Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Treatment of neuroblastoma cells with dibutyryl-adenosine 3':5'-monophosphate or adenine induced axon formation and a three-fold increase in the polyadenylate, poly(A), content of the polysomal mRNA. The extracted poly(A) contained 90% adenylic acid and showed a mobility of 6--7 S in dodecylsulfate-polyacrylamide gel electrophoresis. Treatment with dibutyryl-adenosine 3':5'-monophosphate or adenine, also induced a 4--6 fold increase in a nuclear enzymic activity that incorporated [3H]ATP to an acid-insoluble polymer in a cell-free system. This polymer, like poly(A) extracted from the polysomal mRNA, was bound at high salt concentration to nitrocellulose filters. [3H]ATP incorporation was Mg2+-dependent, sensitive to ribonuclease and EDTA and resistant to deoxyribonuclease and actinomycin D. There was no incorporation of [3H]UTP or [3H]dTTP and addition of TUP, CTP and GTP did not increase the incorporation of [3H]ATP. 5-Bromodeoxyuridine induced axon formation of neuroblastoma cells and poly(A) polymerase activity, without increasing the poly(A) content in the polysomal mRNA. The results indicate that induction of axon formation of neuroblastoma cells is associated with an increase in the activity of poly(A) polymerase. It is suggested that the induction of this enzyme may be generally involved in cell differentiation.
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PMID:Induction of polyadenylate polymerase and differentiation in neuroblastoma cells. 17 99

Escherichia coli B infected with T4 phage ghosts at 10 mM Mg2+ regains its protein synthesizing activity upon addition of ATP, GTP, and their generator to approximately 2% of the intact exponentially growing cells. In contrast to amino acid incorporation by intact cells, this system is sensitive to EDTA or low Mg2+. On the other hand, this system, differing from the regular cell-free system, does not respond to addition of soluble protein and ribonuclease. The ghost-infected cells were able to synthesize beta-galactosidase upon addition of the inducer isopropyl thiogalactoside. The initial rate of the induction was 2.6% of intact cells. For this induction, the addition of cyclic AMP, amino acids, ATP, GTP, UTP, CTP, and their generator was necessary. The induction of beta-galactosidase in these ghost-infected cells was very sensitive to the addition of EDTA, CaCl2, sulfhydryl blocking reagent, rifampin and chloramphenicol but insensitive to DNA synthesis inhibitors such as nalidixic acid and DNase.
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PMID:Protein synthesis in bacteriophage ghost-infected cells. 17 55

Transcription was determined in liver chromatin from rats fed for 6 days, an optimal (20%) or suboptimal (3%) amount of high-quality protein. Transcription by Escherichia coli RNA polymerase (EC 2.7.7.6) was lower after prolonged incubation with chromatin from rats fed 3% as compared with 20% protein. Differences were detected in the transcripts of the two types of chromatin after analysis by sucrose density gradient centrifugation. But no measurable differences were found in the melting profiles at low ionic strength of the two chromatin preparations. Transcription per milligram chromatin DNA was 25-fold higher using E. coli RNA polymerase instead of rat liver RNA polymerase II. The use of UTP as radioactive precursor in the absence of ATP, GTP and CTP resulted in a low labelling of RNA. One [lambda32P]UTP nucleotide was incorporated/8 UMP nucleotides. The product obtained was sensitive to ribonuclease treatment. In the presence of ATP, GTP and CTP [lambda-32P]UTP nucleotide incorporation was reduced and that of UMP nucleotide was increased giving a ratio of 1:188.
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PMID:Transcription of rat liver chromatin by Escherichia coli RNA polymerase: template properties after protein restriction. 36 67

Nuclei from seminal vesicle epithelium of adult guinea pigs were isolated in hypertonic sucrose solution. The incorporation of [3H]UTP by the isolated nuclei into acid-precipitable products was studied. Incorporation required ATP, GTP, CTP, UTP, and Mg+2. It was inhibited by addition of actinomycin D, deoxyribonuclease, or pyrophosphate to the reaction mixture. Thus, incorporation of [3H]UTP by isolated nuclei had the same characteristics that have been demonstrated for the reactions catalyzed by nuclear RNA polymerases. Using alpha-amanitin as a metabolic tool, we established concentrations of (NH4)2SO4. Mg+2, and nucleotides that give maximum assayable activities of nuclear RNA polymerases I and II. When the activities of polymerases I and II were measured in isolated seminal vesicle nuclei of guinea pigs that had been castrated 4 days earlier, a marked decrease in activities was found relative to control values (nuclei from intact animals). No further decrease was found 8 days after castration. Diminished accessibility to the nuclear DNA template and a decrease in the concentration of RNA polymerase molecules seemed to be responsible for the observed effects of castration on activities of RNA polymerases. An increase in ribonuclease activity did not seem to be responsible for the effects of castration. Activities of the enzymes did not change 2, 3, or 4 hours after intraperitoneal injection (2 mg/kg body weight) of each of five different androgens. Similarly, a single intraperitoneal injection of testosterone did not restore enzyme activity of polymerade I or II at any time during the first 24-hour period after hormone administration.
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PMID:RNA polymerase activities in isolated nuclei of guinea pig seminal vesicle epithelium: influence of castration and androgen administration. 90 9

Approximately one-third of the total ATP-hydrolysis activity in isolated HeLa nuclei is sensitive to RNAase (ribonuclease). This activity is selectively extracted with pulse-labelled RNA. In the extracts it co-sediments with various particles with sedimentation coefficients from 10S to 50S, but especially with 24S and 40S particles. ATP hydrolysis by the isolated particles was inhibited extensively (greater than 80%) by RNAase A, heparin and 0.2 M-NaCl. The activity of RNAase-treated particles was recovered when poly(A) was added, but not when DNA was added. The isolated particles exhibited RNAase-sensitive hydrolysis activities for dATP, GTP, CTP and UTP as well as for ATP, and the UTPase activity in the extracts showed nearly the same sedimentation distribution as the ATPase activity. When samples of isolated particles were irradiated with u.v. light in the presence of [alpha-32P]ATP, a 39 kDa polypeptide with a broad distribution from 10S to 50S like that of the ATPase and a 55 kDa polypeptide with a sharp distribution at 24S were photolabelled. Taken together, the data suggest that ATP-hydrolysis activity found in nuclear ribonucleoprotein subfractions appears to be the result of one or two RNA-dependent NTPases that are normally associated with endogenous RNA in a wide variety of particles.
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PMID:Characterization of a ribonuclease-sensitive nucleoside triphosphatase activity from HeLa nuclei. 240 2

Rat liver mitochondria isolated in sucrose-N-tris(hydroxymethyl)methyl-2-aminoethane-sulphonic acid (TES) incorporated [(3)H]UTP into RNA for 1h. Incorporation was inhibited 50% by 1mug of actinomycin D/ml, 1mug of acriflavine/ml and 0.5mug of ethidium bromide/ml but was insensitive to rifampicin, rifamycin SV, streptovarcin and deoxyribonuclease. After the first 10min of incubation, the synthesis was insensitive to ribonuclease. RNA synthesis by mitochondria isolated in sucrose-EDTA was insensitive to actinomycin D and sensitive to ribonuclease during the first 10min of the incubation but thereafter the sensitivities were the same as for mitochondria isolated in sucrose-TES. In a hypo-osmotic medium the relative extent of incorporation of the four ribonucleoside triphosphates into RNA was CTP>UTP=ATP>>GTP. In an iso-osmotic medium the incorporation of CTP and GTP decreased. All four nucleotides were incorporated into RNA in a DNA-dependent process, as indicated by the inhibition by actinomycin D. In addition, CTP and ATP were incorporated into the CCA end of mitochondrial tRNA. ATP was also incorporated into an unidentified acid-insoluble compound, which hydrolysed in alkali to a product that was not ATP, ADP or 5'- or 2(3')-AMP. Atractyloside inhibited the incorporation of ATP into RNA with 50% inhibition at 2-3nmol/mg of protein. The [(3)H]UTP-labelled RNA had peaks of 16S and 13S characteristic of mitochondrial rRNA. In addition a peak at 20-21S was observed as well as heterogeneous RNA sedimenting throughout the gradient. The synthesis of all these species was inhibited by actinomycin D, indicating that rat liver mitochondrial DNA codes for mitochondrial rRNA as well as other as yet unidentified species.
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PMID:Synthesis of ribonucleic acid by isolated rat liver mitochondria. 440 94

A cytoplasmic, microsomal bound RNA-dependent RNA polymerase has been purified 2500-fold from rabbit reticulocyte lysates. The synthesis of RNA with the purified enzyme is absolutely dependent on the addition of an RNA template. The best template is hemoglobin messenger RNA, while bacteriophage RNA and poly(A,G) are less active, and DNA is completely inactive as a template. With poly(A,G) as a template, only UTP and CTP are incorporated into polynucleotide chains, indicating that the RNA polymerase is an RNA replicase and not a terminal transferase. With messenger RNA as a template, all four ribonucleoside triphosphates are required for maximal activity. The RNA-dependent RNA polymerase reaction is extremely sensitive to low concentrations of heme, rifamycin AF/013, and ribonuclease and resistant to actinomycin D and DNase. The discovery of RNA-directed RNA synthesis in reticulocytes offers an additional site for control of gene expression in mammalian cells and provides a possible mechanism for amplification of the expression of specific genes.
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PMID:Reticulocyte RNA-dependent RNA polymerase. 451 33

1. Different reaction steps involved in protein synthesis were studied in skeletal muscles from control and myopathic hamsters. 2. There was no difference between partially purified aminoacyl-tRNA synthetases from myopathic and control animals in yield or catalytic activity, as tested with exogenous deacylated tRNA. 3. However, isolated deacylated tRNA from myopathic muscle was aminoacylated by these synthetases to a lesser extent than that derived from control muscle. 4. Addition of deacylated tRNA isolated from control muscle improved the performance of pH5 enzymes from myopathic muscle in polypeptide synthesis on homologous polyribosomes; tRNA isolated from myopathic animals did not. 5. Preparation of extracts from both types of animals in the presence of the ribonuclease-absorbent bentonite led to an increased capacity of endogenous tRNA to accept amino acids in pH5 enzymes prepared from normal and abnormal tissue, but the difference between the two systems remained the same. 6. Total tRNA nucleotidyltransferase activity, tested with twice-pyrophosphorolysed rat liver tRNA, was identical in both extracts. 7. Added tRNA nucleotidyltransferase incorporated more AMP and CMP into endogenous tRNA with the pH5 enzyme from myopathic muscle than with that from control muscle. 8. Preincubation of deacylated tRNA from myopathic muscle with ATP, CTP and tRNA nucleotidyltransferase more than doubled its subsequent aminoacyl-acceptor activity, and halved the extent of the defect relative to aminoacylation of control tRNA similarly treated. Endogenous tRNA in pH5 enzyme preparations behaved likewise. 9. It is suggested that a 3'-exonuclease in myopathic muscles attacks tRNA molecules in such a way that some of them remain substrates for tRNA nucleotidyltransferase, which may incorporate into RNA not only AMP and CMP, but also GMP. 10. Cell-free protein synthesis in preparations from myopathic hamster muscles is limited by the supply of intact tRNA molecules.
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PMID:Evidence for defective transfer ribonucleic acid in polymyopathic hamsters and its inhibitory effect on protein synthesis. 472 37

The addition of detergent-solubilized influenza C virus to a reaction mixture containing ATP, CTP, GTP, [3H]UTP, and Mg2+ leads to the synthesis of an acid-insoluble, radioactive product, which is ribonuclease-sensitive. The dinucleoside monophosphate ApG clearly enhances the reaction rate, a fact which indicates that influenza C viruses follow the same strategy of transcription as influenza A and B viruses, the other members of the orthomyxovirus family.
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PMID:Influenza-C-virion-associated RNA-dependent RNA-polymerase activity. 654 51

The conformation of the last 201 nucleotides located at the 3'-end of brome mosaic virus (BMV) RNAs was investigated in solution using different chemical and enzymatic probes. Bases were probed with dimethylsulfate (which methylates N-1 positions of A, N-3 positions of C and N-7 positions of G), a carbodiimide (which modifies N-1 positions of G and N-3 positions of U) and diethylpyrocarbonate (which modifies N-7 positions of A). Ribonucleases T1, U2 and S1 were used to map unpaired nucleotides and ribonuclease V1 to monitor paired bases or stacked nucleotides. Cleavage or modification sites were detected by gel electrophoresis either indirectly by analyzing DNA sequence patterns generated by primer extension with reverse transcriptase of the modified RNAs or by direct identification within the statistical cleavage patterns of the RNA. On the basis of these biochemical results, an atomic model was built by computer modeling and its stereochemistry refined. The deduced secondary structure of the RNA confirms data previously proposed by others but contains additional base-pairs (A27-U32, A28-G31, G41-A134, G64-C68, U80-A99, G81-A98, G88-U91, G100-U126, U104-U125, G162-G166 and A172-A191), one new tertiary long-range interaction (U103-U164) and a small triple helical conformation with (G41-A134)-A18 and (C42-G133)-A17 interactions. The new secondary structure also indicates the existence of a second pseudoknot involving pairing between residues A181 to A184 and residues U197 to U194, outside the domain conferring tyrosylation ability to BMV RNA. The main outcome from the model stems from its intricate folding, which allows a new assignment for the domains mimicking the anticodon- and D-loop regions of tRNA. Interestingly, the stem and loop region found structurally to be analogous to the anticodon arm of tRNA(Tyr) does not contain the tyrosine anticodon involved in the aminoacylation process. The structural analogies with canonical tRNA(Tyr) illustrate the functional mimicry existing between the BMV RNA structure and canonical tRNA(Tyr) that allows for their efficient aminoacylation by tyrosyl-tRNA synthetase. This structural model rationalizes mutagenic and footprinting data that have established the importance of specific regions of the viral RNA for recognition by its replicase, (ATP,CTP):tRNA nucleotidyl-transferase and yeast tyrosyl-tRNA synthetase. The new fold has biological implications that can be used as a predictive tool for elaborating new experiments.
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PMID:Solution structure of the 3'-end of brome mosaic virus genomic RNAs. Conformational mimicry with canonical tRNAs. 828 79


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