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PubMedDate not supplied

[Oncogene-directed mutagenesis in vivo. Polyalkylating derivatives of short single-stranded polynucleotides, complementary E1-adeno-oncogene, in the normalization of adenovirus-transformed rodent cell lines].

Polyalkylating derivatives of single-stranded polynucleotides (30-200-mers) complementary to the long E1 oncogene sequences of simian adenovirus SA7 cause inherited normalization of SH2 and G11 cells transformed with adenovirus SA7; certain deletions in the integrated proviral E1A oncogene were observed in several cases during this process. The transformed cells are indifferent to reagents noncomplementary to the E1 region. Thus polyalkylating derivatives of single-stranded 30-200-mers act as addressed mutagenes which react in a specific way with the integrated complementary DNA sequences of E1 oncogene in transformed rodent cells and realize oncogene-directed mutagenesis in vivo. During this treatment temporary normalized cells reverting to the initial transformed phenotype are also produced.

Adenoviruses, Simian↗
PubMedDate not supplied

[Oligo- and polynucleotide probes. A molecular hybridization method].

In this review the main principles and possibilities of a hybridization analyses as a highly specific methods for diagnostics of infections and genetic diseases are discussed. Special attention is paid to the chemical approaches to the preparation of non-radioactive probes based on synthetic oligonucleotides and polynucleotides containing biotin, Eu3+ and enzyme labels. Some versions of the hybridization analysis technique are discussed.

Genetic Markers↗
PubMedDate not supplied

[Effect of cyclic-3',5'-AMP on rat liver polynucleotide phosphorylase activity].

Effect of cAMP on the activity of polynucleotide phosphorylase (PNPase) was studied in polyribosome fraction of rat liver tissue. Intraperitonel administration of cAMP or of theophilline into rats distinctly decreased the PNPase activity in the polyribosome fraction. The cAMP (1-10(-4) M) inhibited the enzymatic activity only by 8% in polyribosome fraction in vitro, as it was estimated by the reaction of phosphorolysis of endogenous RNA and polyA added. Any attempts were proved to be uncucessful to reveal cAMP, ATP-dependent proteinkinase in rat liver, responsible for the decrease in the PNPase activity in the polyribosome fraction. The cAMP inhibited the increase in the PNPase activity, coupled with protein biosynthesis in polyribosomes. Moreover, cAMP caused a decrease in the PNPase activity in reaction of polyA phosphorolysis and did not affect the rate of endogenous RNA phosphorolysis in polyribosome fraction, isolated from postmitochondrial fraction after incubation for 15 min at 30 degrees. The 3',5'-cyclo AMP (2-10(-6)-2-10(-4) M) stimulated incorporation of 14C-leucine into acid-insoluble material, when postmitochondrial fraction was incubated under the same conditions. The data obtained suggest that cAMP either inhibits specifically the PNPase synthesis or represses the coupled with protein biosynthesis formation of active "heavy" type of PNPase from less active "light" type.

Animals↗
PubMed1991

Amino acid sequence of the FV region of a human monoclonal IgM (NOV) with specificity for the capsular polysaccharide of the group B meningococcus and of Escherichia coli K1, which cross-reacts with polynucleotides and with denatured DNA.

The complete amino acid sequences of the VH and VL regions of a biologically significant Ig, IgMNOV, were determined. IgMNOV is reactive with the capsular polysaccharide of the group B meningococcus and of Escherichia coli K1. As reported earlier, it cross-reacts completely with polynucleotides poly(A) and poly(I) and to a lesser extent with denatured DNA and protects newborn rats against infection with E. coli K1, and is equal in potency to the standard horse anti-group B meningococcal serum. The reduced and alkylated chains were sequenced directly, identifying the L chain as lambda-subgroup II and the mu-H chain as subgroup III. The complete sequence of the VL region was determined by sequencing peptides generated by cleavage with Staphylococcus aureus protease, chymotrypsin, and trypsin. The H chain was cleaved with cyanogen bromide followed by enzymatic cleavages to obtain a large part of the VH region sequence. The structure was completed by sequencing tryptic peptides of the Fab fragment and by mass-spectrometric analysis.

Amino Acid Sequence↗
PubMed1976

[The activity of polynucleotide phosphorylase in polyribosomes of regenerating liver of adult rats, liver of newborn rats and in some reinoculated tumours].

Specific activity and level of polynucleotide phosphorylase (PNPase) in polyribosomes of regenerating liver of adult rats, liver of newborn rats and in malignant tumours of rat (sarcoma M-1 and hepatoma 27) were studied. 24 hours after partial hepatectomy the specific activity and level of PNPase in regenerating liver decreased 3--4 times in the fraction of polyribosomes, bound to the endoplasmic reticulum membranes, and remained at a constantly low level in the fraction of free polyribosomes. The PNPase activity also showed a sharp decrease in the fraction of membrane-bound polyribosomes from newborn rats liver and could not be detected either in free or in bound polyribosomes from sarcoma M-1 or hepatoma 27. The PNPase activity in the fraction of bound polyribosomes increased with a decrease in the rate of liver growth (regenerating liver and newborn rats liver), and reached the level normal for adult animals. Possible mechanisms of regulation of the PNPase activity in animal tissue were studied. It was found that a 2-fold administration of cyclic 3,5'-AMP to intact animals (5 mg per 100 g of body weight) with an interval of 8 hours, corresponding to the interval between two peaks of the increase in cyclic 3,5'-AMP concentration following partial hepatectomy, diminished the PNPase specific activity in polyribosomes by 30%. A factor, presumably of protein origin, which induced a release of PNPase from polyribosomes of normal rat liver but did not affect the activity of the liberated enzyme, was detected in the cell sap of sarcoma M-1 and hepatoma 27.

Age Factors↗
PubMedDate not supplied

[The context analysis of polynucleotide sequences. II. Inverted repeats and complementary palindromes in RNA-polymerase genes].

A new approach to the reconstruction of the RNA secondary structure is suggested on the basis of the method of contextual analysis of polynucleotide sequences. The coding gene regions of beta-, beta'-, sigma-subunits of E. coli RNA polymerase and of phage T7 RNA polymerase were analysed. The clusters of non-random inverted repeats were found in all these genes. The mRNA coded by them can be folded into compact secondary structures. The latter are formed by quite long helices with a few cases of mispairing.

Chromosome Inversion↗
PubMed1986

Interaction of three second-generation anthracyclines with polynucleotides, RNA, DNA, and nucleosomes.

The interaction of three second-generation anthracycline derivatives with polynucleotides, supercoiled DNA, and calf thymus nucleosomes has been studied by terbium fluorescence measurements and agarose gel electrophoresis. It was shown that, as expected, N-trifluoroacetyladriamycin-14-valerate had little detectable effect on the fluorescence of this guanine-specific probe except for polydisperse calf thymus linear DNA fragments. The soluble analogue, N-trifluoroacetyladriamycin-14-O-hemiadipate, did show marked effects on terbium fluorescence with all nucleic acids and nucleosomes, but the effects were generally not as striking as were those observed with the epimer, 4'-epi-Adriamycin, which tended to produce a similar effect to its parent drug, Adriamycin, showing that a marked change in the hexose ring did not appreciably affect the interaction of the drug with DNA. Changes in the electrophoretic mobility of supercoiled pBR322 DNA were observed only at very high drug concentrations, much higher than those required with Adriamycin or actinomycin D. The effect was a smearing of the form I DNA and the production of some circular relaxed form II DNA. The drugs produced the effect in the following order: Adriamycin greater than N-trifluoroacetyladriamycin-14-O-hemiadipate greater than or equal to epi-Adriamycin. N-Trifluoroacetyladriamycin-14-valerate had little effect, even at very high drug concentrations (1:2, drug:DNA ratios).

Animals↗
PubMed1986

Replication and transcription of polynucleotides containing ethenocytosine, ethenoadenine and their hydrated intermediates.

Replication with Escherichia coli DNA polymerase I (Pol I) and transcription with DNA-dependent RNA polymerase from Escherichia coli or calf thymus, using as templates synthesized ribo- or deoxyribopolynucleotides containing 1,N6-ethenoadenine (epsilon A) or 3,N4-ethenocytosine (epsilon C), showed that only epsilon C could direct significant misincorporation. The hydrated intermediate of epsilon C caused errors only upon transcription, but not upon replication. epsilon A was a very poor mutagen as assessed by replication with Pol I. Transcription of polynucleotides containing epsilon A under error-prone conditions caused frequent A misincorporation which could not be detected in replication assays. It is concluded that epsilon C may lead to point mutations, specifically directing the misincorporation of thymine. The analogous derivative, epsilon A, is bulky and is likely to be bypassed rather than read. This mechanism could cause frameshift mutation, as generally found for other bulky adducts.

Adenosine↗
PubMedDate not supplied

[Display of 8-hydroxy-GTP substrate properties of UTP in the reaction of polynucleotide synthesis catalyzed by RNA-polymerase from Escherichia coli in the presence of poly[d(AT).d(AT)] template].

8-oxy-GTP was obtained via reaction of GTP with ascorbic acid and addition of hydrogen peroxide. 8-oxy-GTP is recognized and displays substrate properties of UTP on substitution of 8-oxy-GTP for UTP in polynucleotide synthesis catalyzed by E. coli RNA polymerase on a poly[d(A-T)].poly[d(A-T)] template. Such incorporation does not take place at equimolar quantities of GTP and 8-Br-GTP. The incorporation of 8-oxy-GTP instead of UTP, is 2.5-3 times higher upon replacement of Mg2+ by Mn2+ ions. The dinucleotide ApU serving as an initiator rises the incorporation level of 8-oxy-GTP both for Mg2+ and Mn2+ ions. 8-oxy-GTP slightly inhibits poly[r(A-U)] synthesis, but UTP strongly inhibits the incorporation of 8-oxy-GTP. [alpha-32P] 8-oxy-GTP is incorporated mainly instead of UTP, but it can be incorporated also during the substitution of 8-oxy-GTP for ATP.

DNA-Directed RNA Polymerases↗
PubMed1976

An endonuclease from Escherichia coli that introduces single polynucleotide chain scissions in ultraviolet-irradiated DNA.

An endonuclease that makes single polynucleotide chain scissions in ultraviolet-irradiated DNA has been purified from Escherichia coli. The activity has the following properties: (a) unirradiated DNA is attacked very little if at all; (b) single strand DNA is not attacked, whether irradiated or not; (c) there is no requirement for divalent cations and the activity is not affected by the addition of EDTA; (d) the pH optimum is approximately 7; (e) the activity is inhibited by 1 M NaCl, single strand DNA, transfer RNA and double strand DNA; (f) the sedimentation coefficient, S20,w, is approximately 2.6; (g) it is a basic protein. The enzyme is tentatively named E. coli endonuclease III. The physiological function of the endonuclease has not yet been established.

Coliphages↗
PubMed1978

[Animal tissue polynucleotide phosphorylase].

Localization, physico-chemical and catalytic properties and possible biological functions of polynucleotide phosphorylase (PNPase) from animal tissues are discussed. In animal tissue cells PNPase has multiple localization; the major amount of the enzyme is localized in the endoplasmic reticulum ribosomes. In the nuclei PNPase, similar to other endo- and exo-RNAses participates in the processing of precursor molecules of mature forms of RNA, whereas in the cytoplasm it is involved in the destruction of polyribosomes in the polyribosomes of rapidly growing tissues the activity of PNPase is extremely decreased. The mechanisms regulating the PNPase activity in rapidly growing tissues are discussed.

Animals↗
PubMed1986

[Capacity of the polynucleotide phosphorylase-releasing factor to stimulate hybrid cell growth].

The capacity of the partially purified preparation of the polynucleotide phosphorylase releasing factor (PNP-ase RF) from Walker sarcoma for stimulating the growth of hybrid cells and parent myeloma cells has been studied. The preparation of PNP-ase RF at a concentration of 500-50 micrograms/ml has been shown to induce the 3- to 10-fold increase of the number of cells in the culture by the 5th day of incubation without changing the medium.

Animals↗
PubMed1979

Spectroscopic analysis of the interaction of Escherichia coli DNA-dependent RNA polymerase with T7 DNA and synthetic polynucleotides.

We have studied the circular dichroism and ultraviolet difference spectra of T7 bacteriophage DNA and various synthetic polynucleotides upon addition of Escherichia coli RNA polymerase. When RNA polymerase binds nonspecifically to T7 DNA, the CD spectrum shows a decrease in the maximum at 272 but no detectable changes in other regions of the spectrum. This CD change can be compared with those associated with known conformational changes in DNA. Nonspecific binding to RNA polymerase leads to an increase in the winding angle, theta, in T7 DNA. The CD and UV difference spectra for poly[d(A-T)] at 4 degrees C show similar effects. At 25 degrees C, binding of RNA polymerase to poly[d(A-T)] leads to hyperchromicity at 263 nm and to significant changes in CD. These effects are consistent with an opening of the double helix, i.e. melting of a short region of the DNA. The hyperchromicity observed at 263 nm for poly[d(A-T)] is used to determine the number of base pairs disrupted in the binding of RNA polymerase holoenzyme. The melting effect involves about 10 base pairs/RNA polymerase molecule. Changes in the CD of poly(dT) and poly(dA) on binding to RNA polymerase suggest an unstacking of the bases with a change in the backbone conformation. This is further confirmed by the UV difference spectra. We also show direct evidence for differences in the template binding site between holo- and core enzyme, presumably induced by the sigma subunit. By titration of the enzyme with poly(dT) the physical site size of RNA polymerase on single-stranded DNA is approximately equal to 30 bases for both holo- and core enzyme. Titration of poly[d(A-T)] with polymerase places the figure at approximately equal to 28 base pairs for double-stranded DNA.

Circular Dichroism↗
PubMedDate not supplied

[Context analysis of polynucleotide sequences. Methods of detecting non-random repeats. I. Direct repeats in genes of beta-, beta'-, sigma subunits of Escherichia coli RNA-polymerase].

A new method of contextual analysis of polynucleotide sequences in developed. The method finds nonrandom repeats in the sequences of N bases in length with given nucleotide frequencies. The coding regions of genes specifying beta-, beta'-, sigma-subunits of E. coli RNA polymerase were analyzed. The high content of short repeats was found to correspond to the secondary structure of globular proteins coded by the genes. The possible evolutionary role of the nonrandom direct repeats in coding regions of genes is discussed.

DNA Replication↗
PubMedDate not supplied

[Concentration and temperature effects in interactions of the dye pyronine G with polynucleotides].

The interaction of poly(A) and poly(A).poly(U) with pyronine G dye depending on the concentration of components and temperature was studied spectrophotometrically in the visible and UV ranges at pH (6.86). It was found that the interaction of pyronine G with poly(A) and poly(A).poly(U) results in the formation of two types of complexes. The relation of the equilibrium concentrations of these complexes depends on the initial concentrations of the components in solution. The formation of complex I results in shifting the spectrum towards the short wave range with regard to the monomer band and reflects the aggregation of the dye cations. Complex II is characterized by the shift towards the long wave range. Complex II is formed in considerable amounts for poly(A).pyronine G system at large P/D and for poly(A).poly(U).pyronine G system at P/D = 5-6 and is probably due to the interaction between the dye and polynucleotides of the intercalation type or reflects the interaction between the dye and two negatively charged phosphate groups. Analysis of temperature measurements of spectra confirms the formation of various types of complexes in the system studied.

In Vitro Techniques↗
PubMed1984

DNA methylation. Inhibition of de novo and maintenance methylation in vitro by RNA and synthetic polynucleotides.

A partially purified HeLa cell DNA methylase will methylate a totally unmethylated DNA (de novo methylation) at about 3-4% the rate it will methylate a hemimethylated DNA template (maintenance methylation). Our evidence suggests that many, if not most, dCpdG sequences in a natural or synthetic DNA can be methylated by the enzyme. There is a powerful inhibitor of DNA methylase activity in crude extracts which has been identified as RNA. The inhibition of DNA methylase by RNA may indicate that this enzyme is regulated in vivo by the presence of RNA at specific chromosomal sites. The pattern of binding of RNA to DNA in the nucleosome structure and the DNA replication complex may determine specific sites of DNA methylation. An even more potent inhibition of DNA methylase activity is observed with poly(G), but not poly(C), poly(A), or poly(U). The only other synthetic polynucleotides studied which inhibit DNA methylation as well as poly(G) are the homopolymers poly(dC).poly(dG) and poly (dA).poly(dT). These results point out the unique importance of the guanine residue itself in the binding of the DNA methylase to dCpdG, the site of cytosine methylation. The surprising inhibition of the methylation reaction by poly(dA).poly(dT), which is itself not methylated by the enzyme, suggests the possible involvement of adjacent A and T residues in influencing the choice of sites of methylation by the enzyme.

Cell Nucleus↗
PubMed1984

Specificity of dye-ligand interaction with the polynucleotide binding domain of 1,25-dihydroxyvitamin D3-receptor complexes of chicken intestinal cytosol.

The binding of 1,25-dihydroxyvitamin D3-receptor complexes from chick intestinal cytosol to DNA-cellulose and isolated intestinal nuclei is inhibited by several dye-ligands in a dose-dependent manner. Concentrations of Cibacron blue F3GA, blue dextran, Procion red HE3B, and Green A dye causing 50% competition for receptor binding to DNA-cellulose ranged from 2.8 to 3.6 microM. A structural analogue of the anthraquinone moiety of Cibacron blue F3GA, bromaminic acid, was 111-fold less potent in inhibiting DNA-cellulose binding. Moreover, the inhibitory effects of these dye-ligands is not due to a simple electrostatic effect, since two other polyanions, heparin and poly-L-glutamate, are much less effective. Whereas dye-ligands can cause the release of receptors bound to DNA-cellulose, they do not alter the dissociation of 1,25-dihydroxyvitamin D3 from its receptor nor do they affect the apparent equilibrium binding constant of the receptor or the concentration of available sterol-binding sites. The inhibition of binding by dye-ligands is competitive with respect to DNA-cellulose binding, indicating that the effect of these dyes is at a domain common to polynucleotides.

Animals↗