Publications

cloning structural genes for treponema pallidum immunogens and characterisation of recombinant treponemal surface protein, p2 (p2 star).	a genomic library consisting of partially digested 10 to 20 kilobase pair fragments of treponema pallidum deoxyribonucleic acid (dna) was constructed using bacteriophage lambda embl-3 as the vector. positive clones expressing t pallidum antigens were detected with sera from experimentally infected rabbits. treponemal proteins ranging in molecular weight from 37,000 daltons to 120,000 daltons were identified by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and immunoblotting of phage ...	1987	3315959
extracellular production of cloned alpha-amylase by escherichia coli.	overexpression of bacillus stearothermophilus gene coding for thermostable alpha-amylase in escherichia coli was shown to cause outer-membrane damage leading to extracellular location of periplasmic proteins. prolonged high expression of the alpha-amylase gene under laczpo control eventually also lysed cells. surprisingly, expression controlled by the pl promoter of phage lambda allowed specific release of periplasmic proteins into the growth medium without total cell lysis. accumulation of alph ...	1987	3327755
regulation of the aroh operon of escherichia coli by the tryptophan repressor.	regulation of expression of aroh, the structural gene for the tryptophan-sensitive 3-deoxy-d-arabinoheptulosonic acid-7-phosphate synthetase, by the tryptophan repressor and its corepressor, l-tryptophan, was studied in vivo by using aroh-lacz fusions. protein and operon fusions were constructed on multicopy plasmids and subsequently crossed in single copy to the bacterial chromosome via the specialized transducing bacteriophage lambda rz5. analysis of the resulting lysogens demonstrated that ar ...	1987	3106331
identification of polypeptides encoded by an escherichia coli locus (hfla) that governs the lysis-lysogeny decision of bacteriophage lambda.	we report the cloning of the escherichia coli hfla locus, which governs stability of phage lambda cii protein and which has been proposed to encode or regulate a cii-specific protease. the hfla locus was cloned on an 18-kilobase dna fragment by selecting for plasmids that carry the neighboring pura gene. the boundaries of hfla were delimited by analysis of deletions and insertions constructed in vitro and by use of transposon tn1000. maxicell analysis of the proteins encoded by the hfla-containi ...	1987	3040675
inhibition of streptomycin-dependent mutation in escherichia coli on the lytic growth of bacteriophage lambda.	spontaneous streptomycin-dependent mutants (strda) were isolated from escherichia coli c600. on c600 strd, the lytic growth of phage lambda nam and lambda ci857 was inhibited. after e. coli lysogenic strain 1.1485 (lambda ci857) mutated to strda, induction of lambda was decreased greatly. on strda of e. coli strains c600 and 1.1485 (lambda ci857), the plating efficiencies and burst sizes of phage t4 and t7 remained normal. since strda is a mutation in the structural gene for ribosomal protein s1 ...	1987	2960017
control of cloned gene expression by promoter inversion in vivo: construction of improved vectors with a multiple cloning site and the ptac promoter.	we have constructed three gene-expression plasmids which contain (an) invertible promoter(s) and a multiple cloning site. we used either the plac promoter or the ptac-plac tandem promoters, the latter directing a more than fourfold increase in expression of the galk reporter gene in escherichia coli host. all these plasmids were derived from the pnh7a expression plasmid of podhajska et al. [gene 40 (1985) 163-168]. like pnh7a, these vectors have three novel properties: (i) in the 'off phase', th ...	1987	2960590
[phenomenon of restriction alleviation in escherichia coli strains].	the alleviation of foreign dna restriction after treatment of cells by uv and gamma-rays or ocr+-gene product of t3, t7 phages has been studied. both uv and gamma-radiation were shown to induce in restriction alleviation of unmodified phage. the results of restriction alleviation caused by t3 and t7 ocr+-gene products have been evaluated by f-lac+ transfer efficiencies in heterologic crosses and plating of unmodified phage lambda. the phenomenon of restriction alleviation was established to depe ...	1987	2963212
regulation of dnab function in dna replication in escherichia coli by dnac and lambda p gene products.	the dnab protein of escherichia coli, a multifunctional dna-dependent ribonucleotide triphosphatase and datpase, cross-links to atp on ultraviolet irradiation under conditions that support rntpase and datpase activities of dnab protein. the covalent cross-linking to atp is specifically inhibited by ribonucleotides and datp. tryptic peptide mapping demonstrates that atp cross-links to only the 33-kda tryptic fragment (fragment ii) of dnab protein. the presence of single-stranded dna alters the co ...	1987	3034907
sequence determination and comparison of the exfoliative toxin a and toxin b genes from staphylococcus aureus.	the dna encoding the exfoliative toxin a gene (eta) of staphylococcus aureus was cloned into bacteriophage lambda gt11 and subsequently into plasmid pli50 on a 1,391-base-pair dna fragment of the chromosome. exfoliative toxin a is expressed in the escherichia coli genetic background, is similar in length to the toxin purified from culture medium, and is biologically active in an animal assay. the nucleotide sequence of the dna fragment containing the gene was determined. the protein deduced from ...	1987	3040666
a rapid and improved method for generating cdna libraries in plasmid and phage lambda vectors.	we have developed a fast and efficient procedure for generating cdna libraries in plasmid or phage lambda vectors. we used mo-mulv reverse transcriptase to synthesize the first strand and directly added escherichia coli dna polymerase i with rnase h to synthesize the second strand. a special advantage of our procedure is the use of oligodeoxynucleotide adapters to insert the cdna into the vector, avoiding the use of methylating enzymes and subsequent digestion with massive amounts of restriction ...	1987	2445632
structure of cryptic lambda prophages.	when escherichia coli cells lysogenic for bacteriophage lambda are induced with ultraviolet light, cells carrying cryptic lambda prophages are occasionally found among the apparently cured survivors. the lambda variant crypticogen (lambda crg) carries an insertion of the transposable element is2, which increases the frequency of cryptic lysogens to about 50% of cured cells: 43 of these cryptic prophages have been characterized. they all contain substitutions that replace the early segment of the ...	1987	2828640
molecular cloning of treponema pallidum outer envelope fibronectin binding proteins, p1 and p2.	phages directing the synthesis of treponema pallidum fibronectin binding adhesin proteins, p1 and p2, were isolated from an embl-3 bacteriophage lambda library of t pallidum deoxyribonucleic acid (dna). the recombinant phages were identified using antisera generated to treponemal proteins purified in fibronectin-sepharose. recombinant p1 and p2 proteins possessed the same relative molecular weights as the native surface polypeptides of spirochaetes. the structural genes for these proteins were s ...	1987	2962928
new mutations in the prm promoter of bacteriophage lambda.	a prm-ci-lacz fusion inserted into the b2 region of bacteriophage lambda imm21 was used to isolate mutations in the lambda prm promoter. among the mutations causing defects in synthesis of both repressor (ci gene product) and beta-galactosidase, new promoter mutations were identified at positions -11 and -32 relative to the ci transcription start point. both mutations are changes in conserved (consensus) nucleotides in prm, but the mutation at -11, which alters a more highly conserved nucleotide ...	1987	2958391
sequence of amino acids in lamb responsible for spontaneous ejection of bacteriophage lambda dna.	the dna sequence of the promoter-distal half of lamb from shigella sonnei 3070 has been determined and compared with the known sequence for the escherichia coli k12 gene. the only predicted amino acid changes in this region of lamb, the receptor protein for bacteriophage lambda, lie between positions 381 and 390, where seven of the ten amino acids are altered. evidence is presented that indicates that this region is responsible for the ability of the s. sonnei receptor, but not the e. coli recep ...	1987	2958635
a system for in vivo selection of genomic rearrangements with predetermined endpoints in escherichia coli using modified tn10 transposons.	using recombinant dna techniques, the tn10-specific teta gene (coding for tetracycline resistance) has been mutagenized by insertion of a streptomycin-resistance or a kanamycin-resistance gene. the insertions occurred at loci separated by 920 bp. the mutated teta fragments, respectively designated as tes (for tetracycline-streptomycin) and tek (for tetracycline-kanamycin), were subsequently cloned into a phage lambda ciii+cits857cii+ in replacement of the att lambda region. the two recombinant p ...	1987	2824289
construction of a dna-polymerase i overproducing plasmid and isolation of the enzyme.	the pola gene of escherichia coli coding for dna polymerase i was cloned under the control of bacteriophage lambda promoter pl and gene n in a high copy number plasmid vector. the chromosomally located lambda cits repressor gene kept the synthesis of the pola gene product at 28 degrees c at a low level. raising the temperature to 43 degrees c resulted in inactivation of the repressor and overproduction of dna polymerase i, which could easily be purified to homogeneity.	1987	2955618
transposition of tn1000: in vivo properties.	transposition mediated by the tn1000 transposase was investigated by using transposon variants carrying synthetic or wild-type termini but no intact tn1000 genes. transposon tn1001, whose only homologies to tn1000 are in its 38-base-pair terminal inverted repeats, transposed at the same rate as tn1005, an artificial construct carrying wild-type tn1000 termini and approximately 1 kilobase of flanking tn1000 dna at each end, when transposase was supplied in trans. the majority of the transposition ...	1987	2824438
large palindromes in the lambda phage genome are preserved in a rec+ host by inhibiting lambda dna replication.	a large palindrome carried by phage lambda has been shown to prevent growth of the phage on a rec+ strain of escherichia coli. the phage do form plaques on recbc sbcb strains, but the palindrome is not stable--deletions that either destroy the palindrome or diminish its size overgrow the original engineered palindrome-containing phage. we have prepared stocks of lambda carrying a palindrome that is 2 x 4200 base pairs long. these phage stocks are produced by induction of a lysogen in which the t ...	1987	2951734
mismatch repair of deaminated 5-methyl-cytosine.	deamination of 5-methyl-cytosine in double-stranded dna produces a g-t mismatch. heteroduplexes of bacteriophage lambda dna containing a g-t mismatch at the site of a g-5-mec base-pair in one of the parental phages were constructed and used to transfect escherichia coli cells. genetic analysis of the progeny phages derived from such heteroduplexes suggests that, in e. coli, mismatches resulting from the deamination of 5-methyl-cytosine are repaired by a system requiring the e. coli dcm methylase ...	1987	2956428
chi-stimulated patches are heteroduplex, with recombinant information on the phage lambda r chain.	generalized recombination in escherichia coli is elevated near chi sites. in vitro, recbcd enzyme can nick chi a few nucleotides 3' of the terminal gg of the chi sequence (5'-gctggtgg). the simplest model in which this nick at chi participates in chi function predicts that in phage lambda, chi-stimulated recombinants not crossed-over for flanking markers (patches) should be heteroduplex, with recombinant information on the lambda i chain. i report here that patches are heteroduplex, but that rec ...	1987	2949853
mutations that improve the pre promoter of coliphage lambda.	the dya5 mutation, a c----t change at position -43 of the lambda pre promoter, results in a twofold increase in pre activity in vivo. smaller increases in pre activity are found for the dya2 mutation, a t----c change at position -1 of pre, and the dya3 mutation, an a----g change at +5 of pre. the mutant pre promoters retain complete dependence on cii protein for activity. these observations argue, at least for pre-like promoters, that promoter activities are influenced by nucleotide sequences at ...	1987	2953648
role of homology in site-specific recombination of bacteriophage lambda: evidence against joining of cohesive ends.	bacteriophage lambda integration and excision take place at specific loci called attachment sites. earlier work has shown that efficient recombination requires the identical sequence to be present in both attachment sites throughout the seven-base-pair region between the points of strand exchange. a plausible model for the role of homology postulates that int, the site-specific recombinase, makes double-strand breaks at attachment sites such that each broken end has a short single-strand protrus ...	1987	2954163
in vivo dna cloning with a mini-mu replicon cosmid and a helper lambda phage.	a mini-mu bacteriophage, containing the cohesive-end packaging site (cos) from a lambda-phi 80 hybrid phage, a high-copy-number plasmid replicon, and a kanamycin-resistance gene for independent selection, was constructed to clone genes in vivo. this mini-mu element can be derepressed to transpose at a high frequency. dna segments that become flanked by copies of this mini-mu element in the same orientation can be packaged by a helper lambda phage. the resulting lambda lysate can be used to infec ...	1987	2954879
deletion analysis of the dna sequence required for the in vitro initiation of replication of bacteriophage lambda.	supercoiled dna containing the replication origin of bacteriophage lambda can be replicated in vitro. this reaction requires purified lambda o and p replication proteins and a partially purified mixture of escherichia coli proteins (tsurimoto, t., and matsubara, k. (1982) proc. natl. acad. sci. u.s.a. 79, 7639-7643; wold, m. s., mallory, j.b., roberts, j. d., lebowitz, j. h., and mcmacken, r. (1982) proc. natl. acad. sci. u.s.a. 79, 6176-6180). the lambda origin region has four repeats of a 19-b ...	1987	2958451
isolation of escherichia coli rpob mutants resistant to killing by lambda cii protein and altered in pyre gene attenuation.	escherichia coli mutants simultaneously resistant to rifampin and to the lethal effects of bacteriophage lambda cii protein were isolated. the sck mutant strains carry alterations in rpob that allow them to survive cii killing (thus the name sck), but that do not impair either the expression of cii or the activation by cii of the lambda promoters pe and pi. the sck-1, sck-2, and sck-3 mutations modify transcription termination. the growth of lambda, but not of the n-independent lambda variant, l ...	1987	2959654
overproduction of an antisense rna containing the oop rna sequence of bacteriophage lambda induces clear plaque formation.	we have constructed an iptg-inducible plasmid which overexpresses oop rna sequences in escherichia coli. infection of these transformed e. coli cells (sb221/poop5) with lambda+ phage produced clear plaques, whereas lambda+ infection of cells transformed with the plasmid vector (sb221/pjdc406) or the plasmid expressing the oop rna transcript in the other orientation (sb221/poop9) gave rise to turbid plaques characteristic of lambda+. calculations of the percentage of infected cells forming lysoge ...	1987	2448589
n-methyl-n'-nitro-n-nitrosoguanidine-induced resistance to ionizing radiation.	n-methyl-n'-nitro-n-nitrosoguanidine (mnng) pretreatments increase the resistance of escherichia coli to gamma-radiation. the increased resistance is dependent on functional pola, reca, recb, recc, and lexa genes and is partly dependent on recn. the mnng-induced resistance is additive to resistance induced by pretreatment with gamma-radiation but not by increases induced by hydrogen peroxide. the mnng-induced resistance occurs in adaptive response mutants and at pretreatment levels of mnng that ...	1987	3295481
[reduced restriction of phage lambda in escherichia coli k-12 cells after gamma-irradiation].	in gamma-irradiated cells of escherichia coli k-12 restriction alleviation of an unmodified phage lambda is only observed in ab1157 strain. no restriction alleviation by gamma-rays is registered in ab1157 mutants (rec a and ssb-1).	1987	2957724
mutagenesis of bleomycin-damaged lambda phage in sos-deficient and repair endonuclease-deficient escherichia coli.	previous dna sequence analysis of bleomycin-induced forward mutations in repackaged lambda phage has suggested sos-dependent replicative bypass of oxidized apyrimidinic sites as a possible mechanism of mutagenesis. in order to evaluate this hypothesis further, frequencies of mutation to a clear-plaque phenotype were compared for bleomycin-damaged phage grown in various repair-deficient strains of escherichia coli. survival of bleomycin-damaged phage was virtually identical in all host strains. s ...	1988	2453358
salmonella typhimurium lt2 metf operator mutations.	using an escherichia coli lac deletion strain lysogenized with lambda phage carrying a metf-lacz gene fusion (lambda flac), in which beta-galactosidase levels are dependent on metf gene expression, cis-acting mutations were isolated that affect regulation of the salmonella typhimurium metf gene. the mutations were located in a region previously defined as the metf operator by its similarity to the e. coli metf operator sequence. regulation of the metf gene was examined by measuring beta-galactos ...	1988	3147373
changes in dna base sequence induced by gamma-ray mutagenesis of lambda phage and prophage.	mutations in the ci (repressor) gene were induced by gamma-ray irradiation of lambda phage and of prophage, and 121 mutations were sequenced. two-thirds of the mutations in irradiated phage assayed in reca host cells (no induction of the sos response) were g:c to a:t transitions; it is hypothesized that these may arise during dna replication from adenine mispairing with a cytosine product deaminated by irradiation. for irradiated phage assayed in host cells in which the sos response had been ind ...	1988	2966755
cloning and expression of the camp factor of group b streptococci in escherichia coli.	the genetic determinant of the camp factor from a strain of group b streptococcus (gbs; streptococcus agalactiae) was cloned in escherichia coli. total cell dna from the gbs strain r268 was used to construct a gene bank with bacteriophage lambda embl4 in the e. coli k-12 strain le392. recombinant phage plaques were detected by immunoblots by using a specific antiserum raised against purified camp factor. two hybrid phages showing expression of camp factor were identified. subcloning the camp gen ...	1988	3294187
role of the escherichia coli dnak and dnaj heat shock proteins in the initiation of bacteriophage lambda dna replication.	we examined the role of two escherichia coli heat shock proteins, the dnak and dnaj gene products, during the initiation of lambda dv dna replication in vitro. using 14c-labeled lambda p protein we showed that the dnak and dnaj heat shock proteins function together to release lambda p protein from the preprimosomal complex consisting of lambda origin of replication-lambda o-lambda p-dnab protein. hydrolysis of atp, catalyzed presumably by dnak, is required during this reaction. substitution of d ...	1988	2970643
aspects of the regulation of adenylate cyclase synthesis in escherichia coli k12.	in escherichia coli k12 expression of the adenylate cyclase gene is subject to multiple controls. in order to gain understanding of the regulation of adenylate cyclase synthesis, operon and protein fusions were constructed by in vitro recombination either into bacteriophage lambda or low-copy-number plasmids, or directly on the chromosome at the cya locus. the fusions were used in physiological experiments as probes to study transcriptional and translational controls of cya expression. it was fo ...	1988	3049935
rapid isolation of lambda phage dna in micro- and macro-variants.		1988	2974539
coliphage lambda to terminator lowers the stability of messenger rna in escherichia coli hosts.	the effects of the transcription terminators to and tfd on the overall high-level expression of a human interferon-beta gene (ifn-beta) in escherichia coli hosts were compared. deletion mapping shows that mrna lability is caused by sequences at or near the lambda terminator to stem-loop structure. extensive rna secondary structure in this region indicates a potential rnase iii cleavage/binding site. in rnase iii- e. coli hosts, ifn-beta synthesis is indeed considerably enhanced. the bacteriophag ...	1988	2977353
cleavage of the cii protein of phage lambda by purified hfla protease: control of the switch between lysis and lysogeny.	the activity of the cii protein of phage lambda is probably the critical controlling factor in the choice of the lytic or lysogenic pathway by an infecting virus. previous work has established that cii activity is regulated through the turnover of cii protein; the products of the hfla and hflb loci of escherichia coli are needed for a degradative reaction, and lambda ciii functions in stabilizing cii. by using the cloned hfla locus, we have purified a cii-cleaving enzyme that we term hfla. purif ...	1988	2973057
characterization of the types of mutational events that spontaneously occur in a plasmid system.	the immunity region from a ci857 derivative of bacteriophage lambda has been cloned into the ecori site of pbr322 to produce a plasmid that can be used to analyze spontaneous mutagenesis. cells containing this plasmid are temperature-sensitive for growth unless mutations have occurred that somehow prevent the expression of the kil gene in the lambda fragment at non-permissive temperature. 678 such temperature-resistant mutants from 10 independent subcultures each of 2 different reca- e. coli str ...	1988	2827020
activation of recf-dependent recombination in escherichia coli by bacteriophage lambda- and p22-encoded functions.	escherichia coli strains bearing wild-type and mutant alleles of various recombination genes, as well as plasmids that express recombination-related genes of bacteriophages lambda and p22, were tested for their proficiency as recipients in hfr-mediated conjugation. it was found that the homologous recombination systems of both phages could promote recombination in a recb recc mutant host. in addition, the abc function of p22, but not the gam function of lambda, was found to inhibit recombination ...	1988	2842317
[alleviation of type i restriction in the presence of plasmids of group inc i. general characteristics and molecular cloning of the ard gene].	the capability of a number of plasmids of incn and inci groups to alleviate an action of type i ecok, ecob, ecod, and ecoa restriction endonucleases on the unmodified dna was revealed. the efficiency of ecok action on lambda 0 dna is alleviated about 10 divided by 100 fold in e. coli k12 ab 1157 bacteria containing the plasmid of incn group (pkm101, n3, pja4733) or inci group (r144, r648; r621a; colib-p9). we have cloned ard gene of colib-p9 plasmid (sali-c fragment) in pbr322 multicopying vecto ...	1988	2836721
sequences in the 5' proximal segment of the paused transcript affect nusa-mediated enhancement of transcriptional pausing.	nusa protein is a transcription elongation and termination factor that acts to enhance pausing of rna chain growth by rna polymerase at specific sites on dna templates. we demonstrate that this enhancement of pausing in tr1, the transcription termination site between genes cro and cii of phage lambda, is inhibited by dna oligonucleotides complementary to a segment of the nascent rna just preceding the sequence that is thought to be a part of the stem of an rna hairpin that is responsible for pau ...	1988	2839506
structural and functional analysis of tn4430: identification of an integrase-like protein involved in the co-integrate-resolution process.	the 4149-bp transposon tn4430 from bacillus thuringiensis is delineated by 38-bp inverted repeats and codes for a 113-kd protein that shares homology with the transposases (tnpa) of tn3, tn21 and tn501. through transpositional recombination, this protein generates the formation of co-integrates between both donor and target replicons, with duplication of tn4430 molecules. these features are characteristic of transposons of the tn3 family (class ii elements). the second step of the transposition ...	1988	2842151
initiation of lambda dna replication reconstituted with purified lambda and escherichia coli replication proteins.	using highly purified bacteriophage lambda and e. coli replication proteins, we were able to reconstitute an in vitro system capable of replication ori lambda-containing plasmid dna. the addition of a new e. coli factor, the grpe gene product, to this replication system reduced the level of dnak protein required for efficient dna synthesis by at least 10-fold, and also allowed the isolation of a stable dna replication intermediate. based on all available information, we propose a molecular mecha ...	1988	2850011
jekyll, a family of phage-plasmid shuttle vectors.	a series of shuttle vectors has been constructed, which consist of a plasmid carrying a polylinker sequence and an m13 origin integrated into a lambda vector. a short direct repeat flanking the plasmid allows plasmid excision by homologous recombination. sequences are cloned into unique restriction sites within the plasmid, and can be recovered either in phage or plasmid form, or can be packaged further as single-stranded dna phage. these vectors therefore combine the efficiency of phage lambda ...	1988	2854093
illegitimate recombination mediated by calf thymus dna topoisomerase ii in vitro.	we have found that purified calf thymus dna topoisomerase ii mediates recombination between two phage lambda dna molecules in an in vitro system. the enzyme mainly produced a linear monomer recombinant dna that can be packaged in vitro. novobiocin and anti-calf thymus dna topoisomerase ii antibody inhibit this atp-dependent recombination. the recombinant molecules contain duplications or deletions, and most crossovers take place between nonhomologous sequences of lambda dna, as judged by the seq ...	1988	2832845
monoclonal antibodies to a proenkephalin a fusion peptide synthesized in escherichia coli recognize novel proenkephalin a precursor forms.	monoclonal antibodies have been generated to a chimeric peptide comprised of escherichia coli beta-galactosidase fused to the amino acid sequence 69-207 of human preproenkephalin a. two monoclonal antibodies, pe-1 and pe-2, were identified by their ability to recognize the same segment of proenkephalin a fused to the cii gene product of the e. coli bacteriophage lambda. the binding domains of pe-1 and pe-2 have been broadly located, with respect to the primary translation product, within the ami ...	1988	2461943
mutations within the decoding site of escherichia coli 16s rrna: growth rate impairment, lethality and intragenic suppression.	several c----u transitions and small deletions were introduced into the conserved region centered on base c1400 in escherichia coli 16s rrna by in vitro mutagenesis. the mutations were placed within rrnb operons on multicopy plasmids under the transcriptional regulation of either the normal rrnb p1p2 promoters or the temperature-inducible pl promoter from bacteriophage lambda and introduced into e. coli hosts. when expressed from the p1p2 promoters, several of the mutant 16s rrnas impaired cell ...	1988	3047677
molecular cloning and genetic analysis of the determinant for gamma-lysin, a two-component toxin of staphylococcus aureus.	the gamma-lysin determinant of staphylococcus aureus strain smith 5r has been cloned in phage lambda and plasmid vectors in escherichia coli. genetic evidence is presented which demonstrates that gamma-lysin requires the co-operative action of two polypeptides expressed by the closely linked hlga and hlgb genes. recombinants expressed haemolytic activity in agarose medium but not in agar, a known property of gamma-lysin. haemolysis was inhibited by antiserum raised against the 32 kda component o ...	1988	3075655
effect of antiserum against aflatoxin b1-bovine serum albumin complex on aflatoxin b1-induced lysogenesis.	escherichia coli k12 bacteria lysogenic for the lambda phage were used to study the effect of antiserum against aflatoxin b1-induced lysogenesis. the antiserum was obtained from rabbits immunized with water in oil emulsion of aflatoxin b1-bovine serum albumin complex (afb1-bsa). a marked reduction in the degree of lysogenesis was observed when the antiserum was added to the reaction medium prior to microsomal enzyme activation of aflatoxin b1. there was no detectable effect when the antiserum wa ...	1988	3140005
mutant trp repressors with new dna-binding specificities.	oligonucleotide-directed mutagenesis of the codons for glutamine-68 (gln68), lysine-72 (lys72), isoleucine-79 (ile79), alanine-80 (ala80), and threonine-81 (thr81) of the escherichia coli trpr (tryptophan aporepressor) gene was used to make mutant repressors with each of 36 different amino acid changes. mutant repressors were tested for binding to each member of a set of 28 different operators closely related to the consensus trp operator. of the 36 mutant repressors, 11 bind a subset of the 28 ...	1988	3140377
transcriptional activation of bacteriophage lambda dna replication in vitro: regulatory role of histone-like protein hu of escherichia coli.	initiation of bacteriophage lambda dna replication in vivo and in crude in vitro systems is strongly dependent on transcription at or near the lambda replication origin (ori lambda). through its capacity to prevent rna polymerase-mediated 'transcriptional activation' of lambda dna replication, the lambda ci repressor is capable of negatively regulating initiation of lambda dna replication, even when all required replication proteins are present. surprisingly, the strict requirement for transcrip ...	1989	2529119
homologous recombination in prokaryotes: enzymes and controlling sites.	a common step in prokaryotic recombination appears to be the synapsis of the 3'-end of single-stranded dna with duplex dna to form a d-loop. the enzymatic mechanisms by which 3'-ends are produced and by which d-loops are converted into recombinant molecules are illustrated by proposed mechanisms of recombination by the escherichia coli recbcd pathway and the phage lambda red pathway. the enzymes promoting recombination and the special dna sites at which they act are emphasized. recombination by ...	1989	2534386
high level expression of genes cloned in phage lambda gt11.	plasmid cloning vectors have been constructed which allow genes originally cloned in lambda gt11 to be expressed at a high level in escherichia coli. they are based on the pembl and puc vectors, with the genes transcribed from the lac promoter. the ecori site in the vector has been altered to be in the same reading frame as the site used for cloning in lambda gt11. cloned proteins are expressed fused to a 2-kda leader sequence containing a run of six aparagine residues which considerably improve ...	1989	2527780
cloning and dna sequence of plasmid determinant iss, coding for increased serum survival and surface exclusion, which has homology with lambda dna.	escherichia coli k12 cells carrying a cloned 1.4 kb hindiii fragment from plasmid colv2-k94, showed increased survival in guinea pig serum. the recombinant plasmid also conferred group ii surface exclusion, i.e. the cells were reduced in recipient ability towards the incoming plasmid r538drd in conjugation experiments. southern blotting suggested homology with bacteriophage lambda dna and to the insertion element is2. determination of the dna sequence of the fragment demonstrated the presence of ...	1989	2546040
bending of dna by gene-regulatory proteins: construction and use of a dna bending vector.	the binding of a protein to its specific sequence, borne on a dna fragment, retards the mobility of the fragment in a characteristic way during gel electrophoresis. if the protein induces bending in the dna, the contortion can also be monitored by gel electrophoresis, because the amount of retardation of the mobility of the dna-protein complex is dependent upon the position and the degree of the bend induced in the dna fragment [wu and crothers, nature 308 (1984) 509-513]. we have constructed a ...	1989	2533576
the escherichia coli protein, fis: specific binding to the ends of phage mu dna and modulation of phage growth.	we show, using gel retardation, that crude escherichia coli cell extracts contain a protein which binds specifically to dna fragments carrying either end of the phage mu genome. we have identified this protein as fis, a factor involved in several site-specific recombinational switches. furthermore, we show that induction of a mucts62 prophage in a fis lysogen occurs at a lower temperature than that of a wild-type strain, and that spontaneous induction of mucts62 is increased in the fis mutant. d ...	1989	2548061
new derivatives of transposon tn5 suitable for mobilization of replicons, generation of operon fusions and induction of genes in gram-negative bacteria.	three types of new variants of the broad-host-range transposon tn5 are described. (i) tn5-mob derivatives with the new selective resistance (r) markers gmr, spr and tcr facilitate the efficient mobilization of replicons within a wide range of gram-negative bacteria. (ii) promoter probe transposons carry the promoterless reporter genes lacz, nptii, or luc, and nmr, gmr or tcr as selective markers. these transposons can be used to generate transcriptional fusions upon insertion, thus facilitating ...	1989	2551782
mapping of insertion elements is1, is2 and is3 on the escherichia coli k-12 chromosome. role of the insertion elements in formation of hfrs and f' factors and in rearrangement of bacterial chromosomes.	the chromosome of an escherichia coli k-12 strain w3110 contains seven copies of insertion element is1, 12 copies of is2 and six copies of is3. we determined the approximate locations of six copies of is1 (named is1a to is1f), ten copies of is2 (named is2a to is2j), and five copies of is3 (named is3a to is3e) on the w3110 chromosome by plaque hybridization using the "mini-set" of the lambda phage library that includes 476 clones carrying chromosomal segments that cover the w3110 chromosome almos ...	1989	2553981
location and molecular cloning of the structural gene for the deoxyguanosine triphosphate triphosphohydrolase of escherichia coli.	the structural gene for deoxyguanosine triphosphate triphosphohydrolase (dgtpase) (ec 3.1.5.1) and its regulator, opta, have been located on a lambda phage carrying a 17.5kb escherichia coli dna insert. the dna fragment has been excised and ligated into pbr325 and also transferred to another lambda vector. from the results of transduction and transformation experiments, we find that the structural gene for dgtpase is very closely linked to opta and dapd, which locates it at approximately 3.6 min ...	1989	2559296
characterization of the cryptic lambdoid prophage dlp12 of escherichia coli and overlap of the dlp12 integrase gene with the trna gene argu.	the argu (dnay) gene of escherichia coli is located, in clockwise orientation, at 577.5 kilobases (kb) on the chromosome physical map. there was a cryptic prophage spanning the 2 kb immediately downstream of argu that consisted of sequences similar to the phage p22 int gene, a portion of the p22 xis gene, and portions of the exo, p, and ren genes of bacteriophage lambda. this cryptic prophage was designated dlp12, for defective lambdoid prophage at 12 min. immediately clockwise of dlp12 was the ...	1989	2553674
sumo15a: a lambda phasmid that permits easy selection for and against cloned inserts.	we report the construction of a phasmid vector, sumo15a, designed for recombination-based screening of recombinant dna libraries [seed, nucleic acids res. 11 (1983) 2427-2445]. this vector permits rapid selection in escherichia coli for homology-mediated integration and excision between homologous dna inserts cloned in a supf-carrying plasmid and in sumo15a. the region available for recombination spans the homologous sequence shared by the plasmid and the phasmid. supf is the selection tool that ...	1989	2559877
overexpression of n antitermination proteins of bacteriophages lambda, 21, and p22: loss of n protein specificity.	the n protein of bacteriophage lambda (n lambda) modifies escherichia coli rna polymerase in such a way that it transcribes through termination signals, a process called antitermination. n antitermination normally occurs only if the template contains a specific utilization or nut site upstream of the terminators and only in the presence of host-encoded nus proteins. the lambda-related phages 21 and p22 produce n analogs, n21 and n22, but these require different nut sites and show a different pat ...	1989	2651405
cysteine-22 and cysteine-38 are not essential for the functions of maltoporin (lamb protein).	maltoporin in the outer membrane of escherichia coli contains two cysteine residues, at positions 22 and 38 in the primary sequence. the role of these residues in determining structural stability, and their contributions to the maltoporin binding sites for maltodextrins and bacteriophage lambda, was investigated. site-directed mutagenesis was used to alter each of these residues to a serine. a double mutant lacking both cysteines was also isolated. none of the substitutions affected maltodextrin ...	1989	2693195
genetic analysis of the lytic replicon of bacteriophage p1. ii. organization of replicon elements.	the region of bacteriophage p1 dna containing a lytic (vegetative) replicon has been identified by cloning p1 fragments into a phage lambda vector. we present the sequence of that replicon. using a novel fusion vector containing two p1 loxp recombination sites, we have developed a transformation assay for replicon function and have used that assay to identify some of the components of the p1 lytic replicon. among those components is a transcription promoter, p53, whose activity is essential for ...	1989	2661830
cloning, sequencing and expression of the l-2-hydroxyisocaproate dehydrogenase-encoding gene of lactobacillus confusus in escherichia coli.	the gene (l-hicdh) encoding l-2-hydroxyisocaproate dehydrogenase (l-hicdh) from lactobacillus confusus was cloned in escherichia coli. a 69-mer oligodeoxyribonucleotide probe, derived to be complementary to the n-terminal amino acid (aa) coding sequence, was used for screening. the complete nucleotide (nt) sequence of the l-hicdh gene was determined. the 5'-end of the mrna was mapped by primer extension and the promoter identified. downstream from the l-hicdh gene is a typical rho-independent te ...	1989	2684788
characterization and vaccine potential of a novel recombinant coccidial antigen.	a cdna clone derived from sporulated oocysts of eimeria tenella and encoding the expression product gx3262 was identified using a monoclonal antibody raised against eimeria acervulina sporozoites. the cdna fragment containing the coccidial antigen gene was cloned in bacteriophage lambda gt11, transferred to a plasmid, and introduced into escherichia coli for analysis of the gene products. the strain carrying the plasmid produced gx3262 as part of a fusion protein consisting of the first 1,006 am ...	1989	2659532
bacteriophage t4 early promoter regions. consensus sequences of promoters and ribosome-binding sites.	twenty-nine early promoters from bacteriophage t4 and 14 early promoters from bacteriophage t6 were isolated using vector m13hdl17, a promoterless derivative of m13mp8 carrying a linker sequence, the bacteriophage lambda-terminator tr1, and the lacz' gene including part of its ribosome-binding site. the consensus sequence for the t4 promoters is: (sequence; see text). ribosome-binding sites of t4 share the sequence: 5'...g.ggaga..aa.atgaa.a...3' the consensus sequence of the t4 early promoter re ...	1989	2810355
phage genetic sites involved in lambda growth inhibition by the escherichia coli rap mutant.	the rap mutation of escherichia coli prevents the growth of bacteriophage lambda. we have isolated phage mutants that compensate for the host deficiency. the mutations, named bar, were genetically located to three different loci of the lambda genome: bari in the attp site, barii in the ciii ea10 region, and bariii within or very near the imm434 region. the level of lambda leftward transcription correlates with rap exclusion. phage lambda mutants partially defective in the pl promoter or in pl-tr ...	1989	2523838
flanking dna-sequences contribute to the specific binding of ci-repressor and or1.	the binding of ci-repressor to a series of mutant operators containing or1 of the right operator of bacteriophage lambda was investigated. sites or2 and/or or3 were inactivated by either point or deletion mutations. the free energy of binding repressor to or1 in the wildtype operator, delta g1, is -13.7 +/- 0.3 kcal/mol. delta g1 determined for an or2- operator created by a single point mutation in or2 is -13.6 +/- 0.2 kcal/mol. in contrast, delta g1 for the binding of repressor to a cloned synt ...	1989	2525252
effects of all single base substitutions in the loop of boxb on antitermination of transcription by bacteriophage lambda's n protein.	the 'n' antitermination proteins of lambdoid bacteriophages are essential for overcoming multiple transcription terminators located within the major early operons of these phages (1). in order for n proteins to function, a genome sequence specifying n utilization, nut, must be located within an operon, between the promoter and the terminators (2). two components have been identified within nut: 8-base boxa, conserved among different phages and implicated in the recognition of host nusa protein, ...	1989	2527353
translesion synthesis is the main component of sos repair in bacteriophage lambda dna.	agents that interfere with dna replication in escherichia coli induce physiological adaptations that increase the probability of survival after dna damage and the frequency of mutants among the survivors (the sos response). such agents also increase the survival rate and mutation frequency of irradiated bacteriophage after infection of treated bacteria, a phenomenon known as weigle reactivation. in uv-irradiated single-stranded dna phage, weigle reactivation is thought to occur via induced, erro ...	1989	2527845
generation of a large combinatorial library of the immunoglobulin repertoire in phage lambda.	a novel bacteriophage lambda vector system was used to express in escherichia coli a combinatorial library of fab fragments of the mouse antibody repertoire. the system allows rapid and easy identification of monoclonal fab fragments in a form suitable for genetic manipulation. it was possible to generate, in 2 weeks, large numbers of monoclonal fab fragments against a transition state analog hapten. the methods described may supersede present-day hybridoma technology and facilitate the producti ...	1989	2531466
phasing of protein-induced dna bends in a recombination complex.	many of the structures responsible for replication, transcription initiation and recombination arise from complex sets of protein-protein interactions and the folding of dna in three dimensions, with protein-induced bending of dna often playing an integral role. the magnitude and orientation of dna bending induced by various single proteins has been estimated by gel mobility shift methods and by modelling of crystallographic data. the site-specific recombination by which bacteriophage lambda (ph ...	1989	2528698
the terminus of the escherichia coli chromosome is flanked by several polar replication pause sites.	replication of two small 'constrained' regions of the escherichia coli chromosome, one bordered by replication terminator t1 and the other by t2, displays normal velocity in the normal direction whereas it is much slower in the opposite direction (de massy et al., 1987). the presence of multiple polar terminators has been investigated, using a bacteriophage lambda derivative which provides a replication origin movable to predetermined loci and inducible on demand. the amount of dna made from thi ...	1989	2532703
integration of bacteriophage lambda into the cryptic lambdoid prophages of escherichia coli.	bacteriophage lambda missing its chromosomal attachment site will integrate into reca+ escherichia coli k-12 and c at the sites of cryptic prophages. the specific regions in which these recombination events occur were identified in both lambda and the bacterial chromosomes. a noti restriction site on the prophage allowed its physical mapping. this allowed us to identify the locations of rac, qin, and qsr' cryptic prophages on the noti map of e. coli k-12 and, by analogy, to identify the cryptic ...	1990	2139644
a minor arginine trna mutant limits translation preferentially of a protein dependent on the cognate codon.	the escherichia coli argu gene encodes a rare arginine trna (anticodon ucu) that translates the similarly rare aga codon. the argu10(ts) mutation is a transition that changes the first nucleotide of the mature trna from g to a, presumably destabilizing the acceptor stem. this mutation, when present in haploid condition in the chromosome, reduces the growth rate at 30 degrees c and results in cessation of growth after 60 to 90 min at 43 degrees c. the mutation also preferentially limits (compared ...	1990	2139647
a short dna sequence from lambda phage inhibits protein synthesis in escherichia coli rap.	the escherichia coli rap mutant inhibits vegetative growth of bacteriophage lambda. phage mutations termed bar, which overcome the rap defect, have been mapped to three genetic loci in the pl operon. plasmids with a lambda wild-type bar dna segment cloned downstream from an active promoter cannot be maintained in rap mutant bacteria. the viability of a rap mutant strain decreases rapidly after induction of transcription through bar regions present on plasmids. under these (restrictive) condition ...	1990	2147720
transcription-dependent competition for a host factor: the function and optimal sequence of the phage lambda boxa transcription antitermination signal.	ordered development of lambdoid phages relies on systems of transcription termination and antitermination. the phage-encoded n early regulatory proteins, acting with the nus proteins of escherichia coli, modify rna polymerase to a form that overrides many transcription termination signals. these modifications require cis-acting sites, nut, located downstream of the early phage promoters. the nut sites in phages lambda, 21, and p22, which share similarities but are not identical, contain two sign ...	1990	2148536
the use of transgenic mice for short-term, in vivo mutagenicity testing.	in order to develop a short-term, in vivo assay to study the mutagenic effects of chemical exposure, transgenic mice were generated using a lambda shuttle vector containing a lacz target gene. following exposure to mutagens, this target can be rescued efficiently from genomic dna prepared from tissues of the treated mice using restriction minus, in vitro lambda phage packaging extract and restriction minus escherichia coli plating cultures. mutations in the target gene appear as colorless plaque ...	1990	2151115
action of an rna site at a distance: role of the nut genetic signal in transcription antitermination by phage-lambda n gene product.	the n gene product of escherichia coli phage lambda is a transcriptional activator that captures the host rna polymerase and modifies it to a termination-resistant form, permitting gene expression in two large polycistronic operons of the phage genome. antitermination in vitro requires at least one host factor called nusa, which directly binds the n protein as well as rna polymerase, and also a transcribed cis-acting site known as nut, within which lies the hypothesized n-recognition signal, box ...	1990	2151659
vectors for constructing kan gene fusions: direct selection of mutations affecting is10 gene expression.	we describe several vectors for constructing translational fusions to the kan gene of tn5. fusions are constructed in vitro using multi-copy vectors containing unique cloning sites situated between upstream transcriptional terminators and a downstream kan gene lacking transcriptional and translational start signals. multi-copy fusions can be converted to single-copy chromosomal fusions by in vivo recombination with specific phage lambda vectors and vice versa. we find that kan fusions are often ...	1990	2165970
detection of protein-dna complex formation by time-resolved fluorescence depolarization of bound ethidium bromide.	we introduce the use of time-resolved fluorescence spectroscopy to probe the interaction between gene regulatory proteins and dna. changes in the decay kinetics of fluorescence polarization anisotropy of ethidium bromide bound to dna segments report changes in hydrodynamic volume and shape which occurs upon complex formation between protein and dna. we have used the decay of fluorescence polarization anisotropy as a spectroscopic handle on the interaction between several site-specific dna-bindin ...	1990	2291477
site-directed insertion mutagenesis with cloned fragments in escherichia coli by p1 phage transduction.	a cloned gene with an insertion, which was made by introducing cat, was ligated to the cloning site of the phage lambda gt11. p1 phage grown on cells lysogenized with the recombinant lambda phage could transduce the mutant gene into the original site on the escherichia coli chromosome.	1990	2157955
stimulation of mutations suppressing the loss of replication control by small alcohols.	transient exposure of lysogenic escherichia coli cells to small alcohols stimulated the frequency of mutations suppressing the lethal loss of replication control from a prophage fragment of bacteriophage lambda. the stimulation in mutation frequency paralleled the effect of mutagenic agents, and in this sense the alcohols behaved as mutagens. 10-min treatments above distinct threshold concentrations at 23%, 18%, 10% and 4% (v/v) were required in order for methanol, ethanol, isopropanol and propa ...	1990	2143557
lysis protein s of phage lambda functions in saccharomyces cerevisiae.	the lambda s lysis gene was cloned into a saccharomyces cerevisiae expression vector under gal1 control. induction with galactose in s. cerevisiae terminated cell growth and prevented colony formation. several membrane proteins immunoreactive with anti-s antibody accumulated in the membranes, indicating that sodium dodecyl sulfate-resistant oligomers of s are formed, similar to those observed in the membranes of escherichia coli cells killed by expression of the s gene. these observations sugges ...	1990	2147680
a cdna encoding 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase from solanum tuberosum l.	a cdna encoding potato (solanum tuberosum l.) 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase, the first enzyme of the shikimate pathway, was cloned into phage lambda gt11. the clone represents the first cdna for this enzyme from any eukaryotic source. the nucleotide sequence of the cdna was determined, and its identity was confirmed through partial amino acid sequence analysis of the encoded enzyme. the cdna contains a 1527-base pair open reading frame that encodes a polypeptide with a cal ...	1990	1967256
bacterial expression of immunoglobulin vh proteins.	a bacterial expression system in escherichia coli has been developed that produces as much as 10 mg/l of culture of the vh protein associated with monoclonal antibodies specific for the 5-dimethylaminonaphthalene-2-sulfonyl (dns) group. this system has been applied to the expression of the vh genes derived from a low-affinity, igm-producing hybridoma and from a high-affinity, igg-producing cell line. the plasmid vectors (contributed by dr william f. studier) utilize a t7 expression cassette whos ...	1990	2107393
temperature-inducible gene expression in bacillus subtilis mediated by the ci857-encoded repressor of bacteriophage lambda.	an efficient system to control the expression of cloned genes in bacillus subtilis was established by introducing the escherichia coli bacteriophage lambda ci857 repressor-pr promoter system into this host. a staphylokinase reporter gene (sak42d), which was fused to the lambda pr promoter was constitutively expressed in b. subtilis even when the ci857 gene was present on the same plasmid. s1 nuclease mapping of the transcription start point confirmed that the pr promoter was active in b. subtili ...	1990	1699846
lambda vectors for stable cloned gene expression.	the bacteriophage lambda offers a unique opportunity concurrently to minimize segregational instability in recombinant systems by chromosomal integration of the cloned gene and to achieve high cloned gene expression during an abortive lytic phase. lysis leads approximately to a 100-fold amplification of the cloned gene. cell lysis in the lytic state is blocked by a specific mutation (sam), allowing the cell to maintain its integrity, and lambda dna packaging is blocked by other mutations (wam, e ...	1990	1368559
characterization of the pilin gene of moraxella bovis dalton 2d and expression of pili from m. bovis in pseudomonas aeruginosa.	the pilin gene of moraxella bovis dalton 2d was isolated by cloning in pseudomonas aeruginosa. the nucleotide sequence of this gene encodes a prepilin of 156 amino acid residues. when high levels of pilin were expressed from the gene in p. aeruginosa, by using the pl promoter of bacteriophage lambda inserted upstream of the coding sequence, pili which were indistinguishable from pili of m. bovis were produced.	1990	1971258
celb, a gene coding for a bifunctional cellulase from the extreme thermophile "caldocellum saccharolyticum".	"caldocellum saccharolyticum" is an obligatory anaerobic thermophilic bacterium. a gene from this organism, designated celb, has been cloned in escherichia coli as part of a bacteriophage lambda gene library. this gene produces a thermostable cellulase that shows both endoglucanase and exoglucanase activities on test substrates and is able to degrade crystalline cellulose to glucose. the sequence of celb has homology with both exo- and endoglucanases described by others. it appears to have a cen ...	1990	2126700
participation of rec genes of escherichia coli k 12 in w-reactivation of uv-irradiated phage lambda.	the effect of the recombinational deficiency on w-reactivation of uv-damaged phage lambda was explored. in this paper we show that w-reactivation is reduced by the recb21 and recf143 mutations after bleomycin (bm) and uv treatment. combination of these mutations in the recb21recf143 double mutant blocks w-reactivation completely after bm induction, but leaves residual w-reactivation ability after uv-irradiation, which is abolished by the introduction of uvrb deficiency (delta(uvrb-chla]. w-react ...	1990	1689458
effects of medium quality on the expression of human interleukin-2 at high cell density in fermentor cultures of escherichia coli k-12.	we examined the ability of transformed escherichia coli cells in fermentor cultures to accumulate interleukin-2 (il-2) intracellularly under temperature-regulated control of the phage lambda pl promoter. induction of expression was undertaken at different culture optical densities, and specific il-2 accumulation was found to decrease with increasing cell density at induction. induction at higher culture optical densities was also accompanied by decreased growth during induction and increased ace ...	1990	2180368
structural and functional comparison between the stability systems pard of plasmid r1 and ccd of plasmid f.	the stability determined by the systems pard of plasmid r1 and ccd of plasmid f is due to the concerted action of two proteins, a cytotoxin and an antagonist of this function. in this paper we report that ccda and kis proteins, the antagonists of the ccd and pard systems respectively, share significant sequence homologies at both ends. in kis, these regions seem to correspond to two different domains. despite the structural similarities, kis and ccda are not interchangeable. in addition we have ...	1991	2017133
cyclic amp inhibits and putrescine represses expression of the spea gene encoding biosynthetic arginine decarboxylase in escherichia coli.	the spea gene of escherichia coli encodes biosynthetic arginine decarboxylase (adc), the first of two enzymes in a putrescine biosynthetic pathway. the activity of adc is negatively regulated by mechanisms requiring cyclic amp (camp) and camp receptor protein (crp) or putrescine. a 2.1-kb bamhi fragment containing the spea-metk intergenic region, spea promoter, and 1,389 bp of the 5' end of the spea coding sequence was used to construct transcriptional and translational spea-lacz fusion plasmids ...	1991	1646785
hu and integration host factor function as auxiliary proteins in cleavage of phage lambda cohesive ends by terminase.	hu and integration host factor (ihf) are small, basic heterodimeric dna-binding proteins which participate in transcription initiation, dna replication, and recombination. we constructed isogenic escherichia coli strains in which hu, ihf, or both proteins were absent. bacteriophage lambda did not grow in hosts lacking both hu and ihf. phage dna replication and late gene transcription were normal in the double mutants, but packaging of lambda dna was defective. mature phage dna molecules were abs ...	1991	1825651
identification of protein binding sites in genomic dna by two-dimensional gel electrophoresis.	we describe a simple two-dimensional electrophoresis procedure to identify the recognition sites of dna-binding proteins within large dna molecules. using this approach, we have mapped e. coli ihf (integration host factor) binding sites within phage lambda (48 kb) and phage mu (39 kb) dna. we are also able to visualize ihf binding sites in e. coli chromosomal dna (4,700 kb). we present an extension of this technique using direct amplification by pcr of the isolated restriction fragments, which s ...	1991	1827523
heat-inducible reactivation of uv-damaged bacteriophage lambda.	induction of the sos response in uv-irradiated bacteria leads to an increase in the survival of an infecting irradiated bacteriophage lambda (weigle 1953). we report that a similar reactivation of irradiated phage lambda was induced by shifting the culture of recipient bacteria from 30 degrees to 47 degrees c. however, this repair process was nonmutagenic. the amplitude of the phenomenon was increased with the quantity of uv lesions in the phage dna. it was present despite mutations affecting th ...	1991	1827875
a combination of rnase h (rnh) and recbcd or sbcb mutations in escherichia coli k12 adversely affects growth.	colony forming ability of escherichia coli strains carrying the rnh-339::cat mutant allele is strongly dependent on the recbcd and sbcb genes. a mutation inactivating either the recbcd nuclease or exonuclease i (sbcb) is sufficient to restrict severely the efficiency of plating of strains carrying the rnh-339::cat mutation. combining a non-lethal temperature-sensitive mutation in the recbcd nuclease, recb270 (ts) or recc271 (ts), with rnh-339::cat renders strains temperature sensitive for growth ...	1991	1650908
effect of rfah (sfrb) and temperature on expression of rfa genes of escherichia coli k-12.	in order to study the regulation of a large block of contiguous genes at the rfa locus of escherichia coli k-12 which are involved in synthesis and modification of the lipopolysaccharide core, the transposon tnlacz was used to generate in-frame lacz fusions to the coding regions of five genes (rfaq, -g, -p, -b and -j) within this block. the beta-galactosidase activity of strains in which these fusions had been crossed into the chromosomal rfa locus was significantly decreased when the rfah11 (sf ...	1991	1655711