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N P Mertvetsov

Publications and source records attributed to N P Mertvetsov.

At least 55 records · Page 3Linked to original sources
PubMed1987

[Cloning of DNA complementary to mRNA for proopiomelanocortin from the bovine, rat and human hypophysis. Hormonal regulation of proopiomelanocortin mRNA in the rat hypophysis].

Cloning of DNA and complementary mRNA of bovine, rat and human proopiomelanocortin (POMC) was carried out. A structural analysis of the cloned cDNA of POMC was performed. Using restriction fragments of bovine, rat and human POMC cloned cDNA, probes for molecular hybridization based on one-chain bacteriophage M13 were made. Using the dot-hybridization technique with labeled [32P] POMC cDNA, the effect of 17 beta-estradiol and adrenalectomy on the POMC mRNA level in rat hypophysis was studied. The hormone was shown to significantly decrease the POMC mRNA content at a concentration of 4 and 8 micrograms per 100 g of body weight 4 hours after injection. Adrenalectomy caused a 2-3-fold increase in the POMC mRNA level in rat hypophysis after a period of 5-7 days. The possibility of polyhormonal control of POMC genome transcription is discussed.

Adrenalectomy↗
PubMed1986

[Detection of DNA sequences sensitive to glucocorticoids in the thymus of AKR mice and their inactivation in thymoma].

A high increase in transcriptionally active DNA fraction (TA DNA) has been detected in the thymus of young AKR mice and in thymoma. Hybridization of TA DNA with [32P] cDNA synthesized on poly A+-mRNA of cortisol-induced animals has shown that TA DNA of young AKR mice contains 40 times as much cortisol-activated repeated sequences (RS) as that of thymoma. The decrease of cortisol-activated (RS) in AKR thymoma TA DNA was found to be the result of their transition into transcriptionally inactive (TI) DNA. It is concluded that chromatin conformation changes take place in cortisol-activated RS DNA region of AKR mouse thymus before transformation. Unstable conformation of RS DNA in the thymoma can possibly promote their transition into TI DNA.

Animals↗
PubMed1985

A study of [3H]aldosterone binding by nuclear and cytoplasmic receptors of the rat kidney with different content of aldosterone in the organism.

The distribution of specific mineralocorticoid receptors in rat kidney cells was found to depend on aldosterone concentration. With increasing aldosterone concentrations the number of specific receptors for aldosterone in the cytoplasm decreased and their quantity in the nuclei increased. This was evidently due to their enhanced transport from the cytoplasm to the nuclei. It was found that aldosterone (its complex with the receptor) attached to non-histone proteins of chromatin and that the structural integrity of DNA is needed to provide the binding of this complex to the cell nuclei. The quantity of aldosterone acceptor sites in the kidney cell nuclei remained constant when aldosterone concentrations in the organism changed, and, hence, the functional states of the target organ changed too.

Aldosterone↗
PubMed1984

[Changes in the content of matrix RNA coding tyrosine aminotransferase in the rat liver during hydrocortisone induction].

The effects of the glucocorticoid hydrocortisone on the synthesis of specific template RNA coding tyrosine aminotransferase (TAT) in rat liver during hormonal induction were studied. Using hybridization of complementary DNA (cDNA-TAT) with polysomal liver poly-A-mRNA, the content of specific mRNA-TAT in liver polysomes during and after hormonal induction, i. e. 4 and 16 hrs after hydrocortisone injection, respectively, was estimated. It was shown that 4 hrs after the hormone injection that mRNA-TAT content in liver polysomes is increased 3-4-fold, showing a return to the initial level after 16 hrs. Thus, transcription is the main link in the realization of glucocorticoid induction.

Animals↗
PubMed1983

[Immunohistochemical localization of inducible tyrosine aminotransferase isoenzyme in the cells of the normal rat liver and in hydrocortisone induction].

Using immunofluorescent technique, a soluble antigen--hydrocortisone induced isoenzyme of tyrosineaminotransferase--was localized in sections of the intact rat liver. Tyrosineaminotransferase was not detected in all the hepatocytes. 5 hours following hydrocortisone to rats, the intensity of specific fluorescence that characterizes trosineaminotransferase activity in hepatocytes, was found to increase, and clearly outlined zones of entire fluorescence were seen in the liver sections. The data obtained are discussed in terms of hormonal induction mechanisms.

Animals↗
PubMed1983

[Isolation and in vitro translation of polysomes and the RNA matrix from gibberellic acid-treated etiolated dwarf pea shoots].

The effect of gibberellic acid (GA) on the size of polysomes (PS) and on the specific translation activity of epicotyl PS of two dwarf pea varieties was studied. It was shown that GA does not significantly alter the specific translation activity of PS and of mRNA isolated from dwarf pea epicotyl PS. Electrophoretic separation of the polypeptides synthesized in a cell-free protein-synthesizing system in PS of control and GA-treated shoots revealed no differences between them. Some minor qualitative and quantitative differences in the protein composition of the cytoplasm of control and hormone-treated shoots were found. Possible influence of GA on the composition of a definite class of mRNA and on posttranslational processing of plant proteins is discussed.

Cell Fractionation↗
PubMed1982

[Effect of gibberellic acid on RNA synthesis in dwarf peas].

The effect of gibberellic acid (GA) on total RNA and polysomal poly-[A]+-RNA synthesis in epicotylia and embryos of dwarf pea of two varieties differing in their physiological sensitivity to GA was studied. It was found that incubation with GA increases the accumulation of total RNA in pea epicotylia, var. "Pioner" and "Polzunok". The maximal stimulation of RNA accumulation makes up to 40% for the low sensitivity variety "Polzunok" and 150% for the highly sensitive variety "Pioner". GA increases the synthesis of polysomal poly (A)+-mRNA in 5-year-old pea sprouts and that of newly synthesized poly (A)+-mRNA in epicotylian polysomes of both varieties 5, 24, 48 and 72 hrs after incubation with GA. GA at concentrations of 10(-6) and 10(-5) stimulates the incorporation of [3H]uridine into polysomal mRNA during the first 1--3 hours after treatment and enhances the accumulation of newly synthesized mRNA in pea embryonic polyribosomes. The stimulating effect is directly proportional to the dose of the hormone. The mechanisms of GA effect on the transcription and translation in pea plant cells are discussed.

Gibberellins↗
PubMed1980

[Mammalian protein synthesis in the cytoplasm of a plant cell].

Using immunochemical and, subsequently, autoradiographic methods, the authors have shown that after the injection of the total fraction of polyribosomes isolated from the rat liver in the Acetabularia cytoplasm a protein interacting with the antiserum against rat thyrosine aminotransferase is synthesized. Prospects of using Acetabularia as a test-system for the translation of heterogenous mRNA and mRNP are discussed.

Acetabularia↗
PubMed1980

[Expression of the restriction fragment of phage T7 DNA in a cell-free transcription-translation system from E. coli].

The matrix activity of phage T7 DNA and the restriction fragment of phage T7 DNA containing gene 0,3 with a promoter was studied with respect to RNA and protein syntheses in a cell-free transcription-translation system from E. coli. A comparison of the protein products of cell-free synthesis was carried out, using polyacrylamide gel electrophoresis and a subsequent radiofluorography. Data from PAAG suggest that the restriction fragment codes the synthesis of a polypeptide, whose size is identical to that of a polypeptide synthesized on a corresponding gene in phage T7 DNA. A possible use of the cell-free system of coupled transcription-translation for the functional mapping of the genome DNA is discussed.

Cell-Free System↗
PubMed1978

[Indirect immunoprecipitation by rat liver polyribosomes using antibodies to tyrosine aminotransferase].

A fraction of rat liver polyribosomes is isolated, which in its immunochemical characteristics considerably enriched with polyribosomes capable to synthesize hydrocortisone-induced liver tyrosine aminotransferase isoenzyme. This specific polyribosome fraction was purified by immunochemical fractionation of total liver polyribosomes using indirect precipitation. The content of polyribosomes in immunoprecipitates comprise 0.4-0.8% of its initial amount (before immunochemical fractionation). The ratio of specific polyribosomes in immunoprecipitates varies from 20 to 45%, which corresponds to 25-100-fold purification. The data obtained suggest that the method of indirect precipitation can be an efficient step in the isolation procedure of individual mRNA.

Animals↗
PubMed1978

[Effect of cortisol on the content of mRNA coding inducible tyrosine aminotransferase isoenzyme in rat liver].

In vitro estimation of synthesis of inducible tyrosine aminotransferase isoenzyme, directed by poly-A-containing RNA from liver of intact and corticol treated rats, is carried out. Total poly-A-containing RNA from liver polyribosomes of intact and induced rats was translated in cell-free system from wheat germs. Two antibodies immunoprecipitation was used to identify the translocation product (tyrosine aminotransferase). It was found that a synthesis of a specific protein product, precipitated by antibodies to tyrosine aminotransferase, takes place in cell-free system under translation of polysomic poly-A-containing liver RNA. The amount of immunoprecipitated product indicates, that the content of individual poly-A-containing mRNA for inducible tyrosine aminotransferase isoenzyme in liver of cortisol-induced rats is considerably higher than in intact animals.

Animals↗
PubMed1978

[Effect of hydrocortisone on the properties of rat liver polyribosomes, metabolism, and template activity of polysomal poly-A-containing RNA].

The effect of hydrocortisone on the amount of newly synthesized polyribosomal poly-A+-RNA and its translation activity and the distribution of polyribosomes in the induction dynamics according to their size were studied. It was shown that 3-5 hours after intraperitoneal injection of hydrocortisone the incorporation of labelled precursors into polyribosomal poly-A+-mRNA is increased, which is accompanied by rapid accumulation of mRNA in the polyribosomes. Under prolonged induction those parameters come down to the initial level. 4-7 hours after the injection of the hormone the relative amount of heavy polyribosomes (350-412S) in liver cells is increased. It was found that hydrocortisone significantly changes the specific translation activity of polysomal poly-A+-mRNA: it shows an increase 2-4 hours after the hormone injection and returns to the initial level 12 hours after the injection.

Animals↗
PubMed1976

[Isolation and properties of cortisol inducible and cortisol non-inducible isoenzymes of rat liver tyrosine aminotransferase].

Rat liver contains two groups of tyrosine aminotransferase (TAT) isoenzymes; during electrophoresis in agar gel one of the groups moves to the anode and the other--to the catode. Cortisol is shown to induce only the anode isoenzymes of TAT, which were isolated, purified and thoroughly analyzed. The inducible anode isoenzyme of TAT spearated from other proteins is more sensitive to the effect of proteases (trypsin and chymotrypsin) than the catode isoenzyme. Some kinetic parameters of the purified TAT isoenzymes were studied. Both isoenzymes have pH optimum around 7.5; their apparent Km values for tyrosine are also similar. However, the catode isoenzyme of TAT possesses a higher affinity for alpha-ketoglutarate than does the anode isoenzyme. Unlike the latter, the former isoenzyme may use oxaloacetate as an amino group acceptor. Pyridoxal phosphate is firmly bound to the catode isoenzyme and can be readily spearated from the anode isoenzyme during dyalisis. An increased sensitivity of the inducible isoenzyme to proteases is due not only to the possibility of coenzyme dissociation, but also to some specific properties of the apoenzyme. The results obtained support the assumption that a high sensitivity of the inducible isoenzymes to proteases provides for a removal of excessive amounts of the enzymes from the cells under cessation of hormonal induction, thus maintaining enzymatic homostasis in the cell.

Animals↗