| recipient gene duplication during generalized transduction. | an hfr13 delta(proa-lac) deletion recipient, -delta(proa-lac)-f-pure(+)-, has been utilized in a study of the origins of duplications formed during chromosome fragment integration. among the pro(-)lac(+) transductants, some have duplications spanning the f locus. these transductants are, or segregate, strains with f' episomes carrying genes of the duplication. some of the duplications include pure(+), a gene which is not coinherited with lac(+) during bacteriophage p1-mediated transduction. thus ... | 1974 | 4615976 |
| interaction of colicins with bacterial cells. 3. colicin-tolerant mutations in escherichia coli. | mutants that adsorb certain colicins without being killed, i.e., tolerant mutants (tol), were isolated from escherichia coli k-12 strains. selection was done either with colicin k or e2. several groups of mutants showing different phenotypes were found, and some of them showed tolerance to both k and e colicins, which have different receptors. many of these mutants mapped near gal. typical mutants from group ii, iii, and iv were studied in more detail. the mutant loci were contransducible with g ... | 1967 | 4860908 |
| recombination-induced suppression of cell division following p1-mediated generalized transduction in klebsiella aerogenes. | klebsiella aerogenes recombinants resulting from bacteriophage p1-mediated generalized transduction failed to increase in number for approximately six generations after transduction. nevertheless these recombinants continued to grow and became sensitive to penicillin after a transient resistance, suggesting that the cells were growing as long, non-dividing filaments. when filamentous cells were isolated from transduced cultures by gradient centrifugation, recombinants were 1000-fold more frequen ... | 1983 | 6343791 |
| salmonella typhimurium lt2 strains which are r- m+ for all three chromosomally located systems of dna restriction and modification. | we describe the derivation of two strains of salmonella typhimurium lt2 which are r- m+ for all three of the known chromosomal genes for the restriction and modification of dna, hsdlt, hsdsa, and hsdsb; the strains were designated lb5000 and lb5010. lb5000 is a smooth derivative sensitive to phage p22; lb5010 is a gale strain sensitive to phage p1. | 1983 | 6352690 |
| ultraviolet sensitivity gene of escherichia coli b. | the ultraviolet sensitivity gene of escherichia coli b was introduced into a k-12 recipient by transduction with phage p1. the uvs gene of e. coli b is cotransducible with the proc locus of k-12, is closely linked to tsx, is not linked to lacz, and only rarely to pure. the transductants are mucoid, filamentous on irradiation, and show plating-medium response. the order of markers is lacz proc tsx uvs pure. | 1968 | 4870274 |
| requirement of e. coli dna synthesis functions for the lytic replication of bacteriophage p1. | p1 lytic growth was examined in a number of different temperature sensitive mutants of e. coli that affect chromosomal replication. growth was analyzed by measurements of phage burst sizes and specific dna synthesis. efficient p1 growth required each of the bacterial elongation functions dnae (polc), dnaz (sub units of e. coli polymerase iii holoenzyme), and dnag (primase) but was not dependent on the elongation function dnab (mobile promoter). of two initiation functions tested the dnaa functio ... | 1983 | 6359668 |
| generalized transduction between salmonella typhi and salmonella typhimurium by phage j2 and characterization of the j2 plasmid in escherichia coli. | phage j2, a p1-like phage in salmonella typhi, was heteroimmune to phage p1 and existed in the lysogenic state as a plasmid of molecular size 58.6 mdal. the phage j2 plasmid was incompatible with the p1 plasmid (incy group). a j2-sensitive mutant of salmonella typhimurium lt2 was isolated by transduction of j2ap phage into lt2 followed by curing of the prophage. the mutant was used to demonstrate transduction between s. typhi and s. typhimurium by phage j2. | 1983 | 6363617 |
| temperature-sensitive repression of the tryptophan operon in escherichia coli. | mutants of escherichia coli exhibiting temperature-sensitive repression of the tryptophan operon have been isolated among the revertants of a tryptophan auxotroph, trps5, that produces an altered tryptophanyl transfer ribonucleic acid (trna) synthetase. unlike the parental strain, these mutants grew in the absence of tryptophan at high but not at low temperature. when grown at 43.5 c with excess tryptophan (repression conditions), they produced 10 times more anthranilate synthetase than when gro ... | 1969 | 4895848 |
| new suppresor in escherichia coli. | during the genetic mapping of a mutation in the phes gene which confers temperature sensitivity on a strain of escherichia coli k-12, an extragenic suppressor was discovered which restores ability to grow at the restrictive temperature. the suppressor, which has been named supq, is cotransduced by bacteriophage p1 with the pure marker. supq does not suppress a number of amber or ochre mutations. supq(-) is carried by the prototrophic hfr hayes strain ab259, and the presence of the supq(-) allele ... | 1971 | 4937784 |
| the deoxyribonucleic acid modification enzyme of bacteriophage p1. | the bacteriophage p1 modification enzyme, assayed by the specific methylation of unmodified bacteriophage 82 dna, has been purified 500-fold from a bacteriophage p1 lysogen of escherichia coli. the enzyme catalyses the incorporation of approximately 20-24 methyl groups per bacteriophage 82 dna molecule. the sole product of methylation is 6-methylaminopurine. methylation of unmodified bacteriophage dna confers protection against a challenge by purified bacteriophage p1 restriction enzyme. the ph ... | 1972 | 5073742 |
| site-specific recombination and its role in the life cycle of bacteriophage p1. | | 1981 | 6457723 |
| bacteriophage p1 site-specific recombination. iii. strand exchange during recombination at lox sites. | | 1981 | 6460113 |
| characterization of generalized transducing phage phi w39 heteroimmune to phage p1 in escherichia coli w39. | generalized transducing phage similar to phage p1 in escherichia coli was isolated from e. coli w39, an antigenic test strain of the o121 group. this phage, designated phi w39, was reciprocally heteroimmune to phages p1 and p7, but nonreciprocally heteroimmune to phage d6. transduction experiments using various r plasmids with different molecular weights suggested that phage phi w39 could transduce at least 65 megadaltons dna. as in the case of p1 prophage, phi w39 prophage existed as a plasmid ... | 1984 | 6087089 |
| is30, a new insertion sequence of escherichia coli k12. | three independent spontaneous mutations of prophage p1 affecting the ability of the phage to reproduce vegetatively are due to the insertion of a mobile genetic element, called is30. the same sequence is also carried in the r plasmid nr 1-basel, but not in the parental plasmid nr 1. southern hybridisation study indicates that the escherichia coli k 12 chromosome carries several copies of is30 as a normal resident. is30 is 1.2 kb long and contains unique restriction cleavage sites for bglii, clai ... | 1984 | 6090868 |
| reduction of marker discrimination in transductional recombination. | the recovery of phage p1 mediated transductants varies with the marker selected in a manner which cannot be fully accounted for by dosage differences in the donor gene population. this variation in transduction frequency is due primarily to recombinational discrimination in the recipient cell. we show here that increasing the intracellular level of reca protein, which might be expected to increase the contribution of recf mediated events to recombinant formation, decreases this discrimination sl ... | 1984 | 6090869 |
| genetic and physical map of a p1 miniplasmid. | the prophage form of bacteriophage p1 is a unit-copy plasmid which is maintained with great fidelity in its escherichia coli host. the plasmid maintenance functions of p1 are clustered in one region of the genome. an 11.5-kilobase fragment from this region has been cloned into a lambda delta att vector and promotes stable unit-copy plasmid maintenance. the properties of the lambda vector facilitated the isolation of deletion mutants affecting the p1 dna. twenty-eight deletion mutants were isolat ... | 1982 | 6749822 |
| bacteriophage p1 carries two related sets of genes determining its host range in the invertible c segment of its genome. | the bacteriophage p1 genome carries an invertible c segment consisting of 3-kb unique sequences flanked by 0.6-kb inverted repeats. host range mutations of p1 have been mapped in the c segment region. p1 derivatives carrying insertions and deletions in the left half of the c segment in one of two orientations termed c(+) do not affect the plaque-forming ability on escherichia coli k12 and e coli c, whereas those having insertions in the right half of the c segment fail to form plaques on these h ... | 1984 | 6100576 |
| genetic mapping of nth, a gene affecting endonuclease iii (thymine glycol-dna glycosylase) in escherichia coli k-12. | the nth gene of escherichia coli affects the production of endonuclease iii, a glycosylase-endonuclease that attacks dna damaged by oxidizing agents or by ionizing radiation. an nth insertion mutant and a deletion mutant were studied. nth is located between add and tyrs on the linkage map of e. coli k-12 and was 97% linked to tyrs in a transduction with phage p1. | 1985 | 3886628 |
| expression of the bacteriophage p1 cin recombinase gene from its own and heterologous promoters. | the cin recombinase of bacteriophage p1, a protein that catalyses site-specific dna inversions, has been identified and its structural gene has been cloned under the control of different promoters. one of the dna sequences used for the site-specific recombination, cixl, overlaps with the 3' end of the gene, but we show that the presence of this site does not affect cin gene expression from strong promoters. to assay cin activity we have constructed plasmids that carry antibiotic resistance genes ... | 1985 | 3891516 |
| p1 site-specific recombination: nucleotide sequence of the recombining sites. | site-specific recombination between molecules of bacteriophage p1 dna occurs at sites called loxp and requires the action of a protein that is the product of the p1 cre gene. although recombination between two loxp sites is very efficient, recombination between loxp and a unique site in the bacterial chromosome (loxb) is inefficient and generates two hybrid lox sites called loxr and loxl. we present here the nucleotide sequences of all four lox sites. analysis of these sequences indicates that ( ... | 1982 | 6954485 |
| sequence of the site-specific recombinase gene cin and of its substrates serving in the inversion of the c segment of bacteriophage p1. | inversion of the 4.2-kb c segment flanked by 0.6-kb inverted repeats on the bacteriophage p1 genome is mediated by the p1-encoded site-specific cin recombinase. the cin gene lies adjacent to the c segment and the c inversion cross-over sites cixl and cixr are at the external ends of the inverted repeats. we have sequenced the dna containing the cin gene and these cix sites. the cin structural gene consists of 561 nucleotides and terminates at the inverted repeat end where the cixl site is locate ... | 1983 | 6315399 |
| bacteriophage p1 site-specific recombination. purification and properties of the cre recombinase protein. | bacteriophage p1 encodes a site-specific recombination system that consists of a site (loxp) at which recombination occurs and a gene, cre, whose protein product is essential for recombination. the loxp-cre recombination event can be studied in greater detail by the use of an in vitro system that efficiently carries out recombination between two loxp sites. this paper presents a purification and characterization of the cre protein (mr = 35,000), which is the only protein required for the in vitr ... | 1984 | 6319400 |
| genetic analysis of a pleiotropic mutant of klebsiella pneumoniae affected in nitrogen metabolism. | genetic and reversion analyses of a thermosensitive pleiotropic mutant strain of klebsiella pneumoniae with defects in nitrogen fixation and nitrogen metabolism have shown that the pleiotropie behaviour of mutant is due to a single mutation in a gene designated nim. this gene is contransducible with trp at a frequency of about 30% (using bacteriophage p1) and with cys at a frequency of about 14%. the gene order is cys, trp, nim. the defect in the nim mutant is complemented by the e. coli f' elem ... | 1980 | 6989957 |
| identification of the repressor and repressor bypass (antirepressor) polypeptides of bacteriophage p1 synthesized in infected minicells. | p1 infected minicells synthesize approximately 50 phage-encoded polypeptides. phage expression is temporally controlled, demonstrating phage polypeptides synthesized both early and late after infection. the p1 repressor, gpcl1 (mr = 33,000), repressor bypass polypeptide, gpreb a (mr = 27,500) and cistron 10 product, (gp10) (mr = 64,000), have been identified by infection of minicells with p1 amber mutants. the beta-lactamase gene product (gpbla) carried by the closely related p7 and the chloramp ... | 1980 | 6991877 |
| a dnab analog function specified by bacteriophage p7 and its comparison to the similar function specified by bacteriophage p1. | evidence is presented that bacteriophage p7 specifies an analog of the e. coli dna replication protein, dnab. as in the related bacteriophage p1 (d'ari et al., 1975; ogawa, 1975), in lysogens of p7, the production of the analog protein is repressed and constitutive mutants could be isolated. such constitutive mutants could suppress efficiently the thermosensitivity of several dnab(ts) mutations and also rescue a strain carrying a dnab amber mutation. while neither p7 nor the mutant p1bacban (def ... | 1980 | 6993853 |
| enterotoxigenic escherichia coli carrying plasmids coding for antibiotic resistance and enterotoxin production. | nine strains of enterotoxigenic escherichia coli that were resistant to antibiotics were tested for their ability to transfer both antibiotic resistance and enterotoxigenicity to e. coli k12. all nine isolates transferred antibiotic resistance in bacterial conjugation experiments, and in seven of these matings enterotoxigenicity was also transferred. to determine whether the genetic information coding for the production of enterotoxin and antibiotic resistance was located on the same plasmid in ... | 1980 | 6997407 |
| a site-specific, conservative recombination system carried by bacteriophage p1. mapping the recombinase gene cin and the cross-over sites cix for the inversion of the c segment. | the bacteriophage p1 genome carries an invertible c segment consisting of 3-kb unique sequences flanked by 0.6-kb inverted repeats. with insertion and deletion mutants of p1 derivatives the site-specific recombinase gene cin for c inversion) has been mapped adjacent to the c segment and the cix sites (for c inversion cross-over) have been located at the outside ends of the inverted repeats. inversion of the c segment functions as a biological switch and controls expression of the gene(s) respons ... | 1982 | 6327269 |
| the structural gene for amp nucleosidase. mapping, cloning, and overproduction of the enzyme. | a mutant of escherichia coli which contained no detectable amp nucleosidase activity (ec 3.2.2.4) was produced by treatment with nitrosoguanidine and identified by a colorimetric assay for amp nucleosidase in individual colonies from agar plates. conjugation experiments indicated a close linkage between the amp nucleosidase locus (amn) and his. assays for amp nucleosidase in e. coli strains with deletions in the his region established that amn is not located between attp2h and mgl . transduction ... | 1984 | 6327703 |
| site-specific recombination by the bacteriophage p1 lox-cre system. cre-mediated synapsis of two lox sites. | the bacteriophage p1-encoded recombinase cre forms a simple dna-protein complex at the specific recognition site loxp. furthermore, cre is able to mediate a synaptic union of two loxp sites. when two loxp sites are on the same linear dna molecule, cre binds the two sites together to form a circular protein-dna complex. these complexes can be resolved into a linear dna molecule and a closed circular dna molecule, the end products of site-specific recombination. | 1984 | 6333513 |
| mapping of the pola locus of escherichia coli k12: genetic fine structure of the cistron. | the close linkage of the glna gene with pola was exploited to construct a fine structure map of pola by means of generalized transduction with phage p1. nine different pola- alleles were mapped by recombinational crosses. the results indicate a gene order consistent with previous observations (kelley and grindley 1976a; murray and kelley 1979). three mutations, pola5, pola6 and pola12 map within the "carboxy-terminal" or "large-fragment" portion of the gene in unambiguous order. four alleles, kn ... | 1980 | 7000617 |
| the c1 repressor of bacteriophage p1. i. isolation of the c1 protein and determination of the p1 dna region to which it binds. | | 1980 | 7001033 |
| [intergeneric crossing: p1 phage transduction of the malb region in crosses between e. coli and s. typhimurium]. | in the intergeneric crossing of e. coli and s. typhimurium, no effective transduction of the malb gene was observed. the absence of effective transduction suggests the low homology of the malb chromosomal areas in e. coli and s. typhimurium. to carry out the transduction of the malb gene together with the lexa gene from e. coli to s. typhimurium, a hybrid having no restriction of phage p1 and incorporating the malb area of e. coli should be previously created. | 1980 | 7004022 |
| electron microscopy study of early lytic replication forms of bacteriophage p1 dna. | p1 replication intermediates were isolated from the intracellular dna of lytically infected cells and analyzed by electron microscopy. at early times in infection replication intermediates were mainly of two types, circular theta- and sigma-shaped molecules plus a small proportion of linear bubble-shaped molecules. at later times in infection sigma molecules were the predominant replicating form. in contrast, sigma molecules were rarely found in recombination deficient, reca, infected cells. the ... | 1983 | 6359666 |
| genetic and physiological characterization of a spontaneous mutant of escherichia coli b/r with aberrant control of deoxyribonucleic acid replication. | strain tjk16, a low-thymine-requiring thya deob derivative of escherichia coli b/r a, was found to have an increased initiation mass due to a mutation in a gene affecting the control of initiation of deoxyribonucleic acid replication. in contrast to temperature-sensitive initiation mutants, initiation in tjk16 was not temperature sensitive. by phage p1 transduction, it was found that the mutation lies within a small region of the chromosome between dnaa and gyrb; this region includes dnan and re ... | 1981 | 7009574 |
| genetic studies of h group plasmids by bacteriophage p1 transduction. | bacteriophage p1 transduction was used to study the incompatibility group h1 plasmid prg1251, molecular weight 120 x 10(6), and the incompatibility group h2 plasmid psd114, molecular weight 166 x 10(6). the order of resistance (r) determinants on psd114 was deduced from transduction and segregation experiments to be chloramphenicol-tetracycline-kanamycin-streptomycin. resistance to tellurium and to coliphages, which are properties also encoded by many h2 plasmids, were not transduced with the ot ... | 1981 | 7011519 |
| the molecular genetics of bacteriophage p1. | | 1983 | 6364958 |
| naturally occurring r.colbm plasmids belonging to the incfiii incompatibility group. | two escherichia coli strains isolated from urinary tract infections were resistant to streptomycin, kanamycin, neomycin, tetracycline and sulphonamides. the strains also produced colicins b and m. the resistance to streptomycin, kanamycin and neomycin and the ability to produce colicins b and m could be transferred to an e. coli k12 recipient. resistance and colicinogeny markers were transferred together by conjugation, and did not segregate even after interrupted mating or phage p1-mediated tra ... | 1980 | 7014768 |
| isolation and characterization of regulatory mutations affecting the expression of the guaba operon of escherichia coli k-12. | we isolated strains of escherichia coli k 12 in which the lac structural genes were fused to the structural genes of the guaba operon. these strains were used to isolate regulatory mutations that increased the expression of the guaba operon under normal repressing conditions as compared to the wild type parental fusion strain. three classes of guaba specific regulatory mutations were identified. class i regulatory mutations were trans-acting and unlinked to the guaba operon as shown by bacteriop ... | 1984 | 6387393 |
| a nonsense mutation in bacteriophage p1 eliminates the synthesis of a protein required for normal plasmid maintenance. | | 1981 | 6454157 |
| studies on the properties of p1 site-specific recombination: evidence for topologically unlinked products following recombination. | bacteriophage p1 encodes its own site-specific recombination system consisting of a site at which recombination takes place called loxp and a recombinase called cre. a number of lambda and plasmid substrates containing two loxp sites have been constructed. using these substrates we have shown both in vivo and in vitro that a fully functional loxp site is composed of no more than 60 bp. in vitro, when an extract containing cre is used, recombination between loxp sites on supercoiled, nicked-circl ... | 1983 | 6220808 |
| control of circularization of bacteriophage p1 dna in escherichia coli. | | 1981 | 7027600 |
| interaction of the bacteriophage p1 recombinase cre with the recombining site loxp. | the interaction between the p1 recombinase protein cre and the dna site at which it acts, loxp, has been studied by using nuclease protection techniques. the region of dna protected by cre against nuclease attack by dnase i or neocarzinostatin is a 34-base-pair (bp) region containing two 13-bp inverted repeats separated by an 8-bp spacer region. these protected sequences have previously been shown to be required for efficient cre-mediated recombination at loxp. the results of the above protectio ... | 1984 | 6230671 |
| genetic and biochemical analyses of pantothenate biosynthesis in escherichia coli and salmonella typhimurium. | pantothenate (pan) auxotrophs of escherichia coli k-12 and salmonella typhimurium lt2 were characterized by enzymatic and genetic analyses. the panb mutants of both organisms and the pan-6 ("pana") mutant of s. typhimurium are deficient in ketopantoate hydroxymethyltransferase, whereas the panc mutants lack pantothenate synthetase. pand mutants of e. coli k-12 were previously shown to be deficient in aspartate 1-decarboxylase. all mutants showed only a single enzyme defect. the finding that the ... | 1982 | 7037743 |
| effect of bacteriophage p1 lysogeny on lipopolysaccharide composition and the lambda receptor of escherichia coli. | the outer membrane of escherichia coli was altered as a consequence of lysogeny by bacteriophages p1 and p1 cmts. the predominant change was a reduction in the size of lipopolysaccharide to a heptose-deficient form. p1 cmts lysogens were still sensitive to several bacteriophages but were resistant to lambda vir. neither whole cells nor solubilized outer membranes from p1 cmts lysogens were able to inactivate lambda vir, and 32p-labeled lambda vir was unable to adsorb to p1 cmts lysogens. p1 cmts ... | 1984 | 6237098 |
| phage p1 mutant with decreased abortive transduction. | | 1982 | 7090183 |
| the isolation and characterization of escherichia coli dnab::tn10 insertion mutations. | exploitation of the ability of the ban protein encoded by phage p1 to compensate for dnab-defective host mutations, allowed the isolation of dnab::tn10 insertion mutations. the presence of p1bac prophage was required for survival of dnab::tn10 mutants, and such lysogens were cryosensitive. the insertions were shown to map in dnab by transduction and this was confirmed by complementation analysis. the dnab::tn10 (p1bac) strains were non-permissive for lambda growth but did support the growth of l ... | 1981 | 6267428 |
| characterization of p1argf derivatives from escherichia coli k12 transduction. i. is1 elements flank the argf gene segment. | specialized transducing derivatives of the temperate bacteriophage p1 (p1std) are selected by transduction into recipients with deletions in the corresponding genes (stodolsky 1973). when escherichia coli k12 strains are used as donors in such transduction experiments, p1argf derivatives can be selected. the argf gene is unique to these strains (glansdorff et al. 1967). under these experimental conditions p1argf are formed with frequencies 10,000 times greater than other p1std. the majority of t ... | 1981 | 6268940 |
| genetic mapping of the minb locus in escherichia coli k-12. | the minb (minicell production) locus of escherichia coli k-12 was mapped by transduction using bacteriophage p1. minb is located at min 25.6, between purb (min 25.2) and dadr (min 25.8). the mapping was facilitated by the use of insertion zcf-236::tn10, which is inserted at min 25.4. | 1983 | 6296039 |
| 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 restriction--modification genes of phage p1 and plasmid p15b. structure and in vitro transcription. | the ecop1 and ecop15 dna restriction-modification systems are coded by the related p1 prophage and p15b plasmid. we have examined the organization of the genes for these systems using p1 itself, "p1-p15" hybrid phages expressing the ecop15 restriction specificity of p15b and cloned restriction fragments derived from these phage dnas. the results of transposon mutagenesis, restriction cleavage analysis. dna heteroduplex analysis and in vitro transcription mapping allow the following conclusions t ... | 1983 | 6302279 |
| dna restriction--modification enzymes of phage p1 and plasmid p15b. subunit functions and structural homologies. | we have purified the type iii restriction enzymes ecop1 and ecop15 to homogeneity from bacteria that contain the structural genes for the enzymes cloned on small, multicopy plasmids and which overproduce the enzymes. both of the enzymes contain two different subunits. the molecular weights of the subunits are the same for both enzymes and antibodies prepared against one enzyme cross-react with both subunits of the other. bacteria containing a plasmid derivative in which a large part of one of th ... | 1983 | 6302281 |
| physical analysis of the genomes of hybrid phages between phage p1 and plasmid p15b. | the genomes of three plaque-forming recombinant phages between phage p1 and plasmid p15b were characterized by restriction cleavage analysis and electron microscopic heteroduplex studies. the structure of all three p1-15 hybrid genomes differs from that of p1 dna in the res mod region coding for restriction and modification systems ecop15 and ecop1, respectively. p1-15 hybrid 2 shows an additional major difference to p1 around the site of the residential is1 element of p1 and it does not carry a ... | 1983 | 6302282 |
| synthesis of p1 ban protein in minicells infected by p1 mutants. | phage p1 encodes a dnab analog (ban) protein. synthesis of ban protein has been studied in minicells infected by p1 mutants and has been identified as a polypeptide of 56,000 molecular weight by immunoprecipitation using antibody directed against e. coli dnab protein. the amount of ban protein synthesized by p1 mutants increases in the order: p1 wild type, p1bac, p1crr, and p1bac crr. the relative amount of ban protein identified in p1bac- and p1bac crr-infected minicells is approximately the s ... | 1980 | 6988666 |
| phage p1 temperature-sensitive mutants with defects in the lytic pathway. | | 1980 | 6998105 |
| bacteriophage p1-mediated generalized transduction in escherichia coli: fate of transduced dna in rec+ and reca- recipients. | | 1980 | 6998106 |
| bacteriophage p1-mediated generalized transduction in escherichia coli: structure of abortively transduced dna. | | 1980 | 6998107 |
| the variation in frequency with which markers are transduced by phage p1 is primarily a result of discrimination during recombination. | the efficiency of recovery of p1 transductants is marker dependent and normally varies over a 25-fold range. uv irradiation of either transducing lysates for recipient cells results in a selective stimulation of the transduction of markers which are normally transduced poorly. as a result the range in frequency of transduction is reduced to about 3-fold and resembles the gene frequency distribution expected in the donor cells. we conclude that p1 transducing lysates are likely to contain a rando ... | 1980 | 7007821 |
| [lethal and mutagenic action of uv light on salmonellae carrying wild or mutant alleles of the escherichia coli lexa-gene]. | to elucidate the reasons for the absence of uv-mutability in salmonella typhimurium, the lexa gene of escherichia coli has been transduced by phage p1 into s. typhimurium. the functioning of lexa+ allele of e. coli in the chromosome of salmonella failed to cause uv-mutability of the hybrid. the transfer of pkm101 plasmid into the lexa+ hybrid mediates the expressed uv mutability and uv-protective plasmid effect. this plasmid harboured by the lexa hybrid fails to increase uv-resistance and mutabi ... | 1981 | 7014362 |
| 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 |
| genetic mapping of a mutation conferring sensitivity to bacteriophage mu in salmonella typhimurium lt2. | two strains of salmonella typhimurium lt2, sa1475 and ma411, were fortuitously found to be sensitive to bacteriophage mu. the mu-sensitivity allele of sa1475 was called musa1 and shown to be linked to the histidine operon both in conjugation and transduction experiments. the mus allele of ma411 was unlinked to the his region and was tentatively designated musb2. strains carrying large deletions of the his operon were also tested for mu sensitivity; those of which the his-rib region is deleted we ... | 1981 | 7016837 |
| high-affinity arabinose transport mutants of escherichia coli: isolation and gene location. | the gene araf, the product of which is the l-arabinose-binding protein--a component of the high-affinity l-arabinose transport system, was located on the escherichia coli linkage map at 45 min. we established this location using bacteriophage p2 eductates and bacteriophage p1 cotransduction frequencies with the adjacent genetic loci, his (histidine biosynthesis) and mgl (methylgalactoside transport). in addition, we isolated a number of mutants that phenotypically exhibited altered high-affinity ... | 1981 | 7024251 |
| a novel role for site-specific recombination in maintenance of bacterial replicons. | if daughter copies of unit-copy replicons recombine with each other, a replicon dimer results that cannot be partitioned equally to daughter cells at cell division. we present evidence that dimer formation interferes with plasmid equipartition in the case of a miniplasmid derived from the unit-copy plasmid prophage of bacteriophage p1. asymmetric partition occurs, leading to a relatively high rate of loss of the plasmid from the growing population. in contrast, the wild-type p1 plasmid is mainta ... | 1981 | 7026049 |
| the bacteriophage p1 site-specific recombinase cin: recombination events and dna recognition sequences. | | 1984 | 6597763 |
| genome fusion mediated by the site specific dna inversion system of bacteriophage p1. | the genome of bacteriophage p1 contains a segment which is invertible by site specific recombination between sequences near the outside ends of the inverted repeats which flank it. immediately adjacent to this c segment is the coding sequence for cin, the enzyme catalyzing inversion. we show that multicopy plasmids carrying cin and the sequences at which it acts (cix) can form dimers in the absence of the host reca function. further, such plasmids can be cotransduced with p1 markers at high freq ... | 1983 | 6602932 |
| p1 plasmid replication: replicon structure. | bacteriophage p1 lysogenizes escherichia coli as a unit-copy plasmid. we have undertaken to define the plasmid-encoded elements implicated in p1 plasmid maintenance. we show that a 2081 base-pair fragment of the 90,000 base p1 plasmid confers the capacity for controlled plasmid replication. dna sequence analysis reveals several open reading frames in this fragment. the largest is shown to encode a 32,000 mr protein required for plasmid replication. the corresponding gene, repa, has been identifi ... | 1984 | 6699914 |
| 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 |
| characterization of escherichia coli men mutants defective in conversion of o-succinylbenzoate to 1,4-dihydroxy-2-naphthoate. | four independent menaquinone (vitamin k(2))-deficient mutants of escherichia coli, blocked in the conversion of o-succinylbenzoate (osb) to 1,4-dihydroxy-2-naphthoate (dhna), were found to represent two distinct classes. enzymatic complementation was observed when a cell-free extract of one mutant was mixed with extracts of any of the remaining three mutants. the missing enzymes in the two classes were identified by in vitro complementation with preparations of osb-coenzyme a (coa) synthetase or ... | 1982 | 6754698 |
| dna replication and indirect induction of the sos response in escherichia coli. | the sos response can be induced indirectly in escherichia coli by infection with uv irradiated bacteriophage p1, lambda or m13. induction, monitored quantitatively by means of a sfia::lac operon fusion, was stronger with the plasmid phage p1 than with lambda, but the kinetics were similar, showing that plasmid and non-plasmid phages are not fundamentally different in their ability to produce indirect induction. in the absence of lambda dna replication the level of induction was strongly reduced, ... | 1982 | 6814510 |
| surface exclusion between f' plasmids in strains of escherichia coli k-12 carrying a dnab mutation, in the presence or absence of bacteriophage genomes providing a dnab analog function. | in a set of isogenic strains, three out of four different dnab(ts) mutations reduced surface exclusion between f' plasmids. in further studies with a strain carrying one of these mutations (dnab43), surface exclusion remained reduced in the presence of a recombinant plasmid carrying only the region of f that encodes the surface exclusion proteins trasp and tratp. the dnab analog specified by bacteriophage p1 but not that specified by p7 increased the surface excluding ability of the strain carry ... | 1981 | 7035825 |
| 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 |
| suppression of the lexc (ssba) mutation of escherichia coli by a mutant of bacteriophage p1. | a new mutant of bacteriophage p1 designated lxc that suppresses the phenotype of lexc and ssba mutants of escherichia coli was isolated and characterized. the properties of lexc mutants suppressed by the lxc mutation include temperature sensitive growth at 42 degrees c, sensitivity to ultraviolet light and alkylating agents, and a nonmutagenic response following exposure to ultraviolet irradiation. a bac mutant of bacteriophage p1 that suppresses the temperature sensitivity of dnab mutants does ... | 1982 | 7050621 |
| 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 |
| suppression of dnac alleles by the dnab analog (ban protein) of bacteriophage p1. | the dnab analog protein produced by the ban gene of bacteriophage p1 was shown to suppress several escherichia coli dnac alleles. suppression of dnac7 temperature sensitivity in p1 lysogens of a dnac7 mutant was complete at all temperatures. for the dnac2 and dnac28 alleles, suppression was observed only at intermediate temperatures. though these intermediate temperatures were sufficient to completely restrict the mutants, at higher temperatures the suppression was not observed. no suppression o ... | 1981 | 7217002 |
| coliphage p1 morphogenesis: analysis of mutants by electron microscopy. | we used electron microscopy and serum blocking power tests to determine the phenotypes of 47 phage p1 amber mutants that have defects in particle morphogenesis. eleven mutants showed head defects, 30 showed tail defects, and 6 had a defect in particle maturation (which could be either in the head or in the tail). consideration of previous complementation test results, genetic and physical positions of the mutations, and phenotypes of the mutants allowed assignment of most of the 47 mutations to ... | 1983 | 6834479 |
| 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 |
| characterization of bacteriophage j2 of salmonella typhi as a generalized transducing phage closely related to coliphage p1. | phage j2, a lysogenic phage in salmonella typhi j2, was shown to produce tiny plaques on various vi type strains of s. typhi, to be a generalized transducing phage, and to have many characteristics including a serological one in common with phage p1 of escherichia coli. lysogenization of various s. typhi type strains with j2 or p1-group phages usually resulted in the alteration of the phage types of the s. typhi strains, except that phage j2 did not cause alteration of type 53. phage j2 transduc ... | 1981 | 7338730 |
| 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 |
| 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 |
| 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 |
| a circular form of bacteriophage p1 dna made in lytically infected cells of escherichia coli. characterization and kinetics of formation. | | 1980 | 6986712 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |