role of polymeric forms of the bacteriophage phi x174 coded gene a protein in phi xrfi dna cleavage.gene a of the phi x174 genome codes for two proteins, a and a* (linney, e.a., and hayashi, m.n. (1973) nature new biol. 245, 6-8) of molecular weights 60,000 and 35,000, respectively. the phi x a* protein is formed from a natural internal initiator site within the a gene cistron while the phi x a protein is the product of the entire a gene. these two proteins have been purified to homogeneity as judged by sodium dodecyl sulfate polyacrylamide gel electrophoresis. previous studies have shown that ...1979158588
isolation and identification of bacteriophage phi x174 prohead.the morphogenesis of bacteriophage phi x174 has been investigated by using an in vitro dna synthesizing system. an extract of a b-mutant-infected cell is capable of synthesizing infectious phage in vitro when the b gene function is provided by the addition of an ammonium sulfate fraction of a c-mutant-infected-cell extract. this fraction contains the omega complex, a complex of phage-coded proteins with s = 108; the b-mutant extract does not. the purified omega complex, isolated from the c-mutan ...1979159449
construction and characterization of an escherichia coli plasmid bearing a functional gene g of bacteriophage order to study the mutagenic effects of site-specific, covalent modifications of biologically active dna, we need host cells that are permissive for any type of mutation that might be produced in vivo from the modified dna. specifically, we require a general, in vivo complementation system for the bacteriophage phix174 gene g, an essential gene that we have chosen for our initial studies of chemical mutagenesis. toward this end, we have constructed a plasmid (pphixg) that carries a functional ...1978273240
bacteriophage phix174 growth in an escherichia coli dnaits mutant, ks810.a bacteriophage phix174-sensitive escherichia coli dnaits mutant, ks810, was constructed and growth of phix174 in the cells was investigated. phix174 and phix174am3trd could grow normally at 43 degrees c as well as 27 degrees c, therefore we conclude that the growth of bacteriophage phix174 is not dependent upon the host dnai gene product.1978341986
heterologous transfection with bacteriophage phix174 dna: and improved system.a highly efficient and much more reproducible system for the heterologous transfection of several kinds of gram-negative bacterial spheroplasts with bacteriophage phix174 dna was established. by mild washing of the speroplasts, the efficiency of transfection of all non-host heterologous bacterial species tested increased one or more orders of magnitude in producing the progeny phages and/or the infectious intermediates. using the improved heterologous transfection systems, it has become clearer ...1978418813
recombination of bacteriophage phi x174 by the red function of bacteriophage lambda.recombination of bacteriophage phi x174 was effectively promoted when the red function of lambda was supplied by either co-infection with lambda or induction of lambda lysogens. mutations in red alpha and red beta genes of lambda abolished recombination nearly completely, whereas a mutation in gam gene reduced it only slightly. the red-promoted recombination of phi x174 occurred in reca, recb, and pola mutants as well as in wild-type strains of escherichia coli. it was further stimulated when ph ...1979430603
transcription by escherichia coli rna polymerase of a single-stranded fragment by bacteriophage phix174 dna 48 residues in length. 1975806693
the lipopolysaccharide receptor for bacteriophage phix174 and s13. 19751094681
proteolysis of bacteriophage phi x174 prohead accessory protein gpb by escherichia coli ompt protease is not essential for phage maturation in examine whether cleavage of the phi x174 prohead accessory protein, gpb, by the ompt protease is required for phage development in vivo, a phage mutant lacking the ompt cleavage site and an escherichia coli c delta ompt strain were constructed. the results of burst size experiments suggest that neither the cleavage site nor the ompt protein is required for phi x174 development.19921532389
dynamics of phix174 protein e-mediated lysis of escherichia coli.expression of cloned gene e of bacteriophage phix174 induces lysis by formation of a transmembrane tunnel structure in the cell envelope of escherichia coli. ultrastructural studies of the location of the lysis tunnel indicate that it is preferentially located at the septum or at polar regions of the cell. furthermore, the diameter and shape of individual tunnel structures vary greatly indicating that its structure is not rigid. apparently, the contours of individual lysis tunnels are determined ...19921534215
structural differences between the two human complement c4 isotypes affect the humoral immune animal model has been used to address the question of the biological importance of the known structural difference between the two isotypes of human c4, i.e., c4a and c4b. guinea pigs deficient in c4 were reconstituted transiently with either human c4a or c4b protein and immunized with the bacteriophage phi x174. results from this study showed that c4a-reconstituted animals made a secondary response, i.e., switch from igm to igg; whereas the c4b-reconstituted animals did not.19921732415
the role of n3-ethyldeoxythymidine in mutagenesis and cytotoxicity by ethylating agents.the significance of dna ethylation at the central hydrogen-bonding site (n3) of thymine was investigated using an in vitro dna replication system. the system utilized a primed template in which the 3'-end of the primer is eight nucleotides away from n3-ethyldeoxythymidine (n3-et-dt), present at template position 26 from the 3'-end. the 34-nucleotide template corresponds to a specific dna sequence at gene g of bacteriophage phi x174. dna synthesis products were quantitated by electrophoretic sepa ...19911985945
functional division and reconstruction of a plasmid replication origin: molecular dissection of the oriv of the broad-host-range plasmid rsf1010.two single-stranded dna initiation signals (designated ssi) present in the origin of vegetative dna replication (oriv) of the broad-host-range plasmid rsf1010 are essential for the priming of replication of each complementary dna strand of this plasmid in escherichia coli. each of the rsf1010 ssi signals, ssia and ssib, could be replaced by a primosome assembly site from plasmid pacy184 or from bacteriophage phi x174. in these chimeric origins, replication of the strand complementary to that con ...19911986363
translational efficiency of phi x174 lysis gene e is unaffected by upstream translation of the overlapping gene d reading frame.the lysis gene e of bacteriophage phi x174 is entirely embedded in gene d. expression studies of genes d and e in escherichia coli minicells and lysis times obtained in the presence or absence of d translation showed that the simultaneous expression of gene d does not affect protein e production. thus, unlike other overlapping gene pairs, gene e expression is independent from the upstream translation of gene d. lacz fusion studies and primer extension inhibition analysis (toeprinting) revealed a ...19902145264
molecular cloning and dna sequence analysis of escherichia coli pria, the gene encoding the primosomal protein replication factor y.escherichia coli replication factor y (protein n') functions in the assembly of a mobile multiprotein replication-priming complex called the primosome. although the role of factor y in primosome assembly during replication in vitro of bacteriophage phi x174 and plasmid pbr322 dna is clear, its role in e. coli chromosomal replication is not. to address this issue, the gene for factor y has been cloned molecularly and its dna sequence has been determined. the cloned fragment of dna contained an op ...19902162049
biochemical characterization of phi x174-protein-e-mediated lysis of escherichia coli.energetic and permeability properties of escherichia coli cells were determined prior to and during lysis caused by expression of the cloned gene e of bacteriophage phi x174. before onset of cell lysis the transmembrane gradients for k+, na+ or mg2+/ions, the level of atp and the membrane potential, were unaffected. all these parameters changed simultaneously at the time of lysis onset, as monitored by measurements of culture turbidity as well as by determining the various specifications over a ...19892522390
the effect of multivalent ions on the inactivation of bacteriophage phi x174 by lipopolysaccharide from escherichia coli c.the inactivation of bacteriophage phi x174 by lipopolysaccharide from escherichia coli c is promoted by multivalent metal ions and by polyamines. the effect of the two types of cation is similar, and the concentration causing 50% inactivation varies inversely with the charge on the cation, although quadrivalent amines are less active than expected. the increase in activity as the charge rises suggests that electrostatic binding is overwhelmingly important.19852934058
irreversible binding of phage phi x174 to cell-bound lipopolysaccharide receptors and release of virus-receptor 37 degrees c, binding of phi x174 to the lipopolysaccharide receptors in the outer membrane of escherichia coli c is followed by an irreversible ejection of its dna. dna ejection marks the beginning of the eclipse period in the infection cycle. binding data with a phi x mutant fcs70 at 15 degrees c, where the dna ejection, or eclipse, rate is essentially zero, do not follow the law of mass action. this rules out a simple mechanism of reversible binding followed by irreversible dna ejection. a ...19852935183
effect of ssb protein on cleavage of single-stranded dna by phi x gene a protein and a* protein.gene a protein of bacteriophage phi x174 plays a role as a site-specific endonuclease in the initiation and termination of phi x rolling circle dna replication. to clarify the sequence requirements of this protein we have studied the cleavage of single-stranded restriction fragments from phi x and g4 viral dnas using purified gene a protein. the results show that in both viral dnas cleavage occurs at the origin and at one additional site which shows striking sequence homology with the origin reg ...19862937018
replication of uv-irradiated single-stranded dna by dna polymerase iii holoenzyme of escherichia coli: evidence for bypass of pyrimidine photodimers.replication of uv-irradiated circular single-stranded phage m13 dna by escherichia coli rna polymerase (ec and dna polymerase iii holoenzyme (ec in the presence of single-stranded dna binding protein yielded full-length as well as partially replicated products. a similar result was obtained with phage g4 dna primed with e. coli dna primase, and phage phi x174 dna primed with a synthetic oligonucleotide. the fraction of full-length dna was several orders of magnitude higher than ...19862941756
mechanism of replication of bacteriophage phi x174. xxii. site-specific mutagenesis of the a* gene reveals that a* protein is not essential for phi x174 dna replication.the a and a* proteins of phage phi x174 are encoded in the same reading frame in the viral genome; the smaller a protein is the result of a translational start signal with the a gene. to differentiate their respective functions, oligonucleotide-directed site-specific mutagenesis was used to change the atg start codon of the phi x 174 a* gene, previously cloned into pcqv2 under lambda repressor control, into a tag stop codon. the altered a gene was then inserted back into phi x replicative form d ...19872960819
proteolysis of bacteriophage phi x174 prohead protein gpb by a protease located in the escherichia coli outer membrane.the gene b protein (gpb) of bacteriophage phi x174 is required for prohead assembly and is removed from prohead during phage maturation. protease activity was observed in isolated prohead which specifically cleaved gpb. cleavage of gpb produced two fragments that had apparent molecular weights of 12,300 and 3,700 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. amino-terminal sequencing of the fragments confirmed that they resulted from the cleavage of gpb and identified the cleavag ...19882973457
deletion of c-terminal amino acid codons of phix174 gene e: effect on its lysis inducing properties.the lysis gene e of bacteriophage phix174 has been subjected to deletion and fusion analysis. deletions of 11 to 90% of gene e specific nucleotides coding for to c-terminal region of the gene product were cloned under transcriptional control of lambda pl. for this purpose plasmid psu1 was constructed which carries an extended polylinker region downstream of pl. depending on the number of nucleotides after the last gene e specific codon, various c-terminal segments of protein e were replaced by 4 ...19852989789
expression of the cloned bacteriophage phi x174 a* gene in escherichia coli inhibits dna replication and cell division.the a* gene of bacteriophage phi x174 has been cloned into the inducible expression vector pcqv2 under conditions allowing its lethal action to be controlled by the lambda ci857 repressor. upon induction of expression, dna synthesis in escherichia coli carrying the recombinant plasmid is severely inhibited; however, these same cells permit beta-galactosidase induction at a rate similar to that observed in control cells at the inducing (for a*) temperature. cells in which a* is expressed form fil ...19853156255
mutagenic potential of o4-methylthymine in vivo determined by an enzymatic approach to site-specific mutagenesis.o4-alkylthymine-dna adducts have been implicated as causative lesions in chemical mutagenesis and carcinogenesis. to directly assess the mutagenic potential of these adducts in vivo, we have designed an enzymatic technique for introducing nucleotide analogues at predetermined sites of biologically active dna. escherichia coli dna polymerase i was used in vitro to incorporate a single o4-methylthymine residue at the 3' terminus of an oligonucleotide primer opposite the adenine residue of the ambe ...19863464967
the adsorption of bacteriophage phi x174 and its interaction with escherichia coli; a kinetic and morphological study. 19724114179
genetic characterization of the dna of the bacteriophage phi x174 70 s particle. 19724554264
the rep mutation. ii. its effect on escherichia coli and on the replication of bacteriophage phi x174. 19724559689
mapping of host range mutants of bacteriophage phix174. 19734574511
dna methylase induced by bacteriophage phix174.a cytosine-specific dna methylase activity, which is normally absent in the escherichia coli b strain, was found to be induced in these cells by infection with bacteriophage varphix174. in vivo experiments revealed a single 5-methylcytosine residue in the phage dna molecule and 5-methylcytosine residues in the infected host dna, in addition to the 6-methylaminopurine residues present in the uninfected cells. in vitro, a partially purified enzyme from infected cells methylated dna from uninfected ...19734590171
mechanism of formation of bacteriophage phix174 circular and catenated dimer rf+ dna. 19734591368
location of the 5-methylcytosine group on the bacteriophage phi x174 genome.bacteriophage phix174 dna was labeled in vivo with [methyl-(3)h]methionine. the methyl-labeled progeny dna was extracted from purified bacteriophage phix174 particles and was used as template for in vitro synthesis of the complementary strand in the presence of the nucleoside triphosphates and escherichia coli polymerase i. the resultant replicative form dna was then cleaved, in separate experiments, with restriction endonucleases from haemophilus influenzae and h. aegyptius. the dna fragments w ...19744609216
role of the gene beta-product in bacteriophage phi-x174 development. 19744613851
structure of the replicative form of bacteriophage phi x174. v. interconversions between twisted, extended and randomly coiled forms of cyclic dna. 19684868417
the process of infection with bacteriophage phi x174. xvi. synthesis of the replicative form and its relationship to viral single-stranded dna synthesis. 19684868423
influence of the viral genome on ribonucleic acid synthesis in escherichia coli infected with bacteriophage phi-x174. 19684868755
restriction of bacteriophage phix174 by f factor. 19694901159
the process of infection with bacteriophage phix174. xxv. studies with bacteriophage phix174 mutants blocked in progeny replicative form dna synthesis. 19694901860
process of infection with bacteriophage phi-x174. xxxiv. kinetic of the attachment and eclipse steps of the infection.the products of phix cistrons ii, iii, and vii are demonstrated to affect the attachment of the phage to its host escherichia coli c; therefore, by inference, these cistrons influence, directly or indirectly, the structure of proteins in the virus particle. two of the mutations which alter attachment kinetics, ts79 in cistron iii and h in cistron vii, also affect the electrophoretic mobility of the virus and emphasize the role of charge in the attachment interaction with the host. the kinetics f ...19704916322
the replication of bacteriophage phi-x174 in a mutant of escherichia coli strain c. ii. evidence that the c-sm17ts mutation is not at the rep locus. 19714940967
the transition between two forms of bacteriophage phi-x174 differing in heat sensitivity and adsorption characteristics. 19675337711
cloned bacteriophage phi x174 dna sequence interferes with synthesis of the complementary strand of infecting bacteriophage phi x174.the insertion of a particular phi x dna sequence in the plasmid pacyc177 strongly decreased the capacity of escherichia coli cells containing such a plasmid to propagate bacteriophage phi x174. the smallest dna sequence tested that showed the effect was the hindii fragment r4. this fragment does not code for a complete protein. it contains the sequence specifying the c-terminal part of the gene h protein and the n-terminal part of the gene a protein, as well as the noncoding region between these ...19826211550
heat mutagenesis of bacteriophage phi x174 in sos-induced bacteria. 19826214708
in vitro synthesis of bacteriophage phi x174 by purified in vitro system capable of synthesizing infectious phi x174 phage particles was reconstituted from purified components. the synthesis required phi x174 supercoiled replicative form dna, phi x174-encoded proteins a, c, j, and prohead, escherichia coli dna polymerase iii holoenzyme, rep protein, and deoxyuridinetriphosphatase (dutpase, dutp nucleotidohydrolase, ec as well as mgcl2, four deoxyribonucleoside triphosphates, and atp. phage production was coupled to the synthesis of viral ...19836224217
analysis of bacteriophage phi x174 gene a protein-mediated termination and reinitiation of phi x dna synthesis. ii. structural characterization of the covalent phi x a protein-dna the preceeding paper (brown, d. r., roth, m. j., reinberg, d., and hurwitz, j. (1984) j. biol. chem. 259, 10545-10555), it was shown that following bacteriophage phi x174 (phi x) dna synthesis in vitro using purified proteins, the phi x a protein could be detected covalently linked to nascent 32p-labeled dna. this phi x a protein-[32p]dna complex was the product of the reinitiation reaction. the phi x a protein-[32p]dna complex could be trapped as a protein-32p-oligonucleotide complex by the ...19846236216
lysis of escherichia coli after infection with phix174 depends on the regulation of the cellular autolytic system.the relationship between the rate of lysis of escherichia coli infected with bacteriophage phix174 and the physiological state of the host bacteria was determined. the lysis rate was comparable to the growth rate only in cells grown in rich media, whereas in minimal medium it was much slower than the growth rate. lysis of starved cells grown in minimal medium could not be induced by phix174 although progeny phages were produced. lysis of e. coli provoked by expression of the cloned phix174 lysis ...19846236279
improved method for the isolation of the a and a* proteins of bacteriophage phi x174. 19806248369
adenoviral protein-primed initiation of dna chains in vitro.the initiation of dna chains by the 80-kilodalton form of the adenovirus terminal protein has been studied. this protein, which can be covalently linked to dcmp, is isolated complexed to a 140-kilodalton protein possessing dna polymerase activity. in the presence of adenovirus dna-protein, the formation of the 80-kilodalton protein-dcmp complex requires the addition of atp and nuclear extract from uninfected cells in addition to mg2+ and dctp. when single-stranded dna is used in place of the ade ...19826283524
initiation and termination of the bacteriophage phi x174 rolling circle dna replication in vivo: packaging of plasmid single-stranded dna into bacteriophage phi x174 coats.the bacteriophage phi x174 viral (+) origin when inserted in a plasmid can interact in vivo with the a protein produced by infecting phi x174 phages. a consequence of this interaction is packaging of single-stranded plasmid dna into preformed phage coats resulting in infective particles (1). this property was used to study morphogenesis and to analyse the signals for initiation and termination of the rolling circle dna replication in vivo. it is shown that the size of the dna had a strong effect ...19826294617
weigle reactivation and weigle mutagenesis in phage phi x174 by various types of radiation. 19816451803
dna polymerase accuracy and spontaneous mutation rates: frequencies of purine.purine, purine.pyrimidine, and pyrimidine.pyrimidine mismatches during dna replication.dna from the am16 mutant of bacteriophage phi x174 may be replicated in vitro and expressed in vivo to give five classes of revertants. each class may be specifically induced by the appropriate biasing of the concentrations of deoxynucleoside triphosphates in a predictable manner. the frequency of each reversion follows a kinetic rate equation relating it to the concentrations of the triphosphates involved in the substitution. the reversions corresponding to tag leads to gag, aag, cag, tgg, and ...19816457301
species specificity of promoter recognition by rna polymerase and its transfer by the sigma factor.rna polymerase holoenzyme from micrococcus luteus synthesizes in vitro a run-off transcript of 85 nucleotides from a dna fragment containing part of gene e of bacteriophage phi x174. this rna starts with gtp as the 5' terminus 18 nucleotides downstream from the start of gene e on the viral (+)strand. transcription does not occur when the fragment is cleaved 36 nucleotides upstream of the initiation site. no transcript is obtained with rna polymerase core or holoenzyme from escherichia coli. othe ...19826809459
expression of bacteriophage phix174 lysis gene e in staphylococcus carnosus tm300.expression of the cloned phix174 gene e causes lysis of the gram-negative bacterium escherichia coli, which led to the proposal that a two-membrane system is necessary for the protein e lysis function. gene e was cloned in an e. coli/bacillus subtilis shuttle vector and expressed in the gram-positive bacterium staphylococcus carnosus tm300. regulated gene e expression had a lethal effect on s. carnosus; however, no lysis was detected, lending support to the hypothesis.19938486239
aqueous release and purification of poly(beta-hydroxybutyrate) from escherichia coli.the poly(beta-hydroxybutyrate) (phb) biosynthetic genes of ralstonia eutropha that are organized in a single operon (phacab) have been cloned in escherichia coli, where the expression of the genes in the wild-type pha operon from plasmid ptz18u-phb leads to the formation of 50-80% phb/celldry mass when the cells are grown in luria-bertani medium supplemented with 1% glucose (w/v). in combination with the phacab genes, expression of cloned lysis gene e of bacteriophage phix174 from plasmid psh2 h ...19989828460
contributions of polysaccharide and lipid regions of lipopolysaccharide to the recognition by spike g protein of bacteriophage phi x174.a histidine-tagged g protein of bacteriophage phi x174 (hisg) bound strongly with lipopolysaccharide (lps) of escherichia coli c, one of a phi x174-sensitive ra strain. the dissociation constant, kd, was measured to be 0.16 +/- 0.04 microm by fluorometric titration. hisg showed slightly less affinity to lpss of the insensitive rc and rd 2 strains having shorter r-core polysaccharide sequences than that of the sensitive ra strains. the difference between the two types of lps was demonstrated by c ...200312784630
genomic evolution in a virus under specific selection for host recognition.genetic variation in viral structural proteins is often explained by evolutionary escape of strong host defenses through processes such as immune evasion, host switching, and tissue tropism. an understanding of the mechanisms driving evolutionary change in virus surface proteins is key to designing effective intervention strategies to disease emergence. this study investigated the predictability of virus genomic evolution in response to highly specific differences in host receptor structure. the ...200818804189
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