Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| genomic organization of collagenous domains and chromosomal assignment of human 180-kda bullous pemphigoid antigen-2, a novel collagen of stratified squamous epithelium. | we have recently isolated a 1.0-kilobase (kb) cdna encoding 180-kda bullous pemphigoid antigen (bpag2), an autoantigen in blistering skin disease, bullous pemphigoid (giudice, g. j., squiquera, h. l., elias, p. m., and diaz, l. (1991) j. clin. invest. 87, 734-738). the deduced amino acid sequence identified two collagenous domains characterized by gly-x-y repeats. in this study we have elucidated the genomic organization of the corresponding segment in the human bpag2 gene. screening of a genomi ... | 1991 | 1748679 |
| a fully modular vector system for the optimization of gene expression in escherichia coli. | the new expression vector system cytexp is designed to facilitate the optimization of both transcription and translation in escherichia coli, while at the same time allowing the exchange of its major components using unique restriction sites. in vitro mutagenesis can be performed in situ using single-stranded dna generated from the bacteriophage f1 ori sequence. the basic vector pcytexp1 bears a synthetic copy of the intercistronic sequence that enhances the translation of the e. coli atpe gene. ... | 1991 | 1749821 |
| [elimination of introns from the interleukin 1 beta genome by dna amplification and expression of interleukin 1 beta in escherichia coli]. | the use of the polymerase chain reaction was proposed for intron excision from genomic genes with known nucleotide sequences. three exons (5, 6 and 7) of genomic interleukin 1 beta gene were amplified by means of thermostable dna polymerase tthi from thermus thermophilus on the base of cloned in m13 phage human genomic interleukin 1 beta gene. synthetic oligonucleotides complementary to sequences flanking exons were used as primers. the fragments obtained by exon dna amplification were joined in ... | 1991 | 1753956 |
| cloning and physical mapping of dna sequences encompassing a region in n-myc amplicons of a human neuroblastoma cell line. | cloning and physical mapping of dna sequences encompassing n-myc amplicons of a human neuroblastoma cell line were done. a number of lambda phage clones within this region were isolated using the probes prepared by the phenol emulsion reassociation technique. based on the restriction mapping, they were integrated into 8 contigs with sizes of 25-60 kb which, in total, encompassed a 330 kb region. several amplicons, 100, 420, 480 and 520 kb in size as a notl fragment, were identified using hexagon ... | 1991 | 1762918 |
| molecular cloning and structure of the human transforming growth factor-beta 2 gene promoter. | genomic dna extending over 10 kb 5' of the transforming growth factor-beta 2 (tgf-beta 2) coding region was isolated from a human lung fibroblast lambda phage library. a 5.6 kb hind iii fragment containing the 5'-untranslated region and flanking sequences was subcloned and sequenced. s1 nuclease protection analysis identified a transcriptional initiation site 1357 nucleotides 5' of the methionine initiation codon (atg). a "tata box" consensus sequence was identified 30 bp from this transcription ... | 1991 | 1764261 |
| phop/phoq: macrophage-specific modulators of salmonella virulence? | the regulation of gene expression by the two-component regulatory system phop/phoq is necessary for salmonella typhimurium survival within macrophages, defensin resistance, acid resistance, and murine typhoid fever pathogenesis. salmonella experience multiple environments during mammalian infection and survival requires tightly regulated gene expression. after phagocytosis by macrophages, signal transduction by phoq results in the transcription of phop-activated genes (pags) encoding proteins es ... | 1991 | 1766380 |
| transcription of the escherichia coli flic gene is regulated by metal ions. | luxab gene fusions in the escherichia coli genome were used to screen for clones displaying transcriptional changes in the presence of aluminum. one clone was found that contained a luciferase gene fusion in which transcription was increased in the presence of aluminum and which was subsequently shown to be induced by copper, iron, and nickel. cloning of the metal-regulated gene, hybridization to the ordered phage lambda bank of the e. coli chromosome, and sequencing of dna adjacent to the luxab ... | 1991 | 1768097 |
| experience in shotgun sequencing a 134 kilobase pair dna molecule. | until now, large dna sequences have been obtained by cloning fragments of the target molecule into plasmid, cosmid or bacteriophage lambda vectors. the 134 kbp dna sequence of channel catfish virus was determined with relative ease by shotgun cloning of random fragments of genomic dna directly into a bacteriophage m13 vector, sequencing by dideoxynucleotide chain termination, and compilation of the data using staden's database handling programs. experience gained during this endeavour indicates ... | 1991 | 1768862 |
| occurrence of oligopurine.oligopyrimidine tracts in eukaryotic and prokaryotic genes. | a program to analyse the length and frequency distribution of specific base tracts in genomic sequences is described. the frequency of oligopurine.oligopyrimidine tracts (r.y. tracts) in a data base of 163 transcribed genes is analysed and compared. the complete genomes of sv40 virus, n. tobacum chloroplast, yeast 2 micron plasmid, bacteriophage lambda, plasmid pbr322 and the e. coli lac operon are also analyzed. a highly significant overrepresentation of oligopurine and oligopyrimidine tracts i ... | 1991 | 1773055 |
| monoclonal antibody-mediated solid-phase assay for mammalian o6-alkylguanine dna alkyltransferase activity. | we describe a sensitive, rapid, and simple assay for mammalian o6-alkylguanine dna alkyltransferase (o6-agt) utilizing solid-phase dna as the substrate and a monoclonal antibody (mab)-based immuno-slotblot (isb) for quantitation of o6-ethylguanine (o6-etg). lambda-phage dna was treated with n-ethyl-n-nitrosourea and immobilized on newly developed hydrophilic latex beads. after incubation with cell extracts to be assayed for o6-agt activity, the substrate dna could be isolated easily by a brief c ... | 1991 | 1776691 |
| primary structure and tissue distribution of anglerfish carboxypeptidase h. | most peptide hormones are synthesized as part of larger precursor proteins which must be processed after translation to generate bioactive peptides. this usually involves cleavage of the precursor by an endopeptidase at sites marked by basic amino acids, followed by removal of n- or c-terminal basic residues by the action of an aminopeptidase or carboxypeptidase. these processing events have been observed in a variety of species, from yeast to mammals. as part of an effort to characterize prohor ... | 1991 | 1778303 |
| streptomyces marker plasmids for monitoring survival and spread of streptomycetes in soil. | plasmid constructs pnw1 through pnw6 containing a controllable xyle gene (for catechol 2,3-dioxygenase) were introduced into streptomyces lividans strains to provide a selectable marker system. xyle functions in s. lividans under the control of bacteriophage lambda promoters lambda pl and lambda pr. thermoregulated expression of xyle is provided through the lambda repressor ci857. catechol 2,3-dioxygenase activity was increased 2.8-fold from plasmid construct pnw2 (lambda pl, xyle, ci857) and 9. ... | 1991 | 1781690 |
| cloning and expression of a functional rat liver d-beta-hydroxybutyrate dehydrogenase-beta-galactosidase fusion protein in escherichia coli. | a rat liver bacteriophage lambda expression library was probed using polyclonal antibodies raised to purified rat liver d-beta-hydroxybutyrate dehydrogenase (bdh). a clone was selected that contained a 1.2-kb insert. the insert placed in an expression plasmid was utilized to transform escherichia coli. these cells were shown to possess phosphatidylcholine-dependent bdh activity. cells transformed with only the plasmid had no detectable bdh activity in the presence of phosphatidylcholine. the exp ... | 1991 | 1793570 |
| translation control of gene expression. | the bacteriophage lambda ciii gene product is an early regulator of the lysogenic pathway. the availability of a set of ciii expression mutants allowed us to establish the structure-function relationship of the ciii mrna. we demonstrated, using defined in vitro systems, that the ciii mrna is present in two conformations at equilibrium. mutations that have been shown to lead to ciii overexpression were found to freeze the rna in one conformation (structure b), and permit efficient binding to the ... | 1991 | 1797096 |
| the human cystatin gene family: cloning of three members and evolutionary relationship between cystatins and bowman-birk type proteinase inhibitors. | three genes from the human cystatin gene family have been isolated from a bacteriophage lambda library containing hind iii digests of human genomic dna. the cloned genes were identified with three dna probes each containing exon 1, exon 2 and exon 3 of the cst1 gene for cystatin sn. the genes, which we name cst2b, cst4, and cst5, are 6.8 kb, 5.4 kb and 12.5 kb in size, respectively. statistical analysis of dna sequence homology elucidated that the second and third exons of cystatin (family ii) g ... | 1991 | 1801729 |
| molecular cloning and expression of cdna encoding the enzyme that controls conversion of high-mannose to hybrid and complex n-glycans: udp-n-acetylglucosamine: alpha-3-d-mannoside beta-1,2-n-acetylglucosaminyltransferase i. | udp-glcnac:alpha-3-d-mannoside beta-1,2-n-acetylglucosaminyltransferase i (gnt i; ec 2.4.1.101) catalyzes an essential first step in the conversion of high-mannose n-glycans to hybrid and complex n-glycans. cloning of the gene encoding this enzyme was carried out by mixed oligonucleotide-primed polymerase chain reaction amplification of rabbit liver single-stranded cdna using sense and antisense 20- to 24-base-pair (bp) primers. a rabbit liver library in phage lambda gt10 yielded a 2.5-kilobase ... | 1991 | 1824724 |
| genetic analysis of escherichia coli integration host factor interactions with its bacteriophage lambda h' recognition site. | the bacteriophage p22-based challenge phage system was used to study the binding of integration host factor (ihf) to its h' recognition site in the attp region of bacteriophage lambda. we constructed challenge phages that carried h' inserts in both orientations within the p22 pant promoter, which is required for antirepressor synthesis. we found that ihf repressed expression of pant from either challenge phage when expressed from an inducible ptac promoter on a plasmid vector. mutants containing ... | 1991 | 1824766 |
| genetic analysis of the ciii gene of bacteriophage hk022. | the ciii gene product of lambdoid bacteriophages promotes lysogeny by stabilizing the phage-encoded cii protein, a transcriptional activator of the repressor and integrase genes. previous works showed that the synthesis of the bacteriophage lambda ciii protein has specific translational requirements imposed by the structure of the mrna. to gain insight into the mrna structure and its role in regulating ciii translation, we undertook a mutational analysis of the ciii gene of the related bacteriop ... | 1991 | 1824768 |
| complementation of the lytd1 mutation of escherichia coli by either the ci or cro gene of bacteriophage lambda. | the lytd1 mutant of escherichia coli exhibits temperature-sensitive growth which is attributed to cellular autolysis at the restrictive temperature. either of two cloned phage lambda genes, identified as ci and cro, suppressed the lytd1(ts) lysis phenotype, suggesting that lytd encodes a dna-binding protein with a dna-binding specificity similar to that of ci and cro. lytd may be a repressor of a gene(s) involved in cellular autolysis. | 1991 | 1824770 |
| a switch in the formation of alternative dna loops modulates lambda site-specific recombination. | the virally encoded xis protein is one of the components in the site-specific recombination reactions of bacteriophage lambda. it is required for excisive recombination and inhibits integrative recombination. the mechanism of xis inhibition of the integration reaction was investigated by methylation protection assays (footprinting analyses) in conjunction with recombination assays. xis is shown to mediate the formation of a specific attp looped structure involving cooperative and competitive lon ... | 1991 | 1824874 |
| raman spectroscopic studies of the dna cro binding site conformation, free and bound to cro protein. | raman spectra of the dna binding site for cro repressor protein were obtained in the presence and absence of bound cro protein. the 17 base pair fragment is a consensus sequence of the six cro binding sites in phage lambda, except that the second base to the right of the center of pseudosymmetry is altered. analysis of the spectrum of the free dna indicates that the molecule exists in a b-like conformation with deviations from the usual b form occurring mainly in the bands assigned to a-t vibrat ... | 1991 | 1824925 |
| use of exonuclease for rapid polymerase-chain-reaction-based in vitro mutagenesis. | we describe a simple strategy for improving site-specific mutagenesis. we have combined the polymerase chain reaction (pcr) with a phage lambda exonuclease (exo lambda) treatment to produce mutated fragments larger than 2.5 kb. the applicability of this approach has been proven with two overlapping mutated primers. the procedure has also been made more cost-effective by the use of a single mutated primer, which is referred to as smp-pcr procedure. the entire procedure of kinasing the primer, amp ... | 1991 | 1825304 |
| hu and integration host factor function as auxiliary proteins in cleavage of phage lambda cohesive ends by terminase. | hu and integration host factor (ihf) are small, basic heterodimeric dna-binding proteins which participate in transcription initiation, dna replication, and recombination. we constructed isogenic escherichia coli strains in which hu, ihf, or both proteins were absent. bacteriophage lambda did not grow in hosts lacking both hu and ihf. phage dna replication and late gene transcription were normal in the double mutants, but packaging of lambda dna was defective. mature phage dna molecules were abs ... | 1991 | 1825651 |
| stringent control of replication of plasmids derived from coliphage lambda. | the first events of lambda plasmid replication in vivo, which probably regulate this process, are the transcriptional activation of the origin of replication by rna polymerase and the binding of the initiator protein, lambda o, to this nucleotide sequence. the lambda o protein is known for its rapid proteolytic degradation; hence amino acid starvation of escherichia coli should result in inhibition of lambda plasmid replication caused by inhibition of protein synthesis. however, contrary to this ... | 1991 | 1825694 |
| in vivo analysis of overlapping transcription units in the rplkajlrpobc ribosomal protein-rna polymerase gene cluster of escherichia coli. | transcription of the rplkajlrpobc ribosomal protein (rpl) rna polymerase (rpo) gene cluster is governed by a complex set of signals. to dissect the transcription units active in vivo and to quantify the relative contribution of each, an extensive array of rplkajlrpob/lacz gene fusions were constructed on lambda phage derivatives and introduced in single copy into the chromosomes of lac- cells. measurements of beta-galactosidase production from fusions containing wild-type and/or mutagenized rplr ... | 1991 | 1825852 |
| generation of diverse high-affinity human monoclonal antibodies by repertoire cloning. | combinatorial libraries of antibody heavy and light chains derived from the peripheral blood lymphocytes of an individual immunized with tetanus toxoid have been expressed in escherichia coli by using phage lambda vectors. screening of the libraries allowed identification of a large number of human monoclonal fab fragments specific for tetanus toxoid. initial studies suggested considerable sequence diversity in these antibodies. the method should allow the generation of many human monoclonal ant ... | 1991 | 1826052 |
| escherichia coli dnaj and grpe heat shock proteins jointly stimulate atpase activity of dnak. | the products of the escherichia coli dnak, dnaj, and grpe heat shock genes have been previously shown to be essential for bacteriophage lambda dna replication at all temperatures and for bacterial survival under certain conditions. dnak, the bacterial heat shock protein hsp70 analogue and putative chaperonin, possesses a weak atpase activity. previous work has shown that atp hydrolysis allows the release of various polypeptides complexed with dnak. here we demonstrate that the atpase activity of ... | 1991 | 1826368 |
| efficient introduction of cloned mutant alleles into the escherichia coli chromosome. | an efficient method for moving mutations in cloned escherichia coli dna from plasmid vectors to the bacterial chromosome was developed. cells carrying plasmids that had been mutated by the insertion of a resistance gene were infected with lambda phage containing homologous cloned dna, and resulting lysates were used for transduction. chromosomal transductants (recombinants) were distinguished from plasmid transductants by their ampicillin-sensitive phenotype, or plasmid transductants were avoide ... | 1991 | 1826503 |
| vaccinia virus-mediated expression of african swine fever virus genes. | bacteriophage lambda and plasmid clones containing african swine fever virus (asfv) dna inserts, which together covered more than 90% of the genome of a malawi asfv isolate (lil 20/1), were transfected into vaccinia virus (vv)-infected cells. expression of asfv-encoded proteins was assayed at late times after vv infection by immunoprecipitation of [35s]methionine-labeled proteins with hyperimmune serum from asfv-infected pigs, separation of immunoprecipitated proteins by denaturing polyacrylamid ... | 1991 | 1826575 |
| immunodominance is altered in t cell receptor (beta-chain) transgenic mice without the generation of a hole in the repertoire. | despite the tremendous plasticity of the tcr repertoire, t cells recognize a limited number of antigenic sites (frequently a single site, or immunodominant epitope) on a complex protein ag. current models suggest that the immunodominant epitope of a complex protein is the processed peptide that binds to the mhc molecule with the highest affinity. conversely, the inability of the t cell population to recognize a specific epitope, termed a "hole" in the repertoire, can prevent the immunodominance ... | 1991 | 1826701 |
| cloning the ends of size selected sfi i fragments. | as an initial step in the physical mapping of the fragile x region a library of sfi i ends was constructed from the size class of human sfi i dna fragments, which includes the fragment with the locus dxs105. since sfi i recognizes the sequence ggccnnnnnggcc and leaves a 3 base indeterminate "sticky" end, we used a mixture of 64 synthetic deoxynucleotide oligomers to modify these ends for cloning. the oligomers were of the general form aattnnn. ligation of these heptamers to the indeterminate sfi ... | 1991 | 1826809 |
| interference with phage lambda development by the small subunit of the phage 21 terminase, gp1. | bacteriophage lambda development is blocked in cells carrying a plasmid that expresses the terminase genes of phage 21. the interference is caused by the small subunit of phage 21 terminase, gp1. mutants of lambda able to form plaques in the presence of gp1 include sti mutants. one such mutation, sti30, is an a. t-to-g.c transition mutation at base pair 184 on the lambda chromosome. the sti30 mutation extends the length of the ribosome-binding sequence of the nul gene that is complementary to th ... | 1991 | 1826903 |
| detection of homologous recombination between yeast artificial chromosomes with overlapping inserts. | we have developed a system which facilitates the detection of recombination between yeast artificial chromosomes (yac's) carrying homologous inserts. the system consists of a classical yac vector, a new yac vector and two appropriately labelled yeast strains of opposite mating type. the new yac vector differs in markers from the canonical yac vector. to test whether homologous recombination takes place, phage lambda dna was cloned in the two vectors to provide a region of homology. the two const ... | 1991 | 1826951 |
| functional and structural elements of the mrna of the ciii gene of bacteriophage lambda. | the bacteriophage lambda ciii gene product is an early regulatory protein that participates in the lysis-lysogeny decision of the phage following infection. we have previously shown that the translation of the ciii gene is determined by two unique factors: (1) efficient expression is dependent upon the presence of rnaseiii in the cell; (2) alternative mrna structures of the ciii coding region determine the rate of its translation initiation. in this study we demonstrate the presence of the alter ... | 1991 | 1827163 |
| bacteriophage p22 accessory recombination function. | the accessory recombination function (arf) gene of bacteriophage p22 is located immediately upstream of the essential recombination function (erf) gene. three mutant alleles of arf were constructed and installed in p22 in place of the wild-type allele: an out-of-frame internal deletion, an in-frame internal deletion, and an amber mutation. the deletion mutant phages are partially defective in homologous recombination and plaque formation in wild-type and reca hosts; their defects are more severe ... | 1991 | 1827223 |
| bacteriophage lambda p gene shows host killing which is not dependent on lambda dna replication. | bacteriophage lambda, having a mutation replacing glycine by glutamic acid at the 48th codon of cro, kills the host under n- conditions; we call this the hk mutation. in lambda n-n-cl-hk phage-infected bacteria, the late gene r is expressed to a significant level, phage dna synthesis occurs with better efficiency, and the cro activity is around 20% less, all compared to those in lambda n-n-cl-hk(+)-infected bacteria. segments of lambda dna from the left of pr to the right of tr2, carrying cro, c ... | 1991 | 1827224 |
| isolation and preliminary characterization of escherichia coli mutants resistant to lethal action of the bacteriophage lambda p gene. | both spontaneous and ntg-induced mutants of escherichia coli 594 insensitive to the lethal action of lambda p gene were isolated and called rpl (resistant to p lethality). these mutants were of two types, showing different phenotypes. on type i rpl mutants, lambda cl- and lambda v1v3 did not plate, while lambda vir, lambda cl- c17, lambda imm434, and lambda imm21 did; plasmid pmr45 carrying the lambda p gene could not complement lambda imm21p- phage in type i mutants. on the other hand, the type ... | 1991 | 1827225 |
| characterization of a versatile in vitro dna-packaging system based on hybrid lambda/phi 29 proheads. | we have studied the assembly of bacteriophage lambda head proteins on the phage phi 29 connector to produce in vitro chimeric proheads, whose ability to package different types of dna depends on the physical integrity of the phi 29 connector. terminal protein-free phi 29 as well as nonviral dnas have been shown to be efficiently packaged by this hybrid system. an rna, that can be provided by any of the extracts used in the complementation mixture, was required for dna packaging, both by the hybr ... | 1991 | 1827226 |
| abundance and dna sequence of two-base repeat regions in tropical tree genomes. | tandem dna repeats of two-base pairs are potentially important tools for population genetic studies because of their abundance and length variation. as part of our research into the ecology of tropical forest plants, we began a study of dinucleotide repeat regions in several genera of tropical trees. genomic libraries in bacteriophage lambda were screened with the oligonucleotide probes poly(gt) and poly(ag). both types of repeat regions were abundant in the genomes of all six plant species exam ... | 1991 | 1827419 |
| identification of protein binding sites in genomic dna by two-dimensional gel electrophoresis. | we describe a simple two-dimensional electrophoresis procedure to identify the recognition sites of dna-binding proteins within large dna molecules. using this approach, we have mapped e. coli ihf (integration host factor) binding sites within phage lambda (48 kb) and phage mu (39 kb) dna. we are also able to visualize ihf binding sites in e. coli chromosomal dna (4,700 kb). we present an extension of this technique using direct amplification by pcr of the isolated restriction fragments, which s ... | 1991 | 1827523 |
| [specific systems of phosphoenolpyruvate-dependent transport of carbohydrates in enterobacteria]. | the data of foreign researchers on the specific phosphoenolpyruvate-dependent phosphotransferase systems (pts) transporting mannose, aminosugars and natural beta-glucosides are reviewed. the genetical, biochemical and molecular biological aspects of the corresponding pts functioning are presented. the role of those pts in bacteriophage lambda dna penetration into the cell, in streptozotocin resistance is discussed. | 1991 | 1827656 |
| heat-inducible reactivation of uv-damaged bacteriophage lambda. | induction of the sos response in uv-irradiated bacteria leads to an increase in the survival of an infecting irradiated bacteriophage lambda (weigle 1953). we report that a similar reactivation of irradiated phage lambda was induced by shifting the culture of recipient bacteria from 30 degrees to 47 degrees c. however, this repair process was nonmutagenic. the amplitude of the phenomenon was increased with the quantity of uv lesions in the phage dna. it was present despite mutations affecting th ... | 1991 | 1827875 |
| 3'-end formation at the phage lambda tr1 rho-dependent transcription termination site. | the rho-dependent transcription terminator tr1 of bacteriophage lambda stops rna synthesis downstream of the major rightward promoter, pr, shortly after the cro gene. terminated transcripts produced in a purified in vitro transcription system display a heterodisperse set of 3' termini, occurring in clusters located at +290-300, 308-312, 340-345, 385-390, and 440-450 nucleotides from the transcription start site [morgan, w.d., bear, d.g., & von hippel, p.h. (1983) j. biol. chem. 258, 9553-9564]. ... | 1991 | 1827993 |
| cloning of xylanase gene of streptomyces flavogriseus in escherichia coli and bacteriophage lambda-induced lysis for the release of cloned enzyme. | the xylanase gene of streptomyces flavogriseus was cloned in puc8 plasmid and expressed in escherichia coli lysogenic for lambda ci857. lambda-induced lysis of e. coli at 42 degrees c allowed efficient release of cloned enzyme activity in extracellular environment. the xylanase gene was located in the 0.8-kb hindiii fragment and coded for 18,000 mr xylanase. | 1991 | 1828240 |
| rapid assembly of lambda phage contigs within yac clones. | 1991 | 1828295 | |
| footprint of the sigma protein: a re-examination. | escherichia coli rna polymerase is a multi-subunit enzyme that catalyzes rna synthesis, using dna as a template. the sigma subunit of this enzyme plays an important role in the recognition of promoter sites on dna. using dnase i footprinting, utpala ramesh and claude f. meares [(1989) biochem. biophys. res. comm. 160, 121-125] reported that in the absence of the other subunits, sigma binds specifically to the bacteriophage lambda pr promoter dna sequence. we are unable to reproduce that result. | 1991 | 1828339 |
| dna recognition by the helix-turn-helix motif: investigation by laser raman spectroscopy of the phage lambda repressor and its interaction with operator sites ol1 and or3. | the lambda repressor provides a model system for biophysical studies of dna recognition by the helix-turn-helix motif. we describe laser raman studies of the lambda operator sites ol1 and or3 and their interaction with the dna-binding domain of lambda repressor (residues 1-102). raman spectra of the two dna sites exhibit significant differences attributable to interstrand purine-purine steps that differ in the two oligonucleotides. remarkably, the conformation of each operator is significantly a ... | 1991 | 1828373 |
| screening cdna expression libraries in lambda gt11 with a t cell hybridoma. | a t cell hybridoma specific for a protein of plasmodium chabaudi chabaudi has been used to test a system for direct t cell screening of a cdna library of p. chabaudi in the phage lambda gt11. the technique is based upon the rapid separation of the recombinant beta-galactosidase fusion protein from the bacterial mixtures using polystyrene beads coated with anti-beta-galactosidase antibodies. these coated beads are cultured with antigen-presenting cells and the t cell hybridoma. the technique is s ... | 1991 | 1828474 |
| specificity of recognition sequence for escherichia coli primase. | we have surveyed the frequency of each of 64 trinucleotide permutations at every nucleotide frame located from 1 to 15 nucleotides upstream of primer rna-dna transition sites mapped within a 1.5 kb region of the bacteriophage lambda genome and a 1.4 kb region of the escherichia coli genome. we have demonstrated that in both systems initiation of dna synthesis strongly correlates with a cag sequence located 11 nucleotides upstream of the dna start sites. based on the examination of various report ... | 1991 | 1828532 |
| a nonradioactive screening method for cloning genes encoding sequence-specific dna binding proteins. | we have developed a novel nonradioactive screening method for cloning genes encoding sequence-specific dna binding proteins. this method is derived from previously described protocols developed for the same purpose by using radioactively labeled dna probes containing protein recognition sequences. this nonradioactive strategy relies upon the use of a small hapten, digoxigenin. fusion proteins expressed from the recombinant bacteriophage lambda gt11/lambda zap are immobilized on nitrocellulose fi ... | 1991 | 1828652 |
| an additional function for bacteriophage lambda rex: the rexb product prevents degradation of the lambda o protein. | the rex operon of bacteriophage lambda excludes the development of several unrelated bacteriophages. here we present an additional lambda rexb function: it prevents degradation of the short-lived protein lambda o known to be involved in lambda dna replication. we have shown that it is the product of rexb that is responsible for the stabilization of lambda o: when a nonsense mutation is present in rexb, lambda o protein is labile; suppression of the mutation by the corresponding nonsense suppress ... | 1991 | 1828888 |
| the activity of the ciii regulator of lambdoid bacteriophages resides within a 24-amino acid protein domain. | the ciii protein of lambdoid bacteriophages promotes lysogeny by stabilizing the phage-encoded cii protein, a transcriptional activator of the repressor and integrase genes. we have isolated a set of missense mutations in the ciii gene of phage lambda and of phage hk022 that yield inactive ciii proteins. all the mutations are located in the relatively conserved central region of the protein. a comparative analysis of the ciii protein sequence in lambda, hk022, and the lambdoid bacteriophage p22 ... | 1991 | 1828895 |
| conformational transition required for efficient splicing of transcripts from hybrid lambda promoter yeast trna gene fusion. | fusion of a prokaryotic promoter to a yeast trna gene provides a means for uncoupling analyses of mutations affecting splicing from requirements for transcription and other processing steps. for this purpose, a phage lambda promoter was fused to the saccharomyces cerevisiae trnatyr(sup3a) coding sequence. this fusion allows the synthesis of an end-mature precursor by in vitro transcription with escherichia coli rna polymerase. this precursor was accurately spliced by purified yeast endonuclease ... | 1991 | 1828990 |
| murine cdnas coding for the centrosomal antigen centrosomin a. | screening of an induced ehrlich ascites cell-derived lambda gt11 cdna library with an antibody (gp1), immunoreacting specifically with centrosomal antigen(s) of interphase and mitotic cells of different species, released a partial cdna clone (lambda p10a) encoding the carboxy-terminal section of a centrosome-specific antigen. this specificity of the clone lambda p10a could be verified by lacz-directed antigen expression from escherichia coli y1089 lysogenized with the recombinant phage lambda p1 ... | 1991 | 1829085 |
| identification of a plasmid-coded protein required for initiation of cole2 dna replication. | the product of the rep gene of cole2 is required for initiation of cole2 dna replication. the rep gene was placed under the control of the promoters, pl and pr, and the heat-labile cl857 repressor of bacteriophage lambda. the rep protein was identified as a 35 kd protein by the maxicell method in combination with heat-induced expression. the protein was efficiently expressed from these promoters in unirradiated cells and accumulated up to a few per cent of the total cellular proteins. it was par ... | 1991 | 1829159 |
| effects of temperature on excluded volume-promoted cyclization and concatemerization of cohesive-ended dna longer than 0.04 mb. | the 0.048502 megabase (mb), primarily double-stranded dna of bacteriophage lambda has single-stranded, complementary termini (cohesive ends) that undergo either spontaneous intramolecular joining to form open circular dna or spontaneous intermolecular joining to form linear, end-to-end oligomeric dnas (concatemers); concatemers also cyclize. in the present study, the effects of polyethylene glycol (peg) on the cyclization and concatemerization of lambda dna are determined at temperatures that, i ... | 1991 | 1829160 |
| heteroduplex chain polarity in recombination of phage lambda by the red, recbcd, recbc(d-) and recf pathways. | we have examined the chain polarity of heteroduplex dna in unreplicated, bacteriophage lambda splice recombinants when recombination was by the recbcd, recbc(d-), or recf pathway of escherichia coli or the red pathway of lambda. for each of these pathways, recombination is activated by the cutting of cos that accompanies chromosome packaging, and is effected by recombination enzymes acting at the right end created by that cutting. for exchanges occurring near cos, one parent makes a lesser physi ... | 1991 | 1829428 |
| efficient excision of phage lambda from the escherichia coli chromosome requires the fis protein. | the escherichia coli protein fis has been shown to bind a single site in the recombination region of phage lambda and to stimulate excisive recombination in vitro (j. f. thompson, l. moitoso de vargas, c. koch, r. kahmann, and a. landy, cell 50:901-908, 1987). we demonstrate that mutant strains deficient in fis expression show dramatically reduced rates of lambda excision in vivo. phage yields after induction of a stable lysogen are reduced more than 200-fold in fis cells. the defect observed in ... | 1991 | 1829453 |
| multiple effects of fis on integration and the control of lysogeny in phage lambda. | fis is a small, basic, site-specific dna-binding protein present in escherichia coli. a fis-binding site (f) has been previously identified in the attp recombination site of phage lambda (j. f. thompson, l. moitoso de vargas, c. koch, r. kahmann, and a. landy, cell 50:901-908, 1987). the present study demonstrates that in the absence of the phage-encoded xis protein, the binding of fis to f can stimulate integrative recombination and therefore increase the frequency of lambda lysogeny in vivo. a ... | 1991 | 1829454 |
| p lambda zd39: a new type of cdna expression vector for low background, high efficiency directional cloning. | we have developed a new type of bacteriophage lambda vector which provides a strong biological selection against non-recombinants that is independent of the sequences immediately surrounding the cloning site. this system, which we call 'selective substitution', is ideally suited for cdna expression vectors where it is necessary to flank the cdna insert with sequence elements (promoters etc.) required to produce a biologically active mrna in vivo. selective substitution is a general method, which ... | 1991 | 1829518 |
| molecular characterization of human immunodeficiency virus type 1 cloned directly from uncultured human brain tissue: identification of replication-competent and -defective viral genomes. | all presently available replication-competent proviral clones of human immunodeficiency virus type 1 (hiv-1) are derived from cell culture-amplified virus. since tissue culture is highly selective for viral strains with an in vitro growth advantage, such clones may not be representative of the biologically relevant virus present in vivo. in this study, we report the molecular cloning and genotypic characterization of 10 hiv-1 genomes directly from uncultured brain tissue of a patient with aids d ... | 1991 | 1830110 |
| daughter origins can be held together by o protein in phage lambda replicative intermediates. | when lambda replicative intermediates are incubated with initiator protein o, complex molecules are observed in which o interacts with both daughter origin segments and with growing points. in the simplest of these molecules it appears that daughter origins and growing points may all be bound together at a single point. when replicative intermediates are sequentially incubated with single-stranded binding protein and o protein, simpler structures are observed. in this case, both daughter origins ... | 1991 | 1830184 |
| dna replication occurs at discrete sites in pseudonuclei assembled from purified dna in vitro. | bacteriophage lambda dna is assembled into pseudonuclei in xenopus egg extract and replicated semiconservatively under temporal cell cycle control. here, replication is shown to be regulated spatially and to occur at discrete sites that represent clustered replication forks. clustered forks are visualized by incorporation of biotin-19-dutp into nascent dna. pulse-label experiments show that discrete replication foci persist throughout s phase. we conclude that the organization of replication for ... | 1991 | 1830242 |
| deletions induced by gamma rays in the genome of escherichia coli. | an escherichia coli lysogen was constructed with a lambda phage bearing a lacz gene surrounded by about 100 x 10(3) base-pairs of dispensable dna. the lacz mutants induced by gamma rays in this lysogen were more than 10% large deletions, ranging in size from 0.6 x 10(-3) to 70 x 10(3) base-pairs. these deletions were centered, not on lacz, but on a cole1 origin of dna replication located 1.2 x 10(3) bases downstream from lacz. this suggested that this origin of replication was involved in the pr ... | 1991 | 1830341 |
| structure of the bacteriophage lambda cohesive end site. genetic analysis of the site (cosn) at which nicks are introduced by terminase. | a collection of mutations affecting the site (cosn) at which the bacteriophage lambda dna packaging enzyme, terminase, introduces nicks to generate mature lambda chromosomes has been studied. a good correlation was found for mutational effects on burst size, accumulation of unused proheads, packaging of dna into heads and cos cutting by terminase in vitro, indicating that defective cosn cleavage by terminase is the molecular explanation for the phenotypic effects of the mutations. although the b ... | 1991 | 1830343 |
| the last duplex base-pair of the phage lambda chromosome. involvement in packaging, ejection and routing of lambda dna. | cosn is the site at which the bacteriophage lambda dna packaging enzyme, terminase, introduces staggered nicks to generate the cohesive ends of mature lambda chromosomes. genetic and molecular studies show that cosn is recognized specifically by terminase and that effects of cosn mutations on lambda dna packaging and cosn cleavage are well correlated. mutations affecting a particular base-pair of cosn are unusual in being lethal in spite of causing only a moderate defect in cosn cleavage and dna ... | 1991 | 1830344 |
| a severely truncated form of translational initiation factor 2 supports growth of escherichia coli. | we have constructed strains carrying null mutations in the chromosomal copy of the gene for translational initiation factor (if) 2 (infb). a functional copy of the infb gene is supplied in trans by a thermosensitive lysogenic lambda phage integrated at att lambda. these strains enabled us to test in vivo the importance of different structural elements of if2 expressed from genetically engineered plasmid constructs. we found that, as expected, the gene for if2 is essential. however, a protein con ... | 1991 | 1830345 |
| expression of a human monoclonal anti-(rhesus d) fab fragment in escherichia coli with the use of bacteriophage lambda vectors. | a human anti-(rhesus d) antibody (igg1 lambda) fab fragment was cloned from an epstein-barr-virus-transformed cell line and expressed in escherichia coli with the use of bacteriophage lambda vectors. the cloned protein is active in binding to human erythrocytes and permits the development of a recombinant reagent for the prevention of haemolytic disease of the newborn. the method offers a rapid and effective means of rescuing human fabs from potentially unstable cell lines secreting human antibo ... | 1991 | 1830475 |
| isolation and characterization of mutations in the bacteriophage lambda terminase genes. | the terminase enzyme of bacteriophage lambda is a hetero-oligomeric protein which catalyzes the site-specific endonucleolytic cleavage of lambda dna and its packaging into phage proheads; it is composed of the products of the lambda nul and a genes. we have developed a simple method to select mutations in the terminase genes carried on a high-copy-number plasmid, based on the ability of wild-type terminase to kill reca strains of escherichia coli. sixty-three different spontaneous mutations and ... | 1991 | 1830578 |
| hybrid pltl promoter with dual regulation control. | the newly constructed pltl hybrid promoter is composed of the operator and promoter sequences of tac and the -35 to -135 region of the phage lambda pl promoter, which contains the at-rich block and the ol2 and ol3 segments. transcriptional properties of pltl were examined and compared with tac and lambda pl as reference promoters. the hybrid pltl exhibits different and improved properties over tac promoter in four ways: (i) when repressed, the repression is almost complete; (ii) after complete i ... | 1991 | 1830746 |
| energetics of subunit dimerization in bacteriophage lambda ci repressor: linkage to protons, temperature, and kcl. | a common feature of gene regulatory systems is the linkage between reversible protein oligomerization and dna binding. experimental dissection using temperature dependence of the subunit-subunit energetics and their linkage to processes such as ion binding and release is necessary for characterization of the chemical forces that contribute to cooperativity and site specificity. we have therefore studied the effects of temperature, proton activity, and monovalent salt on monomer-dimer assembly of ... | 1991 | 1831045 |
| assembly of transcription elongation complexes containing the n protein of phage lambda and the escherichia coli elongation factors nusa, nusb, nusg, and s10. | the transcription antitermination protein, n, of bacteriophage lambda; the escherichia coli elongation factors nusa, nusb, ribosomal protein s10, and nusg; and a dna template containing a lambda nut (n-ututilization) site are necessary and sufficient for the highly cooperative formation in vitro of stable transcription complexes containing all five elongation factors. mutations in the nut site, nusa, or the beta-subunit of rna polymerase (rnap) that impair antitermination in vivo also abolish th ... | 1991 | 1831176 |
| escherichia coli mutations that block transcription termination by phage hk022 nun protein. | the nun gene product of the lambdoid coliphage hk022 provokes premature transcription termination at, or near, the phage lambda nut sites. termination by nun and antitermination by lambda n protein both require the nut sites and escherichia coli nusa, nusb and nuse proteins. to characterize further the host requirements for nun termination, we selected host mutations that blocked termination at lambda nutr. in addition to mutations in nusa, nusb and nuse, we obtained mutations in rpoc, encoding ... | 1991 | 1831236 |
| behavior of a cross-linked attachment site: testing the role of branch migration in site-specific recombination. | integrative recombination of bacteriophage lambda requires perfect homology between partners over a short segment of dna, the overlap region, that separates the positions of top and bottom strand exchange. we constructed a specific cross-link between complementary strands in the overlap region of one partner, using a method designed to introduce minimal distortion of dna. the modified attachment site could initiate recombination, forming a holliday junction, but could not resolve this junction s ... | 1991 | 1831237 |
| damage and mutagenesis of bacteriophage lambda induced by high ph. | bacteriophage lambda-escherichia coli complexes exhibited remarkable sensitivity to alkaline ph 10.0 at 37 degrees c. the decline in plaque forming units after alkali treatment was more pronounced in complexes with some of the radiation repair defective mutants of e. coli k-12, i.e. uvrareca, reca, rer and lexa mutants as compared to those of uvra, recb and wild-type strains. the red gene of lambda phage and reca gene of e. coli seem to have a complementary effect on the alkali induced lesions. ... | 1991 | 1831875 |
| bacteriophage lambda dna maturation and packaging. | 1991 | 1831966 | |
| a human fab fragment specific for thyroid peroxidase generated by cloning thyroid lymphocyte-derived immunoglobulin genes in a bacteriophage lambda library. | a human fab fragment (sp2) which binds specifically to human thyroid peroxidase has been generated by expressing random combinations of heavy and light chain immunoglobulin genes (derived from graves' thyroid cdna) in a bacteriophage lambda library. in common with many serum tpo autoantibodies, the cloned fab fragment is igg1 kappa and has a high affinity for tpo (approximately 10(-9) m). on the basis of their nucleotide sequences, the heavy and light chain genes coding for sp2 belong to familie ... | 1991 | 1831977 |
| cloning of the reca gene of bordetella pertussis and characterization of its product. | a reca gene of bordetella pertussis was identified in a plasmid library by complementation of a reca mutation in e coli and subcloned as a 2.1-kb sph i dna fragment. southern hybridization experiments showed no similarity to the e coli reca gene, but very strong similarity to other bordetella species. e coli reca mutant cells containing the b pertussis reca gene at high gene dosage were resistant to dna-damaging agents such as methyl methane sulfonate or 4-nitroquinoline-n-oxide, displayed induc ... | 1991 | 1832021 |
| 100ps molecular dynamic simulation of d(tatcacc)2. | a heptanucleotide sequence d(tatcacc)2 from or3 region of bacteriophage lambda is considered sufficient for the recognition of cro protein. we present here results on molecular dynamic simulations on this sequence for 100 ps in 0.02 ps interval. the simulations are done using computer program gromos. the conformational results are averaged over each ps. the iupac torsional parameters for 100 conformations are illustrated using a wheal and a dial systems. several other stereochemical parameters s ... | 1991 | 1832544 |
| structural organization and the transcription initiation site of the human hepatocyte growth factor gene. | the structural organization of the gene coding for human hepatocyte growth factor (hhgf) has been determined by seven overlapping lambda phage genomic clones including three clones that were previously characterized. the gene for hhgf spans about 70 kbp of dna and consists of 18 exons separated by 17 introns. the coding sequence of hhgf consists of multiple putative domains that are homologous to those observed in plasminogen. these regions were found as separate exons in the gene, and the exon- ... | 1991 | 1832556 |
| molecular cloning and nucleotide sequence of the rhizobium phaseoli reca gene. | a recombinant lambda phage carrying the reca gene of rhizobium phaseoli was isolated from a r. phaseoli genomic library by complementation of the fec- phenotype of the recombinant phage in escherichia coli. when expressed in e. coli, the cloned reca gene was shown to restore resistance to both uv irradiation and the dna alkylating agent methyl methanesulphonate (mms). the r. phaseoli reca gene also promoted homologous recombination in e. coli. the cloned reca gene was only weakly inducible in e. ... | 1991 | 1832737 |
| [binding of ssb-protein from ehrlich ascites carcinoma cells with dna and polyribonucleotides]. | binding of ssb-protein from ehrlich ascites tumor to ssdna from m13 phage leads to its compactization. the structure of the complex at the protein/dna ratios far from the saturation level looks like "beads-on the string". dna that was fully saturated with protein forms collapsed globular structure. binding of the protein to the dsdna from phage lambda increases its flexibility and decreases the coil dimensions; no "beads-on the string" structure are seen. the protein possess slight destabilizing ... | 1991 | 1832738 |
| peptidyl-trna hydrolase is involved in lambda inhibition of host protein synthesis. | escherichia coli rap mutants do not support vegetative growth of bacteriophage lambda and die upon transcription of lambda dna bar sites. bacteria harbouring a pth(ts) mutation synthesize thermosensitive peptidyl-trna hydrolase (pth) and die at 42 degrees c from a defect in protein synthesis. we present evidence that both rap and pth(ts) mutations affect the same gene: (i) peptidyl-trna hydrolase activity was found to be defective in rap mutants; (ii) at a threshold temperature, pth cells, like ... | 1991 | 1833189 |
| isolation, characterization, cdna cloning and gene expression of an avian transthyretin. implications for the evolution of structure and function of transthyretin in vertebrates. | a chicken liver cdna library was constructed in bacteriophage lambda gt10. a full-length transthyretin cdna clone was identified by screening with rat transthyretin cdna and was sequenced. a three-dimensional model of chicken transthyretin was obtained by computer-graphics-based prediction from the derived amino acid sequence for chicken transthyretin and from the structure of human transthyretin determined by x-ray diffraction analysis [blake, c.c.f., geisow, m.j., oatley, s.j., rérat, b. & rér ... | 1991 | 1833190 |
| purification of penicillin-binding protein 4 of escherichia coli as a soluble protein by dye-affinity chromatography. | the dacb gene of escherichia coli, coding for penicillin-binding protein 4 (pbp4) was cloned under the control of the phage lambda pr promoter and cro gene translation signals. depression of the phage lambda promoter for 2 h at 42 degrees c in e. coli led to the maximum over-production of pbp4 to 3.8% of the total soluble protein. expression at 42 degrees c but not at 40 degrees c or 37 degrees c led to incomplete processing and aggregation of the preform of pbp4. cibacron navyblue 2g-e was sele ... | 1991 | 1833192 |
| two-stage thermal unfolding of [cys55]-substituted cro repressor of bacteriophage lambda. | it has been shown by scanning calorimetry and 1h nmr spectroscopy that thermal denaturation of mutant lambda phage cro repressor in which val55 was substituted for cys, proceeds in 2 stages in contrast to the wild type protein. at neutral ph values, an additional cooperative transition has been observed at about 100 degrees c. calorimetric measurements on the mutant and its tryptic fragment lead to the conclusion that the two-stage character of thermal unfolding of the mutant is due to a disrupt ... | 1991 | 1833238 |
| a genetic analysis of xis and fis interactions with their binding sites in bacteriophage lambda. | the bacteriophage p22-based challenge-phage system was used to study the binding of xis and fis to their sites in attp of bacteriophage lambda. challenge phages were constructed that contained the x1, x2, and f sites within the p22 pant promoter, which is required for expression of antirepressor. if xis and fis bind to these sites in vivo, they repress transcription from pant, allowing lysogenization to occur. challenge phages carrying the xix2f region in either orientation exhibited lysogenizat ... | 1991 | 1833380 |
| membrane localization of the hfla regulatory protease of escherichia coli by immunoelectron microscopy. | the hfla locus of escherichia coli specifies a multisubunit protease that selectively degrades the cii transcriptional activator of phage lambda. the regulated turnover of cii is critical for the choice between the lytic and lysogenic pathways of viral development. previous cell fractionation work has indicated that hfla is associated with the inner membrane fraction. we have sought to demonstrate that the hfla protease is localized in the cell membrane of intact cells. to achieve this goal, we ... | 1991 | 1833381 |
| the dna binding arm of lambda repressor: critical contacts from a flexible region. | segments of protein that do not adopt a well-ordered conformation in the absence of dna can still contribute to site-specific recognition of dna. the first six residues (nh2-ser1-thr2-lys3-lys4-lys5-pro6-) of phage lambda repressor are flexible but are important for site-specific binding. low-temperature x-ray crystallography and codondirected saturation mutagenesis were used to study the role of this segment. all of the functional sequences have the form [x]1-[x]2-[lys or arg]3-[lys]4-[lys or a ... | 1991 | 1833818 |
| the nut site of bacteriophage lambda is made of rna and is bound by transcription antitermination factors on the surface of rna polymerase. | the boxa and boxb components of the lambda nut site are important for transcriptional antitermination by the phage n protein. we show here that boxa and boxb rna in n-modified transcription complexes are inaccessible to ribonucleases and have altered sensitivity to dimethylsulfate. n and nusa suffice to weakly protect boxb, independently of boxa and other factors. however, efficient protection of the entire nut site from ribonucleases requires boxa and boxb, n, nusa, nusb, s10, and nusg. mutatio ... | 1991 | 1834523 |
| special uses of lambda phage for molecular cloning. | 1991 | 1834918 | |
| [survival curve during virus inactivation]. | the survival curves for bacteriophage lambda and vaccinia virus were shown theoretically and in experiments to have a plateau at prolonged inactivation by uv-irradiation or 8-methoxypsoralen. the level of the plateau is dependent of the accuracy of the repair process. the method for extrapolation of the survival curves is proposed. | 1991 | 1834934 |
| a simple method for direct automated sequencing of pcr fragments. | a simple and rapid method for direct sequencing of pcr-generated fragments has been developed for use on applied biosystems 373a automated dna sequencer utilizing the dyedeoxy terminator chemistry. standard pcr conditions are used to generate a dna fragment, which is subsequently gel-purified to remove excess primers and unwanted pcr products. the sequencing reactions are carried out in a thermal cycler using the purified product as template dna and the dye-deoxy terminators. the sequence of 500 ... | 1991 | 1835395 |
| the role of the oop antisense rna in coliphage lambda development. | we have made a derivative of bacteriophage lambda that makes no oop antisense rna. the mutant phage carries a point mutation that inactivates the oop promoter, po. the phages lambda + and lambda po- have identical plaque morphologies, one-step growth curves, and frequencies of lysogenization of a sensitive host. oop rna synthesis is weakly repressed by the escherichia coli lexa protein. consonant with this inducibility of oop rna synthesis by ultraviolet light, we find a two-fold greater phage b ... | 1991 | 1835509 |
| functional importance of sequence in the stem-loop of a transcription terminator. | intrinsic transcription terminators of prokaryotes are distinguished by a common rna motif: a stem-loop structure high in guanine and cytosine content, followed by multiple uridine residues. models explaining intrinsic terminators postulate that the stem-loop sequence is necessary only to form structure. in the tr2 terminator of coliphage lambda, single-nucleotide changes reducing potential rna stem stability eliminated tr2 activity, and a compensatory change that restored the stem structure res ... | 1991 | 1835546 |
| new methods for the detection of genetic variation. | the possibility to detect variations in the genetic material is limiting to measure dna sequence variations occurring at low frequency, such as somatic mutations responsible for the generation of diversity in the immunoglobulin genes. in order to study mutations, a system has been developed using transgenic mice in which mutant genes are rescued and selected among non mutant genes by the phage lambda as shuttle vector. moreover, it has been developed a two-dimensional dna fingerprinting method b ... | 1991 | 1835568 |
| screening combinatorial antibody libraries for catalytic acyl transfer reactions. | a bacteriophage lambda vector system for the expression of fab fragments from the mouse antibody repertoire in escherichia coli has been described. we have used this system to generate a catalytic antibody from a combinatorial antibody library. monoclonal antibody 43c9 was raised against a transition state analogue of the hydrolysis of carboxyamide. mrna from hybridoma cells expressing this antibody was cloned into phage lambda and clones that expressed the mrna for either the heavy or the light ... | 1991 | 1835693 |
| construction of combinatorial antibody expression libraries in escherichia coli. | a lambda vector system has been developed for the construction and coexpression of diverse populations of heavy and light chain cdna sequences. heavy and light chain sequences within the immunological repertoire are generated by the polymerase chain reaction using primers directed to conserved regions within the variable region framework. two lambda vectors are employed for the independent construction of heavy and light chain cdna libraries. the libraries are randomly combined to produce a popu ... | 1991 | 1835694 |
| dna sequence changes in mutations induced by ultraviolet light in the gpt gene on the chromosome of escherichia coli uvr+ and urva cells. | sequence changes in mutations induced by ultraviolet light are reported for the chromosomal escherichia coli gpt gene in almost isogenic e. coli uvr+ and excision-deficient uvra cells. differences between the mutagenic spectra are ascribed to preferential removal of photoproducts in the transcribed strand by excision repair in uvr+ cells. this conclusion is confirmed by analysis of published results for genes in both uvr+ and uvr- cells, showing a similar selective removal of mutagenic products ... | 1991 | 1836051 |
| validation studies with muta mouse: a transgenic mouse model for detecting mutations in vivo. | mutamouse is a transgenic mouse engineered to detect mutations in vivo in any tissue of choice by using simple laboratory methods. the target is a bacterial lacz gene incorporated via lambda phage into the genome of each mouse cell such that a concatamer of approximately 40 copies exists at a single site on both chromosomes of a homologous pair. in order to assess the potential usefulness of mutamouse in detecting in vivo mutagenesis, several known mutagens/carcinogens were applied to male anima ... | 1991 | 1836178 |