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V V Adler

Publications and source records attributed to V V Adler.

At least 55 records · Page 3Linked to original sources
PubMed1976

[Effect of dexamethasone on RNA synthesis in blood lymphocytes stimulated by phytohemagglutinin].

Phytohemagglutinin (PHA) stimulated RNA synthesis 6 hours after the beginning of incubation of blood lymphocytes in vitro. Dexamethazone in a concentration of 60 mug/ml depressed the RNA synthesis in the blood lymphocytes of donors, treated with PHA, 6 hours after the beginning of cell incubation with the hormone and PHA in vitro. Changes in the action mechanism of the hormone which can lead to the change of sensitivity to glucocorticoids of the same cells at various stages of the cell cycle are analyzed.

Cell Nucleus↗
PubMed1976

[Influence of dexamethasone on RNA synthesis in human peripheral blood lymphocytes].

Biphasic character of dexamethasone action on the lymphoid tissue is observed in the tissue culture of partially purified peripheral blood lymphocytes. Stimulation of the RNA synthesis occurred after 6-hour incubation of lymphocytes with the hormone. Sedimentation analysis of labeled RNA, fractionated in a column containing poly-U sepharose pointed to increase in the quantity of the messenger RNA and enrichment of the cytoplasmic RNA with poly-A sequences. At the same time the Mn++-dependable RNA polymerase sensitive to alpha-amanitin was activated. Inhibition of the RNA synthesis is observed after 24-hour cultivation of lymphocytes with the hormone. Biphasic effect of the steroid is also seen in the reaction of rosetteformation.

DNA-Directed RNA Polymerases↗
PubMedDate not supplied

Isolation of a hybrid between rat ribosomal RNA and DNA.

A procedure for the isolation and purification of a specific hybrid between rat 28S and 18S ribosomal RNA's and nucleolar DNA is described. The method employed includes the following steps: 1) isolation of the nucleolar DNA, 2) hybridization of [14C]rRNA with the nucleolar DNA, and 3) isolation and purification of the rRNA-DNA hybrid complex by chromatography on hydroxylapatite and centrifugation in a CsCl density gradient. In the isolated hybrid complex the RNA:DNA ratio is close to 1:1, and the degree of enrichment of the DNA by the rRNA cistrons is about 1500 times. The hybrid obtained has a sedimentation constant on the order of 20S, is resistant to the action of pancreatic RNase and RNase T1 and sheep brain DNase, and is characterized by high thermostability. Acording to the physicochemical tests used, the rRNA-DNA hybrid complex is a double-stranded poly-nucleotide with an ordered secondary structure.

Animals↗
PubMedDate not supplied

[Signaling pathways that control the growth and survival of prostate tumor cells in the absence of androgens].

Androgen-dependent human prostate adenocarcinoma cell line LNCaP was used to study the effect of androgen deprivation on the cell response to TNF-related cytokines. Several signaling pathways were implicated in cell survival in the absence of androgens. In androgen-deprived LNCaP cells, TNF-alpha and TRAIL stimulated the cell growth and activated the mitogenic and antiapoptotic signaling pathways involving NF-kappa B, STAT3, PI3K, and beta-catenin. The results suggested a role of cytokines in the survival of prostate adenocarcinoma cells deprived of androgens in vitro.

Acetylcysteine↗
PubMedDate not supplied

[Differences in expression and functional organization of the rat tyrosine aminotransferase gene in two lines of Morris hepatoma, 8994 and 7777].

Expression and structural organization of tyrosine aminotransferase (TAT) gene in Morris hepatoma cell line 7777 with active and glucocorticoid-inducible TAT gene and in hepatoma 8994, where TAT gene does not function were analysed. No differences in the number of receptor macromolecules, translocation and nuclear binding of hormone-receptor complexes in hormone sensitive (7777) and resistant (8994) cell lines were demonstrated. Dexamethasone increases TAT gene transcription in 7777 cell line but not 8994. Restriction analysis of TAT gene does not reveal any differences either in structural or in regulatory regions. Gel retardation assay with cloned TAT fragment (-400 b.p.) from normal hepatocytes showed identical shift of mobility in 7777 and 8994 cell lines. Moreover, 5'-flanking sequence (-890 b.p.) of TAT gene linked to the bacterial CAT gene is transiently expressed in both cell lines. We have shown that HpaII site (-105 b.p.) of TAT gene is methylated in those cells where TAT gene does not function (thymus, spleen, Zajdela ascites hepatoma) and is demethylated in TAT gene expressing hepatoma 7777 and normal rat hepatocytes. In hepatoma 8994 there are no DNAse I hypersensitive regions, typical to functioning TAT gene from hepatoma 7777 and normal hepatocytes.

Animals↗
PubMedDate not supplied

[Regulatory protein factor CTCF interacts with a segment of the chicken c-myc oncogene promotor, capable of changing to a noncanonical conformation].

To identify the regions in the chicken c-myc promoter that are necessary for the binding of a nuclear trans-acting factor CTCF--the potential oncogene activator--we used a synthetic analog of the natural binding site that contains three correctly spaced CCCTC-repeats that are known to be involved in CTCF-binding. Gel retardation experiments failed to detect any CTCF-binding activity with this synthetic site. We conclude that GC-transversions made in the regions presumed to be invalid, do in fact interfere with the protein binding. The secondary structure analysis with S1-nuclease shows the presence of an unusual DNA conformation of the CTCF-binding site in the supercoiled plasmids, that can not be detected with the artificial construction. The precise mapping of S1 nuclease cleavage reveals several hypersensitive sites in the CCCTC-zone. Thus, an altered secondary structure may be functionally important for the protein recognition in vivo.

Animals↗
PubMedDate not supplied

[Activation of transcription of the tyrosine aminotransferase gene in the rat McA-RN 7777 hepatoma cell line by cycloheximide].

The expression of the tyrosine aminotransferase (TAT) mRNA after cycloheximide treatment was analysed by Northern blotting method in Morris rat hepatoma cell lines. The level of TAT mRNA increased after 6-8 h of cycloheximide treatment only in the McA-RH 7777 cell line. McA-RH 7777 nuclear run-off assay showed that TAT transcription was induced by cycloheximide treatment. Both glucocorticoid and cycloheximide modulated TAT gene transcription in a synergistic way. There was no induction of TAT expression following cycloheximide or cycloheximide glucocorticoid simultaneous treatment in another cell line (McA-RH 8994), while c-myc and c-fos expression was superinduced by cycloheximide treatment. The possible mechanism of transcription regulation and its damage in hepatoma cells is discussed.

Animals↗
PubMedDate not supplied

[Specific interaction of a nuclear protein factor from the CTF/NF-I family with 2 different promoter regions of the rat tyrosine aminotransferase gene].

Using gel-retardation and DNase I footprinting assays, we have analysed sequence-specific DNA-protein interactions within proximal promoter fragment (from -2 to -210 bp relative to the transcription start) of the rat tyrosine aminotransferase (TAT) gene. Two distinct DNase I protection regions flanked at either boundary by sites of DNase I hypersensitivity were observed with the rat-liver nuclear extracts. The internal sequence of the region I non-coding strand, (-155)TGGGCCACCTTCCAAT(-170), is highly homologous to the NF-I consensus sequence TGG(N)6-7TGCCAA and also shares a CCAAT-box; the region II noncoding strand sequence includes asymmetrically positioned (-37)AGCCAAT(-43) recognition motif. Since there have been a number of reports about multiple DNA-binding factors that recognize CCAAT homologies, both regions were likely to interact with either a single or distinct factors. Here we show that both region I and II of the TAT gene promoter are binding to the same factor related to the human CTF/NF-I. The evidence for that is based on competition experiments using the DNA fragment containing a synthetic consensus sequence for the NF-I recognition site and on the indistinguishable chromatographic properties of the activity specifically binding to each of three DNA fragments containing NF-I consensus, region I and region II sequences.

Animals↗
PubMedDate not supplied

[Nuclear factor A5 from the rat liver that requires a metal for specific interaction in vitro with distal element of the tyrosine aminotransferase gene promoter].

To detect nuclear protein factors which might account for a tissue-specific and inducible expression of the rat tyrosine aminotransferase (TAT) gene promoter, extracts from rat liver and spleen nuclei have been fractionated by heparin-sepharose chromatography and the fractions assayed for sequence-specific binding to the distal TAT gene promoter element (sequence between -313 and -210). Gel retardation experiments carried out in the presence or absence of Mg2+, Ca2+, or Zn2+ ions showed that there are at least two nuclear factors (A3 and A4) binding to the distal promoter element only in the presence of the chelator (20 mM EDTA). Incubation of the protein fractions with Zn2+ or Ca2+ instead of commonly used Mg2+allowed: (i) to avoid 3 2P-DNA-probe degradation by "contaminating" endogenous nucleases; and (ii) to detect another sequence-specific nuclear factor, A5. No other specific binding activities were found in the rat-liver nuclear fractions tested under these conditions. As the metal ions became inaccessible to chelation in excess of EDTA and EGTA when protein factor A5 was complexed to DNA we assumed that factor A5 is metalloprotein which requires Zn or Ca to maintain a structure of its DNA-binding domain. To identify the polypeptide possessing this domain, a protein gel blotting procedure was employed. By incubating gel blots with the 3 2P-DNA-probe in the buffer containing Zn2+, specific binding to the only polypeptide with approximate Mr 30 kDa was clearly revealed. Both gel retardation and gel blotting assays consistently showed that nuclear factor A5 is present in the liver, but not in the spleen extracts.

Animals↗
PubMedDate not supplied

Extraction of tyrosine aminotransferase mRNA by polyribosome immunosorption on sepharose 4B.

Sepharose 4B column with antibody to tyrosine aminotransferase (E.C. 2.6.1.5) (TAT) covalently bound can selectively remove a specific fraction of TAT polysomes from rat liver homogenates. From the polysomes which was adsorbed by immunosorbent one may obtain mRNA containing a segment of poly-adenilate-rich residues, having sedimentation constant of 11--16S. This mRNA may program synthesis of the specific protein in a cell free system. Near 70% of the protein was synthesized in such a system, may react with the antibody to TAT.

Animals↗
PubMedDate not supplied

[Regulation of the transcription of the tyrosine aminotransferase gene by glucocorticoids in Morris hepatoma 7777 and 8994 cells].

Kinetics of tyrosine aminotransferase (TAT) mRNA synthesis in Morris rat hepatoma cell lines 7777 and 8994 after dexamethasone treatment (10(-7) M) was studied by molecular hybridization of the RNA with cloned fragments of TAT gene from rat liver cells. It was demonstrated that initiation of TAT gene transcription increased 20 minutes after glucocorticoid treatment. The level of TAT mRNA was not induced by dexamethasone in rat hepatoma cell line 8994. Actinomycin D prevented the deinduction of TAT by stabilization of TAT mRNA.

Animals↗