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G B Pyrinova

Publications and source records attributed to G B Pyrinova.

10 recordsLinked to original sources
PubMed1989

Inhibition of reverse transcription in rat liver intracisternal A-particles by thymidine derivatives.

The thymidine derivatives araAzT, dTTP(3'N3), TTP(3'NH2), and araTTP(3'N3), were studied as inhibitors of the reverse transcription taking place within endogenous retroviral A-type particles, where retroviral RNAs served as templates and primers, dTTP(3'N3) was shown to be the most efficient inhibitor of retroviral particle reverse transcription. Termination of DNA chain elongation is the basic mechanism of the inhibitory action of dTTP(3'N3). The compound has a very low inhibitory effect on mammalian DNA-dependent DNA polymerases alpha, beta and gamma.

Animals↗
PubMed1986

[Nature of the endogenous retrovirus-like particles of the rat liver].

Previously virus-like particles (VLP) with properties resembling retroviruses were isolated from the liver of Wistar rats. Molecular hybridization and CRIA test were used for further analysis of the VLP. The CRIA method showed that VLP preparation lacked antigenic determinants of the major internal protein of C-type virus. By the dot hybridization technique no homology was detected between VLP and Mo-MuLV DNA, however VLP RNA was found to be homologous to IAP (interstitial A particles) DNA of mice. VLP proviral DNA was detected in the rat genome by the blot hybridization technique. Thus, it was concluded that VLP resemble IAP. A possible role of rat IAP expression is discussed.

Animals↗
PubMed1985

Reverse transcriptase of rat liver associated with the endogenous retrovirus related to the mouse intracisternal A-particles.

Reverse transcriptase activity was found in rat liver enclosed in virus-like particles. Through hybridization with DNA probes of A- and C-type retroviruses and with the help of electron microscopy the virus-like particles have been identified as endogenous retroviruses related to the mouse intracisternal A-particles. Blot hybridization revealed the provirus DNA in the rat genome. The enzyme was isolated from the virus-like particles, purified and characterized. The main properties of the enzyme resemble those of the mammalian retrovirus reverse transcriptase.

Animals↗
PubMed1980

[Effect of exogenous RNA on the activity of poly(A).oligo(dT)-dependent DNA-polymerase in mouse tumors].

The effects of exogenous RNA on the poly(A).oligo(dT)-dependent DNA-polymerase activity of factor and factor-free carcinomas of the mammary gland of C3H mice and Ehrlich ascite carcinoma were studied. It was shown that after intraparenteral injection of the RNA the enzyme activity is increased in the oncornavirus-containing carcinomas and remains unchanged in the virus-free tumours. The effect of RNA is not due to the glucocorticoid release into the blood and is suppressed by actinomycin D one hour prior to the addition of RNA. The increase of the poly(A).oligo(dT)-dependent DNA-polymerase activity of the cytoplasmic fraction of tumour cells is correlated with the rise of cytoplasmic RNA-polymerase activity and the increased incorporation of the precursors into the cytoplasmic RNA. Thus, in virus-containing tumours exogenous RNA induces the synthesis of cytoplasmic RNAs responsible for the synthesis of RNA-dependent DNA-polymerase.

Animals↗
PubMedDate not supplied

[Selective inhibition by 3'-azido-2',3-dideoxythymidine-5'- triphosphate of reverse transcription in retrovirus A particles from the rat liver].

The data presented demonstrate that 3'-azido-2',3'-dideoxythymidine 5'-triphosphate [dTTP (3N3)] specifically inhibits reverse transcription of viral RNA in the endogenous retroviral A-type particles isolated from the rat liver. The inhibitory action of dTTP (3N3) is concerned the termination of DNA synthesis obviously due to the incorporation of this dideoxynucleotide into the 3'-end of the growing DNA chain.

Animals↗
PubMedDate not supplied

[Changes in the RNA-dependent DNA-polymerase activity of retrovirus-like particles in the rat liver during postnatal ontogeny].

The RNA-dependent DNA-polymerase activity was studied in the postmicrosomal fraction and in the microsomal sediment of the liver of the newborn and adult Wistar rats. In the microsomal sediment of 4-6 day old rats the RNA-dependent DNA-polymerase activity was approximately by one order of magnitude higher than in that of 2 week old and adult rats. In the postmicrosomal fraction of 3 day old rats the RNA-dependent DNA-polymerase activity was also higher, but only by 30-35%, than in that of animals of the other age groups. Particles with density of 1.17 g/ml were found in the microsomal sediment of all studied animals. The characteristic morphology, sensitivity of the particle RNA-dependent DNA-polymerase activity to RNAse and the presence of reverse transcriptase allow for these particles to be referred to as retroviruses. A suggestion is put forward that the high intensity of reverse transcription during the early postnatal period can be due to still continuing processes of cell differentiation and enzymatic imprinting.

Animals↗
PubMedDate not supplied

[RNA-dependent DNA polymerase from rat liver].

RNA-dependent DNA-polymerase was isolated from rat liver, and its characteristics were studied. Wistar rat livers were homogenized in the disruptive buffer, centrifuged at 100,000 g and the supernatant was freed of the nucleic acids by DEAE-cellulose (DE-23) chromatography. The further chromatography of the eluate on DEAE-cellulose (DE-52) and phosphocellulose P-11 resulted in the obtaining of 300-400-fold purified RNA-dependent DNA-polymerase. Even more purified enzyme 1500-fold was isolated from the 165,000 g pellet of postmitochondrial rat liver fraction. The main properties of the purified enzyme are characteristic for the retroviral reverse transcriptase. The enzyme catalyzes DNA synthesis when poly(A)+mRNA is used as a template-primer. Its sedimentation constant amounts to 4.6 S. Mg2+ is preferable to Mn2+ as an activator of the enzyme. The optimal pH is 7.8. Among the products of the enzymic reaction hybrid RNA X DNA molecules were identified.

Animals↗
PubMedDate not supplied

[Relation of RNA-dependent DNA-polymerase from the rat liver with virus-like particles].

RNA-dependent DNA-polymerase activity was found in the 165 000 g supernatant and pellet of the postmitochondrial rat liver fraction. Further fractionation of the 165 000 g pellet in the linear sucrose gradient (20-50%) showed that RNA-dependent DNA-polymerase activity was distributed between fractions with densities 1.18-1.19 g/ml and 1.09-1.1 g/ml. In the fractions with 1.18-1.19 g/ml density the enzymic activity could be detected only after Triton X-100 treatment and disappeared after the incubation with pancreatic ribonuclease A. Triton X-100 treatment of the 165 000 g supernatant and the fractions with density 1.09-1.1 g/ml did not increase further the enzymic activity. Electron microscopy revealed in the 1.18 g/ml fraction virus-like particles resembling retroviruses of A and C type. In the light peak "non-mature" virus-like particles were found. The 165 000 g supernatant devoid of virus-like particles contained free RNA-dependent DNA-polymerase activity. The virus-like particles of both types seem to be endogenous rat retroviruses serving as a source of the particular and free reverse transcriptase in the rat liver.

Animals↗