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:3.1.27.5 (RNase)
17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Electrophoretic analyses showed that no RNase-sensitive RNA smaller than the genome was specified by the flavivirus Kunjin in infected Vero cells during the period of maximum RNA and protein synthesis. In contrast, RNA extracted from Sindbis virus-infected cells under similar conditions included the expected 42S RNA (equivalent to the genome) and the smaller 26S (interjacent) RNA. Treatment of the genome of both togaviruses with 12 M urea produced a reversible (possibly conformational) change; measurement of the molecular weights of the treated RNAs by co-electrophoresis with fully denatured ribosomal RNA markers in SDS-polyacrylamide gels yielded a value of 2.1 X 10(6) if 8 M urea was incorporated in the gels and 4.2 X 10(6) if urea was omitted from the gels. These results indicate that flavivirus messenger RNA is represented solely by the intact genome of m.wt. 4.2 X 10(6).
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PMID:Togavirus RNA: reversible effect of urea on genomes and absence of subgenomic viral RNA in Kunjin virus-infected cells. 59 36

In the presence of actinomycin D or a combination of actinomycin D and either camptothecin or alpha-amanatin. Aedes albopictus cells synthesize a variety of single stranded RNA species. These actinomycin D resistant species are ethidium bromide sensitive and they are present in the cell cytoplasm in an RNase resistant structure which has the sedimentation and buoyant density characteristics of mitochondria. Twelve actinomycin D insensitive RNA species can be detected by electrophoresis in 7M urea and 11 of these bind to oligo(dT)-cellulose. An identical set of oligo(dT)-cellulose binding RNA species is obtained when A. albopictus cells are labeled in the presence of camptothecin alone. The actinomycin D insensitive RNA species which bind to oligo(dT)-cellulose hybridize to mitochondrial DNA. These data indicate that the actinomycin D insensitive RNA species have a mitochondrial origin and are not associated with the replication of an inapparent contaminating virus.
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PMID:Origin of the actinomycin D insensitive RNA species in Aedes albopictus cells. 65 22

1. Nitrogen retention was determined by classical N balance techniques in fourteen rapidly growing low-birth-weight infants receiving 3 g protein/kg body-weight and during their 3rd week of life. This was compared with plasma free alkaline ribonuclease (EC 3.I.4.22; RNase) activity and other biochemical measurements of protein nutrition. 2. Plasma RNase showed a significant positive correlation with N retention and a corresponding negative correlation with urine urea-N. These results were unexpected and suggest a different relationship between RNase and N retention in infants compared with that found by other workers in children and adults. 3. The most likely explanation of this apparent anomaly is that in all instances high activities of plasma RNase are associated with a need to conserve N. In the infants studied this may indicate some measure of 'protein economy' and they could therefore benefit from a higher protein intake.
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PMID:Plasma alkaline ribonuclease (EC 3.1.4.22) and nitrogen retention in low-birth-weight infants. 71 28

We have recently shown that 16S RNA can be extracted from 30S ribosomes by an acetic acid-urea precipitation procedure which yields RNA capable of binding 13 individual ribosomal proteins. This is in contrast to phenol extracted 16S RNA which can specifically associate with only 7 proteins2-7. In the experiments reported here, we demonstrate that the difference in protein binding capacities is due to a relatiely more "open" configuration possessed by the acetic acid-urea 16S RNA. Under identical conditions, acetic acid-urea 16S RNA is more susceptible to limited T1-RNase digestion than is phenol-16S RNA. In addition, acetic acid-urea RNA shows a relatively slower electrophoretic mobility. The observable difference in conformation between the two types of RNA is lost by storage at-70 degrees C. This loss is accompanied by a reduction in protein binding capacity of the acetic acid-urea 16S RNA.
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PMID:Evidence that 16S RNA from E. coli can assume two different biologically active conformations. 78 27

Purified influenza virus contains ribonuclease activity. The enzyme does not hydrolyze viral RNA but both 28 S and 18 S host cell RNA are degraded forming large (about 16 S) and small (about 5 S) fragments with the release of the acid-soluble material. It has an optimum temperature of 37 degrees C, requires no divalent ions, and is inhibited by 0.1 M EDTA and 1% SDS. Treatment with 4 M urea increases enzymatic activity considerably (42%) but is not a prerequisite for eliciting ribonuclease activity suggesting that the enzyme is probably located near the surface of the virus particle. Results show that the observed enzyme activity is virus-associated as no host cell protein is detectable in the purified virus.
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PMID:Association of a ribonuclease with the purified influenza virus. 81 84

The cells of Escherichia coli strain CP 78 were labeled with [32P]orthophosphate and the total radioactive RNA was prepared from the cells. The mRNA that codes for a structural lipoprotein in the outer membrane was purified from the total RNA by three successive electrophoreses on polyacrylamide slab gels, twice at pH 8.3 and once at pH 3.5 in 7 M urea. Approximately 0.002% of the total radioactive phosphate used was incorporated into the fraction containing the most purified mRNA. The two-dimensional fingerprint of the T1 ribonuclease digest of the 32P-labeled mRNA showed that the purity of the mRNA was as high as 90%. A preliminary sequence analysis was carried out on the T1 ribonuclease oligonucleotides which had been separated by the fingerprinting procedure. By using the established amino acid sequence of the lipoprotein and the genetic code, three relatively long oligonucleotides were assigned to code for three different parts of the lipoprotein. From these data, the present RNA fraction was identified as the lipoprotein mRNA. From the analysis of the T1 ribonuclease oligonucleotides, the mRNA was estimated to be 360 +/- 10 nucleotides in length. Although the length of the mRNA was enough to code for 2 lipoprotein molecules, T1 ribonuclease digestion of the mRNA yielded only 1 mol/mol of mRNA of the individual oligonucleotides assigned to parts of the amino acid sequence of the lipoprotein. This suggests that the mRNA codes for only 1 molecule of the lipoprotein. It was also found that the mRNA has no polyadenylate sequence at the 3' end.
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PMID:Isolation and identification of the messenger ribonucleic acid for a structural lipoprotein of the Escherichia coli outer membrane. 82 86

Because the ribonucleoprotein forms of the segments of the Uukuniemi virus genome have previously been characterized as circular, we examined the isolated RNAs by electron microscopy under conditions of increasing denaturation. After spreading under moderately denaturing conditions (50 or 60% formamide), 50 to 70% of the molecules were circular. Increasing the formamide concentration to 70 and 85% decreased the number of circular forms, and only linear forms were observed after incubation of the RNA at 60 degrees C for 15 min in 99% formamide. When spread from 4 M urea-80% formamide--another condition known to denature RNA--only 5 to 30% circular molecules were observed. Pretreatment of the RNA with 0.5 M glyoxal at 37 degrees C for 15 min prior to spreading from 50% formamide gave less than 5% cirucular forms. Length measurement of the molecules showed that they were not significantly degraded by any of the methods employed. The circular molecules were destroyed by treatment with pancreatic RNase, but were unaffected by DNase or proteinase K treatment. After complete denaturation of the RNA, the circles could be reformed under reannealing conditions. We conclude that the three size classes of RNA that comprise the Uukuniemi virus genome are circular molecules probably maintained in that form by base pairing between inverted complementary sequences at the 3' and 5' ends of linear molecules.
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PMID:Circular forms of Uukuniemi virion RNA: an electron microscopic study. 85 Mar 4

Two general methods for the isolation of DNA from various sources based on the use of cetyltrimethylammonium bromide (cetavlon, CTA-Br) are described. Cetavlon is a strong cationic detergent precipitating DNA from diluted salt solutions. Cells are lysed and cellular components are dissolved in the presence of cetavlon, 5 M urea, 0.1 M EDTA and 2 M NaCl (KCl). In the first method pure DNA is precipitated in the form of CTA-salt by direct dilution of the lysate to bring the concentration of NaCl (KCl) down to 0.5 M after the removal of the main part of proteins by deproteinization with chloroform. In the first method pure DNA is precipitated in the form of CTA-salt by direct dilution of the lysate to bring the concentration of NaCl (KCl) down to 0.5 M after the removal of the main part of proteins by deproteinization with chloroform. In the second method DNA is purified on the hydroxyapatite column after cell lysis and the removal of cell debris by centrifugation. Both methods are suitable for rapid isolation of pure DNA from various sources with recovery about 80% and average molecular weight 20-10(6) and higher without use of ribonuclease, pronase and amylase.
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PMID:[Two simple methods for isolation of DNA from various sources using cetavlon]. 92 66

The effects of a combination of an alcohol and urea on the transition temperature of bovine ribonuclease were investigated. The combined effects on the transition temperature of ribonuclease of a polyvalent alcohol and urea are about equal to the algebraic sum of the effects of each individual additive. The effects of a monovalent alcohol and urea are not cummulative, especially not at low temperatures (30 degrees C). The presence of urea decreases the hydrophobic effect of a monovalent alcohol, strongly at low temperatures, to a lesser degree at high temperatures (60 degrees C). Consequently, urea hinders the interhydrophobic interactions by affecting the water molecules.
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PMID:The effects from combining urea and an alcohol on the heat-induced reversible denaturation of ribonuclease. 94 44

Circular dichroism (CD) in the 240-300-nm region was used to study the conformation of DNA and RNA complexed with proteins in isolated nucleoli form HeLa cells. Deoxyribonuclease or ribonuclease digestion was employed to obtain (1) the individual CD spectra of nucleolar DNA or RNA in complex form with proteins, or in free form; and (2) the experimental CD baseline correction to exclude contributions from nonnucleic acid sources such as light scattering artifacts and proteins. The CD spectrum of nucleolar DNA in DNA-protein complexes was highly reduced in ellipticity in comparison with protein-free DNA. It showed a positive peak at 283 nm with a molar ellipticity [theta]283 = 1200 deg cm2 dmol-1 and a crossover at 262 nm. Addition of sodium dodecylsulfate shifted the peak to 276 nm with [theta]276 8000 deg cm2 dmol-1 and a crossover at 254 nm. The CD spectrum of nucleolar RNA in RNA-protein complexes was also reduced in comparison with protein-free RNA, showing a peak at 269 nm ([theta]269 = 6900 deg cm2 dmol-1), and a crossover at 250 nm. Addition of sodium dodecyl sulfate shifted the peak to 265 nm with [theta]265 = 18 000 deg cm2 dmol-1 and a crossover at 246 nm. The low ellipticity of both nucleolar DNA and RNA when complexed with proteins was increased by treatment with sodium chloride, urea, or heparin. This suggests that some ionic, hydrophobic, and hydrogen bondings are involved in the nucleic acid-protein interaction in nucleolar chromatin similar to that observed in nuclear chromatin.
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PMID:Circular dichroic studies of the DNA and RNA of nucleoli. 94 79


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