| dual regulatory control of a particle maturation function of bacteriophage p1. | a unique arrangement of promoter elements was found upstream of the bacteriophage p1 particle maturation gene (mat). a p1-specific late-promoter sequence with conserved elements located at positions -22 and -10 was expected from the function of the gene in phage morphogenesis. in addition to a late-promoter sequence, a -35 element and an operator sequence for the major repressor protein, c1, were found. the -35 and -10 elements constituted an active escherichia coli sigma(70) consensus promoter, ... | 2001 | 11418548 |
| structure and chromosomal localization of the mouse bombesin receptor subtype 3 gene. | bombesin (bn)-like peptides/neurotransmitters mediate a broad range of physiological funtions in the gastrointestinal tract and the central nervous system through binding to their specific, high-affinity mammalian bombesin receptors. this family of heptahelical, g-protein coupled receptors includes the gastrin-releasing peptide receptor (grp-r, or bb2), neuromedin b receptor (nmb-r, or bb1), and the bombesin receptor subtype 3 (brs-3, or bb3). the tissue distribution of brs-3 is quite dissimilar ... | 1998 | 9573346 |
| altered directionality in the cre-loxp site-specific recombination pathway. | the site-specific recombinase cre must employ control mechanisms to impose directionality on recombination. when two recombination sites (locus of crossing over in phage p1, loxp) are placed as direct repeats on the same dna molecule, collision between loxp-bound cre dimers leads to excision of intervening dna. if two sites are placed as inverted repeats, the intervening segment is flipped around. cre catalyzes these reactions in the absence of protein co-factors. current models suggest that dir ... | 2001 | 11492999 |
| inducible gene targeting in mice using the cre/lox system. | molecular techniques now allow the design of precise genetic modifications in the mouse. not only can defined nucleotide changes be engineered into the genome of the mouse, but genetic switches can be designed to target expression or ablation of any gene (for which basic molecular information is available) to any tissue at any defined time. these strategies promise to contribute substantially to an increased understanding of individual gene function in development and pathogenesis. a powerful to ... | 1998 | 9608509 |
| cre-loxp-mediated inactivation of the alpha6a integrin splice variant in vivo: evidence for a specific functional role of alpha6a in lymphocyte migration but not in heart development. | two splice variants of the alpha6 integrin subunit, alpha6a and alpha6b, with different cytoplasmic domains, have previously been described. while alpha6b is expressed throughout the development of the mouse, the expression of alpha6a begins at 8.5 days post coitum and is initially restricted to the myocardium. later in ontogeny, alpha6a is found in various epithelia and in certain cells of the immune system. in this study, we have investigated the function of alpha6a in vivo by generating knock ... | 1998 | 9763436 |
| comparative mapping of distal murine chromosome 11 and human 17q21.3 in a region containing a modifying locus for murine plasma von willebrand factor level. | type 1 von willebrand disease (vwd) is a common inherited disorder characterized by mild to moderate bleeding and reduced levels of von willebrand factor (vwf). an animal model for human type 1 vwd, the riiis/j mouse strain, exhibits a prolonged bleeding time and reduced plasma vwf levels. we have previously mapped the defect in riiis/j to distal mouse chr 11, distinct from the vwf locus on chr 6. this locus, mvwf, was localized to an approximately 0.5-cm interval, tightly linked to gip, distal ... | 1998 | 9806826 |
| comparative kinetic analysis of flp and cre recombinases: mathematical models for dna binding and recombination. | the integrase class site specific recombinases flp from saccharomyces cerevisiae, and cre from bacteriophage p1, have been extensively used to direct dna rearrangements in heterologous organisms. although their reaction mechanisms have been relatively well characterised, little comparative analysis of the two enzymes has been published. we present a comparative kinetic analysis of flp and cre, which identifies important differences. gel mobility shift assays show that cre has a higher affinity f ... | 1998 | 9813124 |
| efficient blg-cre mediated gene deletion in the mammary gland. | using the phage p1-derived cre/loxp recombination system, we have developed a strategy for efficient mammary tissue specific inactivation of floxed genes. transgenic mice were generated which express cre dna-recombinase under the control of the mammary gland specific promoter of the ovine beta-lactoglobulin (blg) gene. to test the specificity of cre mediated recombination, we crossed these mice to animals harbouring a floxed dna ligase i allele. we show that the blg-cre construct specifies mamma ... | 1998 | 9859227 |
| dna substrates influence the recombination efficiency mediated by flp recombinase expressed in mammalian cells. | the flp recombinase derived from saccharomyces cerevisiae mediates precise site-specific recombination between a pair of flp recognition targets (frts). like the cre/loxp system derived from bacteriophage p1, the flp/frt system has recently been applied to gene regulation systems using an flp-expressing recombinant adenovirus (rad) (nakano et al, nucleic acids res. 29: e40, 2001). in an attempt to improve the flp/frt system by altering its dna substrates, we compared the recombination efficiency ... | 2001 | 11694078 |
| controlled expression in klebsiella pneumoniae and shigella flexneri using a bacteriophage p1-derived c1-regulated promoter system. | the utility of promoters regulated by the bacteriophage p1 temperature-sensitive c1 repressor was examined in shigella flexneri and klebsiella pneumoniae. promoters carrying c1 operator sites driving lacz expression had induction/repression ratios of up to 240-fold in s. flexneri and up to 50-fold in k. pneumoniae. the promoters exhibited remarkably low basal expression, demonstrated modulation by temperature, and showed rapid induction. this system will provide a new opportunity for controlled ... | 2001 | 11698385 |
| stability and dna binding of the phd protein of the phage p1 plasmid addiction system. | the plasmid addiction module of bacteriophage p1 encodes two proteins, doc, a toxin that is stable to proteolytic degradation, and phd, the toxin's antidote that is proteolytically unstable. phd has been shown to autoregulate its expression by specific dna binding. here, we investigate the secondary structure and thermal stability of phd, the effect of operator dna binding on the structure and stability of phd, and the stoichiometry, affinity, and cooperativity of phd binding to operator subsite ... | 1999 | 9915794 |
| genetic analysis of the mouse x inactivation center defines an 80-kb multifunction domain. | dosage compensation in mammals occurs by x inactivation, a silencing mechanism regulated in cis by the x inactivation center (xic). in response to developmental cues, the xic orchestrates events of x inactivation, including chromosome counting and choice, initiation, spread, and establishment of silencing. it remains unclear what elements make up the xic. we previously showed that the xic is contained within a 450-kb sequence that includes xist, an rna-encoding gene required for x inactivation. ... | 1999 | 10097124 |
| genetic organization of the francisella plasmid pfnl10. | we report here the molecular characterization of pfnl10, a 3990-bp cryptic plasmid of francisella novicida-like f6168. the plasmid was maintained in f. novicida utah 112 and f. tularensis lvs strains. we sequenced the entire plasmid and found six open reading frames (orfs)-orf1, orf2, orf3, orf4, orf5, and orfm. orf3, orf4, orf5, and orfm are located on the same strand, and we designated it the plus strand. orf1 and orf2 are on the complementary strand. the orfs appear to be arranged in two oper ... | 2001 | 11735370 |
| a non-cytotoxic herpes simplex virus vector which expresses cre recombinase directs efficient site specific recombination. | the coding sequences for the bacteriophage p1 recombinase cre were cloned into the genome of a herpes simplex virus type 1 (hsv-1) mutant which is severely impaired for the synthesis of immediate early (ie) proteins. the resulting recombinant, virus in1372, expressed functional cre which mediated the excision in trans of loxp-flanked sequences located in the hsv-1 genome, both in tissue culture cells and in vivo in mouse sensory neurons. infection with in1372 also resulted in recombination, at h ... | 1999 | 10564749 |
| is2 insertion is a major cause of spontaneous mutagenesis of the bacteriophage p1: non-random distribution of target sites. | insertion mutations arising spontaneously in the p1 prophage and affecting vegetative phage reproduction were screened for the presence of insertion sequence 2 (is2). filter hybridization identified 28 out of 44 independent insertions as is2. their target specificity is not random. a region that amounts to < 2% of the phage genome had trapped 15 of the 28 is2 elements. however, precise mapping of nine mutants in this hot spot segment revealed no preferred insertion site. rather, the nine is2 are ... | 1983 | 11894911 |
| a 2-mb sequence-ready contig map and a novel immunoglobulin superfamily gene igsf4 in the loh region of chromosome 11q23.2. | human chromosome 11q23.2 has been proposed to contain a tumor suppressor gene(s) whose deletion has been associated with cancer of the lung and breast and with neuroblastoma. to analyze the genomic structure and to isolate a candidate tumor suppressor gene from this region, we constructed a 2-mb sequence-ready contig map using bacteriophage p1 (p1), bacterial artificial chromosome (bac), and p1-derived artificial chromosome (pac). the map comprises a contig of 24 overlapping p1, bac, and pac clo ... | 1999 | 10610705 |
| development of a p1 phagemid system for the delivery of dna into gram-negative bacteria. | the inability to transform many clinically important gram-negative bacteria has hampered genetic studies addressing the mechanism of bacterial pathogenesis. this report describes the development and construction of a delivery system utilizing the broad-host-range transducing bacteriophage p1. the phagemids used in this system contain a p1 pac initiation site to package the vector, a p1 lytic replicon to generate concatemeric dna, a broad-host-range origin of replication and an antibiotic-resista ... | 2002 | 11932441 |
| mammalian genomes contain active recombinase recognition sites. | recombinases derived from microorganisms mediate efficient site-specific recombination. for example, the cre recombinase from bacteriophage p1 efficiently carries out recombination at its loxp target sites. while this enzyme can function in mammalian cells, the 34bp loxp site is expected to be absent from mammalian genomes. we have discovered that sequences from the human and mouse genomes surprisingly divergent from loxp can support cre-mediated recombination at up to 100% of the efficiency of ... | 2000 | 10689186 |
| tight regulation and modulation via a c1-regulated promoter in escherichia coli and pseudomonas aeruginosa. | we describe the development and analysis of a novel promoter system regulated by the bacteriophage p1 temperature-sensitive c1 repressor. using transcriptional fusions to the lacz reporter gene to monitor gene expression, we show that the ratio of induction/repression can be up to 1500-fold in escherichia coli. the promoters exhibited extremely tight repression and could be modulated over a range of temperatures. the utility of the promoter system was tested in pseudomonas aeruginosa. c1 effecti ... | 2002 | 12000993 |
| molecular organization of the mouse gastrin-releasing peptide receptor gene and its promoter. | the murine gastrin-releasing peptide receptor (mgrp-r) is a member of the g protein-coupled receptor family and mediates important physiological actions of its specific ligand, the gastrointestinal hormone/neurotransmitter grp, including mitogenic properties in the mouse swiss 3t3 fibroblasts. glucocorticoids and increases in intracellular camp are reported to alter grp-r gene transcription, but the molecular basis for these effects is unknown. to begin to identify possible gene regulatory mecha ... | 2000 | 10689196 |
| a sequence-ready physical map of the region containing the human natural killer gene complex on chromosome 12p12.3-p13.2. | we developed a sequence-ready physical map of a part of human chromosome 12p12.3-p13.2 where the natural killer gene complex (nkc) is located. the nkc includes a cluster of genes with structure similar to that of the ca(2+)-dependent lectin superfamily of glycoproteins that are expressed on the surface of most natural killer (nk) cells and a subset of t cells. these killer cell lectin-like receptors (klr) are involved in nk target cell recognition, leading to activation or inhibition of nk cell ... | 2000 | 10783260 |
| 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 |
| identification of a new human cyp2a gene fragment with close linkage to cyp2gp1. | human genomic libraries were screened to identify cyp2g-related cytochrome p450 genes. a genomic fragment comprising exons 7 through 9 of cyp2gp1 and exons 6 through 9 of a previously unidentified cyp2a gene, designated cyp2a7p2, was isolated from an embl3 library; the two genes were arranged in outward opposite directions with about 8 kbp of intervening sequence. the same structure was also detected in a bacteriophage p1 clone, which contained a full-length cyp2gp1 gene, exons 6 through 9 of cy ... | 2001 | 11124222 |
| phylogenetic and functional analysis of the bacteriophage p1 single-stranded dna-binding protein. | bacteriophage p1 encodes a single-stranded dna-binding protein (ssb-p1), which shows 66% amino acid sequence identity to the ssb protein of the host bacterium escherichia coli. a phylogenetic analysis indicated that the p1 ssb gene coexists with its e. coli counterpart as an independent unit and does not represent a recent acquisition of the phage. the p1 and e. coli ssb proteins are fully functionally interchangeable. ssb-p1 is nonessential for phage growth in an exponentially growing e. coli h ... | 2002 | 12208948 |
| interaction of the dnak and dnaj chaperone system with a native substrate, p1 repa. | dnak, the hsp70 chaperone of escherichia coli interacts with protein substrates in an atp-dependent manner, in conjunction with dnaj and grpe co-chaperones, to carry out protein folding, protein remodeling, and assembly and disassembly of multisubunit protein complexes. to understand how dnaj targets specific proteins for recognition by the dnak chaperone system, we investigated the interaction of dnaj and dnak with a known natural substrate, bacteriophage p1 repa protein. by characterizing repa ... | 2002 | 12237299 |
| minimization of the escherichia coli genome using a tn5-targeted cre/loxp excision system. | an increasing number of microbial genomes have been completely sequenced, and functional analyses of these genomic sequences are under way. to facilitate these analyses, we have developed a genome-engineering tool for determining essential genes and minimizing bacterial genomes. we made two large pools of independent transposon mutants in escherichia coli using modified tn5 transposons with two different selection markers and precisely mapped the chromosomal location of 800 of these transposons. ... | 2002 | 12244329 |
| [expression of cre gene in escherichia coli and bioassay its expression product]. | the cre recombinase from bacteriophage p1 can recognize specific dna sequences, cleave dna at specific target sites, and then ligate it to the cleaved dna of a second site. in this study, cre gene was cloned into the pgem-t easy vector via pcr procedure. then the cre gene was inserted into an expression vector pet-29a and expressed in e. coli bl21 (de3). a 38 kd soluble protein was expressed and named cre. cre was purified by deae-52 chromatography. bioassay of the partially purified product sho ... | 2002 | 12385251 |
| doc-mediated cell killing in shigella flexneri using a c1/laci controlled expression system. | in this report we describe the development of a highly stringent and dually regulated promoter system for shigella flexneri. dual regulation was provided by utilizing a promoter susceptible to control by the bacteriophage p1 temperature-sensitive c1 repressor that in turn was under the transcriptional control of laci. the level of induction/repression ratios observed was up to 3700-fold in s. flexneri. the general utility of this promoter system was evaluated by demonstrating that the bacterioph ... | 2002 | 12399040 |
| the p1 plasmid in action: time-lapse photomicroscopy reveals some unexpected aspects of plasmid partition. | the prophage of bacteriophage p1 is a low copy number plasmid in escherichia coli and is segregated to daughter cells by an active partition system. the dynamics of the partition process have now been successfully followed by time-lapse photomicroscopy. the process appears to be fundamentally different from that previously inferred from statistical analysis of fixed cells. a focus containing several plasmid copies is captured at the cell center. immediately before cell division, the copies eject ... | 2002 | 12460532 |
| transgenic mice with hematopoietic and lymphoid specific expression of cre. | bacteriophage p1 cre/loxp based systems can be used to manipulate the genomes ofmice in vivo and in vitro, allowing the generation of tissue-specific conditional mutants. we have generated mouse lines expressing cre recombinase in hematopoietic tissues using the vav regulatory elements, or in lymphoid cells using the hcd2 promoter and locus control region (lcr). the r26r-eyfp cre reporter mouse line was used to determine the pattern of cre expression in each line and enabled the assessment of cr ... | 2003 | 12548562 |
| [progress in the study of the structure and function of cre recombinase]. | the cre recombinase, an integrase from bacteriophage p1, catalyzes site-specific recombination between 34-bp repeats termed loxp sites, in the absence of any additional cofactors and energy. mediated by cre recombinase, specific dna fragments can be excised, inversed or integrated depending on the orientation or position of loxp sites in vitro or in vivo. because of its simplicity and high efficiency, cre/loxp site-specific recombination system has been widely used in gene deletion and function ... | 2002 | 12561193 |
| the applications of fish in tumor pathology. | the current fish technology was greatly improved during the past 10 years. a large number of cosmids and yeast (yacs), bacterial (bacs), phage p1 derived (pacs) artificial chromosomes have been rapidly mapped and are useful as probes. in parallel, methods were established to specifically "paint" entire chromosomes or chromosome segments. using these chromosome libraries as probes, complex rearrangements and marker chromosomes can be identified irrespective of their banding pattern. ripetitive dn ... | 1999 | 10936888 |
| development of a thermally regulated broad-spectrum promoter system for use in pathogenic gram-positive species. | selectively regulating gene expression is an essential molecular tool that is lacking for many pathogenic gram-positive bacteria. in this report, we describe the evaluation of a series of promoters regulated by the bacteriophage p1 temperature-sensitive c1 repressor in enterococcus faecium, enterococcus faecalis, and staphylococcus aureus. using the lacz gene to monitor gene expression, we examined the strength, basal expression, and induced expression of synthetic promoters carrying c1 operator ... | 2003 | 12788740 |
| escherichia coli sspa is a transcription activator for bacteriophage p1 late genes. | the stringent starvation protein a (sspa), an escherichia coli rna polymerase (rnap)-associated protein, has been reported to be essential for lytic growth of bacteriophage p1. unlike p1 early promoters, p1 late promoters are not recognized by rnap alone. a phage-encoded early protein, lpa (late promoter activator protein, formerly called gp10), has been shown to be required for p1 late transcription in vivo. here, we demonstrate that sspa is a transcription activator for p1 late genes. our resu ... | 2003 | 12791143 |
| identification of cre residues involved in synapsis, isomerization, and catalysis. | the cre protein of bacteriophage p1 is a tyrosine recombinase and catalyzes recombination via formation of a covalent protein-dna complex and a holliday junction intermediate. several co-crystal structures of cre bound to its target lox site have provided novel insights into its biochemical activities. we have used these structures to guide the mutagenesis of several cre residues that contact the lox spacer region and/or are involved in intersubunit protein-protein interactions. none of the muta ... | 2003 | 12851389 |
| bacteriophage p1 ban protein is a hexameric dna helicase that interacts with and substitutes for escherichia coli dnab. | since the ban gene of bacteriophage p1 suppresses a number of conditionally lethal dnab mutations in escherichia coli, it was assumed that ban protein is a dna helicase (dnab analogue) that can substitute for dnab in the host replication machinery. we isolated and sequenced the ban gene, purified the product, and analysed the function of ban protein in vitro and in vivo. ban hydrolyses atp, unwinds dna and forms hexamers in the presence of atp and magnesium ions. since all existing conditionally ... | 2003 | 12853607 |
| escherichia coli single-stranded dna-binding protein mediates template recycling during transcription by bacteriophage n4 virion rna polymerase. | coliphage n4 virion rna polymerase (vrnap), the most distantly related member of the t7-like family of rna polymerases, is responsible for transcription of the early genes of the linear double-stranded dna phage genome. escherichia coli single-stranded dna-binding protein (ecossb) is required for n4 early transcription in vivo, as well as for in vitro transcription on super-coiled dna templates containing vrnap promoters. in contrast to other dna-dependent rna polymerases, vrnap initiates transc ... | 2003 | 12876194 |
| crystal structure of a wild-type cre recombinase-loxp synapse reveals a novel spacer conformation suggesting an alternative mechanism for dna cleavage activation. | escherichia coli phage p1 cre recombinase catalyzes the site-specific recombination of dna containing loxp sites. we report here two crystal structures of a wild-type cre recombinase-loxp synaptic complex corresponding to two distinct reaction states: an initial pre-cleavage complex, trapped using a phosphorothioate modification at the cleavable scissile bond that prevents the recombination reaction, and a 3'-phosphotyrosine protein-dna intermediate resulting from the first strand cleavage. in c ... | 2003 | 12954782 |
| studies on lysogenesis. ii. the effect of temperature on the lysogenization of shigella dysenteriae with phage p1. | | 1954 | 13129214 |
| [behavior of the temperate phage p1 on its host, staphylococcus s2]. | | 1953 | 13167489 |
| transduction of linked genetic characters of the host by bacteriophage p1. | | 1955 | 13267987 |
| effect of chloramphenicol on lysogenization by temperate phage p1. | | 1957 | 13456369 |
| the effects of ultraviolet light and ionizing radiation on the transduction of escherichia coli by phage p1. | | 1960 | 13845040 |
| the specific gravity of transducing particles of bacteriophage p1. | | 1962 | 13921337 |
| mapping of the galactose genes of escherichia coli by transduction with phage p1. | | 1963 | 14011089 |
| the control of host-induced modification by phage p1. | | 1964 | 14187915 |
| macromolecular syntheses in the initiation of bacteriophage p1 induction. | | 1964 | 14202270 |
| drug resistance of enteric bacteria. iv. active transducing bacteriophage p1 cm produced by the combination of r factor with bacteriophage p1. | kondo, eiko (gunma university, maebashi, japan), and susumu mitsuhashi. drug resistance of enteric bacteria. iv. active transducing phage p1 cm produced by the combination of r factor with phage p1. j. bacteriol. 88:1266-1276. 1964.-during an investigation of the transduction of r factors with phage p1, a phage lysate capable of transducing the character of chloramphenicol resistance (cm(r)) in extremely high frequency was obtained. the transduction of the cm(r) character with the lysate was con ... | 1964 | 14234780 |
| efficient gene activation in cultured mammalian cells mediated by flp recombinase-expressing recombinant adenovirus. | a recombinant adenovirus (rad) expressing cre recombinase derived from bacteriophage p1 has already been extensively used for the conditional gene activation and inactivation strategies in mammalian systems. in this study, we generated axcaflp, a rad expressing flp recombinase derived from saccharomyces cerevisiae and carried out quantitative comparisons with cre-expressing rad in both in vitro and in cultured cells to provide another efficient gene regulation system in mammalian cells. in the i ... | 2001 | 11266575 |
| high efficiency, site-specific excision of a marker gene by the phage p1 cre-loxp system in the yellow fever mosquito, aedes aegypti. | the excision of specific dna sequences from integrated transgenes in insects permits the dissection in situ of structural elements that may be important in controlling gene expression. furthermore, manipulation of potential control elements in the context of a single integration site mitigates against insertion site influences of the surrounding genome. the cre-loxp site-specific recombination system has been used successfully to remove a marker gene from transgenic yellow fever mosquitoes, aede ... | 2003 | 14602940 |
| translocation pathway of protein substrates in clpap protease. | intracellular protein degradation, which must be tightly controlled to protect normal proteins, is carried out by atp-dependent proteases. these multicomponent enzymes have chaperone-like atpases that recognize and unfold protein substrates and deliver them to the proteinase components for digestion. in clpap, hexameric rings of the clpa atpase stack axially on either face of the clpp proteinase, which consists of two apposed heptameric rings. we have used cryoelectron microscopy to characterize ... | 2001 | 11287666 |
| phage multiplication on two hosts. isolation and activity of variants of staphylococcus phage p1. | | 1952 | 14949003 |
| interruption of coding sequences by heterologous introns can enhance the functional expression of recombinant genes. | sustained expression of recombinant proteins is a critical factor for the effectiveness of numerous applications in the biomedical sciences including the treatment of human disease by gene therapy, the large scale production of therapeutic proteins, as well as the investigation of gene function by transgenesis or cell type specific mutagenesis. although much attention has been paid to the optimisation of regulatory sequences such as promoters, untranslated regions and polyadenylation signals, ef ... | 2001 | 11320412 |
| a signal-arrest-release sequence mediates export and control of the phage p1 endolysin. | the lyz endolysin of bacteriophage p1 was found to cause lysis of the host without a holin. induction of a plasmid-cloned lyz resulted in lysis, and the lytic event could be triggered prematurely by treatments that dissipate the proton-motive force. instead of requiring a holin, export was mediated by an n-terminal transmembrane domain (tmd) and required host sec function. exported lyz of identical sds/page mobility was found in both the membrane and periplasmic compartments, indicating that per ... | 2004 | 15090650 |
| transgenic mice as a model to study the regulation of human transferrin expression in sertoli cells. | understanding the regulation of proteins secreted by human sertoli cells is important for identifying the causes of infertility in men. however, experiments with sertoli cells purified from healthy testes are difficult to perform, for obvious ethical reasons. therefore, experiments with transgenic mouse models could provide an alternative approach to study the function and regulation of a human gene in sertoli cells. | 2004 | 15105395 |
| smallest region of overlapping deletion in 1p36 in human neuroblastoma: a 1 mbp cosmid and pac contig. | in human neuroblastomas, the distal portion of 1p is frequently deleted, as if one or more tumor suppressor genes from this region were involved in neuroblastoma tumorigenesis. earlier studies had identified a smallest region of overlapping deletion (sro) spanning approximately 23 cm between the most distally retained d1s80 and by the proximally retained d1s244. in pursuit of generating a refined delineation of the minimally deleted region, we have analyzed 49 neuroblastomas of different stages ... | 2001 | 11391793 |
| isolation and characterization of the murine transforming growth factor-beta2 promoter. | this report describes the isolation and characterization of the 5' flanking region of the murine transforming growth factor beta-2 (tgf-beta2) gene. a genomic clone containing the promoter region of the gene was isolated after screening a bacteriophage p1 genomic library. the resulting clone was sequenced and compared to promoters for the human and chicken tgf-beta2 genes. the sequence located near the transcription start site is highly conserved. it includes a tata box, an e-box, and a largely ... | 2001 | 11404017 |
| a new family of conditional replicating plasmids and their cognate escherichia coli host strains. | we constructed a family of conditionally replicating plasmids, the ptx1 family, which are based on the incpalpha oriv origin of replication that is dependent on the trfa-encoded protein. we constructed several escherichia coli derivatives expressing trfa from different chromosomal loci, which can be transduced by phage p1 to any e. coli strain. the ptx1 plasmids also carry the oritrp4 origin of transfer, and can be conjugated to e. coli, vibrio cholerae and likely to a broad range of bacteria fr ... | 2004 | 15249062 |
| escherichia coli mazef-mediated cell death as a defense mechanism that inhibits the spread of phage p1. | the escherichia coli gene pair mazef is a regulatable chromosomal toxin-antitoxin module: mazf encodes a stable toxin and maze encodes for a labile antitoxin that overcomes the lethal effect of mazf. because maze is labile, inhibition of maze expression results in cell death. we studied the effect of mazef on the development of bacteriophage p1 upon thermoinduction of the prophage p1cm c1ts and upon infection with virulent phage particles (p1vir). in several e. coli strains, we showed that the d ... | 2004 | 15316771 |
| using an in vivo phagemid system to identify non-compatible loxp sequences. | the site-specific recombination system of bacteriophage p1 is composed of the cre recombinase that recognizes a 34-bp loxp site. the cre/loxp system has been extensively used to manipulate eukaryotic genomes for functional genomic investigations. the creation of additional heterologous loxp sequences potentially expands the utility of this system, but only if these loxp sequences do not recombine with one another. we have developed a stringent in vivo assay to examine the degree of recombination ... | 2001 | 11418130 |
| bacteriophage p1 in retrospect and in prospect. | | 2004 | 15489415 |
| genome of bacteriophage p1. | p1 is a bacteriophage of escherichia coli and other enteric bacteria. it lysogenizes its hosts as a circular, low-copy-number plasmid. we have determined the complete nucleotide sequences of two strains of a p1 thermoinducible mutant, p1 c1-100. the p1 genome (93,601 bp) contains at least 117 genes, of which almost two-thirds had not been sequenced previously and 49 have no homologs in other organisms. protein-coding genes occupy 92% of the genome and are organized in 45 operons, of which four a ... | 2004 | 15489417 |
| definition of a 1-mb homozygous deletion at 9q32-q33 in a human bladder-cancer cell line. | we performed detailed molecular analyses of a suspected homozygous deletion on chromosome 9q32-q33 in a bladder-cancer cell line (kybtds) derived from a superficial papillary transitional cell carcinoma (tcc). we examined 13 sequence-tagged site (sts) markers mapped along 9q32-q33 by polymerase chain reaction (pcr), and used 13 bacterial artificial chromosome (bac)/bacteriophage p1-derived artificial chromosome (pac) genomic clone probes representing these sts markers as probes for dual-color fl ... | 2001 | 11450846 |
| delivery of the cre recombinase by a self-deleting lentiviral vector: efficient gene targeting in vivo. | the cre recombinase (cre) from bacteriophage p1 is an important tool for genetic engineering in mammalian cells. we constructed lentiviral vectors that efficiently deliver cre in vitro and in vivo. surprisingly, we found a significant reduction in proliferation and an accumulation in the g(2)/m phase of cre-expressing cells. to minimize the toxic effect of cre, we designed a lentiviral vector that integrates into the host genome, expresses cre in the target cell, and is subsequently deleted from ... | 2001 | 11553794 |
| phage like it hot: solution structure of the bacteriophage p1-encoded hot protein, a homolog of the theta subunit of e. coli dna polymerase iii. | dna polymerase iii, the main replicative polymerase of e. coli, contains a small subunit, theta, that binds to the epsilon proofreading subunit and appears to enhance the enzyme's proofreading function--especially under extreme conditions. it was recently discovered that e. coli bacteriophage p1 encodes a theta homolog, named hot. the (1)h-(15)n hsqc spectrum of hot exhibits more uniform intensities and less evidence of conformational exchange than that of theta; this uniformity facilitates a de ... | 2004 | 15576035 |
| using an in vivo phagemid system to identify non-compatible loxp sequences. | the site-specific recombination system of bacteriophage p1 is composed of the cre recombinase that recognizes a 34-bp loxp site. the cre/loxp system has been extensively used to manipulate eukaryotic genomes for functional genomic investigations. the creation of additional heterologous loxp sequences potentially expands the utility of this system, but only if these loxp sequences do not recombine with one another. we have developed a stringent in vivo assay to examine the degree of recombination ... | 2001 | 11576551 |
| the molecular chaperone, clpa, has a single high affinity peptide binding site per hexamer. | substrate recognition by clp chaperones is dependent on interactions with motifs composed of specific peptide sequences. we studied the binding of short motif-bearing peptides to clpa, the chaperone component of the atp-dependent clpap protease of escherichia coli in the presence of atpgammas and mg2+ at ph 7.5. binding was measured by isothermal titration calorimetry (itc) using the peptide, aandenyalaa, which corresponds to the ssra degradation motif found at the c terminus of abnormal nascent ... | 2005 | 15657062 |
| detection of illegitimate rearrangement within the immunoglobulin locus on 14q32.3 in b-cell malignancies using end-sequenced probes. | translocation involving the immunoglobulin heavy chain (igh) locus is a recurring event in b-cell oncogenesis. the aim of this study was to characterize clones from bacterial artificial chromosome (bac) libraries and/or bacteriophage p1 artificial chromosome libraries spanning the igh locus for detection of illegitimate rearrangement within the region by fluorescence in situ hybridization (fish). in silico analysis of the igh variable (ighv) dna sequence (nt_001716.v1) was performed to identify ... | 2001 | 11579466 |
| targeted somatic mutagenesis in mouse epidermis. | gene targeting in the mouse is a powerful tool to study mammalian gene function. the possibility to efficiently introduce somatic mutations in a given gene, at a chosen time and/or in a given cell type will further improve such studies, and will facilitate the generation of animal models for human diseases. to create targeted somatic mutations in the epidermis, we established transgenic mice expressing the bacteriophage p1 cre recombinase or the tamoxifen-dependent cre-er(t2) recombinase under t ... | 2000 | 11595821 |
| identification and characterization of a novel allele of escherichia coli dnab helicase that compromises the stability of plasmid p1. | bacteriophage p1 lysogenizes escherichia coli cells as a plasmid with approximately the same copy number as the copy number of the host chromosome. faithful inheritance of the plasmids relies upon proper dna replication, as well as a partition system that actively segregates plasmids to new daughter cells. we genetically screened for e. coli chromosomal mutations that influenced p1 stability and identified a novel temperature-sensitive allele of the dnab helicase gene (dnab277) that replaces ser ... | 2005 | 15687186 |
| structural basis for the function of stringent starvation protein a as a transcription factor. | stringent starvation protein a (sspa) of escherichia coli is an rna polymerase-associated transcriptional activator for the lytic development of phage p1 and is essential for stationary phase-induced acid tolerance of e. coli. we report the crystal structure of yersinia pestis sspa, which is 83% identical to e. coli sspa in amino acid sequence and is functionally complementary in supporting the lytic growth of phage p1 and acid resistance of an e. coli sspa mutant. the structure reveals that ssp ... | 2005 | 15735307 |
| limited use of the cre/loxp recombination system in efficient production of loxp-containing minicircles in vivo. | the cre/loxp recombination system of bacteriophage p1 is one of the most powerful tools in genome engineering. we report, however, that the activity of the cre/loxp system interferes with the stability of the multicopy loxp-bearing plasmids in escherichia coli reca bacteria. due to the predominantly unidirectional cre-mediated high-order multimer formation of these plasmids, the number of their copies (overall yield) gradually decreases. intermolecular recombination reduces the copy number of pl ... | 2004 | 15737402 |
| a new family of mobilizable suicide plasmids based on broad host range r388 plasmid (incw) and rp4 plasmid (incpalpha) conjugative machineries and their cognate escherichia coli host strains. | we describe the construction of the psw family of conditionally replicating plasmids which are based on the incx oriv origin (oriv(r6kgamma)) of replication that is dependent on the pir-encoded protein. we constructed several escherichia coli derivatives expressing pir from different chromosomal loci, and the pir gene could be transduced by phage p1 to any e. coli strain. these chromosomal constructions generate dapa and thya knockouts, which lead to diaminopimelate or thymidine auxotrophies, re ... | 2005 | 15748991 |
| sspa is required for acid resistance in stationary phase by downregulation of h-ns in escherichia coli. | the stringent starvation protein a (sspa) is a rna polymerase-associated protein and is required for transcriptional activation of bacteriophage p1 late promoters. however, the role of sspa in gene expression in escherichia coli is essentially unknown. in this work, we show that sspa is essential for cell survival during acid-induced stress. apparently, sspa inhibits stationary-phase accumulation of h-ns, a global regulator which functions mostly as a repressor, thereby derepressing multiple str ... | 2005 | 15819627 |
| [a simple and visible assay for cre recombinase activity in escherichia coli by using two incompatible plasmids]. | the cre/loxp system derived from bacteriophage p1 is widely used to carry out complex manipulations of dna molecules both in vitro and in vivo. in order to further characterize and modify the cre/loxp system, a convenient method for assaying the recombination efficiency is needed. a simple and visible assay is described, in which two incompatible plasmids, separately carrying the cre gene and loxp-flanked gfp gene, were co-transferred into e. coli. the cre gene was inserted into a kanamycin-resi ... | 2005 | 15847178 |
| effect of deletion mutation on the recombination activity of cre recombinase. | cre recombinase from bacteriophage p1 is widely used in both in vitro and in vivo dna manipulations. based on a structural and functional analysis, three deleted cre mutants were constructed and expressed in escherichia coli. mutated recombinases were purified and their recombination activities were determined in vitro. our results revealed that the mutant with amino-terminal deletion retains the recombination activity as high as wild type cre; however, the carboxy-terminal deletion and the midd ... | 2005 | 15912212 |
| characterization of eastern oyster (crassostrea virginica gmelin) chromosomes by fluorescence in situ hybridization with bacteriophage p1 clones. | chromosome identification is an essential step in genomic research, which so far has not been possible in oysters. we tested bacteriophage p1 clones for chromosomal identification in the eastern oyster crassostrea virginica, using fluorescence in situ hybridization (fish). p1 clones were labeled with digoxigenin-11-dutp using nick translation. hybridization was detected with fluorescein-isothiocyanate-labeled anti-digoxigenin antibodies and amplified with 2 layers of antibodies. nine of the 21 p ... | 2005 | 15933900 |
| comparative analysis of sequence-specific dna recombination systems in human embryonic stem cells. | the great potential of human embryonic stem cells (hescs) in basic research, regenerative medicine, and gene therapy is widely recognized. controlled manipulation of hesc genomes through sequence-specific dna recombination (ssr) may play a significant role in future hesc applications. however, very little is known about the functionality of ssr systems in hescs. we demonstrate here that mutant phage lambda integrase, phage p1 cre recombinase, and mutant gammadelta resolvase displayed distinct ac ... | 2005 | 15955832 |
| the doc toxin and phd antidote proteins of the bacteriophage p1 plasmid addiction system form a heterotrimeric complex. | the toxin (doc) and antidote (phd) proteins of the plasmid addiction system of bacteriophage p1 were purified as a complex. cocrystals of the complex contained a 2:1 molar ratio of phd:doc as assayed by dye binding following sds-polyacrylamide gel electrophoresis and as determined by amino acid analysis. gel filtration and analytical ultracentrifugation revealed that the two addiction proteins interact in solution to form a p2d trimer composed of one doc and two phd molecules. these results supp ... | 1999 | 10358024 |
| the bacteriophage p1 hot gene product can substitute for the escherichia coli dna polymerase iii {theta} subunit. | the theta subunit (hole gene product) of escherichia coli dna polymerase (pol) iii holoenzyme is a tightly bound component of the polymerase core. within the core (alpha-epsilon-theta), the alpha and epsilon subunits carry the dna polymerase and 3' proofreading functions, respectively, while the precise function of theta is unclear. hole homologs are present in genomes of other enterobacteriae, suggestive of a conserved function. putative homologs have also been found in the genomes of bacteriop ... | 2005 | 16077097 |
| a sequence-ready 840-kb pac contig spanning the candidate tumor suppressor locus dbc1 on human chromosome 9q32-q33. | a putative tumor suppressor locus involved in bladder cancer has been mapped to human chromosome 9q32-q33 and designated dbc1. our previous microsatellite-based deletion mapping study indicated that dbc1 was localized between d9s1848 and afma239xa9. we have constructed an 840-kb sequence-ready contig composed of bacteriophage p1-derived artificial chromosomes (pacs), which encompasses dbc1. clones were initially identified by screening a pac library with markers localized to the region by physic ... | 1999 | 10444335 |
| nuclear magnetic resonance solution structure of the escherichia coli dna polymerase iii theta subunit. | the catalytic core of escherichia coli dna polymerase iii holoenzyme contains three subunits: alpha, epsilon, and theta. the alpha subunit contains the polymerase, and the epsilon subunit contains the exonucleolytic proofreading function. the small (8-kda) theta subunit binds only to epsilon. its function is not well understood, although it was shown to exert a small stabilizing effect on the epsilon proofreading function. in order to help elucidate its function, we undertook a determination of ... | 2005 | 16199579 |
| agroinfiltration as a tool for transient expression of cre recombinase in vivo. | agroinfiltration was used to express transiently cre recombinase from bacteriophage p1 in planta. activation of gfp expression after cre-mediated excision of a bar intervening sequence served as a marker to monitor site-specific recombination events in lox-target n. benthamiana plants. gfp expressing regenerants from a. tumefaciens infiltrated leaves were obtained with an efficiency of about 34%. in 20% of the regenerants bar gene excision was due to the expression of stably integrated cre gene, ... | 2005 | 16245170 |
| genome engineering in bacillus anthracis using cre recombinase. | genome engineering is a powerful method for the study of bacterial virulence. with the availability of the complete genomic sequence of bacillus anthracis, it is now possible to inactivate or delete selected genes of interest. however, many current methods for disrupting or deleting more than one gene require use of multiple antibiotic resistance determinants. in this report we used an approach that temporarily inserts an antibiotic resistance marker into a selected region of the genome and subs ... | 2006 | 16369025 |
| directed evolution of the site specificity of cre recombinase. | cre recombinase from bacteriophage p1 recognizes a 34-bp recombination site, loxp, with exquisite sequence specificity and catalyzes the site-specific insertion, excision, or rearrangement of dna. to better understand the molecular basis of protein-dna recognition and generate recombinases with altered specificities, we have developed a directed evolution strategy that can be used to identify recombinases that recognize variant loxp sites. to be selected, members of a library of cre variants pro ... | 2002 | 11904359 |
| cre reporter system to monitor the translocation of type iii secreted proteins into host cells. | central to the study of type iii secretion systems is the availability of reporter systems to monitor bacterial protein translocation into host cells. we report here the development of a bacteriophage p1 cre recombinase-based system to monitor the translocation of bacterial proteins into mammalian cells. bacteriophage p1 cre recombinase fused to the secretion and translocation signals of salmonella enterica serovar typhimurium of the type iii secreted protein sope was secreted in a type iii secr ... | 2006 | 16428755 |
| efficient recombination in diverse tissues by a tamoxifen-inducible form of cre: a tool for temporally regulated gene activation/inactivation in the mouse. | in recent years, the cre integrase from bacteriophage p1 has become an essential tool for conditional gene activation and/or inactivation in mouse. in an earlier report, we described a fusion protein between cre and a mutated form of the ligand binding domain of the estrogen receptor (cre-er) that renders cre activity tamoxifen (tm) inducible, allowing for conditional modification of gene activity in the mammalian neural tube in utero. in the current work, we have generated a transgenic mouse li ... | 2002 | 11944939 |
| a chromosomal locus which controls the ability of shigella flexneri to evoke keratoconjunctivitis. | the primary step in the pathogenesis of bacillary dysentery is the penetration of intestinal epithelial cells by shigellae. lacking this capacity, shigella flexneri becomes avirulent. by means of intergeneric conjugation between various escherichia coli k-12 hfr strains and s. flexneri 2a virulent recipients and by reciprocal transduction analysis with phage p1 vir, we established a locus on the genome of s. flexneri 2a which is necessary for the ability of this strain to penetrate epithelial ce ... | 1971 | 16557949 |
| transduction by bacteriophage p1: abnormal phage function of the transducing particles. | | 1958 | 16590247 |
| introduction of transposon tn5 into myxococcus for analysis of developmental and other nonselectable mutants. | the transposon tn5, which carries a gene for kanamycin resistance, can be introduced into myxococcus xanthus, an organism that undergoes a primitive cycle of development, from escherichia coli by the specialized transducing phage p1::tn5. tn5 dna sequences, but no p1 sequences, are found in the stable kanamycin-resistant transductants. tn5 transposes from p1 to many different chromosomal sites in myxococcus. in each independent transductant of myxococcus examined, the tn5 element is found in a d ... | 1981 | 16592958 |
| e-cadherin is a survival factor for the lactating mouse mammary gland. | the ca(++)-dependent cell adhesion molecule e-cadherin is expressed throughout mouse development and in adult tissues. classical gene targeting has demonstrated that e-cadherin-deficient embryos die at the blastocyst stage. to study the involvement of e-cadherin in organogenesis, a conditional gene inactivation scheme was undertaken using the bacteriophage p1 recombinase cre/loxp system. mice with homozygous loxp sites in both alleles of the e-cadherin (cdh1) gene were generated and these mice w ... | 2002 | 12049767 |
| high efficiency site-specific genetic engineering of the mosquito genome. | current techniques for the genetic engineering of insect genomes utilize transposable genetic elements, which are inefficient, have limited carrying capacity and give rise to position effects and insertional mutagenesis. as an alternative, we investigated two site-specific integration mechanisms in the yellow fever mosquito, aedes aegypti. one was a modified cre/lox system from phage p1 and the other a viral integrase system from streptomyces phage phi c31. the modified cre/lox system consistent ... | 2006 | 16640723 |
| structure of the theta subunit of escherichia coli dna polymerase iii in complex with the epsilon subunit. | the catalytic core of escherichia coli dna polymerase iii contains three tightly associated subunits, the alpha, epsilon, and theta subunits. the theta subunit is the smallest and least understood subunit. the three-dimensional structure of theta in a complex with the unlabeled n-terminal domain of the epsilon subunit, epsilon186, was determined by multidimensional nuclear magnetic resonance spectroscopy. the structure was refined using pseudocontact shifts that resulted from inserting a lanthan ... | 2006 | 16740953 |
| dilated cardiomyopathy resulting from high-level myocardial expression of cre-recombinase. | conditional gene inactivation in mice using the bacteriophage p1 cre-loxp recombination system requires transgenic expression of cre-recombinase driven by a tissue-specific or inducible promoter. | 2006 | 16762803 |
| consecutive gene deletions in aspergillus nidulans: application of the cre/loxp system. | the ability to perform multiple gene deletions is an important tool for conducting functional genomics. we report the development of a sequential gene deletion protocol for the filamentous fungus aspergillus nidulans using the cre/loxp recombinase system of bacteriophage p1. a recyclable genetic marker has been constructed by incorporating loxp direct repeats either side of the neurospora crassa pyr-4 gene (encodes orotidine 5'-monophosphate decarboxylase) which is able to complement the a. nidu ... | 2006 | 16783565 |
| [expression of genes of prophage p1 escherichia coli in cells of phytopathogenic erwinia]. | it is shown that the temperate coliphage p1cmcts100 can transduce resistance to chloramphenicol in the cells of phytopathogenic bacteria erwinia horticola and e. carotovora subsp. atroseptica. in the latter case the extrachromosomal dna is inherited by recipient cells as the authentic prophage p1. the prophage p1 expresses rectification-modification ecop1, as well as the genes of lysogenic conversion in phytopathogenic erwinia. here the character of superinfection of transductants of e. atrosept ... | 2006 | 16786627 |
| mutator and antimutator effects of the bacteriophage p1 hot gene product. | the hot (homolog of theta) protein of bacteriophage p1 can substitute for the escherichia coli dna polymerase iii theta subunit, as evidenced by its stabilizing effect on certain dnaq mutants that carry an unstable polymerase iii epsilon proofreading subunit (antimutator effect). here, we show that hot can also cause an increase in the mutability of various e. coli strains (mutator effect). the hot mutator effect differs from the one caused by the lack of theta. experiments using chimeric theta/ ... | 2006 | 16885451 |
| comparative polytene chromosome maps of d. montana and d. virilis. | chromosomal inversion polymorphism was characterized in finnish drosophila montana populations. a total of 14 polymorphic inversions were observed in finnish d. montana of which nine had not been described before. the number of polymorphic inversions in each chromosome was not significantly different from that expected, assuming equal chance of occurrence in the euchromatic genome. there was, however, no correlation between the number of polymorphic inversions and that of fixed inversions in eac ... | 2007 | 16906413 |
| structure of the escherichia coli dna polymerase iii epsilon-hot proofreading complex. | the epsilon subunit of escherichia coli dna polymerase iii possesses 3'-exonucleolytic proofreading activity. within the pol iii core, epsilon is tightly bound between the alpha subunit (dna polymerase) and subunit. here, we present the crystal structure of epsilon in complex with hot, the bacteriophage p1-encoded homolog of , at 2.1 a resolution. the epsilon-hot interface is defined by two areas of contact: an interaction of the previously unstructured n terminus of hot with an edge of the epsi ... | 2006 | 16973612 |
| unmodified cre recombinase crosses the membrane. | site-specific recombination in genetically modified cells can be achieved by the activity of cre recombinase from bacteriophage p1. commonly an expression vector encoding cre is introduced into cells; however, this can lead to undesired side-effects. therefore, we tested whether cell-permeable cre fusion proteins can be directly used for lox-specific recombination in a cell line tailored to shift from red to green fluorescence after loxp-specific recombination. comparison of purified recombinant ... | 2002 | 12060697 |