Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| mechanism of ribosome frameshifting during translation of the genetic code. | some frameshift mutations are strongly suppressed by limitation for particular aminoacyl-trna species. here, we show that ribosome frameshifting at a specific tryptophan codon during trp-trna limitation accounts for suppression of a group of downstream frameshift alleles in the riib gene of bacteriophage t4. genetic and physiological observations strongly suggest that ribosome frameshifting at this position depends on the binding of a noncognate (leucine) trna. | 1983 | 6339944 |
| 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 |
| ribonuclease bn: identification and partial characterization of a new trna processing enzyme. | a new ribonuclease, rnase bn, has been identified and partially purified from a strain of escherichia coli lacking rnase ii and rnase d by using the artificial trna precursor trna-c-[14c]u as substrate. this enzyme is present in e. coli b but absent from the trna processing mutant strain bn which is unable to process extraneous 3' residues on certain phage t4-specified trna precursors. the properties of rnase bn clearly distinguish this enzyme from other known e. coli exoribonucleases. it is opt ... | 1983 | 6344080 |
| circular permutation analysis of phage t4 dna by electron microscopy. | phage t4 is known to have a linear duplex chromosome that is circularly permuted and terminally repeated. we found, by denaturation and self-reannealing experiments, that circular permutation in t4 native dna is not random. their multimodal distribution of permutation is compatible with the "headful packaging" model with the additional specifications that the encapsulation of dna starts at several sites and these are not random distributed. | 1983 | 6346725 |
| r plasmid dihydrofolate reductase with a dimeric subunit structure. | dihydrofolate reductase specified by plasmid r483 from a trimethoprim-resistant strain of escherichia coli has been purified 2,000-fold to homogeneity using dye-ligand chromatography, gel filtration, and polyacrylamide gel electrophoresis. the protein migrated as a single band on nondenaturing polyacrylamide gel electrophoresis and had a specific activity of 250 mumol/mg min(-1). the molecular weight was estimated to be 32,000 by gel filtration and 39,000 by ferguson analysis of polyacrylamide g ... | 1983 | 6350298 |
| incorporation of thymine-containing dna precursors in plasmolysed cells infected by the t4 non-lethal recombination defective mutants. | incorporation of tdr is aberrant in cells plasmolysed 15 min after infection by the recombination defective t4 chi and omega mutants. the in situ results parallel those obtained in vivo: at high tdr concentrations both t4 chi and t4 omega induced incorporation is slightly reduced compared to wild type, whereas at low tdr concentration incorporation induced by t4 chi is reduced and that induced by t4 omega is increased compared to wild type. no differences between wild type and mutant induced tdr ... | 1983 | 6355762 |
| [primary structure of the elongation factor g from escherichia coli. vi. structure of peptides of cyanogen bromide cleavage of the g-factor molecule]. | peptides obtained as a result of cyanogen bromide cleavage of the g-factor have been studied. all 12 peptides embracing the whole structure of fragment t4 have been isolated. for their amino acid sequence determination, cyanogen bromide peptides have been further cleaved with trypsin, chymotrypsin, thermolysin, staphylococcal glutamic protease and bnps-skatole. the complete primary structure of 9 from 12 cyanogen bromide peptides has been determined. | 1983 | 6385997 |
| initiation site of deoxyribonucleotide polymerization at the replication origin of the escherichia coli chromosome. | a new round of chromosomal replication of a temperature-sensitive initiation mutant (dnac) of escherichia coli was initiated synchronously by a temperature shift from a nonpermissive to a permissive condition in the presence of arabinosyl cytosine. increased amounts of nascent dna fragments with homology for the chromosomal segment containing the replication origin (oric) were found. the nascent dna fragments were purified and treated with alkali to hydrolyze putative primer rna and to expose 5' ... | 1983 | 6191181 |
| escherichia coli can lacks a trna-processing nuclease. | escherichia coli strain can is unable to support the growth of bacteriophage t4 strains requiring the suppressor function of t4 trnaser. biochemical analysis of the mutant strain revealed that it is deficient in a rnase which acts on the artificial trna precursor trna-c-u. | 1983 | 6194149 |
| self cleavage of a precursor rna from bacteriophage t4. | we found that a precursor of an rna molecule from t4-infected escherichia coli cells (p2spl; precursor of species 1) has the capacity to cleave itself in a specific position. this cleavage is similar to a cleavage carried out by the aid of a protein, rnase f, that has been previously identified. this cleavage could lead to the maturation of an rna (species 1) found in t4-infected e. coli cells. the reaction is time and temperature-dependent and is relatively slow as compared to the protein-depen ... | 1984 | 6198526 |
| the effect of a bacteriophage t4-induced polypeptide on host rna polymerase interaction with promoters. | after infection of escherichia coli with bacteriophage t4, the host rna polymerase acquires several small phage-induced polypeptides (stevens, a. (1974) biochemistry 13, 493-503) and its alpha subunits get adp-ribosylated by a virus-specific enzyme (zillig, w., mailhammer, r., skorko, r., and rohrer, h. (1977) curr. top. cell. regul. 12, 263-271). the modified polymerase displays changed enzymatic properties including sensitivity to increased salt concentration and a higher transition temperatur ... | 1984 | 6386813 |
| molecular organization of the head of bacteriophage teven: underlying design principles. | structure and assembly of the bacteriophage t4 head are described as revealed by results obtained in this laboratory. subunit arrangement of the major coat protein, soc and hoc in the head shell has been determined (figs. 2 and 21). two new approaches for studying the assembly pathway are presented: wild type infection at 19 degrees c and gene 23 cold sensitive mutants. we propose an assembly pathway in which the prehead is formed in one direction, starting from the neck and ending at the distal ... | 1984 | 6399817 |
| [intracellular neutralization of bacteriophage t4 by antiphagic serum]. | specific antiserum, introduced into the spheroplasts of escherichia coli b infected with bacteriophage t4, has been shown to neutralize phage particles formed within the cells. | 1984 | 6524168 |
| human t cell antigens involved in cytotoxicity against allogeneic or autologous chemically modified targets. association of the leu 2a/t8 antigen with effector-target cell binding and of the t3/leu 4 antigen with triggering. | monoclonal antibodies (mab) recognizing human t cell differentiation antigens were employed to analyze the role of these antigens on t cell-mediated cytotoxicity against autologous 2,4,6-trinitrophenyl (tnp)-modified targets. the okt3/anti-leu 4 and anti-leu 2a/okt8 mab inhibited t cell-mediated cytotoxicity against autologous or unrelated tnp-modified targets, in the absence of complement and at the effector cell level. these cytotoxic effector cells were t3+, t8+, t11+, t4-. to analyze the rol ... | 1984 | 6610558 |
| incorporation of 1,n6-ethenoadenosine into the 3' terminus of trna using t4 rna ligase. 2. preparation and ribosome interaction of fluorescent escherichia coli trnametf. | a fluorescent derivative of trnametf from escherichia coli has been prepared which contains 1,n6-etheno-adenosine (epsilon a) in the place of adenosine 73, the fourth residue from the 3' end. the labeled trna, trnametf epsilon a73, is fully active with respect to aminoacylation, formylation and formylmethionyl transfer to puromycin. the preparation procedure entails the chemical removal of four nucleotides from the 3' end of trnametf, ligation of the truncated molecule with epsilon a 3',5'-bisph ... | 1984 | 6363067 |
| effect of temperature on transition and transversion mutagenesis: characterization of wild type and a mutator t4 dna polymerase mutant. | the effect of temperature on genetically well-defined mutational pathways was examined in the bacteriophage t4. the mutational site was a t4 rii ochre mutant which could revert to rii+ via a transversion or to the amber convertant via a transition. temperature did not strongly affect any of the pathways examined in a wild-type background; however, increased temperature reduced the mutational activity of a mutator dna polymerase mutant. possible models to explain the role of temperature in mutage ... | 1984 | 6375839 |
| heterogeneity of mammalian dna ligase detected on activity and dna sequencing gels. | a new method to detect dna ligase activity in situ after nadodso4 polyacrylamide gel electrophoresis has been developed. after renaturation of active polypeptides the ligase reaction occurs in situ by incubating the intact gel in the presence of mg++ and atp. further treatment with alkaline phosphatase removes the unligated 5'-32p-end of oligo (dt) used as a substrate and active polypeptides having ligase activity are identified by autoradiography. analysis on dna sequencing gels of the oligo (d ... | 1984 | 6377238 |
| selective affinity chromatography of dna polymerases with associated 3' to 5' exonuclease activities. | the use of 5'-amp as a ligand for the affinity chromatography of dna polymerases with intrinsic 3' to 5' exonuclease activities was investigated. the basis for this is that 5'-amp would be expected to act as a ligand for the associated 3' to 5' exonuclease. the requirements for binding of escherichia coli dna polymerase i, t4 dna polymerase, and calf thymus dna polymerase delta, all of which have associated 3' to 5' exonuclease activities, to several commercially available 5'-amp supports with d ... | 1984 | 6377960 |
| cleavage of trna precursors by the rna subunit of e. coli ribonuclease p (m1 rna) is influenced by 3'-proximal cca in the substrates. | trna precursor molecules that contain the cca sequence found at the 3' termini of all mature trnas are cleaved in vitro more readily by m1 rna, the catalytic subunit of e. coli rnaase p, than precursors that lack this sequence. the sensitivity to the cca sequence is not apparent when precursors are cleaved by the reconstituted rnaase p holoenzyme that contains both m1 rna and the protein subunit. these results have been obtained with monomeric precursor molecules encoded by the e. coli and human ... | 1984 | 6380759 |
| defining a bacteriophage t4 late promoter: bacteriophage t4 gene 55 protein suffices for directing late promoter recognition. | the rna polymerase from bacteriophage t4-infected escherichia coli, which specifically initiates transcription at phage t4 late promoters, is extensively modified by adp-ribosylation of core subunits and by binding several virus-encoded subunits. we show here that one of these subunits, the phage t4 gene 55 protein, designated gp55, alone endows unmodified rna polymerase core enzyme from uninfected e. coli with the ability to selectively initiate transcription at the phage t4 late promoters, wit ... | 1984 | 6382259 |
| pyrimidine dimer induction in e. coli dna by cerenkov emission associated with high energy x-irradiation. | the induction of pyrimidine dimers in e. coli dna by secondary ultraviolet light associated with 6 mvp x-rays in the dose range 20-90 gy has been demonstrated using t4 endonuclease v. under the experimental conditions used in these experiments the major component of this secondary u.v. light is cerenkov emission. | 1984 | 6094375 |
| identification, physical map location and sequence of the denv gene from bacteriophage t4. | the denv gene from bacteriophage t4, which codes for endonuclease v, a small dna repair enzyme, has been cloned and identified by an approach combining dna sequencing and genetics, independent of the phenotypic effect of the cloned gene. appropriate denv+ and denv- deletion mutants were mapped physically to define precisely a region encompassing the denv gene. this region was sequenced in order to identify a protein-coding sequence of the correct size for the denv gene (400-500 bp). finally, ide ... | 1984 | 6095188 |
| regulation of a new bacteriophage t4 gene, 69, that spans an origin of dna replication. | we have determined the dna sequence and transcription patterns in a 3-kb segment (between 15 and 18 kb on the standard phage t4 map) spanning an origin of dna replication. a new gene, 69, spans this origin. gene 69 codes for two overlapping proteins that share a common c-terminal segment. defective dna replication in an appropriate amber mutant shows that at least the larger of the two proteins is required for efficient t4 dna replication. the two proteins coded by gene 69 are expressed from dif ... | 1984 | 6098451 |
| rna splicing in prokaryotes: bacteriophage t4 leads the way. | 1985 | 2580641 | |
| release of respiratory control in escherichia coli after bacteriophage adsorption: process independent of dna injection. | adsorption of phages t4, t5, and bf23 to previously starved escherichia coli cells triggered the immediate release of respiratory control. a similar stimulation of respiration was induced after t4 ghost attachment, showing that this process was independent of the mechanism of dna injection. rather, this change in the respiratory rate was related to the transient depolarization of the cytoplasmic membrane also induced after phage and ghost adsorption. both processes were suppressed by addition of ... | 1985 | 2981800 |
| the dna restriction endonuclease of escherichia coli b. ii. further studies of the structure of dna intermediates and products. | the dna intermediates and final products formed by the type i restriction endonuclease, ecob, were further characterized. dna cleaved on only one strand (hemi-restricted dna) contains gaps of approximately 70-100 nucleotides, while the fully restricted products contain 3'-single-stranded tails averaging approximately 70-100 nucleotides for each strand cleaved. the gaps and tails are formed with the release of an equal number of nucleotides as small oligonucleotides that are soluble in acid. afte ... | 1985 | 2985610 |
| molecular cloning and physical mapping of the genome of fish lymphocystis disease virus. | a defined and complete gene library of the fish lymphocystis disease virus (fldv) genome was established. fldv dna was cleaved with ecori, bamhi, ecori/bamhi and ecori/hindiii and the resulting fragments were inserted into the corresponding sites of the pacyc184 or pat153 plasmid vectors using t4 dna ligase. since fldv dna is highly methylated at cpg sequences (darai et al., 1983; wagner et al., 1985), an escherichia coli gc-3 strain was required to amplify the recombinant plasmids harboring the ... | 1985 | 2996221 |
| t4-induced alpha- and beta-glucosyltransferase: cloning of the genes and a comparison of their products based on sequencing data. | bacteriophage t4 alpha- and beta-glucosyltransferases link glucosyl units to the 5-hmdc residues of its dna. the monoglucosyl group in alpha-linkage predominates over the one in beta linkage. having recently reported on the nucleotide sequence of gene alpha gt (1) we now determined the nucleotide sequence of gene beta gt. the genes were each cloned on a high expression vector under the control of the lambda pl promoter. after thermo-induction the proteins were isolated and purified to homogeneit ... | 1985 | 2999696 |
| isolation of altered reca polypeptides and interaction with atp and dna. | in this paper we describe the partial proteolytic digestion of reca proteins from escherichia coli and proteus mirabilis and the production and isolation of truncated reca polypeptides. a proteolytic fragment of the p. mirabilis reca protein bound single-strand dna and atp normally but has altered duplex dna binding properties. this protein was shown to initiate but not complete dna strand transfer from a dna duplex to a complementary single strand. the product of the e. coli reca1 allele bound ... | 1985 | 3881430 |
| nuclear magnetic resonance observation and dynamics of specific amide protons in t4 lysozyme. | we have produced t4 lysozyme using a bacterial expression system which allows efficient incorporation of isotopically labeled amino acids in lysozyme. by using conditions that repress the expression of various transaminases, we have incorporated 15n-labeled amino acid into the five phenylalanine residues of the protein. the relatively large spin--spin coupling (87 +/- 3 hz) between the 15n nucleus and the phenylalanine amide protons may then be exploited in a variety of ways to selectively obser ... | 1985 | 3888265 |
| a defective phage system reveals bacteriophage t4 replication origins that coincide with recombination hot spots. | plasmid transduction mediated by bacteriophage t4 has been used to study putative t4 dna replication origins cloned as inserts in the escherichia coli plasmid pbr322. two particular inserts from the t4 genome allow high-frequency plasmid transduction, suggesting that each insert might contain a t4 replication origin. t4 infection of these plasmid-containing cells produces large numbers of defective phage particles that contain long linear concatamers of the plasmid dna. during a second cycle of ... | 1985 | 3889905 |
| plasmid-dependent inhibition of growth of bacteriophage t4 ndd mutants. | mutants of bacteriophage t4 that fail to induce nuclear disruption (ndd mutants) are unable to grow in the wild-type escherichia coli strain ct447. this inhibition of the growth of ndd mutants occurs only in the presence of a large (ca. 80-megadalton) plasmid resident in ct447 cells. | 1985 | 3897193 |
| nucleotide sequences of two serine trnas with a gga anticodon: the structure-function relationships in the serine family of e. coli trnas. | we have determined the nucleotide sequence of the major species of e. coli trnaser and of a minor species having the same gga anticodon. these two trnas should recognize the ucc and ucu codons, the most widely used codons for serine in the highly expressed genes of e. coli. the two sequences differ in only one position of the d-loop. neither trna has a modified adenosine in the position 3'-adjacent to the anticodon. this can be rationalized on the basis of a structural constraint in the anticodo ... | 1985 | 3898020 |
| oligodeoxynucleotides covalently linked to intercalating agents: a new class of gene regulatory substances. | oligodeoxynucleotides have been covalently linked to a 9-aminoacridine derivative via their 3'-phosphate group. specific complexes are formed with the complementary sequence of the oligonucleotide. the stability is strongly increased due to intercalation of the acridine derivative. absorption, fluorescence, nuclear magnetic resonance and circular dichroism have been used to characterize complex formation. the stability of the complexes depends on the length of the linker between the acridine der ... | 1985 | 3910111 |
| purification of bacteriophage t7 dna-membrane complex and its application to the in vitro recombination reaction. | in order to construct an in vitro recombination system of t7 dna, the reaction products of which resemble those in vivo in structure, t7 dna-membrane complex which is free from concomitant dnase activity was purified from t7 phage-infected cells. t7-infected cells were lysed with t4 lysozyme/brij58, and t7 dna-membrane complex was purified through three successive density gradient centrifugations. the properties of the complex on exposure to defined nucleases and observation of the complex by el ... | 1985 | 3912387 |
| [hybrid plasmid with bacterial and fungal markers carrying the denv gene of t4 phage and restoring the uv-resistance of e. coli uvra]. | the hybrid plasmid pybp2 with bacterial (ampr), yeast (leu2) and bacteriophage t4 (denv) genes has been constructed. the plasmid transformed escherichia coli csr603 uvra reca amps leua phr- to ampicillin resistance, leucine independence, uv-resistance similar to the one of uvra+ reca strain. cell-free extracts of transformed escherichia coli cells contain low level of ultraviolet-endonuclease activity in contrast to nontransformed cells containing no enzyme. | 1985 | 3916217 |
| nucleotide sequence of the thymidylate synthetase gene (thyp3) from the bacillus subtilis phage phi 3t. | the thyp3 gene, encoding thymidylate synthetase, from the bacillus subtilis phage phi 3t has been cloned and the nucleotide sequence determined. the derived amino acid sequence indicates a subunit mr of 32 748. the primary amino acid sequence is compared with the sequences of the analogous proteins specified by escherichia coli (thya), lactobacillus casei, (thya) and phage t4 (td). extensive conservation exists in all four sequences implying a shared tertiary structure. | 1985 | 3924741 |
| influence of template primary and secondary structure on the rate and fidelity of dna synthesis. | high resolution gel electrophoresis was used to monitor the successive addition of dnmp residues onto the 3'-oh ends of discrete 5'-32p-primers, during dna synthesis on natural templates. resulting autoradiographic banding patterns revealed considerable variation in the relative rates of incorporation at different positions along the template. the pattern of "pause sites" along the template was unique for each of three different dna polymerases (polymerase i (the "large fragment" form of escheri ... | 1985 | 3972819 |
| new control elements of bacteriophage t4 pre-replicative transcription. | bacteriophage t4 pre-replicative genes are transcribed, by escherichia coli rna polymerase, in two alternative modes: an early mode and a middle mode. middle mode transcription is under the control of at least one viral protein, pmota. we have identified two additional viral genes, motb and motc, that map in the dispensable region of the t4 genome, between genes 39 and 56. pmotb and pmotc are diffusible factors which provide an alternative to the mota dependent mode of middle transcription of ma ... | 1985 | 3999145 |
| half-site editing: an in vitro mutagenesis procedure for truncating a dna fragment and introducing a new restriction site. | half-site editing is an in vitro mutagenesis procedure designed for use in making precise plasmid constructions. like many in vitro mutagenesis techniques, this procedure involves hybridization of a mutagenic oligonucleotide primer to single-stranded template dna followed by polymerization with dna polymerase i (klenow). half-site editing differs from other techniques in two main ways. first, t4 dna polymerase treatment truncates the target dna at a point determined by the primer and repairs any ... | 1986 | 3006543 |
| microinjection of escherichia coli uvra, b, c and d proteins into fibroblasts of xeroderma pigmentosum complementation groups a and c does not result in restoration of uv-induced unscheduled dna synthesis. | the uv-induced unscheduled dna synthesis (uds) in cultured human fibroblasts of repair-deficient xeroderma pigmentosum complementation groups a and c was assayed after injection of identical activities of either uvr excinuclease (uvra, b, c and d) from escherichia coli or endonuclease v from phage t4. under conditions where the t4 enzyme was able to induce repair synthesis in both xp complementation groups in agreement with earlier observations (de jonge et al., 1985), no effect of the uvrabcd e ... | 1986 | 3014326 |
| a specific model for the conformation of single-stranded polynucleotides in complex with the helix-destabilizing protein gp32 of bacteriophage t4. | 1986 | 3017469 | |
| a plasmid expression vector that permits stabilization of both mrnas and proteins encoded by the cloned genes. | two new expression vectors have been constructed to take advantage of several useful properties of bacteriophage t4-infected escherichia coli. these plasmids, prdb8 and prdb9, contain the promoter region and start codon of t4 gene 32, a contiguous multiple cloning site (mcs), and translation and transcription termination signals. dna fragments inserted into the mcs are transcribed and translated at a high level in both uninfected and phage t4-infected cells. furthermore, the extreme stability of ... | 1986 | 3026907 |
| expression of the denv gene of coliphage t4 in uv-sensitive rad mutants of saccharomyces cerevisiae. | a plasmid containing the denv gene from bacteriophage t4, under the control of the yeast alcohol dehydrogenase i (adc1) promoter, conferred a substantial increase in uv resistance in the uv-sensitive saccharomyces cerevisiae mutants rad1-2 and rad3-2. the uv resistance of the denv+ yeast cells was cell cycle dependent and correlated well with the level of the denv gene product as measured by immunoblotting and by a photoreversal assay for pyrimidine dimer-dna glycosylase activity. | 1986 | 3540595 |
| thymine glycol lesions terminate chain elongation by dna polymerase i in vitro. | single-strand circular dna from bacteriophage m13mp9 was chemically modified with osmium tetroxide to introduce specifically cis-thymine glycol lesions, a major type of dna damage produced by ionizing radiation. an oligonucleotide primer was extended on damaged and undamaged templates using either the large fragment of e. coli pol i or t4 dna polymerase. the reaction products were analysed by electrophoresis alongside a dna sequence ladder. synthesis on the damaged templates terminated at positi ... | 1986 | 3511447 |
| the relative cytotoxicity and mutagenicity of cyclobutane pyrimidine dimers and (6-4) photoproducts in escherichia coli cells. | in order to calculate the relative cytotoxicity and mutagenicity of (5-6) cyclobutane pyrimidine dimers and (6-4) photoproducts, we have measured survival and mutation induction in uv-irradiated excision-deficient e. coli uvra cells, with or without complete photoreactivation of the (5-6) dimers. radioimmunoassays with specificity for (5-6) dimers or (6-4) photoproducts have shown that maximum photoreactivation eliminates all of the (5-6) dimers produced up to 10 jm-2 254-nm light, while it has ... | 1986 | 3517633 |
| persistence of dna synthesis arrest sites in the presence of t4 dna polymerase and t4 gene 32, 44, 45 and 62 dna polymerase accessory proteins. | dna synthesis by phage t4 dna polymerase is arrested at specific sequences in single-stranded dna templates. to determine whether or not t4 dna polymerase accessory proteins 32, 44, 45 and 62 eliminated recognition of these arrest sites, unique primer-templates were constructed in which dna synthesis began at a dna primer located at different distances from palindromic and nonpalindromic arrest sites. nucleotide positions that caused polymerase to pause or leave the template were identified by s ... | 1986 | 3517810 |
| the dna scanning mechanism of t4 endonuclease v. effect of nacl concentration on processive nicking activity. | t4 endonuclease v is a pyrimidine dimer-specific endonuclease which generates incisions in dna at the sites of pyrimidine dimers by a processive reaction mechanism. a model is presented in which the degree of processivity is directly related to the efficacy of the one-dimensional diffusion of endonuclease v on dna by which the enzyme locates pyrimidine dimers. the modulation of the processive nicking activity of t4 endonuclease v on superhelical covalently closed circular dna (form i) which cont ... | 1986 | 3525529 |
| effects of exposure of dna to methyl mercury on its activity as a template-primer for dna polymerases. | a previous publication [frenkel, cain, and chao, biochem. biophys. res. commun. 127, 849-856 (1985)] described the observation that double-stranded dna which was briefly exposed to methyl mercury (mehg) and purified to remove free methyl mercury was transcribed at a higher rate by rna polymerase ii from wheat germ. the specificity of this phenomenon has now been investigated by examining the activity of this mehg-exposed dna as a template-primer for dna polymerases. dna synthesis by the bacterio ... | 1986 | 3525750 |
| expression of the bacteriophage t4 denv structural gene in escherichia coli. | the expression of the t4 denv gene, which previously had been cloned in plasmid constructs downstream of the bacteriophage lambda hybrid promoter-operator olpr, was analyzed under a variety of growth parameters. expression of the denv gene product, endonuclease v, was confirmed in dna repair-deficient escherichia coli (uvra reca) by western blot analyses and by enhancements of resistance to uv irradiation. | 1986 | 3536845 |
| purification and characterization of the t4 bacteriophage uvsx protein. | gene uvsx of bacteriophage t4 encodes a 40,000-dalton protein that plays a key role in the major pathway for genetic recombination in t4-infected cells. mutations at the uvsx locus lead to increased sensitivity to various dna-damaging agents, reduced phage bursts, decreased genetic recombination, and early arrest of dna synthesis. like the escherichia coli reca protein, the purified uvsx protein is a dna-dependent atpase that catalyzes pairing between homologous single- and double-stranded dna m ... | 1986 | 2939071 |
| selective inhibition of escherichia coli recbc activities by plasmid-encoded gams function of phage lambda. | the gam locus of bacteriophage lambda encompasses two coding sequences with the same reading frame and translational stop, one corresponding to an mr 11646 polypeptide (gams gene), the other to an mr 16349 polypeptide (gaml gene). a dna segment encoding gams but not gaml was placed under lambda pr promoter control (regulated by the cits857-coded repressor) on a multicopy plasmid, and an insertion mutation (gams201) was constructed. expression of gams+, but not gams201, inhibited escherichia coli ... | 1986 | 2943636 |
| [transmission of amber mutants of bacteriophage t4. iii. thermostability of the replication of amber mutants in cells of a non-permissive host is typical for the majority of phage tail genes]. | the article deals with determination of the spreading of the earlier discovered phenomenon of the temperature sensitivity of multiplication of t4 phage amber mutants. on the basis of the study of the dependence of multiplication of 50 amber mutants in 22 genes of t4 phage tail in the cells of non-permissive host on the incubation temperature in the range of 15-41 degrees c, the following conclusion is drawn: temperature sensitivity of multiplication of amber mutants appears to be gene-specific a ... | 1987 | 2953651 |
| receptor-recognizing proteins of t-even type bacteriophages. constant and hypervariable regions and an unusual case of evolution. | proteins 38 of bacteriophages t2, k3, ox2 and m1 are located at the free ends of their long tail fibers and function as adhesins, i.e. they mediate binding to the bacterial receptors. the latter three phages use the escherichia coli outer membrane protein ompa as a receptor, while t2 uses the outer membrane proteins ompf or ttr. the dna sequences of genes 38 of phages ox2 and m1 have been determined and are compared with those known for t2 and k3. the genes encode 262(t2), 260(k3), 266(ox2) and ... | 1987 | 2958637 |
| 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 |
| synthesis and reactivity of intermediates formed in the t4 rna ligase reaction. | the intermediate adenylated donor derivatives a(5')pp(5')dtp and a(5')pp(5')gpgpgp have been prepared from suitable phosphorylating reagents activated by 1-hydroxybenzotriazole. phosphodiester bond formation between donor and acceptor oligonucleotides as catalyzed by t4 rna ligase is shown to be more efficient when the adenylated form of the donor molecule is used. | 1987 | 3299268 |
| temperature sensitivity of the multiplication of bacteriophage t4 amber mutants on nonpermissive host: characterization of the phenomenon. | the existence of temperature sensitivity of the multiplication of amber mutants on a nonpermissive host has been established for a considerable number of mutants in tail and head genes and for mutants in some other t4 genes as well. temperature sensitivity of multiplication appears to be gene specific, and is typical of amber mutants in genes the products of which are not numerous per phage or which play the role of catalytic factor. moreover, in most cases temperature sensitivity is characteris ... | 1987 | 3310383 |
| genetic recombination between closely linked makers of bacteriophage t4. iv. mutations which interfere with mismatch repair. | t4 phage mutations mco1 and mco3 reduced recombination between multiple closely linked markers preferentially and were located between gene 24 and gene 25. the mco1 and the mco3 mutants complemented each other. the results of uv-cross reactivation experiments indicated that the mco1 and the mco3 mutants could rescue the markets of uv-damaged phage, but could not segregate them from flanking mutations. therefore, it is concluded that mco1 mutation and mco3 mutation interfere with mismatch repair. | 1987 | 3312727 |
| the essential role of recombination in phage t4 growth. | 1987 | 3327469 | |
| genetic delineation of functional components of the group i intron in the phage t4 td gene. | 1987 | 3331339 | |
| prohead core of bacteriophage t4 can act as an intermediate in the t4 head assembly pathway. | bacteriophage t4 assembly was impaired in escherichia coli hdb3-1 at an incubation temperature below 30 degrees c. naked prohead cores (head scaffold) bound to the inner surface of the plasma membrane accumulated, and the major shell protein (gp23) precipitated into visible intracellular aggregates in the cytoplasm. shifting the temperature to 42 degrees c allowed newly synthesized gp23 to assemble around the accumulated cores. we conclude that synchronous assembly of the scaffold and shell is n ... | 1987 | 3537341 |
| purification of the t4 endonuclease v. | a new purification protocol has been developed for the rapid isolation to physical homogeneity of t4 endonuclease v. the enzyme was purified from an escherichia coli strain which harbors a plasmid containing the t4 denv structural gene downstream of the lambda rightward promoter. the purification of the enzyme was monitored by pyrimidine dimer-specific nicking activity, western blot analysis and silver or coomassie blue staining of sds-polyacrylamide gels. milligram quantities of the enzyme have ... | 1987 | 3547104 |
| a new epistasis group for the repair of dna damage in bacteriophage t4: replication repair. | the gene 32 mutation ama453 sensitizes bacteriophage t4 to the lethal effects of ultraviolet (uv) irradiation, methyl methanesulfonate and angelicin-mediated photodynamic irradiation when treated particles are plated on amber-suppressing host cells. the increased uv sensitivity caused by ama453 is additive to that caused by mutations in both the t4 excision repair (denv) and recombination repair (uvswxy) systems, suggesting the operation of a third kind of repair system. the mutation uvs79, with ... | 1987 | 3552872 |
| cloning and purification of a unique lysozyme produced by bacillus phage phi 29. | a dna fragment of the bacteriophage phi 29 chromosome, encoding the entire sequence of phi 29 gene 15, has been cloned into the escherichia coli expression vector pplc245 under the control of the phage lambda major leftward promoter, pl. upon heat induction, a protein with an apparent molecular mass of 26 kda was overproduced. the molecular mass of this protein corresponds to the 28 kda predicted for the product of gene 15 from its nucleotide sequence. the overproduced protein has been purified ... | 1987 | 3469652 |
| [plasmid vectors of "insertion inactivation" of the trimethoprim resistance marker]. | we demonstrate the possibility of using the t4 phage frd gene as an insertion inactivation marker within pbr322, in plasmids with changing copy number and expression of foreign genes under control. the structural part of the frd genes contains unique recognition sites for ecori and sali endonucleases. transformants with recombinant plasmids carrying the frd gene grow on media with up to 500 mkg/ml trimethoprim, whatever the gene dosage. | 1987 | 3032740 |
| use of a phage vector for rapid synthesis and cloning of single-stranded cdna. | we have developed a technique for synthesis of single stranded complementary dna (ss cdna) using specifically designed phage ssdna as vector primer. this vector (ppbs27) was constructed by introducing a poly(dt) tail adjacent to the xbai site of ptz18r, which can exist either as a plasmid in escherichia coli or as a ssdna phage. the ppbs27 phage vector is linearized with xbai using a restriction-site-directed fragment and used to anneal a mixture of poly(a) + rna for cdna synthesis by reverse tr ... | 1987 | 3036656 |
| structural and functional relationships between prokaryotic and eukaryotic dna polymerases. | the bacillus subtilis phage luminal diameter 29 dna polymerase, involved in protein-primed viral dna replication, was inhibited by phosphonoacetic acid (paa), a known inhibitor of alpha-like dna polymerases, by decreasing the rate of elongation. three highly conserved regions of amino acid homology, found in several viral alpha-like dna polymerases and in the luminal diameter 29 dna polymerase, one of them proposed to be the paa binding site, were also found in the t4 dna polymerase. this prokar ... | 1987 | 3127204 |
| a family of autocatalytic group i introns in bacteriophage t4. | 1987 | 2841063 | |
| dna synthesis is blocked by cigarette tar-induced dna single-strand breaks. | dna single-strand breaks are caused by aqueous extracts of cigarette tar, due to the reduction of oxygen to superoxide by tar and the subsequent production of hydroxyl radicals. the action of dna metabolism enzymes on these single-strand breaks has been studied to probe the consequences of these lesions for dna repair. our results demonstrate that cigarette tar-induced nicks are blocked at the 3' terminus since they are totally incapable of activating dna for dna synthesis by escherichia coli dn ... | 1987 | 2820603 |
| sequence effect on alkali-sensitive sites in uv-irradiated sv40 dna. | ultraviolet light at 254 nm induces various kinds of dna damage. we have located and quantified the pyrimidine (6-4) pyrimidone photoproducts along three hundred and forty two nucleotides of sv40 dna. the level of photoproduct induction varies greatly according to the position on the dna, but unlike what happens with pyrimidine dimers, the very adjacent nucleotides do not play a major role in the frequency of formation. a new alkali-sensitive site has been found on the aca sequence after uv irra ... | 1987 | 2825122 |
| molecular cloning and characterization of the gene encoding cholinephosphate cytidylyltransferase in saccharomyces cerevisiae. | 1. the structural gene for cholinephosphate cytidylyltransferase (cct) was isolated from a saccharomyces cerevisiae genomic library by means of complementation in a mutant of the yeast defective in the enzyme. the cloned dna restored both the growth and cholinephosphate cytidylyltransferase activity of the mutant. whereas the enzyme of the mutant was thermolabile, the enzyme produced by the transformant was indistinguishable in heat stability from that produced by the wild type. 2. strains carry ... | 1987 | 2826147 |
| 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 |
| general method for quantifying base adducts in specific mammalian genes. | a general method has been developed to measure the formation and removal of dna adducts in defined sequences of mammalian genomes. adducted genomic dna is digested with an appropriate restriction enzyme, treated with escherichia coli uvrabc excision nuclease (abc excinuclease), subjected to alkaline gel electrophoresis, and probed for specific sequences by southern hybridization. the abc excinuclease incises dna containing bulky adducts and thus reduces the intensity of the full-length fragments ... | 1988 | 2836856 |
| enzyme binding-inhibiting assay for iodothyronine 5'-monodeiodinase (5'-md) and its application to isolation of complementary deoxyribonucleic acid clones for the 5'-md in rat liver. | to identify and/or quantify type i t4 5'-monodeiodinase (5'-md) immunologically, polyclonal antibodies were produced by immunization of rabbits with solubilized microsomal proteins (smp) from rat liver. pilot studies showed that the antibody binds to, but does not neutralize, rat liver enzyme. we have employed the polyclonal antibody to develop a 5'-md enzyme binding-inhibiting assay (mbia). for this purpose, active, inactive, or synthetic 5'-md was preincubated with rabbit antibody and removed ... | 1988 | 2841089 |
| the influence of a double-stranded hindrance on dna synthesis performed by dna polymerase alpha, t4 dna polymerase, dna polymerase i (klenow fragment) and amv reverse transcriptase. | the influence of a double-stranded region on dna synthesis performed by a series of dna polymerases on a single-stranded template was studied. two types of double-stranded hindrances were employed: a stable hairpin formed by the template alone and a region formed by the template and an extraneous oligonucleotide complementary to the template. while t4 and calf thymus alpha dna polymerases are strongly arrested at the beginning of either of the two double-stranded hindrances, the klenow fragment ... | 1988 | 2449362 |
| dependence of m1 rna substrate specificity on magnesium ion concentration. | we have constructed a plasmid expressing e. coli m1 rna, the catalytic rna subunit of ribonuclease p, under the control of a phage t7 promoter. the active m1 rna species synthesized in vitro by t7 rna polymerase from this vector was reacted with the trna(gln) - trna(leu) precursor rna (band k) encoded by phage t4. only the trna(leu) moiety of this dimeric precursor rna contains the 3' terminal c-c-a sequence common to all trnas. we observed that protein-free m1 rna was capable of processing the ... | 1988 | 2453026 |
| symmetric transcription of bacteriophage t4 base plate genes. | dot-blot and northern-blot experiments, using strand-specific rna probes, show that part of the bacteriophage t4 dna that codes for six of the base plate structural genes (gp 51, 27, 28, 29, 48 and 54), is transcribed in vivo from both dna strands. the r dna strand transcripts contain sequences which are translated into structural proteins. antisense l strand rna is about 100 fold less abundant than rna molecules transcribed from the r dna strand. | 1988 | 2468563 |
| site-directed mutagenesis of the t4 endonuclease v gene: role of lysine-130. | the dna sequence of the bacteriophage t4 denv gene which encodes the dna repair enzyme endonuclease v was previously constructed behind the hybrid lambda promoter olpr in a plasmid vector. the olpr-denv sequence was subcloned in m13mp18 and used as template to construct site-specific mutations in the denv structural gene in order to investigate structure/function relationships between the primary structure of the protein and its various dna binding and catalytic activities. the lys-130 residue o ... | 1988 | 3132202 |
| amp-dependent dna relaxation catalyzed by dna ligase occurs by a nicking-closing mechanism. | in the presence of amp and mg2+, a covalently closed duplex dna containing negative superhelical turns was treated with dna ligase isolated from bacteriophage t4-infected e. coli. this resulted in the gradual and not sudden loss of superhelical turns as for example in the case of type i dna topoisomerase. all dna products remain covalently closed. since t4 enzyme-mediated dna relaxation is inhibited by both pyrophosphate and by atp this suggests that dna relaxing and dna joining activities proba ... | 1988 | 3137526 |
| a possible effect of heme on the fate of dna ligase activity extracted from differentiating mouse erythroleukemia cells. | when mouse erythroleukemia (mel) cells were induced to differentiate by growth in the presence of dimethyl sulfoxide, hexamethylene bisacetamide (hmba), or hemin, the apparent activity of dna ligase extractable from inducer-treated cells decreased 70 to 80% when compared to untreated cells. earlier work had indicated that these changes did not occur in a differentiation-resistant mel cell variant and suggested that the decrease in the level of dna ligase activity might be related to the differen ... | 1988 | 3180046 |
| nucleotide and deduced amino acid sequence of stp: the bacteriophage t4 anticodon nuclease gene. | pre-existing host trnas are reprocessed during bacteriophage t4 infection of certain escherichia coli strains. in this pathway, trnalys is cleaved 5' to the wobble base by anticodon nuclease and is later restored in polynucleotide kinase and rna ligase reactions. anticodon nuclease depends on prr, a locus found only in host strains that restrict t4 mutants lacking polynucleotide kinase and rna ligase; and on stp, the t4 suppressor of prr restriction. stp was cloned and the nucleotide sequences o ... | 1988 | 3280805 |
| an in vitro assay for frameshift mutations: hotspots for deletions of 1 bp by klenow-fragment polymerase share a consensus dna sequence. | the fidelity of in vitro dna synthesis catalyzed by the large fragment of dna polymerase i was examined. the templates, specifically designed to detect shifts to the +1 or to the -1 reading frame, are composites of m13mp8 and bacteriophage t4 riib dna and were designed to assist in the identification of the types of frameshifts that are the specific consequence of dna polymerization errors. in vitro polymerization by the klenow fragment produced only deletions, rather than the mixture of duplica ... | 1988 | 3282984 |
| effect of ph on the base-mispairing properties of 5-bromouracil during dna synthesis. | we have utilized an electrophoretic assay of misincorporation to investigate the possibility that ionization of 5-bromouracil (bu) may play a role in its mispairing during dna synthesis in vitro. we examined the effects of increasing ph on the relative rates of formation of bu.g and t.g mispairs during chain elongation catalyzed by various dna polymerases. for the klenow fragment of escherichia coli dna polymerase i, increasing ph facilitated bu.g mispair formation (relative to t.g mispairing) w ... | 1988 | 3284589 |
| mutant 16s ribosomal rna: a codon-specific translational suppressor. | we have isolated an unusual codon-specific translational suppressor in escherichia coli. the suppressor resulted from a spontaneous mutation in a chromosomal gene during a selection for suppressors of the auxotrophic nonsense mutation trpa(uga211). the suppressor allows readthrough of uga mutations at two positions in trpa and at two sites in bacteriophage t4. it does not, however, suppress amber (uag) or ochre (uaa) mutations that were tested in both genomes, some of which were at the same posi ... | 1988 | 3288986 |
| yeast gene rad52 can substitute for phage t4 gene 46 or 47 in carrying out recombination and dna repair. | the rad52 gene of saccharomyces cerevisiae and genes 46 and 47 of bacteriophage t4 are essential for most recombination and recombinational repair in their respective organisms. the rad52 gene was introduced into expression vectors that were used to transform escherichia coli. the expression of rad52 was then induced, and the ability of rad52 to complement phage mutants defective in gene 46 or 47 was determined with respect to the three criteria of phage growth, recombination, and recombinationa ... | 1988 | 3045825 |
| in vitro and in vivo recombination-related reactions of escherichia coli reca protein and glucosyl-hydroxymethyl-deoxycytidine dna. | recombination of t4 phage is not controlled by the host reca gene but by an analogous phage gene, uvsx. we have tested the hypothesis that reca protein is inactive in t4-infected cells because it is unable to catalyze reactions involving single stranded dna containing glucosyl-hydroxylmethyl-deoxycytidine. we found, however, that with modified and unmodified deoxycytidine containing dnas, uvsx protein and reca protein catalyze in vitro reactions related to dna recombination, but in t4-infected c ... | 1988 | 3054489 |
| dna polymerase of bacteriophage t4 is an autogenous translational repressor. | in bacteriophage t4 the protein product of gene 43 (gp43) is a multifunctional dna polymerase that is essential for replication of the phage genome. the protein harbors dna-binding, deoxyribonucleotide-binding, dna-synthesizing (polymerase) and 3'-exonucleolytic (editing) activities as well as a capacity to interact with several other t4-induced replication enzymes. in addition, the t4 gp43 is a repressor of its own synthesis in vivo. we show here that this protein is an autogenous repressor of ... | 1988 | 3054876 |
| mischarging escherichia coli trnaphe with l-4'-[3-(trifluoromethyl)-3h-diazirin-3-yl]phenylalanine, a photoactivatable analogue of phenylalanine. | the boc-protected derivative of a photoactivatable, carbene-generating analogue of phenylalanine, l-4'-[3-(trifluoromethyl)-3h-diazirin-3-yl]phenylalanine [(tmd)phe], was used to acylate 5'-o-phosphorylcytidylyl(3'-5')adenosine (pcpa). a diacyl species was isolated which upon successive treatments with trifluoroacetic acid and 0.01 m hcl yielded a 1:1 mixture of 2'(3')-o-(tmd)phenylalanyl-pcpa and of its 2'-5'-phosphodiester isomeric form. adapting a procedure introduced by hecht's group [heckle ... | 1988 | 3061465 |
| bacteriophage t4 dna polymerase determines the amount and specificity of ultraviolet mutagenesis. | ultraviolet mutagenesis in bacteriophage t4 proceeds via error-prone repair (epr) and requires the functional integrity of the uvswxy system which mediates genetic recombination, recombinational repair, and mutability by diverse dna damaging agents. current opinion holds that mutagens acting through epr generate dna damage which blocks the progress of the replication complex and that epr consists of the facilitated bypass of such inaccurate, damaged templates. this notion predicts that the t4 dn ... | 1988 | 3063950 |
| late sigma factor of bacteriophage t4. formation and properties of rna polymerase-promoter complexes. | bacteriophage t4 late gene promoters do not display sequence homology in the -35 region (christensen, a. c., and young, e. t. (1982) nature 299, 369-371), suggesting an unusual geometry of rna polymerase-promoter interaction. we have analyzed in vitro utilization of a late t4 promoter by rna polymerase reconstituted from e. coli core enzyme (e) and bacteriophage t4 late sigma factor (sigma gp55). the e sigma gp55 holoenzyme forms a stable promoter complex which lacks protein-dna contacts upstrea ... | 1988 | 3335538 |
| induction of helper and suppressor t cells by nonoverlapping determinants on the large protein antigen, beta-galactosidase. | the fine specificity of the t cell repertoire directed against t helper (th)-inducing and t suppressor (ts)-inducing determinants was examined with cyanogen bromide and tryptic peptides of escherichia coli beta-galactosidase (gz), a large tetrameric protein (monomer molecular weight = 116 kda). immunization with cyanogen bromide fragment 2 [cb-2, amino acids (a.a.) 3-92] induced both specific th and ts cells. study of the induction of these functionally opposite t cell subpopulations with trypti ... | 1988 | 2963778 |
| the mechanism of homologous dna strand exchange catalyzed by the bacteriophage t4 uvsx and gene 32 proteins. | a strand exchange reaction between a single-stranded dna circle and a homologous linear double-stranded dna molecule is catalyzed by a mixture of two t4 bacteriophage proteins, the uvsx protein (a dna-dependent atpase that resembles the reca protein) and the gene 32 protein (a helix-destabilizing protein). the products are different from those formed in the corresponding reca protein-catalyzed reaction; rather than producing a linear single strand plus a nicked circular double-stranded (form ii) ... | 1988 | 2967823 |
| single amino acid changes that alter the dna sequence specificity of the dna-[n6-adenine] methyltransferase (dam) of bacteriophage t4. | bacteriophage t4 codes for a dna-[n6-adenine] methyltransferase (dam) which recognizes primarily the sequence gatc in both cytosine- and hydroxymethylcytosine-containing dna. hypermethylating mutants, damh, exhibit a relaxation in sequence specificity, that is, they are readily able to methylate non-canonical sites. we have determined that the damh mutation produces a single amino acid change (pro126 to ser126) in a region of homology (iii) shared by three dna-adenine methyltransferases; viz, t4 ... | 1989 | 2510127 |
| impaired expression of certain prereplicative bacteriophage t4 genes explains impaired t4 dna synthesis in escherichia coli rho (nusd) mutants. | the escherichia coli rho 026 mutation that alters the transcription termination protein rho prevents growth of wild-type bacteriophage t4. among the consequences of this mutation are delayed and reduced t4 dna replication. we show that these defects can be explained by defective synthesis of certain t4 replication-recombination proteins. expression of t4 gene 41 (dna helicase/primase) is drastically reduced, and expression of t4 genes 43 (dna polymerase), 30 (dna ligase), 46 (recombination nucle ... | 1989 | 2544560 |
| superhelical stress restrained in plasmid dna during repair synthesis initiated by the uvra, b and c proteins in vitro. | purified uvra, uvrb, uvrc, uvrd, pola and lig proteins from escherichia coli have been used to assess the effect of nucleotide excision repair on the conformation of native negatively supercoiled plasmid dna in an in vitro test system. the analysis of labeled reaction products on specific gel systems suggests that the uvr excinuclease has the ability to restrain the superhelical stress in the template dna during the repair process. this feature, observed in the case of the uvr system is not foun ... | 1989 | 2557590 |
| a simple and versatile method for the preparation of vector-primers by adapter-end-primer ligation. | a group of efficient cdna cloning strategies employs vector-primers where cdna synthesis starts from the oligo(dt)-primer tail, which is conventionally attached to cloning vectors by use of terminal deoxynucleotidyl transferase. an alternative, efficient and more versatile method of vector-primer preparation is to directly ligate, by use of t4 dna ligase, a double-digested vector, e.g., ptz18r/pst i/bam hi, to a synthetic (bam hi)-adapter-end-primer, 5'-pgatcc-tn or 5'-pgatcc-site-specific seque ... | 1989 | 2561065 |
| dna polymerase alpha activity is not affected by protein kinases or alkaline phosphatase. | recent studies with crude or partially purified cell extracts have suggested that dna polymerase alpha activity may be regulated by enzymatic phosphorylation. to further investigate these findings, we have examined the effects of protein kinases and phosphatases on highly purified dna polymerase alpha from mouse cells. incubation of dna polymerase alpha with a variety of protein kinases, including protein kinase c, had no effect on polymerase activity. in addition, treatment of the polymerase wi ... | 1989 | 2930569 |
| preparation of 2-azidoadenosine 3',5'-[5'-32p]bisphosphate for incorporation into transfer rna. photoaffinity labeling of escherichia coli ribosomes. | 2-azidoadenosine was synthesized from 2-chloroadenosine by sequential reaction with hydrazine and nitrous acid and then bisphosphorylated with pyrophosphoryl chloride to form 2-azidoadenosine 3',5'-bisphosphate. the bisphosphate was labeled in the 5'-position using the exchange reaction catalyzed by t4 polynucleotide kinase in the presence of [gamma-32p]atp. polynucleotide kinase from a t4 mutant which lacks 3'-phosphatase activity (atp:5'-dephosphopolynucleotide 5'-phosphotransferase, ec 2.7.1. ... | 1989 | 2647526 |
| [effect of he-ne laser radiation on the bacteriophage t4-escherichia coli system]. | exposure of t4 bacteriophage, having no red light chromophores, to he-ne laser (lambda = 632.8 nm) of 10(3)-6 x 10(4) j/m2 does not influence its lytic properties. irradiation of e. coli wp2 bacteria with doses of 4-6 x 10(3) j/m2 causes a 1.25-1.35-fold increase in their ability to keep on the development of nonirradiated bacteriophage t4. | 1989 | 2654997 |
| nucleotide sequences of bacteriophage t4 genes 13, 14 and 15. | 1989 | 2657662 |