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:3.1.27.1 (RNase)
16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study presents 8 dogs of German Shepherd breed (6 males, 2 females, 2-5 years of age at onset of the disease) with a lupus like syndrome characterized by febrile polyarthritis, wasting, nephropathy, cutaneous lesions and high positive titres of ANA (antinuclear antibodies) of speckled type. The serum autoantibodies were further characterized by double immunodiffusion against ENA (extractable nuclear antigen), ELISA for Histone antibodies (Histon fraction H-24A and H-3S), indirect IF on rat-liver sections, non treated and RNase/DNase digested sections for DNP/RNP antibodies, and smears of a hemoflagellate C. luciliae for antibodies vs doubbel strained DNA, (dsDNA). Thus, the high ANA titres in these dogs represent varying types of autoantibodies against nucleoproteins of both DNA and RNA nature, associated histone antigens and non-histone antibodies (RNA and Sm) as well. Rheumatoid Factor titres in serum from these dogs were low or negative. Immunoglobulin deposits at dermo-epidermal junctions were demonstrated in some of the dogs with hyperkeratotic skin lesions. High concentration of serum-IgG was a constant finding in combination with anemia and in most cases leukopenia probably related to the chronic inflammatory process in these animals. Autoimmune hemolytic anemia (AIHA) or thrombocytopenia was not detected in these dogs.
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PMID:Serum auto antibodies and clinical/pathological features in German shepherd dogs with a lupuslike syndrome. 195 Aug 49

The fine structure, nature and fate of the components of the nucleolus were studied in young (steps 1, 2), intermediate (steps 3, 4, 5) and mature spermatids (steps 6, 7, 8) of man and monkey, by use of several cytochemical techniques (alcoholic PTA; sodium tungstate: EDTA; HAPTA; nuclease-gold complexes; NOR silver staining). As controls, comparative ultrastructural and cytochemical observations of the nucleolus in spermatids and Sertoli cells were made in the same sections of seminiferous tubules. In the young spermatids of the two species studied, the nucleolar masses exhibited identical features. Segregation of the nucleolar components took place in the nuclei of step 1 spermatids. No typical fibrillar center was observed. In spermatids at steps 1 and 2, the nucleolar masses appeared to be made up of two fibrillar components of equal density, one spherule-shaped, the other forming cords, both surrounded by clusters of 15-20 nm-diameter granules. Alcoholic PTA and sodium tungstate yielded a selective positive contrast of the two fibrillar components whereas EDTA and RNase-gold reacted with the peripheral granular material. Treatment with RNase-gold and DNase-gold complexes resulted in preferential labeling at the periphery of the fibrillar components. After NOR silver staining, numerous small silver grains were localized over the fibrillar cords, suggesting the persistence of specific acidic non-histone proteins. On the contrary, the spherule was never stained. In intermediate spermatids, when the nucleolar components were dissociated, scattered clusters of granules stained by EDTA and HAPTA remained in the entire nucleoplasm. Nucleolar disintegration was accompanied by dispersion of argyrophilic material.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cytochemical variations in the nucleolus during spermiogenesis in man and monkey. 205 40

In the sea urchin embryo, late histone genes are transcribed at low levels during cleavage and blastula formation and at substantially higher levels in later stages of embryogenesis. To investigate the molecular basis of the stage-specific expression of a late H2B histone gene, we injected mutant genes lacking portions of 5'- and 3'-flanking regions into Lytechinus pictus embryos and monitored their expression by RNase protection. A 200-bp region located 489 bp downstream of the mRNA 3' terminus was necessary for the increase in transcription of the late H2B gene at the mid-blastula stage of development. DNase I and methylation interference footprint analyses located only one factor-binding site in this region, and gel mobility shift experiments showed that the DNA-binding activity of this factor (designated H2B abp 1) paralleled the transcriptional activity of the L1 H2B gene. Additional mutagenesis and microinjection experiments located the activator element to a 32-bp DNA segment that includes the H2B abp 1-binding site. These experiments also showed that the 32-bp fragment functions independently of position and orientation and therefore has the hallmarks of an enhancer. That this fragment contains most or all of the L1 H2B gene transcription-stimulatory activity makes it unusual among enhancerlike elements, which generally consist of several clustered factor-binding sites that act additively or cooperatively to affect transcription. The nucleotide sequence of the L1 H2B enhancer element suggests that the trans-acting factor that interacts with it is a member of the antennapedia or engrailed class of homeodomain proteins.
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PMID:Activation of a late H2B histone gene in blastula-stage sea urchin embryos by an unusual enhancer element located 3' of the gene. 224 80

Analysis of DNA-protein structures composed of nuclear matrix attached DNA and the most tightly bound proteins was performed. Although the previously described non-histone proteins (1) were present the buoyant density of the complex was the same as that of pure DNA. RNA inaccessible to RNase in 0.4 M NaCl but digestible in low ionic strength buffer was detected. This RNA is not a nascent one. It turned out to be homogeneous and represent a novel type of small nuclear RNA. Partial sequence of this RNA is presented.
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PMID:Complexes of nuclear matrix DNA with proteins tightly bound to DNA contain a specific small-size RNA of a novel type. 235 Mar 57

Seven cationic substances--human and egg-white lysozyme, RNase, protamine, histone, poly-L-lysine and poly-L-arginine; five cationic lysosomal fractions from human polymorphonuclears (PMNs); RNA; poly-L-glutamic acid; DNA; heparin; endotoxin; mastocytotropic agent compound 48/80; and cytochalasin B were tested for the influence on chemotaxis and random migration of human PMNs using under-agarose migration and Boyden chambers with two filters and [51Cr]PMNs. The above substances were either preincubated with PMNs, added to chemoattractants, or used instead of chemoattractants. In under-agarose migration method chemotaxis was inhibited by 11-35% when egg-white lysozyme, protamine, heparin, endotoxin, or compound 48/80 was added to the cells. High concentration of cytochalasin B inhibited chemotaxis by 73%. Cationic fractions I and V and low concentration of cytochalasin B enhanced chemotaxis by 11%, 41%, and 30%, respectively. When human and egg-white lysozyme, DNA, or cytochalasin B was added to the chemoattractants, motility of PMNs was inhibited. Cationic fractions II and V from human PMNs, when used as chemoattractants, enhanced cellular motility by 143-167%. Random migration was enhanced by heparin and inhibited by cytochalasin B and by cationic fractions from human PMNs. These findings suggest that various cationic and anionic substances and cationic fractions from human PMNs have heterogeneous influence on random migration and chemotactic activity of human PMN. Analysis relating chemotaxis to phagocytosis and to intracellular bactericidal activity (ICBA) has shown several patterns. Protamine, poly-L-lysine, poly-L-arginine, and agent compound 40/80 all inhibit chemotaxis and enhance phagocytosis and ICBA; cationic fractions II and V enhanced all three functions, whereas cytochalasin B suppressed phagocytosis and ICBA and had concentration-dependent modulatory influence on chemotaxis. It implies diverse mechanisms of action and possible impact on inflammatory reactions.
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PMID:Modulation of locomotor activity of polymorphonuclear cells by cationic substances and cationic lysosomal fractions from human neutrophils. 241 86

Autoantibodies to a DNA-binding heterodimer consisting of 70,000 and 80,000 dalton subunits were identified in 30-50% of human autoimmune sera from patients with systemic lupus erythematosus (SLE), mixed connective tissue disease (MCTD), and scleroderma. Three murine monoclonal antibodies (mAb) against the heterodimer were produced in BALB/c mice by immunizing with isolated human B cell nuclei. By immunofluorescence, the mAb and autoimmune sera demonstrated both speckled nucleoplasmic staining and diffuse nucleolar staining in all human cell types examined. The nucleoplasmic staining was sensitive to DNase but not RNase pretreatment, while the nucleolar staining was sensitive to RNase but not DNase pretreatment. Biochemical characterization of the 70,000 and 80,000 dalton proteins using the mAb indicated that two forms of the antigen, with different mobilities on sucrose gradients, are present in human B cells. A 10 S form consists of the physically associated 70,000 and 80,000 dalton proteins, while a larger, 10-20 S form probably represents the same two proteins bound to DNA. Binding of the proteins to nucleolar RNA could not be confirmed in biochemical studies. These studies indicate that non-histone, DNA-binding proteins may be more frequently recognized by autoantibodies in SLE, MCTD, and scleroderma than has been previously recognized. Along with previous studies on RNA-binding proteins such as Sm, RNP, Ro, and La, the present findings suggest that nucleic acid-binding proteins, as a class, may be particularly frequent targets of autoimmunity in SLE and related disorders.
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PMID:Use of monoclonal antibodies for the characterization of novel DNA-binding proteins recognized by human autoimmune sera. 257 41

The organization of the intranuclear elements observed in histone-depleted (2 M NaCl-extracted) HeLa cell nuclei was investigated by means of electron microscopy and two-dimensional gel electrophoresis. This work was mainly aimed at verifying whether or not an intranuclear skeleton or matrix existed, which could explain the stable attachment of RNA to the residual nuclear structure after high-salt extraction, and its three-dimensional organization. We compared the ultrastructure and the polypeptide composition of RNA-containing and RNA-depleted (RNase-treated) nuclear residues, and we visualized intermediate stages of RNase action on the intranuclear material. We showed that this material was made of two types (fibrillar and granular) of salt-resistant RNP components equally sensitive to RNase when the enzyme was used prior to high-salt extraction. At least in our material and under our experimental conditions, no intranuclear matrix could be distinguished from the residual RNP material. Our results further suggest that formation of such a matrix is a path-dependent phenomenon.
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PMID:Structural aspects of intranuclear matrix disintegration upon RNase digestion of HeLa cell nuclei. 258 85

The turnover rates of some mRNAs vary by an order of magnitude or more when cells change their growth pattern or differentiate. To identify regulatory factors that might be responsible for this variability, we investigated how cytosolic fractions affect mRNA decay in an in vitro system. A 130,000 X g supernatant (S130) from the cytosol of exponentially growing erythroleukemia cells contains a destabilizer that accelerates the decay of polysome-bound c-myc mRNA by eightfold or more compared with reactions lacking S130. The destabilizer is deficient in or absent from the S130 of cycloheximide-treated cells, indicating that it is labile or is repressed when translation is blocked. It is not a generic RNase, because it does not affect the turnover of delta-globin, gamma-globin, or histone mRNA and does not destabilize a major portion of polysomal polyadenylated mRNA. The destabilizer accelerates the turnover of the c-myc mRNA 3' region, as well as subsequent 3'-to-5' degradation of the mRNA body. It is inactivated in vitro by mild heating and by micrococcal nuclease, suggesting that it contains a nucleic acid component. c-myb mRNA is also destabilized in S130-supplemented in vitro reactions. These results imply that the stability of some mRNAs is regulated by cytosolic factors that are not associated with polysomes.
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PMID:Regulation of c-myc mRNA stability in vitro by a labile destabilizer with an essential nucleic acid component. 274 42

Using S1 nuclease protection assays, we have examined the representation of cell cycle-dependent H4 histone RNAs in the nuclear matrix and nonmatrix nuclear fractions of human cells. Cytoplasmic and nuclear fractions were prepared from exponentially growing HeLa S3 cells by double detergent (sodium deoxycholate and NP40) lysis. The nuclear matrix and nonmatrix nuclear fractions were then prepared by digestion of nuclei with RNase-free DNase I and subsequent high-salt [0.4 M (NH4)2SO4] extraction. Subcellular fractions were characterized by 1) DNA, RNA, and protein composition; 2) electrophoretic analysis of the proteins in each fraction; 3) the representation of 45S ribosomal RNA precursors and processed 18S and 28S ribosomal RNAs; and 4) the presence of mitochondrial RNAs. In contrast to ribosomal and messenger RNA precursors, which are largely associated with the nuclear matrix, the human H4 histone RNAs in the nucleus were found predominantly in the nonmatrix nuclear fraction. The presence of H4 histone RNA in the nonmatrix nuclear fraction appeared to be coupled to DNA replication, since inhibition of DNA synthesis by hydroxyurea resulted in a loss of histone RNA from the nucleus. Our results suggest either that the association of histone RNAs with the nuclear matrix is very transient or that posttranscriptional modifications of the rapidly processed histone gene transcripts do not involve the nuclear matrix.
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PMID:Localization of human histone gene transcripts predominantly in the nonmatrix nuclear fraction. 301 90

Galactosyltransferase (EC 2.4.1.22) requires bivalent metal ions for its activity. However, preparations of this enzyme solubilized from Golgi membranes of lactating rat mammary gland were shown to be activated not only by Mn2+, Ca2+ and Mg2+, but also by spermine, spermidine, lysyl-lysine, ethylenediamine and other diaminoalkanes, and by a range of basic proteins and peptides, including clupeine, histone, polylysine, ribonuclease, pancreatic trypsin inhibitor, cytochrome c, melittin, avidin and myelin basic protein. Both N-acetyl-lactosamine synthetase and lactose synthetase activities were enhanced. A basic protein fraction was isolated from bovine milk and shown to activate galactosyltransferase at low concentrations. The polyanions ATP, casein, chondroitin sulphate and heparin reversed the activation of galactosyltransferase by several of the above substances. Galactosyltransferase, assayed as a lactose synthetase, showed a 10-fold greater affinity for glucose when Mn2+ ions were replaced by clupeine or by ribonuclease as cationic activator. Evidence was obtained for the presence of an endogenous cationic activator in solubilized Golgi membrane preparations which evoked a similar low apparent Km,glucose. The findings are discussed in the light of cationic activations of glycosyltransferases generally, of the porous nature of the Golgi membrane, and of the unlikelihood of bivalent metal ions being the physiological activators of galactosyltransferase. It is suggested that the natural cationic activator of lactose synthetase may be a secretory protein acting in a manner analogous to the enzyme's activation by alpha-lactalbumin. A scheme is proposed for the two-stage synthesis of lactose and phosphorylation of casein within the cell, to accommodate the apparent incompatibility of these two processes.
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PMID:Cationic activation of galactosyltransferase from rat mammary Golgi membranes by polyamines and by basic peptides and proteins. 310 66


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