| [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 |
| analysis of the escherichia coli proba locus by dna and protein sequencing. | a 2.9 kb dna fragment carrying the escherichia coli proba region, which encodes the first two enzymes of the proline biosynthetic pathway, was subcloned onto an expression plasmid carrying both the bacteriophage lambda pl promoter (lambda pl) and the lambda gene encoding a thermolabile ci repressor protein (ci857). derepression of the lambda pl promoter by thermal inactivation of the ci857 repressor protein resulted in the simultaneous overproduction of the prob (gamma-glutamyl kinase) and proa ... | 1984 | 6089111 |
| expression of normal and transforming h-ras genes in escherichia coli and purification of their encoded p21 proteins. | the h-ras gene of the balb murine sarcoma virus (balb-msv) was placed under the transcriptional control of the tightly regulated pl promoter of bacteriophage lambda in the expression vectors pev-vrf-1 and prc23. upon derepression of the pl promoter, large amounts (10-20% of total cellular protein) of the h-ras gene product p21 are synthesized in escherichia coli. we constructed three h-ras gene expression vectors, designated pjcl-h5, pjcl-e30, and pjcl-33. pjcl-h5 directs the synthesis of p21, a ... | 1984 | 6089191 |
| analysis of two potential shuttle vectors containing herpes simplex virus defective dna. | two potential shuttle vectors which contained the identical herpes simplex virus type 1 (hsv-1) defective particle dna (ddna), but prokaryotic dna of different origins, were examined for their stability when propagated in eukaryotic cells, and for their efficiency as shuttle vectors. each chimeric molecule contained a 9.5 kilobase-pair (kb) ecori fragment (hsv12-7) representing a single unit of a class i hsv-1 ddna. this ddna was cloned into the bacteriophage lambda (lambda) vector lambda gtwes ... | 1984 | 6090565 |
| site-specificity of abnormal excision: the mechanism of formation of a specialized transducing bacteriophage lambda plac5. | molecular mechanism of the specialized transducing bacteriophage lambda plac5 formation has been studied. phage-bacterial dna junctions in lambda plac5 dna are localized and primary structure of regions of the abnormal excisional recombination leading to the phage formation is elucidated; the crossover region proved to be comparable with the central part of attp and attb sites (the core and the adjacent tetranucleotide) in length and degree of homology. bacterial insert in lambda plac5 dna is sh ... | 1984 | 6091038 |
| extension of bacteriophage lambda host range: selection, cloning, and characterization of a constitutive lambda receptor gene. | a set of plasmids has been constructed that carry a constitutive lamb gene (lambc phenotype) from escherichia coli and that confer functional phage lambda receptors to bacteria other than e. coli. this e. coli lambc strain has been selected to escape both maltose-inducible and glucose-repressible control. constitutivity results from an is-3 insertion, carrying a mobile promoter, proximal to lamb. the lambc dna has been cloned into both broad and narrow host-range plasmids, and the resulting ptro ... | 1984 | 6091132 |
| 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 |
| resolution of synthetic att-site holliday structures by the integrase protein of bacteriophage lambda. | site-specific recombination of the bacteriophage lambda genome into and out of the host bacterial genome is postulated to involve the formation of holliday structure intermediates by reciprocal single-strand exchanges. synthetic analogues of the predicted recombination intermediates are resolved in vitro by the protein product of the lambda int gene. some of the structural features and reaction conditions for this genetic recombination can now be defined. | 1984 | 6092961 |
| plasmid vectors for the rapid isolation and transcriptional analysis of human beta-globin gene alleles. | we describe the construction and characterization of miniplasmid vectors that can be used to isolate and express normal and mutant alleles of the human beta-globin gene. these vectors, designated pi sv beta plasmids, contain a bacterial origin of replication and selectable marker, a 5'-flanking beta-globin dna fragment that can be used for recombination screening (seed, 1983), and simian virus 40 (sv40) sequences that allow accurate and efficient expression of the beta-globin gene transfected in ... | 1983 | 6094959 |
| cloning, nucleotide sequence and high level expression of the gene coding for the connector protein of bacillus subtilis phage phi 29. | the phi 29 dna restriction fragment hindiii-d, shown to contain gene 10 coding for the connector protein, has been cloned in plasmid pplc28 under the control of the pl promoter of phage lambda. after heat induction to inactivate the lambda repressor, a protein with the electrophoretic mobility of the connector protein p10 was synthesized, accounting for about 30% of the total escherichia coli protein after 3 h of induction. the 2205 nucleotide-long sequence of the cloned hindiii-d fragment has b ... | 1984 | 6096227 |
| l factor that is required for beta-galactosidase synthesis is the nusa gene product involved in transcription termination. | the dna-dependent in vitro synthesis of escherichia coli beta-galactosidase requires the presence of a soluble protein referred to as l factor [kung, h., spears, c. & weissbach, h. (1975) j. biol. chem. 250, 1556-1562]. in the present study, comparison of physical, immunological, and biological properties shows that l factor is the product of the e. coli nusa gene. the nusa gene product is known to interact with bacteriophage lambda n gene protein and to prevent premature termination of transcr ... | 1980 | 6154941 |
| 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 |
| rna splicing mutation in an aberrantly rearranged immunoglobulin lambda i gene. | the mouse cell line mopc 315 is an iga (lambda ii)-producing myeloma. we have studied a derivative of mopc 315 that secretes normal lambda ii chains but no heavy chain. this derivative, mopc 315-26, was found to contain a rearranged lambda i gene in addition to a rearranged lambda ii gene. the rearranged lambda i gene was cloned into bacteriophage lambda dna and its structure was studied. the lambda i gene was found to have arisen by an aberrant recombination event that resulted in a single base ... | 1981 | 6171827 |
| assembly pathway of newly synthesized lamb protein an outer membrane protein of escherichia coli k-12. | the assembly of newly induced lamb protein (phage lambda receptor) was investigated in an operon fusion strain of escherichia coli, in which the lamb gene is expressed under lac promoter control. the induction kinetics both for total cellular and for cell surface-exposed lamb protein were studied by immunochemical detection methods, using two distinct antisera directed against detergent-solubilized lamb trimers and completely denatured lamb monomers, respectively. anti-trimer antibodies recogniz ... | 1984 | 6204059 |
| 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 |
| solid-phase sequence analysis of polypeptides eluted from polyacrylamide gels. an aid to interpretation of dna sequences exemplified by the escherichia coli unc operon and bacteriophage lambda. | an approach to sequencing proteins by the solid-phase method combined with isolation of proteins and polypeptides by gel electrophoresis is described. mixtures of proteins or polypeptides resulting from digests are fractionated in the presence of dodecylsulphate in polyacrylamide gels. they are detected with coomassie blue, eluted, selectively reacted with porous glass derivatives and sequenced in their amino-terminal regions with the aid of a new microsequencer. alternatively they can be analys ... | 1982 | 6210528 |
| 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 |
| a comparison of the requirements for antitumour activity and antibacteriophage lambda activity for a series of non-intercalative dna-binding agents. | a series of non-intercalative dna-binding agents, comprising mainly bisquaternary ammonium heterocyclic compounds, has been found to inhibit strongly the production of bacteriophage lambda following its induction in escherichia coli. the inhibition is much greater than that found with a number of dna intercalating agents, including 9-aminoacridine, ethidium and daunorubicin. the inhibition correlated significantly with antitumour effect, as measured in a life extension assay with l1210 leukaemia ... | 1982 | 6212240 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| phasmid vectors for identification of genes by complementation of escherichia coli mutants. | a bacteriophage lambda cloning vector was designed to facilitate the isolation of genes from procaryotic organisms by complementation of escherichia coli mutants. this vector, lambda se4, was constructed by attaching a very-low-copy-number replication system (from the plasmid nr1) and a spectinomycin resistance gene to the left arm of lambda 1059 (karn et al., proc. natl. acad. sci. u.s.a. 77:5172-5176, 1980). this phasmid cloning vector is capable of growing lytically as a phage in a nonimmune ... | 1985 | 2985547 |
| overproduction of staphylokinase in escherichia coli and its characterization. | a recombinant plasmid which directs the overproduction in escherichia coli of staphylokinase from staphylococcus aureus has been constructed by placing the staphylokinase gene, sak, under the control of bacteriophage lambda pr promoter in the plasmid. when an e. coli strain having the plasmid was induced, the staphylokinase activity in the periplasmic fraction increased about 60-fold and the 15.5-kda protein corresponding to the mature form reached about 25% of the periplasmic proteins. at the s ... | 1985 | 3891339 |
| on some genetic aspects of phage lambda resistance in e. coli k12. | most mutations rendering e. coli k12 resistant to phage lambda, map in two genetic regions mala and malb.-the malb region contains a gene lamb specifically involved in the lambda receptor synthesis. twenty-one independent lamb mutations studied by complementation belonged to a single cistron. this makes it very likely that lamb is monocistronic. among the lamb mutants some are still sensitive to a host range mutant of phage lambda. mutations mapping in a proximal gene essential for maltose metab ... | 1972 | 4558324 |
| new method for large-scale preparation of covalently closed lambda dna molecules. | a combination of mutations in bacteriophage lambda and its host escherichia coli k-12 provides a convenient system for the isolation of large quantities of covalently closed circular dna molecules. we describe two procedures for the large scale preparation of lambda dna in the duplex circular form. | 1974 | 4610176 |
| features of bacteriophage lambda: analysis of the complete nucleotide sequence. | | 1983 | 6222866 |
| ultraviolet- and x-ray-induced responses of a deoxyribonucleic acid polymerase-deficient mutant of escherichia coli. | escherichia coli k-12, polal(-) is a mutant strain whose extracts are deficient in kornberg deoxyribonucleic acid (dna) polymerase activity. we have compared the mutant and parental strains on the basis of a number of responses to ultraviolet (uv) and x-irradiation. for both types of radiation, the mutant is more sensitive by approximately the same factor as measured by reduction in colony formation, depression of dna synthesis, and enhancement of dna degradation. the rate of repair of x-ray-ind ... | 1971 | 4935330 |
| gene transfer into animal cells after fusion with bacteriophage lambda-infected e coli protoplasts. | | 1983 | 6227013 |
| escherichia coli plasmid vectors for high-level regulated expression of the bacteriophage lambda xis gene product. | the bacteriophage lambda xis protein is one of the proteins required for site-specific excisive recombination by which the lambda prophage is excised from the escherichia coli bacterial chromosome. we cloned the lambda xis gene under the control of several prokaryotic promoters to obtain a sufficient source of the protein for biochemical studies. our results demonstrate that e. coli lac promoter and lambda pl promoter fusions to the xis gene produce high levels of xis protein. induction of the e ... | 1983 | 6229452 |
| immunolabelling of bacteriophage lambda receptor protein (lamb) on thin sections of e. coli embedded in lowicryl. | lamb is one of the major cellular proteins when e. coli is grown in the presence of maltose and is localized in the outer membrane. previous immunolabellings obtained with monoclonal antibodies showed that this protein is a transmembrane protein and led to the detection of 4 epitopes exposed on the cell surface and 2 located on the inner surface of the outer membrane (scheckman et al., 1983). in the present study, we have used this biological model in order to see whether these two classes of ep ... | 1984 | 6084531 |
| a v-sis oncogene protein produced in bacteria competes for platelet-derived growth factor binding to its receptor. | the oncogene of simian sarcoma virus, v-sis, encodes a protein which is homologous to human platelet-derived growth factor (pdgf). this v-sis-encoded protein was expressed in bacteria using an inducible promotor of lambda phage. soluble extracts from these bacteria contained a substance which competed with 125i-pdgf for pdgf receptor sites in fibroblast membranes. the receptor competition activity was correlated with the presence of the v-sis-encoded protein as assessed by genetic and immunochem ... | 1984 | 6088510 |
| facile and gentle method for quantitative lysis of escherichia coli and salmonella typhimurium. | garrett et al. (mol. gen. genet. 182:326-331, 1981) constructed strains of escherichia coli harboring derivatives of plasmid pbr322 that carry the lysis genes (s, r, and rz) of phage lambda. the plasmid construction placed the genes under control of the lactose operon operator-promotor (and thus of lac repressor). induction of e. coli strains carrying these plasmids resulted in rapid lysis of the culture unless the s gene was defective, in which case the cells grew normally. a freeze-thaw treatm ... | 1984 | 6232260 |
| antitermination of e. coli rrna transcription is caused by a control region segment containing lambda nut-like sequences. | we have localized the antitermination system involved in e. coli ribosomal rna transcription and compared it with antitermination in the lamboid bacteriophages. in vivo experiments with gene-fusion plasmids were used to examine the ability of specific areas of the rrng control region to convert an ordinary transcription complex into antitermination transcription complex. a 67 bp restriction fragment immediately following the rrng p2 promoter decreased transcription termination about 50%. this fr ... | 1984 | 6091902 |
| genetic analysis of clear-plaque mutations induced in bacteriophage lambda by 9-aminoacridine. | clear-plaque mutations were induced in the ci and cii genes of lambda by treating lysogenic cells with 9-aminoacridine (9aa). mapping of the mutations revealed that there were two hot spots for 9aa mutagenesis in ci, and one strong hot spot in cii. the hot spots in ci mapped close to 1 of the 3 runs of 4 g/c base-pairs and near the only run of 5 g/cs, respectively, in this gene. of 36 ci mutations tested, at most one mapped near a run of 6 a/t base-pairs. by analogy, the sequence responsible for ... | 1984 | 6239977 |
| [bacteriophage lambda integration into host chromosome (biochemistry of int protein and pleiotropic effects of host factors) (author's transl)]. | | 1980 | 6243784 |
| studies on the e. coli gronb (nusb) gene which affects bacteriophage lambda n gene function. | escherichia coli mutants, called gronb, which block the growth of bacteriophage lambda at the level of action of the gene n product, have been isolated as survivors at 42 degrees c of bacteria carrying a) the defective prophage lambda bio11 i lambda ci857 delta h1 or b) the pcr1 plasmid containing the ecori immunity fragment of phage lambda ci857. in addition, gronb bacterial mutants have been isolated at 37 degrees c, as large colony formers in the presence of lambda i lambda ci h434, lambda i ... | 1980 | 6161293 |
| cloning of the replication gene o of e. coli bacteriophage lambda and its expression under the control of the lac promoter. | the expression of the replication gene o of bacteriophage lambda was put under the control of the lac promoter-operator region integrated into the pbr322 cloning vehicle. the new plasmid pkk104 was introduced into minicells and the o gene induced by isopropyl-beta-thiogalactoside (iptg). the o protein could be identified as a major component in extracts from these cells, in association with the cell membrane fractions. the molecular weight of the o protein in sds gels is about 33 000, and it is ... | 1980 | 6254838 |
| bacteriophage lambda cloning vehicles for studies of genetic recombination. | a pair of bacteriophage lambda cloning vehicles has been constructed for use in studies of genetic recombination. these phages, lambda rva and lambda rvb, have the following properties: (1) each vector has a single hindiii site in the immunity region, at which segments of dna can be inserted. (2) these hindiii sites are flanked by selectable markers with the following phenotypes: spi+/- (fec+/-) to the left, and imm lambda or imm434 to the right. (3) there is essentially no sequence homology bet ... | 1980 | 6254844 |
| identification of transfer rna suppressors in escherichia coli. iv. amber suppressor su+6 a double mutant of a new species of leucine trna. | an escherichia coli dna fragment containing an su+6 amber suppressor gene (supp) was cloned into a lambda gt lambda ch vector by the shotgun method, selecting a su+6 transducing phage lambda psu+6. through prophage integration followed by induction occurring at the transducing region of the lambda psu+6 in su- e. coli, a counterpart transducing phage carrying the wild-type allele (su degrees 6) was isolated (lambda psu degrees 6). the fingerprint of a trna encoded by lambda psu degrees 6 was ide ... | 1984 | 6207302 |
| cloning of the exonuclease iii gene of escherichia coli. | overproducers of exonuclease iii (exo iii) were found within a colony bank containing cole1-escherichia coli hybrid plasmids. through the enzymatic ligation of restriction enzyme fragments, the exo iii gene, xth, was transferred to a thermoinducible, integration-proficient lambda phage and to a chimeric cole1-lambda plasmid that was thermoinducible for lambda-directed dna replication. transfer of the xth gene was facilitated by a technique involving prior selection for tn5 insertions into plasmi ... | 1980 | 6260569 |
| the nus mutations affect transcription termination in escherichia coli. | the nusa1 and nusb5 mutations in a partial suppression of polarity and thus transcription termination in escherichia coli. as these mutations block the transcription antitermination activity of bacteriophage lambda n gene product, they paradoxically seem to enhance transcription termination at phage termination sites. the rho mutation hdf026 displays almost identical properties. the observations suggest that the nusa and nusb gene products may act as termination factors analogous to rho protein. | 1981 | 6265784 |
| identity of a chi site of escherichia coli and chi recombinational hotspots of bacteriophage lambda. | | 1982 | 6210783 |
| isolation of beta-globin-related genes from a human cosmid library. | a human gene library was constructed using an improved cloning technique for cosmid vectors. human placental dna was partially digested with restriction endonuclease mboi; size-fractionated and ligated to bamhi-cut and phosphatase-treated cosmid vector pjb8. after packaging in lambda phage particles, the recombinant dna was transduced into escherichia coli 1400 or hb101 followed by selection on ampicillin for recombinant e. coli. 150 000 recombinant-dna-containing colonies were screened for the ... | 1981 | 6266915 |
| cosmid cloning and transposon mutagenesis in salmonella typhimurium using phage lambda vehicles. | we have constructed a strain of salmonella typhimurium which contains the malb region from escherichia coli and carries the bacteriophage lambda receptor protein in its outer membrane. phage lambda adsorbs to this strain but cannot grow, thus providing a very useful system for transposon mutagenesis of s. typhimurium using lambda vehicles carrying transposons. this system can also be used for cosmid cloning. | 1981 | 6268936 |
| [artificial tn2551 transposon with replicative properties]. | a hybrid plasmid, pbe10 was constructed. it consists of dnas of rsf2124 (cole1 :: tn3) plasmid and pub110 plasmid of staphylococcus aureus. the latter can be stably maintained in bacillus subtilis. bamhi cleaved pub110 was introduced into the bamhi site of transposon tn3 and the resulting enlarged tn3 (tn2551) was transposed from pbe10 onto phage lambda and than to pmb9 (tc) and rsf1010(sm su) plasmids. restriction and heteroduplex analysis of pmb9 :: tn2551(pbe21) and rsf1010 :: :: tn2551(pbe32 ... | 1981 | 6273258 |
| beta protein of bacteriophage lambda promotes renaturation of dna. | the protein encoded by the red beta gene of bacteriophage lambda was found to promote reannealing of complementary single strands of dna. reannealing activity was optimal at ph 6.0 and required a divalent cation. a threshold temperature of at least 15 degrees c was necessary in order to detect activity. the reaction was linear with time for about 20 min, but the extent of reaction was dependent upon the amount of beta protein added. reannealing of complementary single strands was confirmed by me ... | 1981 | 6273399 |
| construction and characterization of a tufa-lacz fusion coding for an e. coli ef-tu-beta-galactosidase chimeric protein. | a new phage lambda cloning vector was constructed that has a single ecori site upstream from weakly expressed laci-z gene isolated by müller-hill and kania (1974). an ecori fragment containing the complete tufa gene of e. coli was cloned on the vector and the recombinant phage was crossed into the str operon that has tufa as its last gene. subsequent selection gave rise to a tufa-lacz fusion that codes for a chimeric peptide. the fused peptide has a molecular weight of 148,000 and contains 40% o ... | 1981 | 6276696 |
| transcriptional termination sites in the b2 region of bacteriophage lambda that are unresponsive to antitermination. | a bacteriophage lambda cloning vector carrying the trp/lacw205 substitution is described. the vector facilitates the fusion in vitro of genetic control signals to the lacz structural gene of escherichia coli. this system was used to define transcriptional termination sites in the lambda b2 region. this region contains termination sites that are unresponsive to the lambda antiterminating proteins pq and pn. | 1982 | 6285144 |
| molecular cloning and amplification of the gene for thymidylate synthetase of e. coli. | the thya gene of escherichia coli, which directs the synthesis of the enzyme thymidylate synthetase, has been subcloned from a recombinant lambda phage (hickson et al., 1982) into the multicopy plasmid pbr325 to give the plasmid ppe245. to identify the thya gene product, the transposon tn1000 was inserted into ppe245 and derivative plasmids isolated that were no longer able to complement thya mutations. when proteins synthesised by these plasmids and by ppe245 were labelled and analysed on sds-p ... | 1982 | 6290329 |
| abelson murine leukemia virus: structural requirements for transforming gene function. | the integrated abelson murine leukemia virus (a-mulv) genome cloned in bacteriophage lambda gtwes.lambda b was used to localize viral genetic sequences required for transformation. comparison of the biological activity of cloned a-mulv genomic and subgenomic fragments showed that subgenomic clones that lacked the 5' long terminal repeat and adjoining sequences (300 base pairs downstream of the repeat) were not biologically active. in contrast, subgenomic clones that lacked the 3' long terminal r ... | 1982 | 6291048 |
| escherichia coli plasmid vectors containing synthetic translational initiation sequences and ribosome binding sites fused with the lacz gene. | the construction of a series of escherichia coli plasmid vectors suitable for assaying the effects of gene control signals fused with the e. coli lacz gene is reported. a synthetic deoxyoligonucleotide dodecamer 5'-catgaattcatg gtacttaagtac-5' containing two translation initiation codons (atg) separated by an ecori site was ligated with a lacz gene derivative which lacks the codons for the first eight amino acids in plasmid pmc1403 (casadaban et al., 1980). two ribosome-binding sequences were sy ... | 1982 | 6293930 |
| construction of recombinant lambda phages that carry the e. coli recb and recc genes. | a fragment of the e. coli chromosome including the recc gene has been cloned by in vitro recombinant dna techniques into a phage lambda vector to give the recombinant phage lambda drecc. this was used to derive the phage lambda drecbc by in vivo recombination. on lysogenisation of recb and recc mutants with lambda drecbc wild levels of uv-resistance and recbc dnase activity were restored. infection of e coli with lambda drecbc led to the synthesis of phage-coded proteins of 125 kilodaltons (kd) ... | 1982 | 6211590 |
| probing cii and hima action at the integrase promoter pi of bacteriophage lambda. | plasmids were constructed to supply cii-coded protein for activation of the phage promoter pi. using a fusion which expresses lacz from pi. we can accurately follow activation of pi without having to assay int activity in vivo. a large excess of cii protein compared to a normal lytic infection stimulates lacz expression about 10-fold over the basal level. the int-c226 constitutive allele of pi is not further activated by cii even though its level of lacz expression is less than the maximal cii-a ... | 1982 | 6295882 |
| plasmid vectors capable of transferring large dna fragments to yeast. | we have constructed several cloning vectors which can be used in vitro packaging and yeast transformation. these plasmids have been designed for the convenient cloning of large segments of dna and their transfer to yeast. they contain bacterial plasmid dna sequences for replication and selection in escherichia coli, yeast 2-microns plasmid dna sequences or chromosomal replicators and yeast markers necessary for replication and selection in yeast, and the cohesive ends of bacteriophage lambda whi ... | 1981 | 6299664 |
| purification of the bacteriophage lambda xis gene product required for lambda excisive recombination. | excision of the lambda prophage from the chromosome of its escherichia coli host requires the products of the two viral genes int and xis. this paper reports a purification of the lambda xis gene product using a complementation assay in which functional xis must be added to purified int and an e. coli-derived host factor extract. excisive recombination between a left (attl) and right (attr) prophage attachment site cloned on the same plasmid dna substrate occurred efficiently under these conditi ... | 1982 | 6213611 |
| protein degradation in escherichia coli: the lon gene controls the stability of sula protein. | escherichia coli lon mutants are defective in the atp-dependent proteolysis of abnormal proteins. the mutants are also sensitive to ultraviolet light (uv) in that septation is inhibited after exposure to uv. sula mutations, isolated as suppressors of uv sensitivity unlinked to lon, do not affect proteolysis but allow septation to occur after dna damage. we have confirmed the hypothesis that the product of the sula gene is degraded by lon proteolysis. if sula (the product of sula) is a uv-inducib ... | 1983 | 6300834 |
| site-specific recombination by gin of bacteriophage mu: inversions and deletions. | a 3000-bp invertible segment in the dna of bacteriophage mu determines the host range of the phage. the inversion is catalyzed by the phage-coded protein gin; the recombination sites are short inverted repeats. gin protein is only made in low amounts by mu. to further investigate the gin-mediated recombination reaction a gin overproducing strain was constructed. the gin gene was cloned on a plasmid behind the pl-promotor of phage lambda. this results in a 100-fold higher inversion frequency of a ... | 1983 | 6305017 |
| use of lambda phasmids for deletion mapping of non-selectable markers cloned in plasmids. | a nonselectable gene carried on a poorly selectable recombinant plasmid has been physically mapped by deletion analysis. our method involved cloning the plasmid into a coliphage lambda vector and treating the recombinant phage with a chelator. virtually all particles surviving this treatment carried large deletions within the plasmid insert. further deletion analysis was done by inserting a selectable lambda sequence into one such deletion derivative and repeating the chelator selection. chelato ... | 1983 | 6305773 |
| site-specific dna condensation and pairing mediated by the int protein of bacteriophage lambda. | the int protein of bacteriophage lambda catalyzes the site-specific integrative recombination that inserts lambda dna into the host chromosome. the attachment site region of lambda dna required for this reaction spans 230 base pairs and includes four separable binding sites for int protein. we have used the electron microscope to determine the functional consequences of the interaction of int with its multiple binding sites. we find that int condenses a 230-base pair segment of dna into a compac ... | 1982 | 6310548 |
| integration of viral dna into the genome of the adenovirus type 2-transformed hamster cell line he5 without loss or alteration of cellular nucleotides. | hamster cell line he5 has been established from primary lsh hamster embryo cells by transformation with adenovirus type 2 (ad2) (1). each cell contains two to three copies of integrated ad2 dna (2, 3). we cloned and sequenced the sites of junction between viral and cellular dnas. the terminal 10 and 8 nucleotides of ad2 dna were deleted at the left and right sites of junction, respectively. the integrated viral dna had an internal deletion between map units 35 and 82 on the ad2 genome. at the in ... | 1983 | 6316259 |
| mutations in the dna gyrb gene that are temperature sensitive for lambda site-specific recombination, mu growth, and plasmid maintenance. | we report the isolation of two mutations in the gyrb gene of escherichia coli k12 obtained from an initial selection for resistance to coumermycin a1 and a subsequent screening for bacteria that fail to support site-specific recombination of phage lambda, i.e., him-. these two mutations have a temperature-sensitive him- phenotype, supporting site-specific recombination efficiently at low temperature, but inefficiently at high temperatures. like other him mutants, the gyrb-him mutants fail to pla ... | 1984 | 6319362 |
| cleavage of lambda repressor and synthesis of reca protein induced by transferred uv-damaged f sex factor. | transfer of a uv-damaged f sex factor to a recipient lambda lysogen induces prophage lambda development. under these conditions reca protein synthesis was induced and lambda repressor cleaved, as observed upon direct induction, that is, when the recipient lambda lysogen was directly exposed to uv-light. the efficiency of induction of reca protein synthesis in recipient bacteria which had received an irradiated f-lac factor was about 80% of that measured upon direct induction. we observed the sim ... | 1982 | 6213837 |
| mrna processing in escherichia coli: an activity encoded by the host processes bacteriophage f1 mrnas. | to examine the regions of the male-specific filamentous bacteriophage f1 genome that include signals for mrna processing, the 5' endpoints of the major in vivo phage mrnas have been located in the f1 dna sequence by s1 nuclease mapping. the 5' ends of the purified mrnas and additional phage-specific rnas transiently visible early after infection occur in clusters of t-rich residues within genes that code for three phage proteins. when a 270-nucleotide region encompassing the 5' endpoints of thre ... | 1984 | 6322124 |
| analysis of lambda insertions in the fucose utilization region of escherichia coli k-12: use of lambda fuc and lambda arga transducing bacteriophages to partially order the fucose utilization genes. | escherichia coli k-12 strains have deletions for the normal lambda integration site were lysogenized with bacteriophage lambda at a site within the l-fucose utilization system (fuc). the frequency of lambda integration at this site is approximately 2 x 10(-8) to 5 x 10(-7). studies of the lytic properties of these strains indicated very infrequent cell lysis with a relatively low phage burst size. transductional ability of the phage lysates was found to be normal, comparable to that found in con ... | 1982 | 6214544 |
| mutation and w-reactivation of lambda phage by mitomycin c in the excision-defective escherichia coli. | | 1982 | 6216402 |
| formation of oligomeric structures from plasmid dna carrying cos lambda that is packaged into bacteriophage lambda heads. | plasmids that carry cos lambda, the region necessary for lambda phage packaging and that are as small as four kilobases in size can be packaged into lambda phage heads in head-to-tail tandem oligomeric structures. multimeric oligomers as large as undecamers have been detected. oligomer formation depends upon the products of red and gam of lambda, and the general recombination occurs between different plasmids that share homologous dna regions. the packaging efficiency of plasmids depends on its ... | 1983 | 6217189 |
| 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 |
| 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 |
| stabilization of proteins by a bacteriophage t4 gene cloned in escherichia coli. | the cloned bacteriophage t4 pin gene functions to stabilize several different kinds of proteins in escherichia coli bacteria. incomplete proteins such as puromycyl polypeptides, abnormal but complete proteins such as the lambda phage tso protein, and labile eukaryotic proteins encoded by genes cloned in e. coli such as mature human fibroblast interferon are stabilized in cells in which the t4 pin gene is expressed. the cloned t4 pin gene does not seem to affect the turnover of normal e. coli pro ... | 1983 | 6340113 |
| a phi 80 function inhibitory for growth of lambdoid phage in him mutants of escherichia coli deficient in integration host factor. ii. physiological analysis of the abortive infection. | derivatives of phage lambda with the rightmost 3% of the genome (the qsr region) from the related phage phi 80 fail to grow at low temperatures (e.g., 32 degrees) in escherichia coli hosts deficient in either protein component of ihf (integration host factor), the products of the hima and hip/himd genes. the abortive infection of lambda (qsr)80 in mutants defective for ihf was studied in detail. this infection is characterized by a lack of cell lysis and an inhibition of phage dna replication af ... | 1985 | 3155886 |
| involvement of the htpr gene product of escherichia coli in phage lambda development. | growth of phage lambda at high temperature requires a functional htpr host gene. the stages of the phage growth cycle shown to be dependent on htpr gene function include prophage excision and particle morphogenesis. two types of morphogenetic abnormalities have been detected. one is a defect in phage tail assembly that results from a deficiency in tail fibers even though gpj is produced. the severity of this defect is phage-strain specific. the second morphogenetic defect is less clearly defined ... | 1985 | 3156447 |
| 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 |
| mapping of the glucose dehydrogenase gene in bacillus subtilis. | a 4.0-kilobase dna fragment containing the developmentally regulated gene for glucose dehydrogenase (gdh) from bacillus subtilis was incorporated into the plasmid pgx345, which contains a marker conferring chloramphenicol resistance (cat). the resistance marker of the resulting integration vector was used to map the gdh gene on the b. subtilis chromosome. using pbs1 transduction, the gene order was determined to be aroi cat (gdh) mtlb dal. the cat (gdh) marker was also cotransformable with mtlb. ... | 1984 | 6438057 |
| cloning and expression of bradyrhizobium japonicum uptake hydrogenase structural genes in escherichia coli. | to identify the structural genes for the components of bradyrhizobium japonicum uptake hydrogenase (mr 60,000 and 30,000), we have expressed these genes in escherichia coli and shown that the products cross-react with antibodies to the respective hydrogenase subunits. we constructed subclones of overlapping dna fragments from an uptake hydrogenase-complementing cosmid, phu52 [lambert, g. r., cantrell, m. a., hanus, f. j., russell, s. a., haddad, k. r. & evans, h. j. (1985) proc. natl. acad. sci. ... | 1986 | 3532119 |
| purification and characterization of the integration protein specified by bacteriophage lambda. | | 1980 | 6444632 |
| repressor for the sn-glycerol-3-phosphate regulon of escherichia coli k-12: cloning of the glpr gene and identification of its product. | the glpr gene encoding the repressor for the glp regulon of escherichia coli was cloned from a library of hindiii dna fragments established in bacteriophage lambda. phages harboring glpr were isolated by selection for sn-glycerol-3-phosphate dehydrogenase function encoded by glpd, which is adjacent to glpr on the e. coli linkage map. restriction endonuclease analysis and recloning of dna fragments localized glpr to a 3-kilobase-pair ecori-sali segment of dna. strains exhibiting constitutive expr ... | 1985 | 3881401 |
| cloning of colicin e1 tolerant tolc (mtcb) gene of escherichia coli k12 and identification of its gene product. | a mutation in the tolc(mtcb) gene of escherichia coli k12 results in increased sensitivity to sodium dodecylsulfate (sds), sodium deoxycholate, basic dyes, mitomycin c, and bleomycin, and makes the cell tolerant to the killing action of colicin e1. from lysogens with lambda ci857s7 integrated at a secondary attachment site, a transducing phage (lambda dtolc+) that transduces a tolc recipient to sds resistance was isolated. a recombinant dna molecule was constructed in vitro from plasmid pbr322 a ... | 1982 | 6219270 |
| pseudovirulent mutants of lambda b221poricasna resulting from mutations in or near oric, the e. coli origin of dna replication. | mutants of the specialized transducing phage lambda b221poricasna have been isolated which form plaques on lambda lysogens. genetic and physical evidence is presented to show that the mutations responsible for the pseudovirulent phenotype map in or near oric, the origin of chromosomal replication in escherichia coli. | 1980 | 6446650 |
| proteolytic processing of phage lambda tail protein gph: timing of the cleavage. | we describe a method for the rapid partial purification of intermediate structures of phage lambda tail assembly, using formaldehyde-fixed escherichia coli cells to precipitate tail-related structures. the purification depends on the specific interaction between the e. coli lambda receptor protein and lambda tail protein gpj. protein compositions of tail assembly intermediates were analyzed to determine when in the assembly sequence the minor tail protein gph is cleaved. gph joins the tail precu ... | 1983 | 6220513 |
| transcription antitermination by bacteriophage lambda n gene product. | | 1980 | 6447798 |
| lambda mutation in the escherichia coli rho gene that inhibits the n protein activity of phage lambda. | certain escherichia coli rho mutations, exemplified by rho026, block the growth of phage lambda by interfering with phage gene expression. the phage gene n, whose product suppresses transcription termination, appears to be expressed normally in the mutants, and the functional stability of the n protein is not affected. our data suggest that these rho mutations allow transcription to terminate despite the presence of n. other e. coli mutants displaying a similar phenotype (nus(-)) fail to propaga ... | 1983 | 6225121 |
| [genetic properties of phage lambda recombinant molecules. the effect of an inserted fragment on the hybrid yield and recombination with respect to the h- and vir-markers]. | the yield of mature phages in lambda gt-lambda dm34, lambda gt-lambda dm225 and lambda gt-lambda dm234 is 2, 8 and 8 times lower (respectively) as compared to the wild type. the output of hvir-recombinants in lambda gt-lambda dm225 is more than an order lower as compared to the other phages. as distinct from two other hybrids, the decrease in lambda gt-lamba dm225 yield cannot be explained by red-genotype and a shortening of the phage genome as well as the decrease in the output hvir-recombinant ... | 1980 | 6449098 |
| lack of induction of non-targeted mutations in intact bacteriophage by uvb (313 nm), uva (334 nm, 365 nm) and visible (405 nm) irradiation of host cells. | mutation to virulence has been measured in intact bacteriophage lambda 15 infected into host cells pre-treated with uvc (254 nm), uvb (313 nm), uva (334 nm, 365 nm) or visible (405 nm) radiations. we have confirmed that uvc radiation leads to a large enhancement (maximum enhancement factor of 140 in wild-type) of the background spontaneous mutation frequency (non-targeted mutagenesis) and have further shown that this is at least partially dependent on excision repair (maximum enhancement factor ... | 1984 | 6229698 |
| replication defective rp4 plasmids recovered after chromosomal integration. | phh6000 is a composite replicon made by the in vitro ligation of the incp plasmid rp4 to a fragment of bacteriophage lambda capable of autonomous replication. derivatives were selected in which it had integrated into the escherichia coli chromosome by homologous recombination with the resident lambda prophage, and plasmids were subsequently regenerated from the integrated molecules. although of the same molecular size as phh6000, all had altered properties: those recovered from the chromosome of ... | 1984 | 6231650 |
| expression of the replication region of phage lambda dna cloned into pbr322 in e. coli minicells. | replication region of bacteriophage lambda dna was cloned into pbr322 plasmid by the use of two restriction enzymes--psti and hindiii. the restriction analysis of four obtained plasmids revealed that lambda dna was cloned in both orientations. recombinant plasmids were transferred to the minicell-producing strain of e. coli and synthesis of the plasmid-mediated proteins was analysed by polyacrylamide-gel electrophoresis. all four recombinant plasmids produced lambda dna replication proteins po a ... | 1982 | 6218724 |
| purification and characterization of reca protein from salmonella typhimurium. | reca protein was purified to homogeneity from salmonella typhimurium ta98 strain after induction of the cells by nalidixic acid. the purification was monitored with a radioimmune assay and involved a specific elution of the protein by atp from a single-stranded dna-cellulose column. from 240 liters of cell culture we obtained 40 mg of reca protein which was more than 98% pure. this protein exhibited the same molecular weight as measured on sodium dodecyl sulfate-polyacrylamide gel and the same i ... | 1983 | 6219107 |
| an integration-proficient int mutant of bacteriophage lambda. | we have isolated and characterized a novel int mutant of phage lambda. this mutant promotes efficient recombination between the phage and bacterial attachment sites, but, unlike wild type, does not promote efficient recombination of any other pair of attachment sites tested in most conditions. in particular, recombination between two phage or two prophage attachment sites is poor relative to the wild type frequency. we attribute this unusual phenotype to differences in the distribution of int pr ... | 1984 | 6238223 |
| construction and properties of a cole1::tn3-cos lambda plasmid for determining rna polymerase binding sites on cole1 and tn3. | to determine the location of the rna polymerase binding sites on the cole1 plasmid and tn3 transposon, a special hybrid cole1::tn3-cos lambda molecule was constructed which contains the left arm of phage lambda dna and the right lambda terminal fragment. this permits orienting cole1 molecules, since the rna polymerase binding pattern of these two lambda fragments are known to be distinct. cole1 dna contains seven binding sites and tn3 binds three rna polymerases, with some of the latter probably ... | 1980 | 6247244 |
| the ral gene of phage lambda. i. identification of a non-essential gene that modulates restriction and modification in e. coli. | host controlled restriction in escherichia coli can be relieved by pre-infecting restricting cells with modified lambda helper phages. this process, in which intact unmodified phage genomes are allowed to escape restriction attack, is mediated by a newly identified lambda function called ral. the ral gene has been located by deletion mapping between ciii and n. efficient expression of the ral gene requires the product of the regulator gene n. polyacrylamide gel analysis of the lambda proteins sp ... | 1980 | 6256607 |
| overproduction of the ecorii endonuclease and methylase by escherichia coli strains carrying recombinant plasmids constructed in vitro. | recombinant dna molecules were constructed from the plasmid pil203 and the ecori-fragment of n3 plasmid containing ecorii endonuclease and methylase genes and also a gene for resistance to sulfanilamide. the pil203 plasmid, used as a vector, consisted of the bam hi-ecori-fragment of the plasmid pbr322 conferring resistance to ampicillin and the bam hi-ecori-fragment of lambda phage containing promoters, a thermosensitive mutation in the ci gene and a suppressible amber mutation in the cro gene. ... | 1981 | 6266480 |
| localization of the metjblf gene cluster of escherichia coli in lambda met transducing phage. | the position of the metjblf gene cluster in the transducing phage lambda met102 was determined by ligation of its leftmost ecori fragment (102-1) to the lambda bcdef (nin5) ecori fragment of lambda gtl (lambda bc) and characterization of the resultant recombinant phage. the new transducing phage carries about 6kb of bacterial dna which contains the entire met gene cluster including the promoter of its rightmost member metf. reasonable estimates of the coding capacity required for the four genes ... | 1982 | 6294471 |
| identification of sequences necessary for packaging dna into lambda phage heads. | several species of dna molecules are packaged into lambda phage heads if they carry the region around the cohesive end site of lambda phage (cos lambda). the minimal functional sequence around cos lambda needed for packaging was examined by cloning in pbr322. the results showed that the minimal region contained 85 bp around cos lambda; 45 bp of the left arm of lambda phage and 40 bp of the right arm. a 75-bp region located to the right of the minimal region seems to enhance packaging. a 223-bp f ... | 1982 | 6299893 |
| cloning of the dnab gene of escherichia coli: the dnab gene of gropb534 and gropb612 and the replication of phage lambda. | fragments of the e. coli chromosome that carry the dnab gropb534 or gropb612 alleles have been cloned into a cosmid vector. the resulting recombinant plasmids contained the genes uvra, grop (b534 or b612), and lexa. further subcloning into high copy number plasmids, during which the uvra and lexa genes were removed successively, yielded a gropb534 and gropb612 dna fragment of about 2.4 kb each. both fragments contained an overlapping 1.8 kb segment of dna in which the sites of all restriction en ... | 1984 | 6319960 |
| [c1 and cro repressors of lambda phages. i. construction of vectors for expression of cro repressor of bacteriophage lambda imm434]. | eight derivatives of recombinant plasmid pbrcro434, that consists of pbr322 and fragment of immunity region of phage lambda imm434 have been constructed and characterised. these derivatives contain the deletions in the region adjacent to or3 operator and in the structural gene of cro-repressor of lambda imm434. the deletions have been produced by the treatment of pbrcro434 with exonuclease iii of escherichia coli and s1 nuclease of aspergillus orizae and precisely mapped. the unique ecori-restri ... | 1984 | 6323976 |
| cloning and manipulation of the escherichia coli cyclopropane fatty acid synthase gene: physiological aspects of enzyme overproduction. | like many other eubacteria, cultures of escherichia coli accumulate cyclopropane fatty acids (cfas) at a well-defined stage of growth, due to the action of the cytoplasmic enzyme cfa synthase. we report the isolation of the putative structural gene, cfa, for this enzyme on an e. coli-cole1 chimeric plasmid by the use of an autoradiographic colony screening technique. when introduced into a variety of e. coli strains, this plasmid, plc18-11, induced corresponding increases in cfa content and cfa ... | 1984 | 6325391 |
| lambda placmu: a transposable derivative of bacteriophage lambda for creating lacz protein fusions in a single step. | we isolated a plaque-forming derivative of phage lambda, lambda placmu1 , that contains sequences from bacteriophage mu enabling it to integrate into the escherichia coli chromosome by means of the mu transposition system. the mu dna carried by this phage includes both attachment sites as well as the ci, ner (cii), and a genes. lambda placmu1 also contains the lacz gene, deleted for its transcription and translation initiation signals, and the lacy gene of e. coli, positioned next to the termina ... | 1984 | 6327627 |
| identification of the phom gene product and its regulation in escherichia coli k-12. | plasmids containing the chromosome region of escherichia coli encoding phom, whose product is a positive regulator of alkaline phosphatase expression, were isolated from the clarke and carbon plasmid bank. a 9.9-kilobase ecori fragment of plasmid plc17-39 (subcloned into pbr322) was able to complement both phom and thrb mutations. restriction endonuclease analysis and in vitro mutagenesis of the hybird plasmids enabled the localization of the phom gene locus to 3 kilobases of the cloned chromoso ... | 1984 | 6330029 |