Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rhodium(II) acetate, propionate, and butyrate showed a considerable variation in their antitumor activity against Ehrlich ascites tumor cells in mice, with the butyrate complex being the most active. The three complexes markedly inhibited DNA synthesis of Ehrlich ascites tumor cells in vivo. Rhodium (II) butyrate was the most potent inhibitor followed by the propionate complex. One hour after administration, rhodium(II) propionate and butyrate induce more uridine-5-3H incorporation into RNA than is seen in the controls. Equilibrium dialysis studied showed that rhodium(II) acetate-1-14C binds to single stranded DNA, poly-A, ribonuclease A, and bovine serum albumin but not to highly polymerized native calf thymus DNA, poly-G, or poly-C. In these cases binding occurred at the two axial positions of rhodium(II) acetate to a nitrogen donor in the ligands. The formation constants of the rhodium(II) acetate and propionate complexes with 5'-adenosine monophosphate were determined. The rhodium(II) propionate complex was more stable. Sedimentation and viscosity measurements of poly-A and poly-A/rhodium(II) acetate complexes indicate a high degree of intramolecular crosslinking in the rhodium(II) acetate/poly-A complex. The rhodium(II) carboxylate complexes were also found to be potent inhibitors of purified DNA polymerase I and RNA polymerase from Escherichia coli.
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PMID:Interaction of Rhodium(II) carboxylates with molecules of biologic importance. 110 39

Age-associated alterations in the chromatin functions of human diploid cells have been observed. These alterations include: (1) a decline in the rate of histone acetylation; (2) a reduction in the rate of RNA synthesis as measured by (a) the rate of 3H-uridine incorporated into the RNA of young and old cells; (b) comparison of the template activity of isolated chromatin from young and old cells using E. coli RNA polymerase and (c) measurement of chromatin template activity using the endogenous RNA polymerase of young and old cells. It is suggested that the nondividing state of old cells may be the result of the inability to synthesize specific RNA molecules (and perhaps specific proteins) necessary for the cell to continue through the cell cycle.
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PMID:Alterations in chromatin functions during aging in vitro. 111 31

During chain elongation RNA polymerase exists as a ternary DNA-enzyme-RNA complex in which a discrete length of the nascent RNA chain proximal to the 3'-OH terminus will be bound to the product binding site (Krakow, J. S., and Fronk, E. (1969) J. Biol. Chem. 244, 5988). We have utilized the poly[d(A-T)]-directed reaction to determine the length of the nascent poly[r(A-U)] protected from attack by pancreatic ribonuclease. Following release of the ribonuclease resistant oligo[r(A-U)] from the ternary complex, its size was determined by ion exchange chromatography on DEAE-cellulose, gel filtration on Bio-Gel P-10, and the ratio of 3'-terminal uridine to internal 2':3'-UMP following alkaline hydrolysis. The results indicate that the length of the nascent protected fragment is approximately 12 residues.
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PMID:Studies on the product binding sites of the Azotobacter vinelandii ribonucleic acid polymerase. 112 30

DNA-dependent RNA polymerases I and II were purified from pig kidney nuclei by chromatography on DEAE-Sephadex and phosphocellulose. When nonlimiting amounts of double-stranded DNA were used as the template, the in vitro transcription was markedly stimulated by spermidine and spermine. Maximal stimulation of RNA polymerase I occurred at 2-5 mM spermidine and 0.5-2 mM spermine, whereas optimal polyamine concentrations for RNA polymerase II were 5-10 and 1-5 mM for spermidine and spermine, respectively. DNA transcription by polymerase II was stimulated to a greater extent than that of polymerase I. Higher spermine (5-10 mM) concentrations were strong inhibitors of both polymerases under these conditions. The apparent Km of RNA polymerases I and II for UTP was unchanged at optimal polyamine concentration; under the same conditions the maximal reaction velocity was increased two- to three-fold and was essentially due to an increase in the rate of chain elongation. Thus, in a typical experiment the average chain length as determined by the UMP/uridine ratio increased from 570 to 1330 and the chain elongation rate increased from 0.64 to 1.44 nucleotides times sec-1 in the presence of spermine. When limiting quantities of native DNA were employed as the template, both RNA polymerases I and II were inhibited by 1-2 mM spermine. Kidney chromatin could be transcribed by homologous RNA polymerases with an efficiency ranging from 2 to 10% of that with native DNA. When chromatin was used in nonlimiting amounts instead of DNA, RNA polymerase II activity was again stimulated about two-fold at 2 mM spermine. Under these conditions, RNA polymerase I activity was inhibited by spermine. The inhibition of RNA synthesis in vitro at limiting quantities of templates (DNA or chromatin) could be overcome by preincubation of the enzyme with templates before polyamines were added. This inhibition thus appears to be due to a block in the initiation of RNA chains. Similar inhibition of transcription by RNA polymerase II was also observed with limiting quantities of chromatin as the template.
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PMID:DNA-dependent RNA polymerases I and II from kidney. Effect of polyamines on the in vitro transcription of DNA and chromatin. 116 98

Acridine dyes inhibit the incorporation of 3H-thymidine and 3H-uridine in intact cells to the same extent as Actinomycin D. In contrast to Actinomycin D, RNA synthesis by DNA - dependent RNA polymerase in a cell-free system is inhibited at lo2 higher concentrations of acridine dyes, only. Possible differential effects on the cell membrane resulting in decreased intracellular pools of uridine and thymidine are discussed.
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PMID:[The effect of actinomycin d, acridine dyes and related substances on the biosynthesis of nucleic acids in normal and leukemic white blood cells. Comparative investigation in intact cells and in a cell-free system (author's transl)]. 117 98

1. At 3 weeks after ovariectomy, mammary glands (5th pair) of adult Swiss mice show (i) no significant decrease in weight, (ii) 20% of the original rate of incorporation of [(3)H]-uridine into RNA (after a 30min pulse), and (iii) 90% of the original rate of incorporation of l-[(3)H]leucine into protein (after a 15min pulse). 2. A single injection of oestradiol-17beta into these ovariectomized mice produces, during the next 17h, a series of discrete bursts of increased incorporation of [(3)H]uridine into mammary-gland RNA; the bursts, which are variable in height, reach peaks at approx. 1, 9, 12 and 16h after hormone administration; an increase is already detected at 15min, the earliest time-point investigated; each burst lasts for approx. 2h. There is no significant stimulation of [(3)H]uridine incorporation into RNA of liver and quadriceps femoris muscle. 3. Nuclear incorporation of [(3)H]UTP into RNA of mammary gland in vitro is linear with time for up to 20min at 15 degrees C; it requires CTP, GTP and ATP and is inhibited by actinomycin D. Also, the incorporation is strongly inhibited by alpha-amanitin in high salt concentrations but only weakly in low salt concentrations, a result indicating that RNA polymerase II activity predominates in high salt, whereas RNA polymerase I activity predominates in low salt concentrations. Injection of oestradiol-17beta in vivo followed by measurement of nuclear RNA synthesis in vitro shows a definite increase in both RNA polymerase activities 30min after oestradiol-17beta injection, the earliest time-point investigated, a higher increase at 1h, a decline at 4h, and again a large increase at 12h. These results in general agree with the changes in precursor incorporation into RNA measured directly in the animal and suggest that changes in [(3)H]uridine uptake into RNA are not precursor-pool-dependent.
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PMID:Polyphasic changes in incorporation of precursors into ribonucleic acid of oestradiol-stimulated mammary gland. 122 Jun 81

Natural changes in the transcription of rRNA genes were studied in nucleoli from three oogenic stages of the newt Triturus alpestris with electron microscope, auto-radiographic, and biochemical techniques. From determinations of the uridine triphosphate pool sizes and [3H]uridine uptake, phosphorylation, and incorporation into 28S and 18S rRNAs in vivo it was estimated that the rate of rRNA synthesis was about 0.01% in previtellogenic oocytes and 13% in mature oocytes when compared to midvitellogenesis. Spread preparations of nucleoli showed significant morphological changes in the transcriptional complexes. The total number of lateral fibrils, i.e., ribonucleoproteins containing the nascent rRNA precursor, were drastically decreased in stages of reduced synthetic activity. This indicates that rRNA synthesis is regulated primarily at the level of transcription. The resulting patterns of fibril coverage of the nucleolar chromatin axes revealed a marked heterogeneity. On the same nucleolar axis occurred matrix units that were completely devoid of lateral fibrils, matrix units that were almost fully covered with lateral fibrils, and various forms of matrix units with a range of lateral fibril densities intermediate between the two extremes. Granular particles that were tentatively identified as RNA polymerase molecules were not restricted to the transciptional complexes. They were observed, although less regularly and separated by greater distances, in untranscribed spacer regions as well as in untranscribed gene intercepts. The results show that the pattern of transcriptional control of rRNA genes differs widely in different genes, even in the same genetic unit.
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PMID:Regulation of transcription of genes of ribosomal rna during amphibian oogenesis. A biochemical and morphological study. 126

A photoactive nucleotide analogue of UTP, 5-azido-uridine 5'-triphosphate (5-N3UTP), has been demonstrated to interact with the RNA polymerase of the vesicular stomatitis virus (VSV) transcription complex. Kinetic studies indicated that 5-N3UTP served as an efficient replacement for UTP in in vitro polymerase reactions. The Km for the azido analogue was 27 microM and that of the natural substrate, UTP, was 7 microM. Photolysis of [gamma-32P]5-N3UTP in the presence of VSV transcription complexes resulted in selective radio-labelling of the L protein. This photolabelling was saturable with an apparent Kd of 28 microM. The L protein was protected from [gamma-32P]5-N3UTP-mediated photolabelling by competing natural substrates (UTP, CTP, ATP, GTP). The stoichiometry of photoprobe incorporation into the transcription complex was close to unity with respect to the L protein. These data provide evidence that the nucleotide-binding domain of the VSV RNA polymerase contains amino acid residues of the L protein.
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PMID:The L protein of vesicular stomatitis virus transcription complexes is specifically photolabelled by 5-azido-uridine 5'-triphosphate, an analogue of the RNA polymerase substrate uridine 5'-triphosphate. 130 62

Rho-independent terminators are characterized by two major functional regions, one upstream from the termination site having a sequence capable of forming an RNA hairpin in the nascent transcript, the second extending, from the base of this hairpin, seven to nine nucleotides along the transcript to the actual sites of termination (3'-tail region). This latter region of the transcript is often rich in uridine residues. Both regions are postulated to play central roles in the termination process. We have constructed a series of hybrid rho-independent, transcription terminators in which sequences upstream and downstream from the RNA hairpin for the Escherichia coli trp attenuator (trpatt+) are interchanged with sequences from trpatt mutant (1419) or from the phage T7 early terminator (T7Te). Similar hybrids have been constructed for T7Te, replacing flanking sequences with trpatt regions. The effects of such changes on transcription termination have been tested in vitro with purified E. coli RNA polymerase to determine the intrinsic termination efficiency (%T) of each hybrid terminator. Both the trpatt+ terminator and T7Te are highly efficient rho-independent terminators in vitro. However, replacement of trpatt+ sequences upstream and downstream from the RNA-terminator hairpin with the comparable T7Te sequences reduces %T dramatically, suggesting that the RNA-terminator hairpin does not function independently from its flanking regions. Regions downstream from the actual termination/release site are shown to be of considerable importance in determining %T for terminators bearing the T7Te or trpatt1419 3'-tail region, but have little effect on terminators with the trpatt+ 3'-tail region. For terminators bearing the T7Te or trpatt1419 3'-tail region that are inefficient, efficient termination is restored by elevated concentrations of KCl in the reaction. The results do not fit well with models for termination in which %T is determined by a two-step process in which the terminator-RNA hairpin, and a seven to 12 base-pair DNA-RNA hybrid structure rich in uridine residues, act independently to cause the polymerase to pause, and to release the transcript, respectively. DNA sequences both upstream and downstream from these regions, as well as DNA sequences downstream from the transcript termination site, can significantly affect the termination process. Conversely, terminators lacking a 3'-tail region rich in uridine residues can be highly efficient, but only when joined with appropriate sequence immediately downstream from the termination site. This suggests that the 3'-tail region acts in some manner other than the formation of an unstable DNA-RNA hybrid that facilitates termination.
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PMID:Parameters affecting transcription termination by Escherichia coli RNA. II. Construction and analysis of hybrid terminators. 137 66

2'-Fluoro- and 2'-amino-2'-deoxynucleoside 5'-triphosphates have been investigated as substrates for T7 RNA polymerase. Michaelis-Menten kinetic parameters are reported for the incorporation of 2'-fluoro-2'-deoxyuridine, 2'-fluoro-2'-deoxycytidine, and 2'-amino-2'-deoxyuridine into runoff transcripts. The 2'-amino derivative of uridine is a better substrate than the 2'-fluoro derivative. Gel electrophoretic analysis shows that full-length transcripts with a length of 2500 nucleotides can be obtained with the analogues, although a considerable amount of shorter fragments accompanies the full-length product. In keeping with the kinetic analysis, the 2'-aminouridine triphosphate gives a cleaner product than the 2'-fluoro analogue. Transcription of two tRNA genes shows that such shorter templates can be transcribed to full-length products essentially without premature termination with any of the analogues.
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PMID:2'-Fluoro- and 2'-amino-2'-deoxynucleoside 5'-triphosphates as substrates for T7 RNA polymerase. 139 Jul 41


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