iwasaki, h., michikawa, t., furuichi, t., and mikoshiba, k. (1999) j. biol. chem. 274, 316-327). here we report that trypsin-fragmented mouse ip3r1 (mip3r1) retains significant inositol 1,4,5-trisphosphate (ip3) binding activity that is comparable to the intact receptor in affinity, capacity, and specificity ... | 1999 | 9867847 |
| expression of a recombinant fab antibody fragment against cruzipain, the major cysteine proteinase of trypanosoma cruzi. | cruzipain, the major proteinase of trypanosoma cruzi, plays an important role in the biology of this parasite. this study reports the development of a recombinant fab antibody, using rna isolated from the anti-ag163b6 hybridoma against cruzipain. this procedure involves the use of cdnas obtained with the aid of a specific set of primers complementary to the complete light kappa chain (l kappa) and the first two domains of the igg1 heavy chain (vh/ch1). these products were subsequently cloned in ... | 1998 | 9875219 |
| expression of a tyrosine phosphorylated, dna binding stat3beta dimer in bacteria. | the signal transducer and activator of transcription (stat) proteins deliver signals from the cell membrane to the nucleus. an n-terminally truncated fragment of murine stat3beta, stat3betatc (127-722), was produced in bacteria. stat proteins must be specifically phosphorylated at a single tyrosine residue for dimerization and dna binding. therefore, stat3betatc was coexpressed with the catalytic domain of the elk receptor tyrosine kinase. stat3betatc was quantitatively phosphorylated by this ki ... | 1998 | 9877182 |
| expression of the mnb (dyrk) protein in adult and embryonic mouse tissues. | mnb is a human homologue of the drosophila minibrain gene which encodes a serine/threonine protein kinase that is required in distinct neuroblast proliferation centers during postembryonic neurogenesis. the high degree of homology of the human gene to the murine gene (dyrk) allowed us to use a human polyclonal anti-mnb antibody to study the expression pattern of the protein in adult and embryonic mouse tissues. western blot analysis and immunohistochemical methods were used to define the detaile ... | 1998 | 9878567 |
| regulation and functional involvement of macrophage scavenger receptor marco in clearance of bacteria in vivo. | the scavenger receptors expressed by macrophages are thought to play an important role in the immune response against bacteria by mediating binding and phagocytosis. a novel member of the class a scavenger receptor family, macrophage receptor with collagenous structure (marco), has recently been identified. in this study we have generated a panel of mabs with specificities for different domains of this receptor. two of those reacting with the c-terminal cysteine-rich domain block ligand binding ... | 1999 | 9916718 |
| the chaperonin groel binds to late-folding non-native conformations present in native escherichia coli and murine dihydrofolate reductases. | dihydrofolate reductases from mouse (mudhfr) or escherichia coli (ecdhfr) are shown to refold via several intermediate forms, each of which can bind to the chaperonin groel. when stable complexes with groel are formed, they consist of late-folding intermediates. in addition, we find that late-folding intermediates that are present in the native enzyme bind to groel. for the e. coli and murine proteins, the extent of protein bound increases as the temperature is increased from 8 degreesc to 42 de ... | 1999 | 9917411 |
| characteristics of a highly labile human type 5 17beta-hydroxysteroid dehydrogenase. | 17beta-hydroxysteroid dehydrogenases (17betahsds) play an essential role in the formation of active intracellular sex steroids. six types of 17betahsd have been described to date, which only share approximately 20% homology. human type 5 17betahsd complementary dna is unique among the 17betahsds because it belongs to the aldo-keto reductase family, whereas the others are members of the short chain alcohol dehydrogenases. the characteristics of human type 5 17betahsd were investigated in human em ... | 1999 | 9927279 |
| dna cleavage and degradation by the sbccd protein complex from escherichia coli. | the sbccd protein is a member of a group of nucleases found in bacteriophage t4 and t5, eubacteria, archaebacteria, yeast, drosophila, mouse and man. evidence from electron microscopy has revealed a distinctive structure consisting of two globular domains linked by a long region of coiled coil, similar to that predicted for the members of the smc family. that a nuclease should have such an unusual structure suggests that its mode of action may be complex. here we show that the protein degrades d ... | 1999 | 9927737 |
| direct interaction of microtubule- and actin-based transport motors. | the microtubule network is thought to be used for long-range transport of cellular components in animal cells whereas the actin network is proposed to be used for short-range transport, although the mechanism(s) by which this transport is coordinated is poorly understood. for example, in sea urchins long-range ca2+-regulated transport of exocytotic vesicles requires a microtubule-based motor, whereas an actin-based motor is used for short-range transport. in neurons, microtubule-based kinesin mo ... | 1999 | 9930703 |
| the neurotransmitter receptor-anchoring protein gephyrin reconstitutes molybdenum cofactor biosynthesis in bacteria, plants, and mammalian cells. | the molybdenum cofactor (moco), a highly conserved pterin compound complexing molybdenum, is required for the enzymatic activities of all molybdenum enzymes except nitrogenase. moco is synthesized by a unique and evolutionarily old pathway that requires the activities of at least six gene products. some of the proteins involved in bacterial, plant, and invertebrate moco biosynthesis show striking homologies to the primary structure of gephyrin, a polypeptide required for the clustering of inhibi ... | 1999 | 9990024 |
| molecular basis for the enterocyte tropism exhibited by salmonella typhimurium type 1 fimbriae. | salmonella typhimurium exhibits a distinct tropism for mouse enterocytes that is linked to their expression of type 1 fimbriae. the distinct binding traits of salmonella type 1 fimbriae is also reflected in their binding to selected mannosylated proteins and in their ability to promote secondary bacterial aggregation on enterocyte surfaces. the determinant of binding in salmonella type 1 fimbriae is a 35-kda structurally distinct fimbrial subunit, fimhs, because inactivation of fimhs abolished b ... | 1999 | 10026202 |
| cloning of cdna for canine interleukin-18 and canine interleukin-1beta converting enzyme and expression of canine interleukin-18. | cloning of canine interleukin-18 (il-18) and canine interleukin-1beta converting enzyme (ice) cdna was carried out by using murine il-18 cdna and human ice cdna, respectively, as probes. sequence homology to known sequences of human, mouse, or rat genes was noted at nucleotide and amino acid levels. canine il-18 mrna was expressed in various canine organs, whereas canine ice mrna was expressed in only a few, particularly in the brain and testis. cloned canine il-18 cdna was expressed in escheric ... | 1999 | 10048765 |
| expression of murine coronavirus recombinant papain-like proteinase: efficient cleavage is dependent on the lengths of both the substrate and the proteinase polypeptides. | proteolytic processing of the replicase gene product of mouse hepatitis virus (mhv) is essential for viral replication. in mhv strain a59 (mhv-a59), the replicase gene encodes two predicted papain-like proteinase (plp) domains, plp-1 and plp-2. previous work using viral polypeptide substrates synthesized by in vitro transcription and translation from the replicase gene demonstrated both cis and trans cleavage activities for plp-1. we have cloned and overexpressed the plp-1 domain in escherichia ... | 1999 | 10074111 |
| modulation of the remote heme site geometry of recombinant mouse neuronal nitric-oxide synthase by the n-terminal hook region. | the role of two essential residues at the n-terminal hook region of neuronal nitric-oxide synthase (nnos) in nitric-oxide synthase activity was investigated. full-length mouse nnos proteins containing single-point mutations of thr-315 and asp-314 to alanine were produced in the escherichia coli and baculovirus-insect cell expression systems. the molecular properties of the mutant proteins were analyzed in detail by biochemical, optical, and electron paramagnetic resonance spectroscopic technique ... | 1999 | 10075660 |
| antibodies reactive with the n-terminal domain of plasmodium falciparum serine repeat antigen inhibit cell proliferation by agglutinating merozoites and schizonts. | the serine repeat antigen (sera) is a vaccine candidate antigen of plasmodium falciparum. immunization of mice with escherichia coli-produced recombinant protein of the sera n-terminal domain (se47') induced an antiserum that was inhibitory to parasite growth in vitro. affinity-purified mouse antibodies specific to the recombinant protein inhibited parasite growth between the schizont and ring stages but not between the ring and schizont stages. when percoll-purified schizonts were cultured with ... | 1999 | 10085023 |
| role of fimbriae-mediated adherence for neutrophil migration across escherichia coli-infected epithelial cell layers. | this study examined the role of p and type 1 fimbriae for neutrophil migration across escherichia coli-infected uroepithelial cell layers in vitro and for neutrophil recruitment to the urinary tract in vivo. recombinant e. coli k-12 strains differing in p or type 1 fimbrial expression were used to infect confluent epithelial layers on the underside of transwell inserts. neutrophils were added to the upper well, and their passage across the epithelial cell layers was quantified. infection with th ... | 1998 | 10094621 |
| excision repair of 8-hydroxyguanine in mammalian cells: the mouse ogg1 protein as a model. | 8-hydroxyguanine (8-oh-gua) is a major mutagenic lesion produced on dna by the oxidative stress induced by either the endogen metabolism or the exposure to external agents. in bacteria and yeast this modified base can be removed by specific dna glycosylases. recently a human gene coding for an 8-oh-gua dna glycosylase/ap lyase has been identified by its homology to the yeast ogg1. this gene is located in human chromosome 3p25, a region commonly rearranged in various cancers, specially in lung tu ... | 1998 | 10098454 |
| intracellular salmonella typhimurium induce lysis of human polymorphonuclear leukocytes which is not associated with the salmonella virulence plasmid. | the interaction between salmonella typhimurium and human polymorphonuclear leukocytes (pmns) was analyzed in vitro. three s. typhimurium strains, the wild-type strain ou5043, its isogenic virulence plasmid-cured strain ou5048, and lt2, which represented the types that exhibited three mouse virulence levels, respectively, were used in this study. there was no correlation between the recovery of intracellular s. typhimurium from pmns and the presence or absence of the virulence plasmid, or the str ... | 1999 | 10100741 |
| tissue expression and amino acid sequence of murine udp-n-acetylglucosamine-2-epimerase/n-acetylmannosamine kinase. | neuraminic acids are widely expressed as terminal carbohydrates on glycoconjugates and are involved in a variety of biological functions. the key enzyme of n-acetylneuraminic acid synthesis is udp-n-acetylglucosamine-2-epimerase/n-acetylmannosamine kinase, which catalyses the first two steps of neuraminic acid biosynthesis in the cytosol. in this study we report the complete amino acid sequence of the mouse udp-n-acetylglucosamine-2-epimerase/n-acetylmannosamine kinase. the orf of 2166 bp encode ... | 1999 | 10103025 |