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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Functional elements of vaccinia virus late promoters were characterized by mutagenesis. Synthetic oligonucleotides were inserted into a plasmid vector containing the lacZ gene of Escherichia coli flanked by sequences from the thymidine kinase (TK) gene of vaccinia virus. The lacZ gene, under control of the synthetic promoter, was introduced into the vaccinia virus genome at the TK locus by homologous recombination, and each of the 122 recombinants thus obtained was assayed for beta-galactosidase expression. The relative amounts and 5' ends of lacZ mRNAs specified by a subset of the recombinants were determined by primer extension. The analysis indicated that late promoters may be considered in terms of three regions; an upstream sequence of about 20 base-pairs, rich in T and A residues, separated by a spacer region of about six base-pairs from a highly conserved (-1)TAAAT(+4) element within which transcription initiates. All single nucleotide substitutions within the three A residues of the TAAAT, as well as the addition of a fourth A residue, caused drastic reductions in promoter strength. All substitutions of the T residues at -1 and +4 were also detrimental to promoter activity, to an extent that depended on the strength of the promoter as determined by the upstream sequence. mRNA synthesis appeared to initiate within the three A residues regardless of promoter strength. The 5'-poly(A) leader, which is a unique feature of poxvirus late mRNAs, was diminished in length when either of the T residues at -1 and +4 was mutated, was absent or limited to a few nucleotides when any of the three A residues was substituted, but was unaffected by changes outside the TAAAT sequence. The data are consistent with a model for the generation of the normal 5'-poly(A) leader by an RNA polymerase slippage mechanism requiring three consecutive A residues. Single nucleotide substitutions within the six base-pairs upstream and three base-pairs downstream from the TAAAT sequence had modest effects on promoter strength. The most and least favourable changes led to a fourfold increase and an eightfold decrease in activity, respectively. Sequences further upstream were essential for late promoter function; tracts of T or A residues enhanced expression up to 20-fold, the former conferring much greater activity. Highest expression was obtained with a tract of 18 or 20 T residues.(ABSTRACT TRUNCATED AT 400 WORDS)
J Mol Biol 1989 Dec 20
PMID:Structure of vaccinia virus late promoters. 251 87

Ten recombinants between the viruses of vaccinia and ectromelia were isolated that cause the ectromelia virus specific lesions in mice. The structure of recombinant viral genomes, the efficiency of viral propagation in mice, the nature of lesions induced by viruses have been studied. Eight of obtained recombinants have a DNA insertion originating from the right end of ectromelia viral genome, nine recombinants have an insertion originating from the left end, seven recombinants possess both insertions. The latter recombinants have more pronounced pathogenicity for mice. Both revealed regions are supposed to define the specific pathogenicity of ectromelia virus for mice.
Mol Gen Mikrobiol Virusol 1989 Aug
PMID:[Vaccinia and ectromelia recombinant viruses, causing an infection, characteristic for ectromelia, in mice]. 255 32

The monospecific antiserums to the major proteins p12, p19, p20, p42, p61 of the vaccinia virus coat were obtained and analyzed. The dynamics of the proteins accumulation in the infected cells has been studied. Products of the cell-free translation of the total viral mRNA precipitated by the obtained antiserums were identified. The p20 protein has been found to be a result of p12 protein reversible oligomerization under the conditions of electrophoresis. The antigenic relation of p12 and p20 proteins to a p42 protein, also a p12 oligomer, has been demonstrated. The possibility is discussed to use the obtained antiserums for mapping of the genes corresponding to structural proteins in the genome of the vaccinia virus.
Mol Gen Mikrobiol Virusol 1989 Oct
PMID:[Analysis of structural proteins and products of cell-free translation of vaccinia virus of mRNA using mono-specific antibodies]. 261 70

Three monospecific antisera to the major 35 kD (p35) surface protein of vaccinia and ectromelia viruses have been obtained. Two of them are obtained to p35 protein isolated by electrophoresis in the presence of sodium dodecylsulfate from the protein fractions of vaccinia virus, soluble in NP40 and NP40 with dithiothreitol (NP40 and DTT-fractions). The third serum is obtained to NP40-fraction of ectromelia virus, containing practically only p35 protein. The obtained antisera were compared in the reactions with the different fractions of viral proteins in two versions of solid phase radioimmunoassay. The effect of such reagents as sodium dodecylsulfate, NP40, 2-mercaptoethanol, ethanol on the antigenic properties of p35 protein from vaccinia virus is discussed.
Mol Gen Mikrobiol Virusol 1989 Sep
PMID:[Changes in antigenic properties of the p35 protein of vaccinia virus in various protein fractions of the virion with the use of monospecific antisera]. 261 75

The left HindIII-A-Sal fragment of the vaccinia virus DNA has been analyzed by the technique of mRNA hybridizational selection with the subsequent translation in cell-free protein-synthesizing system from the rabbit reticulocytes. The viral mRNA hybridizable with the fragment was shown to direct the synthesis of 12, 17, 27, 42, 70 kD polypeptides in the cell-free protein-synthesizing system. Each of 12 and 42 kD polypeptides was demonstrated to react specifically with antisera to structural p12 and p42 coat proteins. The structural coat proteins p12, p20, p42 of the vaccinia virus are concluded to be the products of the same viral gene.
Mol Gen Mikrobiol Virusol 1989 Nov
PMID:[Immunochemical analysis of the products of translation of mRNA hybridized with the left HindIII-A-Sa1-fragment of vaccinia virus DNA]. 262 51

9-(trans-2',trans-3'-dihydroxycyclopent-4'-enyl)-adenine (DHC), a specific inhibitor of S-adenosyl-L-homocysteine (AdoHcy) hydrolase, has been used in this study to elucidate the mechanism by which DL-homocysteine (Hcy) potentiates the antiviral effects of AdoHcy hydrolase inhibitors as reported by De Clercq [Biochem. Pharmacol. 36:2567-2575 (1987)]. The potentiating effects of Hcy on the antiviral effects of DHCA were determined using murine L929 cells infected with vaccinia virus. When virus-infected cells were incubated with DHCA alone or in combination with various concentrations of Hcy, the following IC50 values (concentrations of the drug required to reduce by 50% viral plaque formation) were observed: 0.30 microM (0 mM Hcy), 0.15 microM (0.3 mM Hcy), 0.09 microM (1.0 mM Hcy), and 0.04 microM (3.0 mM Hcy). In the drug combination studies, increased cellular toxicity, compared with DHCA alone, was observed only at the highest concentration of Hcy (3.0 mM); thus, at lower concentrations Hcy increased the antiviral effectiveness [ID50 (concentration of the drug required to reduce the increase in cell number by 50%)/IC50] of DHCA. For example the following ID50/IC50 values were observed for DHCA alone or in combination with Hcy: 64 (0 mM Hcy), 113 (0.3 mM Hcy), 151 (1.0 mM Hcy), and 88 (3.0 mM Hcy). In these studies, Hcy was also observed to potentiate the increase in cellular levels of AdoHcy and the ratio of AdoHcy/S-adenosyl-L-methionine (AdoMet) in DHCA-treated cells. In earlier studies, our laboratory has shown that antiviral effects of DHCA are caused by only slight elevations in intracellular levels of AdoHcy [from 50 pmol/mg of protein (controls) to 100-200 pmol/mg of protein (drug-treated)] and slight elevations in the ratios of AdoHcy/AdoMet [from 0.05-0.1 (control) to 0.15-0.20 (drug-treated)]. Thus, in the presence of Hcy, lower concentrations of DHCA are needed to increase the intracellular concentration of AdoHcy and the AdoHcy/AdoMet ratio to levels that suppress replication of vaccinia virus. Murine L929 cells were shown to contain DHCA-sensitive and DHCA-insensitive forms of AdoHcy hydrolase. Based on the results of labeling experiments using [2,8-3H]adenosine and [35S]methionine, the elevated levels of AdoHcy were shown to arise from the reaction of [2,8-3H]adenosine and Hcy, catalyzed by the DHCA-insensitive form of AdoHcy hydrolase.
Mol Pharmacol 1989 Sep
PMID:Elucidation of the mechanism by which homocysteine potentiates the anti-vaccinia virus effects of the S-adenosylhomocysteine hydrolase inhibitor 9-(trans-2',trans-3'-dihydroxycyclopent-4'-enyl)-adenine. 277 28

cDNAs for rodent P(1)450, P(3)450, and P450a were expressed in the modified vaccinia virus-T7 RNA polymerase system. Each P450 exhibited its appropriate molecular weight and characteristic enzyme activity. Aryl hydrocarbon hydroxylase activity was catalyzed by P(1)450, acetanilide hydroxylase by P(3)450, and testosterone 7 alpha-hydroxylase by P450a. Ethoxycoumarin deethylase was exhibited by both P(1)450 and P(3)450. Each expressed P450 was also analyzed for its ability to activate 19 carcinogens of diverse classes to their mutagenic forms. Most notable was the activation of several polycyclic aromatic hydrocarbons by P1 and the activation of acetylaminofluorene, 4-aminobiphenyl, and several heterocyclic amine food pyrolysate products by P(3)450. P450a, in contrast, showed slight mutagen activation only toward N-hydroxy-2-acetyl aminofluorene. The vaccinia virus-T7 RNA polymerase system described here can express cDNAs for diverse forms of P450, each of which can then be characterized for substrate and product specificity and for mutagen activation.
Mol Carcinog 1989
PMID:Mutagen activation by cDNA-expressed P(1)450, P(3)450, and P450a. 278 89

The vaccinia virus cDNA expression system was used to produce human cytochrome P450 IA2 in a hepatoma cell line that is devoid of significant basal levels of P450. The expressed enzyme yielded a reduced carbon monoxide-bound difference spectrum with a lambda max of 449 nm. Catalytic activities and mutagen activation ability of the human enzyme were assessed and directly compared with results obtained with the orthologous mouse IA2, which was also expressed using vaccinia virus. Both the human and mouse enzymes were able to catalyze efficiently the p-hydroxylation of aniline. Mouse IA2 also catalyzed ethoxyresorufin O-deethylation, and its activity was sevenfold greater than expressed human IA2. The mouse and human enzymes also activated several promutagens and procarcinogens. Mouse IA2 was five- to sevenfold more active than the human enzyme for activation of the procarcinogens 2-acetylaminofluorene and benzo[a]pyrene-trans-7,8-dihydrodiol and the promutagens Glu-P-2 and Trp-P-1. Comparable activities were observed with 2-aminoanthracene, 2-aminofluorene, and Glu-P-1. These data demonstrate the utility of cDNA expression for examining the activities of human P450s and further suggest potentially important differences in catalytic activities of orthologous P450s found in different species.
Mol Carcinog 1989
PMID:Human cDNA-expressed cytochrome P450 IA2: mutagen activation and substrate specificity. 280 20

3'-Azido-2',3'-dideoxythymidine (az-T) inhibited effectively the reproduction of some retroviruses; among these viruses were the four serological subgroups of sarcoma Raus virus in chicken embryo, avian myeloblastosis virus and erythroblastosis virus in chicken. This inhibition was specific towards retroviruses and practically was not observed in the case of infections DNA- and RNA-genome model viruses of vaccinia and influenza, at whose reproduction reverse transcriptase is not involved. Three other 3'-modified nucleosides did not block the above-listed retroviruses. For chickens, az-T showed low toxicity. The molecular mechanisms of the action of az-T are discussed.
Mol Biol (Mosk)
PMID:[The effect of 3'-azido-2',3'-dideoxythymidine on experimental viral infections]. 282 79

The antibiotic G418 was shown to be an effective inhibitor of vaccinia virus replication when an appropriate concentration of it was added to cell monolayers 48 h before infection. Genetic engineering techniques were used in concert with DNA transfection protocols to construct vaccinia virus recombinants containing the neomycin resistance gene (neo) from transposon Tn5. These recombinants contained the neo gene linked in either the correct or incorrect orientation relative to the vaccinia virus 7.5-kilodalton gene promoter which is expressed constitutively throughout the course of infection. The vaccinia virus recombinant containing the chimeric neo gene in the proper orientation was able to grow and form plaques in the presence of G418, whereas both the wild-type and the recombinant virus with the neo gene in the opposite polarity were inhibited by more than 98%. The effect of G418 on virus growth may be mediated at least in part by selective inhibition of the synthesis of a subset of late viral proteins. These results are discussed with reference to using this system, the conferral of resistance to G418 with neo as a positive selectable marker, to facilitate constructing vaccinia virus recombinants which contain foreign genes of interest.
Mol Cell Biol 1985 Aug
PMID:Neomycin resistance as a dominant selectable marker for selection and isolation of vaccinia virus recombinants. 301 37


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