Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.1 (RNase)
 16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Messenger ribonucleoprotein particles were isolated from the polysomes of logarithmically growing plant cell cultures, pulse-labeled with [3H] adenosine for 30 min. More than 80% of the labeled RNP was present in particles sedimenting between 80 S and 30 S on sucrose density gradients, but was not associated with ribosomal subunits. The size distribution differs from those reported for polysomal mRNP particles to date. After fixation with glutaraldehyde the labeled RNP particles had a buoyant density of 1.38 g/cm3 in CsCl gradients. Radioactively labeled RNA extracted from the RNP particles showed a heterodisperse size distribution and contained poly (A) stretches as determined by affinity chromatography and ribonuclease digestion experiments.
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PMID:Messenger ribonucleoprotein particles from plant cell cultures. 15 Jan 47

Transcriptive complex in the cytoplasm of Sendai virus infected cells included parental RNA in the form of ribonucleoprotein, nascent RNA and polysomes. Its buoyant density in CsC1 was 1.45 g/ml. The complex dissociated three hours after the infection, and nascent RNA was fully separated from the parental RNP. The template for polysomes within the complex was identified under conditions when the complex was dissociated in cycloheximide-treated cells. Polysomes were revealed in the association with nascent RNA. They sedimented in preribosmal region of sucrose gradient, and had a buoyant density in CsC1 of 1.49 g/ml. Mild treatment with ribonuclease split the polysomes into monoribosomes.
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PMID:[Formation of polysomes in virus-specific RNA in the transcriptive complex of Sendai virus infected cells]. 17 26

Clinical and laboratory findings were correlated from 46 patients with IgG localization in epidermal nuclei in a speckled (particulate) pattern on direct immunofluorescence of normal skin. Cutaneous manifestations included lupus erythematosus (LE), swollen hands or sclerodactyly, alopecia, vasculitis, and dyspigmentation. Systemic manifestations included arthritis or arthralgia, Raynaud's phenomenon, serositis, vascular headaches, mild renal disease, myositis, and sicca syndrome. High titer (mean = 1:142, 800) serum antibody to extractable nuclear antigen (ENA) was found in 81%. Eighty-six percent had antibody to an RNase-sensitive antigenic component of ENA (ribonucleoprotein or RNP); 14% had antibody to an RNase-resistant ENA termed Sm. Deposition of IgG in a speckled pattern in epidermal nuclei is an immunopathologic marker for a subset of connective tissue disease characterized by antibody to ENA. Those with Sm specificity had systemic LE (SLE); Those with RNP specificity had Raynaud's phenomenon usually associated with overlapping features of SLE, scleroderma, and/or dermatomyositis.
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PMID:Speckled (particulate) epidermal nuclear IgG deposition in normal skin. Correlation of clinical features and laboratory findings in 46 patients with a subset of connective tissue disease characterized by antibody to extractable nuclear antigen. 34 15

Nuclear 30S RNP particles were studied by means of fluorescence techniques. It's shown that fluorescamin interacts with NH2-groups of protein molecule. As a result, covalent fluorescent label is formed. Quantum yield (rho), fluorescence spectra, lifetime of excited state (tau) and polarization of fluorescamin complexes with 30S particles were studied. Excitation spectra have their maximum at 395 nm, and fluorescence spectrum at 480 nm. These figures correspond to spectra of fluorescamin complexes with NH2-groups of lysine. Mean quantum yield (rho = 0.27) and lifetime of excited state of fluorescence (tau = 7.8 nsec) were measured. It's shown that fluorescamin forms two types of fluorescent complexes in 30S particles. These complexes differ only by their rho(rho1 = 0.11, rho2 = 0.30) and rho(rho1 = 3.6 nsec, rho2 = 10.0 nsec) by 2.7 times. Migration radius between fluorescamin bound to protein and ethydium bromide adsorbed on double-stranded regions of pre-mRNA in RNP-particles was measured. It's equal to 32 A. Adsorbtion isotherms of ethydium bromide were measured by fluorescence in 0.1 and 0.4 M NaCl. Data obtained showed that 6% of pre-mRNA in 30S particles bound the dye as a strong complex, i. e. this part of pre-mRNA is double-stranded. RNase treatment of RNP had no effect on this value. But the increase of NaCl concentration up to 0.4 M caused the dissociation of protein subunits to some extent followed by appearance of up to 40% free NH2-groups interacting with fluorescamin. Measuring of energy migration from fluorescamin to ethydium bromide showed that double-stranded pre-mRNA regions strictly bound to protein sticked out from RNP particle at a distance of about 27 A. The increase of NaCl concentration up to 0.4 M leads to disruption of this strict bond of double-stranded regions with protein. As a result, these regions of pre-mRNA become labile and move away from the RNP particle at more than 30 A. According to theoretical calculations, there is about 1--2 pre-mRNA hairpins (18--9 base pairs respectively) per one 30S particle.
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PMID:[Nuclear ribonucleoproteins containing pro-mRNA. XIV. Structural study using ethidium and fluorescamine]. 44 Mar 9

The properties of the ribonuclease resistant cytoplasmic ribonucleoprotein particles were studied in contact-inhibited and serum induced proliferating 3T3 cells. The RNP particles were fractionated by oligo (dT)-cellulose chromatography and banded in CsSO4 gradients. The main RNP fraction, eluted with 25% formamide, contained the major ribonuclease resistant RNA sequences in both resting and growing cells. The protein component of this fraction had a molecular weight of about 72,000 in contact-inhibited cells and 81,000 in serum induced cells.
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PMID:Polyadenylate-protein complexes in resting and growing 3T3 cells. 47 41

The perichromatin granules were studied in hepatocytes of experimental rats injected with cycloheximide because the increased number of these nuclear components after such treatment facilitated their cytochemical investigation. Most perichromatin granules were sensitive to the digestion with pepsin and ribonuclease. In contrast, small population of perichromatin granules was resistent to such digestion under conditions which remove known RNA containing components such as ribosomes, nucleolar RNP components and interchromatin granules. The size of these resistent perichromatin granules was reduced and they consisted of filaments the width of which was similar to that of filaments in the chromatin. Moreover, a small population of perichromatin granules was sensitive to the digestion with pepsin and deoxyribonuclease. The size of these granules was only slightly reduced. All these observations indicate that most perichromatin granules contain the RNA and some the DNA. A possibility also exists that the perichromatin granules might contain both RNA and DNA but in various proportions. In addition, partial digestion with pepsin followed by a complete digestion with ribonuclease and deoxyribonuclease removed perichromatin granules as well as other nucleoprotein structures. On the other hand, such digestion facilitated the visualization of the nuclear and cytoplasmic skeleton (matrix) in situ.
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PMID:Further cytochemical studies on the perichromatin granules. 47 92

Nuclear RNP from Triturus oocytes is organized as strings of beads which can be converted into 20-nm-diameter monoparticles with mild RNase treatment or into 5-nm-thick linear fibrils with low salt treatment. The protein component comprises a heterogeneous size-range of polypeptides which differ from the polypeptides of the other nucleoproteins of oocytes. The RNA is of high molecular weight, sediments mostly in excess of 50 S, and is capable of assuming considerable secondary structure. Duplex regions in the form of hairpin loops are present and may serve as focal points in the condensation of the RNP transcript fibres to generate the periodic beaded structure. The structure of the beads may be maintained by means of protein-protein interaction since at salt concentrations between 1 and 2 M NaC1 all of the proteins are released in a cooperative manner as various sized aggregates which sediment at 15-30 s. There are no specific proteins obviously peculiar to either the beaded or the fibrillar RNP configuration. The various properties of nuclear RNP are compared with those of chromatin.
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PMID:The structure of nuclear ribonucleoprotein of amphibian oocytes. 56 Oct 88

Small molecular weight RNA species (smwRNAs) were studied in rat liver nuclei with and without chromatin as well as with and without nuclear envelope and nucleoplasm. From all the species identified, only two, N5 and 5Sb, were related to ribosomes. The others were localized exclusively in the nuclear skeleton or the spongelike network that was described in the preceding communication. This network or protein matrix contains a less abundant but exclusive set of molecules designated 5Sa, N1, and 4.5S, as well as other more abundant molecules which also exist in rat liver endoplasmic reticulum but not in polysomes or postribosomal RNP complexes. The smwRNAs behave like HnRNA; they remain located in the nuclear skeleton when nuclei are deprived of nucleoplasm and chromatin. With the information presently available, it is not possible to know whetherer both species are in the same or different RNP complexes and whether some of the smwRNAs contribute to the architecture of the nuclear skeleton. Distinct from any other nuclear RNA species, smwRNAs have two unique properties: facility of extraction, and resistance to nuclear ribonuclease digestion.
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PMID:Rat liver nuclear skeleton and small molecular weight RNA species. 56 14

The dependence of activation of latent RNAse of RNP particles isolated from rat skeletal muscles, on the concentration of K+ and Mg2+ in the incubation medium and on temperature was studied. During a short-term exposure (20 min 18 degrees) of RNP particles in the buffers containing K+ at concentrations varying from 0.05 M to 0.25 M and Mg2+ at concentrations from 0.001 M to 0.01 M no effect of endogenous ribonuclease was observed. It was shown that a significant activation of latent RNAse occurs during the incubation at room temperature in 24 hours provided that the incubation medium contains Mg2+ at concentrations not higher that 0.004 M. In the presence of 0.004 M Mg2+ degradation of polysomal mRNA and partial degradation of 18 S--rRNA takes place. At Mg2+ concentration as low as 0.001 M not only mRNA but also both rRNAs are accessible to the action of activated ribonuclease. 20 min heating of RNP particles up to 55 degrees C causes insignificant degradation of the polysomes and 18 S--rRNA. The increase in temperature by 5 degrees c results in the activation of latent RNAse followed by an almost complete degradation of mRNA and rRNA. The relationship between the integrity of the ribosomal structure and activation of latent ribonuclease is discussed.
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PMID:[Activation of latent RNAse activity of RNP particles from rat skeletal muscles]. 85 24

Disruption of purified lymphocytic choriomeningitis (LCM) virus with Nonidet P-40 in 0.5 M KCl followed by sucrose gradient centrifugation in 0.3 M KCl led to the isolation of two viral nucleoproteins (RNPs) as well as 40S and 60S ribosomal subunits. The largest viral RNP sedimented heterogenously at 123S to 148S and was associated with 23S and 31S viral RNA. The other viral RNP sedimented at 83S and was associated with 23S viral RNA. The buoyant density in CsCl was determined to be 1.32 g/cm3 for the viral RNP. Densities of 1.52 and 1.60 g/cm3 were determined for the 40S and 60S subunits, similar to those of the BHK-21 cells subunits dissociated by 0.5 M KCl. The viral RNPs were partly sensitive to RNase.
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PMID:Characterization of ribonucleoproteins and ribosomes isolated from lymphocytic choriomeningitis virus. 97 89


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