Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
|---|
| production and characterization of human 293 cell lines expressing the site-specific recombinase cre. | we have constructed 293 cell lines expressing the site-specific cre recombinase from bacteriophage p1, that acts on a 34 bp target sequence called loxp. stably transformed cells were obtained by transfection with a plasmid containing cre and a selectable marker under the control of viral promoters. the resulting 293cre cell lines could be used to induce expression from adenovirus vectors containing reporter genes under the control of a cre responsive "molecular switch." high efficiency recombina ... | 1996 | 9131017 |
| genomic targeting with an mbp-cre fusion protein. | the cre recombinase of bacteriophage p1 catalyses site-specific recombination between lox-recombination target sites both in prokaryotic and eukaryotic cells and has thus become a popular tool in genetic research. stable, cre-mediated integration of dna sequences at pre-existing lox sites in the eukaryotic genome is facilitated when a cre recombinase protein rather than a cre-expression plasmid is used to direct site-specific recombination (baubonis and sauer (1993) nucleic acids res., 21, 2025- ... | 1996 | 8996087 |
| decrease in the linking number of plasmid dna in dnaa mutants of escherichia coli. | we made use of agarose gel electrophoresis in the presence of chloroquine to examine the linking number of plasmids in temperature-sensitive dnaa mutants, including dnaa5 and dnaa46 mutants. the linking number of dna prepared from dnaa mutants growing at 37 degrees c was lower than that from wild type cells yet there was no significant difference when cells were grown at 28 degrees c. complementation analysis with a plasmid containing the wild type dnaa gene and phage p1-mediated transduction co ... | 1996 | 8573119 |
| three functions of bacteriophage p1 involved in cell lysis. | amber and deletion mutants were used to assign functions in cell lysis to three late genes of bacteriophage p1. two of these genes, lyda and lydb of the dar operon, are 330 and 444 bp in length, respectively, with the stop codon of lyda overlapping the start codon of lydb. the third, gene 17, is 558 bp in length and is located in an otherwise uncharacterized operon. a search with the predicted amino acid sequence of lyda for secondary motifs revealed a holin protein-like structure. comparison of ... | 1996 | 8576044 |
| site-specific spontaneous deletions in three genome regions of a temperate streptococcus thermophilus phage. | site-specific spontaneous deletions were observed with high frequency in three regions of the genome of the temperate streptococcus thermophilus phage phi sfi21. deletion sizes were 750 bp (type 1), 2.7 kb (type 2), and 1 kb (type 3). combinations of types 1 and 3 and 2 and 3 were observed. the mutants grew lytically although with reduced burst sizes. type 2 mutants lost the capacity to lysogenize host cells. upon serial passage, the deletion mutants overgrew the wild-type phage. no direct or in ... | 1996 | 8623559 |
| targeted dna recombination in vivo using an adenovirus carrying the cre recombinase gene. | conditional gene expression and gene deletion are important experimental approaches for examining the functions of particular gene products in development and disease. the cre-loxp system from bacteriophage p1 has been used in transgenic animals to induce site-specific dna recombination leading to gene activation or deletion. to regulate the recombination in a spatiotemporally controlled manner, we constructed a recombinant adenoviral vector, adv/cre, that contained the cre recombinase gene unde ... | 1996 | 8632992 |
| an arrayed bacteriophage p1 genomic library of pneumocystis carinii. | we have constructed an arrayed, large insert, multiple coverage genomic library of pneumocystis carinii dna using the bacteriophage p1 cloning system. the library consists of approximately 4800 independent clones with an average insert size of approximately 55 kbp individually arrayed in 50 microtiter plates, and is readily screened on ten or fewer microtiter plate-sized filters using a high density colony replicating device. screening of the library for unique p. carinii sequences detected an a ... | 1996 | 8640187 |
| sequence scanning: a method for rapid sequence acquisition from large-fragment dna clones. | a strategy of "sequence scanning" is proposed for rapid acquisition of sequence from clones such as bacteriophage p1 clones, cosmids, or yeast artificial chromosomes. the approach makes use of a special vector, called lambdascan, that reliably yields subclones with inserts in the size range 8-12 kb. a number of subclones, typically 96 or 192, are chosen at random, and the ends of the inserts are sequenced using vector-specific primers. then long-range spectrum pcr is used to order and orient the ... | 1996 | 8643692 |
| the 21q22.1 sts marker, vn02 (est00541 cdna), is part of the 3' sequence of the human na+/myo-inositol cotransporter (slc5a3) gene. | the human osmoregulatory na+/myo-inositol cotransporter gene (slc5a3) was recently cloned and localized to the region of 21q22. fine mapping of this gene was accomplished by identifying yac clones that contain slc5a3 and utilizing known sts markers for 21q22.1 and 21q22.2 sub-bands that map to the positive yac clones. two bacteriophage p1 clones containing the slc5a3 gene gave a positive pcr product when screened with the 21q22.1 marker vn02, an expressed sequence tag (est00541). through dna seq ... | 1996 | 8646889 |
| phage display vectors for in vivo recombination of immunoglobulin heavy and light chain genes to make large combinatorial libraries. | new phage display vectors for in vivo recombination of immunoglobulin (ig) heavy (vh) and light (vl) chain variable genes, to make single-chain fv fragments (scfv), were constructed. the vh and vl genes of monoclonal antibody (mab) ep-5c7, which binds to both human e- and p-selectin, were cloned into a puc19-derived plasmid vector, pcw93, and a pacyc184-derived phagemid vector, pcw99, respectively. upon induction of cre recombinase (phage p1 recombinase), the vh and vl genes were efficiently rec ... | 1996 | 8654992 |
| rapid mapping of genomic p1 clones: the mouse l-isoaspartyl/d-aspartyl methyltransferase gene. | we report the mapping of the gene for the murine protein-l-isoaspartate (d-aspartate) o-methyltransferase (ec 2.1.1. 77) from a 129 mouse strain. this gene encodes an enzyme present in all tissues that can catalyze the first step of a repair reaction in which age-damaged proteins containing abnormal l-isoaspartyl (or d-aspartyl) residues can be converted to forms containing normal l-aspartyl residues. we first mapped the restriction sites from a genomic p1 clone using a rapid method generally ap ... | 1996 | 8661142 |
| adenovirus vector technology: an efficient method for constructing recombinant adenovirus and on/off switching of gene expression. | an efficient method of constructing recombinant adenoviruses (ad) has been established. the expression unit to be introduced into recombinant ad was first inserted into the unique swai site of the full-length ad genome cloned in a cassette cosmid. the cassette bearing the expression unit was then cotransfected to 293 cells together with the ad dna-terminal protein complex digested at several sites with ecot22i. the use of the parent ad dna-terminal protein complex instead of the deproteinized ad ... | 1996 | 8677800 |
| autoregulation of the plasmid addiction operon of bacteriophage p1. | the p1 plasmid addiction operon increases the apparent stability of a plasmid that carries it by killing plasmid-free (cured) segregants. the operon consists of a gene encoding an endotoxin responsible for death on curing (doc), preceded by a gene encoding a relatively unstable antidote that can prevent host death (phd). when the copy number of the operon was increased, expression of a lacz reporter fused to the promoter of the operon decreased, indicating that expression of the operon was stabi ... | 1996 | 8702525 |
| the escherichia coli k-12 gntp gene allows e. coli f-18 to occupy a distinct nutritional niche in the streptomycin-treated mouse large intestine. | escherichia coli f-18 is a human fecal isolate that makes type 1 fimbriae, encoded by the fim gene cluster, and is an excellent colonizer of the streptomycin-treated mouse intestine. e. coli f-18 fima::tet, lacking type 1 fimbriae, was constructed by bacteriophage p1 transduction of the fim region of the e. coli k-12 strain orn151, containing the tetracycline resistance gene from tn10 inserted in the fima gene, into e. coli f-18. e. coli f-18 fima::tet was found to occupy a distinct niche in the ... | 1996 | 8751890 |
| phage hk022 roi protein inhibits phage lytic growth in escherichia coli integration host factor mutants. | temperate coliphage hk022 requires integration host factor (ihf) for lytic growth. the determinant responsible for this requirement was identified as a new gene (roi) located between genes p and q. this gene encodes a dna-binding protein (roi) containing a helix-turn-helix motif. we have shown that roi binds a site within its own gene that is closely linked to an ihf binding site. by gel retardation experiments, we have found that ihf binding stabilizes the interaction of roi with its gene. we h ... | 1996 | 8763934 |
| phenotypes of dnaa mutants of escherichia coli sensitive to phenothiazine derivatives. | the activation of dnaa protein by cardiolipin is inhibited by fluphenazine in vitro. we therefore examined the sensitivity of temperature-sensitive dnaa mutants of escherichia coli to fluphenazine and other phenothiazine derivatives. among the eight dnaa mutants tested, dnaa5, dnaa46 dnaa602, and dnaa604, mutants with mutations in the putative atp binding site of dnaa protein, showed higher sensitivities to phenothiazine derivatives than did the wild-type strain. the dnaa508 and dnaa167 mutants, ... | 1996 | 8804395 |
| antibody expression from the core region of the human igh locus reconstructed in transgenic mice using bacteriophage p1 clones. | mice carrying transgenic human immunoglobulin gene miniloci can be used for the production of human monoclonal antibodies. the human variable region (v) gene segments in these miniloci undergo productive rearrangement in mouse lymphoid tissue to yield a population of b lymphocytes expressing a repertoire of antibodies. many of the miniloci studied to date have included only a small number of germline gene segments in an artificially compact configuration. here we describe the use of the bacterio ... | 1996 | 8812473 |
| generation of a transcriptional map for a 700-kb region surrounding the polycystic kidney disease type 1 (pkd1) and tuberous sclerosis type 2 (tsc2) disease genes on human chromosome 16p3.3. | a 700-kb region of dna in human chromosome 16p13.3 has been shown to contain the polycystic kidney disease 1 (pkd1) and the tuberous sclerosis type 2 (tsc2) disease genes. an estimated 20 genes are present in this region of chromosome 16. we have initiated studies to identify transcribed sequences in this region using a bacteriophage p1 contig containing 700 kb of dna surrounding the pkd1 and tsc2 genes. we have isolated 96 unique exon traps from this interval, with 23 of the trapped exons conta ... | 1996 | 8828041 |
| site-directed mutagenesis techniques in the study of escherichia coli serine hydroxymethyltransferase. | the 3340-bp fragment containing the escherichia coli glya gene coding for serine hydroxymethyltransferase was reduced in size by pcr, and the 1600-bp fragment obtained was cloned into the vector pbr322 in both orientations (5'-3', and 3'-5'). this dna manipulation allowed us to perform site-directed mutagenesis by pcr on the glya gene. to overcome the problem of the presence of wild-type protein in the various mutant enzyme preparations, the e. coli strain gs245 used to express recombinant serin ... | 1996 | 8860659 |
| organization of the mouse cardiac natriuretic peptide locus encoding bnp and anp. | the genes encoding the mouse atrial natriuretic peptide and b-type natriuretic peptide were previously shown to be physically linked on mouse chromosome 4 (steinhelper me, 1993, structure, expression, and genomic mapping of the mouse natriuretic peptide type-b gene. circ res 72: 984-992). in the present study the spatial relationship and orientation of the mouse atrial natriuretic peptide and b-type natriuretic peptide transcription units were identified and a physical map of the mouse cardiac n ... | 1996 | 8877792 |
| transgene coplacement and high efficiency site-specific recombination with the cre/loxp system in drosophila. | studies of gene function and regulation in transgenic drosophila are often compromised by the possibility of genomic position effects on gene expression. we have developed a method called transgene coplacement, in which any two sequences can be positioned at exactly the same site and orientation in the genome. transgene coplacement makes use of the bacteriophage p1 system of cre/loxp site-specific recombination, which we have introduced into drosophila. in the presence of a cre transgene driven ... | 1996 | 8889532 |
| structure of the human gene encoding the protein repair l-isoaspartyl (d-aspartyl) o-methyltransferase. | the protein l-isoaspartyl/d-aspartyl o-methyltransferase (ec 2.1.1.77) catalyzes the first step in the repair of proteins damaged in the aging process by isomerization or racemization reactions at aspartyl and asparaginyl residues. a single gene has been localized to human chromosome 6 and multiple transcripts arising through alternative splicing have been identified. restriction enzyme mapping, subcloning, and dna sequence analysis of three overlapping clones from a human genomic library in bac ... | 1996 | 8914929 |
| the bacteriophage p1 lytic replicon: directionality of replication and cis-acting elements. | we have identified the direction of replication of a bacteriophage p1 lytic replicon. this was accomplished by constructing lambda p1 lysogens that contain a functional p1 lytic replicon and analysing which of two nearby bacterial dna markers flanking the lambda prophage were amplified when that replicon was activated. we demonstrate that both dna markers are coordinately amplified, a result consistent with lytic replication proceeding in a bidirectional fashion. to analyze the role of various e ... | 1996 | 8917092 |
| bypass of lethality with mosaic mice generated by cre-loxp-mediated recombination. | the analysis of gene function based on the generation of mutant mice by homologous recombination in embryonic stem cells is limited if gene disruption results in embryonic lethality. mosaic mice, which contain a certain proportion of mutant cells in all organs, allow lethality to be circumvented and the potential of mutant cells to contribute to different cell lineages to be analyzed. to generate mosaic animals, we used the bacteriophage p1-derived cre-loxp recombination system, which allows gen ... | 1996 | 8939573 |
| construction of a 750-kb bacterial clone contig and restriction map in the region of human chromosome 21 containing the progressive myoclonus epilepsy gene. | the gene responsible for progressive myoclonus epilepsy of the unverricht-lundborg type (epm1) is located on human chromosome 21q22.3 in a region defined by recombination breakpoints and linkage disequilibrium. as part of an effort to clone the epm1 gene on the basis of its chromosomal location, we have constructed a 753-kb bacterial clone contig that encompasses the region containing the gene. because dna markers from the region did not identify intact yeast artificial chromosome (yac) clones a ... | 1996 | 8963899 |
| subregion- and cell type-restricted gene knockout in mouse brain. | using the phage p1-derived cre/loxp recombination system, we have developed a method to create mice in which the deletion (knockout) of virtually any gene of interest is restricted to a subregion or a specific cell type in the brain such as the pyramidal cells of the hippocampal ca1 region. the cre/loxp recombination-based gene deletion appears to require a certain level of cre protein expression. the brain subregional restricted gene knockout should allow a more precise analysis of the impact o ... | 1996 | 8980237 |
| drosophila rosa gene, which when mutant causes aberrant photoreceptor oscillation, encodes a novel neurotransmitter transporter homologue. | the drosophila receptor oscillation a (rosa) mutations, which cause electroretinogram (erg) defects, including oscillations, were localized to the 24f4-25a2 region of chromosome 2l. genomic fragments from this region, isolated from bacteriophage p1 clones, included those that detect transcriptional defects in rosa mutants in rna blot experiments. one of these genomic fragments was used to screen a head cdna library. the largest cdna clone (3.6 kb) isolated was shown to rescue a rosa mutant in p ... | 1996 | 10876650 |
| efficient gene activation in mammalian cells by using recombinant adenovirus expressing site-specific cre recombinase. | a recombinant adenovirus (ad) expressing cre recombinase derived from bacteriophage p1 was constructed. to assay the cre activity in mammalian cells, another recombinant ad bearing an on/off-switching reporter unit, where a lacz-expression unit can be activated by the cre-mediated excisional deletion of an interposed stuffer dna, was also constructed. co-infection experiments together with the cre-expressing and the reporter recombinant ads showed that the cre-mediated switching of gene expressi ... | 1995 | 7479022 |
| positional cloning of the nude locus: genetic, physical, and transcription maps of the region and mutations in the mouse and rat. | mutations in the nude locus in mice and rats produce the pleiotropic phenotype of hairlessness and athymia, resulting in severely compromised immune system. to identify the causative gene, we utilized modern tools and techniques of positional cloning. specifically, spanning the region in which the nude locus resides, we constructed a genetic map of polymorphic markers, a physical map of yeast artificial chromosomes and bacteriophage p1 clones, and a transcription map of genes obtained by direct ... | 1995 | 7490093 |
| efficient regulation of gene expression by adenovirus vector-mediated delivery of the cre recombinase. | we have constructed an e1-defective adenovirus (ad) vector designated adcag-cre containing the cre recombinase gene derived from bacteriophage p1 under control of the cytomegalovirus immediate early enhancer-chicken beta-actin hybrid (cag) promoter. we examined the cre-loxp-based recombination by this ad vector in c2c12 cells bearing a reporter gene construct cag-cat-z, which directs expression of the e. coli lacz gene upon cre-mediated excision of the cat gene located between the cag promoter a ... | 1995 | 7503713 |
| dna supercoiling in a thermotolerant mutant of escherichia coli. | a spontaneously occurring, nalidixic acid-resistant (nalr), thermotolerant (t/r) mutant of escherichia coli was isolated. bacteriophage p1-mediated transduction showed that nalr mapped at or near gyr a, one of the two genes encoding dna gyrase. expression of gyra+ from a plasmid rendered the mutant sensitive to nalidixic acid and to high temperature, the result expected for alleles mapping in gyra. plasmid linking number measurements, made with dna from cells grown at 37 degrees c or shifted to ... | 1995 | 7565605 |
| site-specific recombination mediated by an adenovirus vector expressing the cre recombinase protein: a molecular switch for control of gene expression. | we have constructed replication-defective human adenovirus (ad) type 5 vectors containing the gene for the cre recombinase from bacteriophage p1 under control of the human cytomegalovirus immediate-early promoter (adcre). expression of the protein was detected in replication-permissive (293) and in nonpermissive (mrc5) cell lines, and its biochemical activity was demonstrated in a cell-free recombination assay using a plasmid containing two loxp sites. to study cre-mediated recombination in an i ... | 1995 | 7609024 |
| cre-mediated site-specific translocation between nonhomologous mouse chromosomes. | chromosome rearrangements, such as large deletions, inversions, or translocations, mediate migration of large dna segments within or between chromosomes, which can have major effects on cellular genetic control. a method for chromosome manipulation would be very useful for studying the consequences of large-scale dna rearrangements in mammalian cells or animals. with the use of the cre-loxp recombination system of bacteriophage p1, we induced a site-specific translocation between the dek gene on ... | 1995 | 7638200 |
| transduction, restriction and recombination patterns in escherichia coli. | chromosomal dna from several escherichia coli reference (ecor) strains was transduced by bacteriophage p1 into e. coli strain k12 w3110 trpa33. recombination patterns of the transductants were determined by restriction fragment length polymorphism over a 40-kb region centering on a single marker (trpa+) in the tryptophan operon. these experiments demonstrate that transduction between different strains of e. coli can result in recombinational replacements that are small in comparison to the entra ... | 1995 | 7705636 |
| atp hydrolysis is required for dna cleavage by ecopi restriction enzyme. | the type iii restriction endonuclease ecopi, coded by bacteriophage p1, cleaves unmodified dna in the presence of atp and magnesium ions. we show that purified ecopi restriction enzyme fails to cleave dna in the presence of non-hydrolyzable atp analogs. more importantly, this study demonstrates that ecopi restriction enzyme has an inherent atpase activity, and atp hydrolysis is necessary for dna cleavage. furthermore, we show that the progress curve of the reaction with ecopi restriction enzyme ... | 1995 | 7723013 |
| site-specific recombination in the replication terminus region of escherichia coli: functional replacement of dif. | the replication terminus region of the escherichia coli chromosome encodes a locus, dif, that is required for normal chromosome segregation at cell division. dif is a substrate for site-specific recombination catalysed by the related chromosomally encoded recombinases xerc and xerd. it has been proposed that this recombination converts chromosome multimers formed by homologous recombination back to monomers in order that they can be segregated prior to cell division. strains mutant in dif, xerc ... | 1995 | 7729430 |
| partition of p1 plasmids in escherichia coli mukb chromosomal partition mutants. | the partition system of the low-copy-number plasmid/prophage of bacteriophage p1 encodes two proteins, para and parb, and contains a dna site called pars. parb and the escherichia coli protein ihf bind to pars to form the partition complex, in which pars is wrapped around parb and ihf in a precise three-dimensional conformation. partition can be thought of as a positioning reaction; the plasmid-encoded components ensure that at least one copy of the plasmid is positioned within each new daughter ... | 1995 | 7730268 |
| site-specific integration of dna into wild-type and mutant lox sites placed in the plant genome. | the bacteriophage p1 cre-lox site-specific recombination system has been used to integrate dna specifically at lox sites previously placed in the tobacco genome. as integrated molecules flanked by wild-type lox sites can readily excise in the presence of cre recombinase, screening for mutant lox sites that can resist excisional recombination was performed. in gene integration experiments, wild-type and mutant lox sites were used in conjunction with two strategies for abolishing post-integration ... | 1995 | 7742860 |
| physical mapping, cloning, and identification of genes within a 500-kb region containing brca1. | brca1 is a breast/ovarian cancer susceptibility gene on human chromosome 17q21. we describe a complete and detailed physical map of a 500-kb region of genomic dna containing the brca1 gene and the partial cloning in phage p1 artificial chromosomes. approximately 70 exons were isolated from this region, 11 of which were components of the brca1 gene. analysis of the other exons revealed a rho-related g protein and the interferon-induced leucine-zipper protein ifp-35. | 1995 | 7753812 |
| headful packaging revisited: the packaging of more than one dna molecule into a bacteriophage p1 head. | like a variety of other bacteriophages, such as t4 and p22, bacteriophage p1 packages dna by a "headful" mechanism in which the capacity of the viral capsid determines the size of the single dna molecule that is packaged. because of the long-standing and general acceptance of this packaging mechanism, we were surprised to discover that some of our observations, using the in vitro p1 packaging system, could be explained by the packaging of less than headful-sized (< 110 kb) dna molecules into a p ... | 1995 | 7776370 |
| the lytic replicon of bacteriophage p1 is controlled by an antisense rna. | the lytic replicon of phage p1 is used for dna replication during the lytic cycle. it comprises about 2% of the p1 genome and contains the p1 c1 repressor-controlled operator-promoter element op53.p53 and the kila and the repl genes, in that order. transcription of the lytic replicon of p53 and synthesis of the product of repl, but not kila, are required for replicon function. we have identified an additional promoter, termed p53as (antisense), at the 5'-end of the kila gene from which a 180 bas ... | 1995 | 7784198 |
| cloning, characterization, and chromosomal localization to 4p16 of the human gene (lrpap1) coding for the alpha 2-macroglobulin receptor-associated protein and structural comparison with the murine gene coding for the 44-kda heparin-binding protein. | we report the molecular cloning of the human gene (symbol lrpap1) coding for the alpha 2-macroglobulin receptor-associated protein (a2mrap), as well as the gene coding for the 44-kda heparin-binding protein (hbp-44), its murine counterpart. for both, genomic cosmid clones were isolated, and for the human gene a bacteriophage p1 clone containing the entire a2mrap gene was also retrieved. the genes were characterized after subcloning: in both species, the known coding part of the cdna is encoded b ... | 1995 | 7789983 |
| gene structure and chromosomal localization of the human hsd11k gene encoding the kidney (type 2) isozyme of 11 beta-hydroxysteroid dehydrogenase. | 11 beta-hydroxysteroid dehydrogenase (11 beta hsd) converts glucocorticoids to inactive products and is thus thought to confer specificity for aldosterone on the type i mineralocorticoid receptor in the kidney. recent studies indicate the presence of at least two isozymes of 11 beta hsd. in vitro, the nad(+)-dependent kidney (type 2) isozyme catalyzes 11 beta-dehydrogenase but not reductase reactions, whereas the nadp(+)-dependent liver (type 1) isozyme catalyzes both reactions. we have now char ... | 1995 | 8530071 |
| analysis of the human gene encoding the kidney isozyme of 11 beta-hydroxysteroid dehydrogenase. | 11 beta-hydroxysteroid dehydrogenase (11 beta-hsd) catalyzes the conversion of cortisol to cortisone. this activity may be deficient in the syndrome of apparent mineralocorticoid excess (ame). 11 beta-hsd l (type i), isolated from liver, is widely expressed and utilizes nadp+ as a cofactor. the gene for 11 beta-hsd l was found to be normal in patients of ame. a second isoform, 11 beta-hsd k (type ii), isolated from kidney, is more tissue specific in expression and utilizes nad+ as a cofactor. th ... | 1995 | 8547172 |
| cin-mediated recombination at secondary crossover sites on the escherichia coli chromosome. | the cin recombinase is known to mediate dna inversion between two wild-type cix sites flanking genetic determinants for the host range of bacteriophage p1. cin can also act with low frequency at secondary (or quasi) sites (designated cixq) that have lower homology to either wild-type site. an inversion tester sequence able to reveal novel operon fusions was integrated into the escherichia coli chromosome, and the cin recombinase was provided in trans. among a total of 13 cin-mediated inversions ... | 1995 | 7868587 |
| intra-chromosomal rearrangements generated by cre-lox site-specific recombination. | chromosomal rearrangements are useful genetic and breeding tools but are often difficult to detect and characterize. to more easily identify and define chromosome deletions and inversions, we have used the bacteriophage p1 cre-lox site-specific recombination system to generate these events in plants. this involves three steps: (i) the introduction of two lox sites into one locus in a plant genome, including one site within a modified ds transposon; (ii) ac transposase-mediated transposition of t ... | 1995 | 7885845 |
| the rpoe gene encoding the sigma e (sigma 24) heat shock sigma factor of escherichia coli. | previous work has established that the transcription factor sigma e (sigma 24) is necessary for maintaining the induction of the heat shock response of escherichia coli at high temperatures. we have identified the gene encoding sigma e using a genetic screen designed to isolate trans-acting mutations that abolish expression from either htra or rpohp3, two promoters recognized uniquely by sigma e-containing rna polymerase. such a screen was achieved by transducing strains carrying a single copy o ... | 1995 | 7889935 |
| techniques in mammalian genome mapping. | increasing emphasis is being given to genomic cloning using escherichia coli vectors of intermediate insert capacity, such as bacteriophage p1, p1-derived artificial chromosomes and the f factor based bacterial artificial chromosomes. these vectors are being used in addition to yeast artifical chromosomes (yacs) in recognition of the difficulties encountered with yac stability and with handling of yac dnas (problems that will not easily be overcome). nonetheless, yacs remain the most practical c ... | 1995 | 7894081 |
| towards cloning the familial breast-ovarian cancer gene on chromosome 17. | the past year has seen a great deal of excitement in the field of breast cancer genetics. since linkage of the familial breast-ovarian cancer gene (brca1) to chromosome 17, the critical region has been narrowed to 1.0-1.5 mb by recombination studies, a detailed physical map has been constructed and much of the region has been cloned in yeast artificial chromosome, bacteriophage p1 and cosmid vectors. the focus now lies on identifying the genes housed within the brca1 region and scanning them for ... | 1994 | 7919922 |
| purification and dna-binding activity of the paca subunit of the bacteriophage p1 pacase enzyme. | the bacteriophage p1 packaging site (pac) cleavage enzyme (pacase) consists of two phage encoded proteins, paca and pacb. both proteins are necessary for the recognition and cleavage of pac and for subsequent packaging of cleaved dna into phage particles. we have purified paca to homogeneity from a bacterial strain that overproduces the protein. purified paca complements an escherichia coli extract containing the pacb protein for dna cleavage at the pac site and recognizes and binds to methylate ... | 1994 | 7932754 |
| faithful cleavage of the p1 packaging site (pac) requires two phage proteins, paca and pacb, and two escherichia coli proteins, ihf and hu. | the paca and pacb subunits of the bacteriophage p1 dna packaging enzyme (pacase) are necessary for cleavage of the phage packaging site (pac). in the accompanying paper, we show that the paca subunit of the enzyme specifically binds to pac in the absence of pacb, but requires factors present in an escherichia coli extract to do so. we show here that either of two e. coli dna binding proteins, integration host factor (ihf) or hu, can replace this extract and promote the binding of paca to pac. ih ... | 1994 | 7932755 |
| c1 repressor-mediated dna looping is involved in c1 autoregulation of bacteriophage p1. | c1 repressor is required to repress the lytic functions of a p1 prophage in vivo. transcription of the c1 gene is autoregulated via the c1-controlled operator op99a,b which overlaps the promoter of the c1 gene. it is negatively affected by lxc corepressor and the dna region upstream of c1, which contains the additional operators op99c, d, and e. we have explored these effects by constructing a set of lacz reporter plasmids with op99a,b and varying parts of the upstream dna region. transcription ... | 1994 | 7989363 |
| mutations affecting a regulated, membrane-associated esterase in salmonella typhimurium lt2. | mutations at the apea locus in salmonella typhimurium lead to loss of a soluble enzyme ("protease i") that hydrolyzes the chromogenic endoprotease substrate n-acetyl phenylalanine beta-naphthyl ester. we have isolated pseudorevertants of s. typhimurium apea mutations that have regained the ability to hydrolyze this compound. these pseudorevertants contain mutations (aper) that lead to overproduction of a membrane-bound esterase different from protease i. the aper locus is phage p1 cotransducible ... | 1994 | 8028584 |
| genome structure and evolution in drosophila: applications of the framework p1 map. | physical maps showing the relative locations of cloned dna fragments in the genome are important resources for research in molecular genetics, genome analysis, and evolutionary biology. in addition to affording a common frame of reference for organizing diverse types of genetic data, physical maps also provide ready access to clones containing dna sequences from any defined region of the genome. in this paper, we present a physical map of the genome of drosophila melanogaster based on in situ hy ... | 1994 | 8041703 |
| cloning of the region between hla-dmb and lmp2 in the human major histocompatibility complex. | the human mhc is one of the most extensively mapped regions of the human genome. almost all of the class ii region of the mhc has already been cloned in cosmids but a gap remained between the dmb and lmp2 genes. previously, screening of several complete cosmid libraries had failed to bridge this gap, which may contain novel antigen processing or presentation genes. we constructed cosmid libraries from two different sources in order to clone the region: (a) a library with fourfold coverage made f ... | 1994 | 8045787 |
| second-site suppressors of the bacteriophage p1 virs mutant reveal the interdependence of the c4, icd, and ant genes in the p1 immi operon. | the immi operon of phage p1 contains the genes c4, icd, and ant, which are transcribed in that order from the same constitutive promoter, p51b. the gene c4 encodes an antisense rna which inhibits the synthesis of an antirepressor by acting on a target ant mrna. interaction depends on the complementarity of two pairs of short sequences encompassing virs+ and the ribosome-binding site involved in ant expression. accordingly, in a p1 virs mutant phage, antirepressor is synthesized constitutively. w ... | 1994 | 8051007 |
| characterization of the genomic structure, chromosomal location and promoter of human prostaglandin h synthase-2 gene. | prostaglandin h synthase (pghs) is the rate-limiting enzyme in the conversion of arachidonic acid to prostanoids. the human pghs has two isoforms. pghs-1 is a house keeping gene whereas pghs-2 is an inducible gene. we reported here the isolation of the entire pghs-2 gene and its 5'-flanking region from a human bacteriophage p1 genomic library. the gene containing 10 exons is 7.5 kb in length and located at chromosome 1. the transcriptional start site was mapped at 134 bases upstream from the atg ... | 1994 | 8074655 |
| cre recombinase-mediated site-specific recombination between plant chromosomes. | we report the use of the bacteriophage p1 cre-lox system for generating conservative site-specific recombination between tobacco chromosomes. two constructs, one containing a promoterless hygromycin-resistance gene preceded by a lox site (lox-hpt) and the other containing a cauliflower mosaic virus 35s promoter linked to a lox sequence and the cre coding region (35s-lox-cre), were introduced separately into tobacco plants. crosses between plants harboring either construct produced plants with th ... | 1994 | 8127869 |
| partition of nonreplicating dna by the par system of bacteriophage p1. | p1 plasmid encodes a cis-acting centromere analog, pars, and two par proteins that together stabilize plasmids by partitioning them to daughter bacteria. we infected immune bacteria with bacteriophage lambda into which pars had been inserted. the presence of p1 par proteins in the infected cells was found to delay the appearance of cells cured of the nonreplicating, extrachromosomal lambda-pars dna. this stabilization of lambda-pars, approximated in a computer simulation, demonstrates that activ ... | 1994 | 8132477 |
| a new bacteriophage p1-derived vector for the propagation of large human dna fragments. | we have designed a p1 vector (pcypac-1) for the introduction of recombinant dna into e. coli using electroporation procedures. the new cloning system, p1-derived artificial chromosomes (pacs), was used to establish an initial 15,000 clone library with an average insert size of 130-150 kilobase pairs (kb). no chimaerism has been observed in 34 clones, by fluorescence in situ hybridization. similarly, no insert instability has been observed after extended culturing, for 20 clones. we conclude that ... | 1994 | 8136839 |
| preparation and screening of an arrayed human genomic library generated with the p1 cloning system. | we describe here the construction and initial characterization of a 3-fold coverage genomic library of the human haploid genome that was prepared using the bacteriophage p1 cloning system. the cloned dna inserts were produced by size fractionation of a sau3ai partial digest of high molecular weight genomic dna isolated from primary cells of human foreskin fibroblasts. the inserts were cloned into the pad10sacbii vector and packaged in vitro into p1 phage. these were used to generate recombinant ... | 1994 | 8146166 |
| pid, a new member of the p1 bacteriophage group. | phage p1d produces particles of essentially uniform head size and differs from p1 in its range and tail length. the dimensions of phage p1 are reassessed. the p1 phage group shows signs of morphological evolution. | 1994 | 8149311 |
| glutathione s-transferase-sspa fusion binds to e. coli rna polymerase and complements delta sspa mutation allowing phage p1 replication. | bacteriophage p1 is unable to form plaques on e. coli hosts lacking a functional sspa gene. however, sspa mutants can be infected by p1, resulting in the synthesis of p1 early gene products and accumulation of p1 dna, but without p1 late gene product formation or host lysis. overexpression of the stringent starvation protein (sspa) as a glutathione-s-transferase fusion results in complementation of the sspa mutation and production of viable viral particles as in sspa+ strains. this suggests that ... | 1994 | 8198564 |
| tko'ed: lox, stock and barrel. | the generation of panels of mutant mice by homologous recombination has greatly increased the ability to assess the function of particular gene products in vivo. the ability to control the developmental stage, the tissue and the nature of the mutation would be an important innovation. a recent report demonstrates that the conservative site-specific recombination of bacteriophage p1, namely cre-lox, can be used successfully in combination with homologous recombination to generate temporal- and ce ... | 1994 | 7840765 |
| the antirepressor of phage p1. isolation and interaction with the c1 repressor of p1 and p7. | two antirepressor proteins, ant1 and ant2, of molecular weight 42 and 32 kda, respectively, are encoded by p1 as a single open reading frame, with the smaller protein initiating at an in-frame start codon. another open reading frame, icd, 5' upstream of and overlapping ant1 is required for ant1 expression. using appropriate ant gene-carrying plasmids we have overproduced and purified ant1/2 in the form of a protein complex and ant2 as a single protein. sequence analysis confirmed the n-terminal ... | 1993 | 8224242 |
| plasmid pbrint: a vector for chromosomal insertion of cloned dna. | plasmid pbrint is a pbr322 derivative [bolivar et al., gene 2 (1977) 95-113; balbás et al., gene 50 (1986) 3-40] that allows the insertion and replacement of dna sequences into the escherichia coli chromosome by homologous recombination. this method uses the inability of e. coli strain atcc47002 (jc7623) to replicate covalently closed circular (ccc) pbr322-derived plasmids, and the convenience of xgal+iptg screening for recombinants. the vector also contains suitable selection markers (ap and cm ... | 1993 | 8294004 |
| disruption of targeted gene in bacterial chromosome by using a temperature-sensitive plasmid. | the temperature-sensitive plasmid, psak3, was used in tryptophan-producing strains for tryptophanase gene disruption to block the degradation of tryptophan. plasmid psak3, which consisted of the psc103 plasmid containing a tetracycline resistant gene and a disrupted tryptophanase gene inserted by a kanamycin resistant gene, was integrated into the homologous site on the chromosome by gene recombination. through raising the temperature of cultivation to 42 degrees c and double antibiotics screeni ... | 1993 | 8333867 |
| [biological safety investigations of the production of human insulin by genetically-engineered e. coli k-12 cells. 3. plasmid transfer by natural transformation and transduction]. | the transfer of the expression plasmid of human insulin psw3 by natural transformation and by transduction with phage p1 was investigated in laboratory media and in surface water samples. whereas pseudomonas stutzeri could be transformed by shuttle vectors which could replicate in this microorganism, no transformants were found with the insulin expression vector. e. coli k-12 could be transduced by phage p1vir only with chromosomal markers, not with plasmid dna. as the production strain w3110iqm ... | 1993 | 8338615 |
| amplification of the ends of dna fragments cloned in bacteriophage p1. | 1993 | 8373578 | |
| mutants of escherichia coli with increased fidelity of dna replication. | to improve our understanding of the role of dna replication fidelity in mutagenesis, we undertook a search for escherichia coli antimutator strains with increased fidelity of dna replication. the region between 4 and 5 min of the e. coli chromosome was mutagenized using localized mutagenesis mediated by bacteriophage p1. this region contains the dnae and dnaq genes, which encode, respectively, the dna polymerase (alpha subunit) and 3' exonucleolytic proofreading activity (epsilon subunit) of dna ... | 1993 | 8375645 |
| plasmid addiction genes of bacteriophage p1: doc, which causes cell death on curing of prophage, and phd, which prevents host death when prophage is retained. | p1 lysogens of escherichia coli carry the prophage as a stable low copy number plasmid. the frequency with which viable cells cured of prophage are produced is about 10(-5) per cell per generation. here we show that a significant part of this remarkable stability can be attributed to a plasmid-encoded mechanism that causes death of cells that have lost p1. in other words, the lysogenic cells appear to be addicted to the presence of the prophage. the plasmid withdrawal response depends on a gene ... | 1993 | 8411153 |
| precise deletions in large bacterial genomes by vector-mediated excision (vex). the trfa gene of promiscuous plasmid rk2 is essential for replication in several gram-negative hosts. | we have developed a simple and efficient method of vector-mediated excision (vex) for in vivo generation of precisely defined deletions in large bacterial genomes. the system uses homologous recombination with small cloned fragments on specialized pvex plasmids to insert directly repeated bacteriophage p1 loxp sites at positions flanking the region to be deleted. in the presence of cre recombinase, the loxp sites are efficiently recombined to produce the deletion. deletion endpoints can be direc ... | 1993 | 8450534 |
| turbo cloning: a fast, efficient method for cloning pcr products and other blunt-ended dna fragments into plasmids. | the method uses a novel plasmid vector, p9lox5, containing a site-specific recombination sequence lox from the lox/cre recombinase system of bacteriophage p1. there are two distinct stages. firstly, vector and fragment dnas are ligated intermolecularly under conditions of macromolecular crowding (15% polyethylene glycol 6000) which accelerate blunt-end joining a thousandfold. secondly, circular recombinant molecules are efficiently excised from the ligation products by cre recombinase acting on ... | 1993 | 8451184 |
| a combined molecular and cytogenetic approach to genome evolution in drosophila using large-fragment dna cloning. | methods of genome analysis, including the cloning and manipulation of large fragments of dna, have opened new strategies for uniting molecular evolutionary genetics with chromosome evolution. we have begun the development of a physical map of the genome of drosophila virilis based on large dna fragments cloned in bacteriophage p1. a library of 10,080 p1 clones with average insert sizes of 65.8 kb, containing approximately 3.7 copies of the haploid genome of d. virilis, has been constructed and c ... | 1993 | 8486077 |
| cloning, expression, and characterization of the icd gene in the immi operon of bacteriophage p1. | the immi operon of p1 contains the genes c4, icd (formerly called orfx), and ant which are constitutively transcribed in that order from a single promoter, p51b. c4 is an antisense rna which is processed from the precursor transcript. c4 rna acts as a translational repressor of icd, thereby also inhibiting antirepressor (ant) synthesis. we have cloned the icd and the overlapping icd and ant genes. we show, by means of plasmid deletion analysis, that icd is translationally coupled to ant. an inte ... | 1993 | 8491703 |
| conformation of the origin of p1 plasmid replication. initiator protein induced wrapping and intrinsic unstacking. | the origin of plasmid dna replication in bacteriophage p1 has five 19 base-pair sites that bind the plasmid-encoded initiator, repa. here we show, using a dna band retardation assay, that repa can bend dna that carries one or more of the repa binding sites. repa binding to supercoiled dna carrying the five sites, directly repeated and phased two turns of b-dna apart, absorbs about one positive superhelical turn of dna as determined by two-dimensional gel electrophoresis. this indicates that the ... | 1993 | 8496963 |
| fine-structure analysis of the p7 plasmid partition site. | the par region of bacteriophage p7 is responsible for active partition of the p7 plasmid prophage into daughter cells. the cis-acting partition site was defined precisely as a 75-bp sequence that was necessary and sufficient to promote correct segregation of an unstable vector plasmid when the two p7 partition proteins, para and parb, were supplied in trans. roughly the same region was necessary to exert partition-mediated incompatibility. the minimal site contains an integration host factor (ih ... | 1993 | 8501048 |
| independent control of immunoglobulin switch recombination at individual switch regions evidenced through cre-loxp-mediated gene targeting. | we have employed a method based on the cre-loxp recombination system of bacteriophage p1 to generate a mouse strain in which the jh segments and the intron enhancer in the igh locus are deleted. by analysis of immunoglobulin isotype switch recombination in heterozygous mutant b cells activated by lipopolysaccharide plus interleukin-4, we show that, on the mutant chromosome, switch recombination at the mu gene switch region is strongly suppressed, whereas the switch region of the gamma 1 gene is ... | 1993 | 8513499 |
| purification of the c1 repressor of bacteriophage p1 by fast protein liquid chromatography. | a fast protein liquid chromatographic method is described for the purification of the c1 repressor of bacteriophage p1 and its truncated form c1*. by using one crude extract, both repressor proteins were purified in parallel to homogeneity and were shown to interact specifically with p1 operator dna in vitro. the method involves an affinity chromatographic step on heparin-sepharose, followed by a combination of ion-exchange chromatography on q sepharose and s sepharose. the availability of a hom ... | 1992 | 12126108 |
| exchange of gene activity in transgenic plants catalyzed by the cre-lox site-specific recombination system. | the cre-lox site-specific recombination system of bacteriophage p1 was used to excise a firefly luciferase (luc) gene which had previously been incorporated into the tobacco genome. the excision event was due to site-specific dna recombination between two lox sequences flanking the luc gene and was catalyzed by the cre recombinase introduced by cross-fertilization. recombination resulted in the fusion of a promoter with a distally located hygromycin phosphotransferase (hpt) coding sequence and t ... | 1992 | 1310059 |
| a phage t4 in vitro packaging system for cloning long dna molecules. | recombinant plasmid dnas containing long dna inserts that can be propagated in escherichia coli would be useful in the analysis of complex genomes. we tested a bacteriophage t4 in vitro dna packaging system that has the capacity to package about 170 kb of dna into its capsid for cloning long dna fragments. we first asked whether the t4 in vitro system can package foreign dna such as concatemerized lambda imm434 dna and phage p1-pbr322 hybrid dna. the data suggest that the t4 system can package f ... | 1992 | 1314208 |
| control of segregation of chromosomal dna by sex factor f in escherichia coli. mutants of dna gyrase subunit a suppress letd (ccdb) product growth inhibition. | the leta (ccda) and letd (ccdb) genes, located just outside the sequence essential for replication of the f plasmid, apparently contribute to stable maintenance of the plasmid. the letd gene product acts to inhibit partitioning of chromosomal dna and cell division of the host bacteria, whereas the leta gene product acts to suppress the activity of the letd gene product. to identify the target of the letd gene product, temperature-sensitive growth-defective mutants were screened from bacterial mu ... | 1992 | 1316444 |
| cre-lox recombination in escherichia coli cells. mechanistic differences from the in vitro reaction. | the mechanism of the cre recombinase of bacteriophage p1 in escherichia coli cells was analyzed by topological methods in order to determine the important features of the in vivo reaction. lambda infection was used to introduce the cre gene into cells containing plasmid substrates. the products of cre resolution on substrates with directly repeated sites were predominantly free circles, even though decatenation by dna gyrase was blocked by the drug norfloxacin. recombination by cre was greatly s ... | 1992 | 1324323 |
| using bacteriophage p1 system to clone high molecular weight genomic dna. | 1992 | 1336104 | |
| genetic characterization of the mechanism by which certain strains of escherichia coli survive in high kanamycin concentrations. | by genetic studies, it was tried to find the mechanism by which a bacterial fraction from different isolated clinical cultures resistant to 25 micrograms/ml of kanamycin can grow in media containing 500 micrograms/ml of kanamycin (at a frequency of about 10(-5)). this study was done in six clinical isolates of escherichia coli resistant to more than three antibiotics. the results from the bacterial fraction (subpopulation) resistant to high concentrations of kanamycin in the level of resistance ... | 1992 | 1345305 |
| cloning high molecular weight dna fragments by the bacteriophage p1 system. | the cloning of high molecular weight genomic dna promises to provide the means of mapping chromosomes, isolating genes, and understanding long-range effects on gene expression. this review describes the background and some recent advances in cloning of high molecular weight dna using the bacteriophage p1 system. | 1992 | 1369729 |
| toxic effects of high levels of ppgpp in escherichia coli are relieved by rpob mutations. | a controversy has surrounded the questions of whether or not guanosine tetraphosphate (ppgpp) is a specific inhibitor of bacterial rrna and trna synthesis, especially during normal exponential growth, and whether the rna polymerase is the target of ppgpp action. to answer these questions, a pbr322-derived plasmid, pkt28, was constructed that carries the escherichia coli rela gene encoding a ppgpp synthetase under control of the lacuv5 promoter. the plasmid was used to transform the ppgpp reporte ... | 1992 | 1370817 |
| bacteriophage p1 gene 10 is expressed from a promoter-operator sequence controlled by c1 and bof proteins. | gene 10 of bacteriophage p1 encodes a regulatory function required for the activation of p1 late promoter sequences. in this report cis and trans regulatory functions involved in the transcriptional control of gene 10 are identified. plasmid-borne fusions of gene 10 to the indicator gene lacz were constructed to monitor expression from the gene 10 promoter. production of gp10-lacz fusion protein became measurable at about 15 min after prophage induction, whereas no expression was observed during ... | 1992 | 1400162 |
| stoichiometry of the cre recombinase bound to the lox recombining site. | the site-specific recombinase cre from bacteriophage p1 binds and carries out recombination at a 34 bp lox site. the lox site consists of two 13 bp inverted repeats, separated by an 8 bp spacer region. both the palindromic nature of the site and the results of footprinting and band shift experiments suggest that a minimum of two cre molecules bind to a lox site. we report here experiments that demonstrate the absolute stoichiometry of the cre-lox complex to be one molecule of cre bound per inver ... | 1992 | 1408747 |
| a mouse genomic library in the bacteriophage p1 cloning system: organization and characterization. | using the bacteriophage p1 cloning system, we have constructed a two to three times coverage, high-molecular-weight (hmw) genomic library from mouse c127 fibroblast cells. the library consists of about 127,500 clones with an average insert size of about 70 kb that are organized into 300 primary pools containing approximately 425 clones per pool. for screening purposes the primary pools are combined into secondary pools (approximately 4250 clones each) and tertiary pools (approximately 21,250 clo ... | 1992 | 1421762 |
| mutational analysis of the bacteriophage p1 late promoter sequence ps. | the bacteriophage p1 late promoter sequence ps controls the expression of the genes in the tail-fibre operon. transcription from ps only occurs during the second half of the p1 vegetative growth cycle and is positively regulated by the product of the phage gene 10. in this study degenerate oligonucleotides were used as primers in site-directed mutagenesis reactions in order to construct a large set of point mutations within the late promoter sequence ps. a total of 35 independent single point mu ... | 1992 | 1447774 |
| design of a novel system for the construction of vectors for agrobacterium-mediated plant transformation. | the loxp-cre site-specific recombination system of phage p1 was used to develop a novel strategy to construct cointegrate vectors for agrobacterium-mediated plant transformation. a pti disarmed helper plasmid (pal1166) was constructed by replacing the oncogenic t-dna by a loxp sequence and a spectinomycin resistance marker in the octopine-type ptib6 plasmid. the cre gene was cloned into an unstable incp plasmid. a third plasmid, which did not replicate in agrobacterium and contained another loxp ... | 1992 | 1494341 |
| tissue- and site-specific dna recombination in transgenic mice. | we have developed a method of specifically modifying the mammalian genome in vivo. this procedure comprises heritable tissue-specific and site-specific dna recombination as a function of recombinase expression in transgenic mice. transgenes encoding the bacteriophage p1 cre recombinase and the loxp-flanked beta-galactosidase gene were used to generate transgenic mice. genomic dna from doubly transgenic mice exhibited tissue-specific dna recombination as a result of cre expression. further charac ... | 1992 | 1495975 |
| dna inversion regions min of plasmid p15b and cin of bacteriophage p1: evolution of bacteriophage tail fiber genes. | plasmid p15b and the genome of bacteriophage p1 are closely related, but their site-specific dna inversion systems, min and cin, respectively, do not have strict structural homology. rather, the complex min system represents a substitution of a cin-like system into an ancestral p15b genome. the substituting sequences of both the min recombinase gene and the multiple invertible dna segments of p15b are, respectively, homologous to the pin recombinase gene and to part of the invertible dna of the ... | 1992 | 1534556 |
| bacteriophage p1 genes involved in the recognition and cleavage of the phage packaging site (pac). | the packaging of bacteriophage p1 dna is initiated by cleavage of the viral dna at a specific site, designated pac. the proteins necessary for that cleavage, and the genes that encode those proteins, are described in this report. by sequencing wild-type p1 dna and dna derived from various p1 amber mutants that are deficient in pac cleavage, two distinct genes, referred to as paca and pacb, were identified. these genes appear to be coordinately transcribed with an upstream p1 gene that encodes a ... | 1992 | 1538406 |
| a positive selection vector for cloning high molecular weight dna by the bacteriophage p1 system: improved cloning efficacy. | the bacteriophage p1 cloning system can package and propagate dna inserts that are up to 95 kilobases. clones are maintained in escherichia coli by a low-copy replicon in the p1 cloning vector and can be amplified by inducing a second replicon in the vector with isopropyl beta-d-thiogalactopyranoside. to overcome the necessity of screening clones for dna inserts, we have developed a p1 vector with a positive selection system that is based on the properties of the sacb gene from bacillus amyloliq ... | 1992 | 1549564 |
| identification of cryptic lox sites in the yeast genome by selection for cre-mediated chromosome translocations that confer multiple drug resistance. | the cre recombinase efficiently causes site-specific dna recombination at loxp sites placed into the eukaryotic genome. since the loxp site of phage p1 is 34 base-pairs in size, the natural occurrence of this exact sequence is unlikely in any eukaryotic genome. however, related sequences may exist in eukaryotic genomes that could recombine at low efficiency with an authentic loxp site. this work identifies such cryptic lox sites in the yeast genome using a positive selection procedure that allow ... | 1992 | 1554399 |
| the bof protein of bacteriophage p1 exerts its modulating function by formation of a ternary complex with operator dna and c1 repressor. | bacteriophage p1 encodes several regulatory elements for the lytic or lysogenic response, which are located in the immc, immi, and immt regions. their products are the c1 repressor of lytic functions with the c1 inactivator protein coi, the c4 repressor of antirepressor synthesis and the modulator protein bof, respectively. we have studied in vitro the interaction of the components of the immc and immt regions with c1-controlled operators using highly purified bof, c1, and coi proteins. bof prot ... | 1992 | 1601883 |
| the c4 repressor of bacteriophage p1 is a processed 77 base antisense rna. | the c4 repressors of the temperate bacteriophages p1 and p7 inhibit antirepressor synthesis and are essential for establishment and maintenance of lysogeny. using in vivo complementation tests we have previously shown that c4 is an antisense rna acting on a target, ant mrna, which is transcribed from the same promoter. here we identify the c4 repressor molecule of p1 as a 77 +/- 1 base rna by mapping its termini and show that the c4 rna in p7 lysogens has the same or a similar size. p1 c4 rna is ... | 1992 | 1620606 |
| plasmid cloning vectors for the conjugal transfer of dna from escherichia coli to streptomyces spp. | we have constructed cloning vectors for the conjugal transfer of dna from escherichia coli to streptomyces spp. all vectors contain the 760-bp orit fragment from the incp plasmid, rk2. transfer functions need to be supplied in trans by the e. coli donor strain. we have incorporated into these vectors selectable antibiotic-resistance markers (amr, thr, spr) that function in streptomyces spp. and other features that should allow for: (i) integration via homologous recombination between cloned dna ... | 1992 | 1628843 |