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)

Endogenous protein kinase activity was detected in the outer plasma membrane of 373 and SV40 transformed 3T3 cells. When intact cells were incubated with [gamma-32P]ATP, there was a transfer of [32P]phosphate into an acid-insoluble product. The reaction was: (a) linear as a function of time (up to 30 min), (b) proportional to the number of cells present and (c) dependent on temperature and Mg2+ concentration. The acid-insoluble product was susceptible to pronase but not RNase or DNase. More specifically, phosphomonoester bonds to serine and threonine were identified. There was less than 3% hydrolysis of the [gamma-32P]ATP during the reaction; moreover, free [32P]phosphate failed to substitute for the ATP. The reaction product was located on the cell surface, as evidenced by the fact that it could be removed by mild trypsin treatment of intact 3T3 cells. Further evidence for the surface location of the kinase was shown by its activity in phosphorlating exogenous substrate, histone, and phosvitin. The level of phosphorylation increased by 2- to 4-fold prior to the start of S phase when quiescent 3T3 cells were stimulated to reinitiate growth by the addition of serum. The SV40 3T3 cells had from 5- to 10-fold more activity per cell than the quiescent 3T3 cells. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and radioautography show at least 25 phosphorylated proteins; the surface label pattern of 3T3 cells differs from that of SV40-transformed 3T3 cells.
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PMID:Endgoenous protein kinase in outer plasma membrane of cultured 3T3 cells. Nature of the membrane-bound substrate and effect of cell density, serum addition, and oncogenic transformation. 18 98

The binding characteristics of [125I]-labeled L-triiodothyronine (T3) to chromatin isolated from rat liver nuclei were investigated. Binding of T3 to chromatin showed temperature-, incubation time-, and DNA concentration-dependence. According to Scatchard analysis, the apparent equilibrium dissociation constant was 225 pM, with a maximum binding capacity of about 0.2 pmoles per mg DNA. Displacement studies with unlabeled thyroxine (T4) and T3 showed that the binding sites for T4 might be the same as T3 but the binding affinity of the former was less than that of the latter. The binding was completely inhibited by the eukaryotic RNA polymerase inhibitor, rifampicin AF/021, but not by the prokaryotic inhibitor, rifampicin and alpha-amanitin. These observations indicate that the receptors for T3 have certain properties in common with RNA polymerase or other enzyme proteins which are sensitive to the rifampicin derivative. The hormone--chromatin fragments complex was solubilized from residual chromatin by digestion with DNase, but not with RNase, suggesting that the T3 receptors localize in the DNase-sensitive regions of DNA in the chromatin. This provides a useful method to use to investigate the localization of the receptor proteins in the chromatin and the interaction of the hormone-receptor complex with DNA.
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PMID:Binding characteristics of L-triiodothyronine to isolated rat liver chromatin. 19 15

By equilibrium ultracentrifugation and electrophoresis in agarose gel data were obtained on the binding of [3H]cyclic adenosine monophosphate ([3H]cAMP) to the transcriptional complex of mitochondria with the density 1.825 g/ml in CsCl ethydium bromide. Treatment of the complex with RNase, DNase and pronase change the density of [3H]cAMP bound material; rifampicin prevents detection of [3H]cAMP. Study of inner membrane lysates showed that [3H]cAMP is bound to structures active in RNA and protein synthesis in mitochondria. The conclusion is made that cAMP is involved in formation of the transcriptional complex much as it is involved in initiation of transcription in bacterial operons.
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PMID:Detection of [3H]cyclic AMP in the transcription complex of rat liver mitochondria. 19 94

The possibility of using DNA-injected Xenopus laevis oocytes and eggs for studying the control of transcription in eukaryotes has been investigated. When purified DNA of simian virus 40 (SV40) is injected into Xenopus laevis oocytes, tritiated RNA precursors are incorporated into DNase-I-resistant, RNase-A- and alkali-sensitive material that hybridizes specifically to SV40 DNA. This viral transcription continues for at least 5 days and occurs only when the injected DNA is directed to the nucleus of the oocyte. The quantity of SV40-specific RNA produced is roughly proportional to the amount of DNA injected; above 1 ng per oocyte, most of the nonribosomal RNA made in successfully injected oocytes is virus-specific. Transcription also occurs, although at a lower efficiency, after injection of the DNA into unfertilized eggs. The DNAs of adenovirus 5, cloned Drosophila melanogaster histone genes, and even bacteriophage phiX174 replicative form, bacteriophage phi80plac, and the ColE1 plasmid are also transcribed after injection into oocytes or eggs.
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PMID:Purified DNAs are transcribed after microinjection into Xenopus oocytes. 19 3

The activities of enzymes catalyzing the formation of nucleic acid precursors, nucleoside kinases, as well as of those involved in the degradation of nucleic acids, were studied in nuclei of the liver of healthy persons, human hepatomas and the liver of patients with cancer of gastrointestinal tract. The activities of thymydine kinase and uridine kinase in the human hepatoma nuclear sap were found to increase 40- to 50-fold and 120- to 150-fold, respectively, as compared to those in normal human liver. The activities of DNase and RNase in the fraction of chromatin protein of human hepatomas, on the contrary, decreased almost to zero. As to the liver of patients with cancer of gastrointestinal tract, drastic alterations in the activities of nucleoside kinases and nucleases in the direction characteristic of tumors themselves were observed. This phenomenon is regarded as a manifestation of the systemic effects of the tumor on the host.
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PMID:[Enzymes of anabolic and catabolic nucleic acid pathways in human hepatomas, in liver of healthy persons, and in liver of patients with cancer of gastrointestinal tract]. 19 26

Properties of Aleutian disease virus (ADV) were studied using feline kidney cells, line CRFK, to assay virus by the induction of nuclear antigen. ADV nuclear antigen was detected by immunofluorescent staining. Titers of virus obtained from mink spleens at 10-8 days after infection were usually between 10(3) and 10(5) infectious units per gram of spleen. ADV was purified by fluorocarbon extraction, differential centrifugation, biogel A-15 chromatography and CsCl equilibrium centrifugation. The molecular weight of the virus was estimated to be 3-5 X 10(5) daltons. The density of antigen-inducing virus in equilibrium CsCl gradients was 1.32--1.34 g/cm3. On velocity sucrose gradients, antigen-inducing virus had a sedimentation coefficient of approximately 110S. The virus was not neutralized by sera from chronically infected mink and ferrets and by sera from experimentally infected mink. ADV was resistant to ionic and nonionic detergents and lipid solvents. The titer of partially purified virus was reduced as much as 700-fold by proteolytic enzymes but not by DNase or RNase. The virus was inactivated slowly at 56 degrees C; the initial half-life was 90 minutes. It is concluded that the properties of ADV can be determined by assay in CRFK cells, thus facilitating virological study of the disease.
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PMID:Properties of Aleutian disease virus assayed with feline kidney cells. 20 29

To evaluate extracellular hydrolytic enzymes in an in vivo system, plastic chambers were glued over rabbit dermal BCG lesions in various stages of development, after the central epithelium was removed with a scalpel. They were filled with tissue culture medium and left in place 2 days. The following enzymes in the fluid were assayed: collagenase (an enzyme secreted but not stored in macrophages); lysozyme (both secreted and stored); DNase and RNase (released on cell death and possibly regurgitated but not secreted); and, as a control, lactic dehydrogenase (released only on cell death). Tissue sections were prepared and studied histologically for the type of cell infiltrate, for beta-galactosidase (our marker enzyme for macrophage activation), and for necrosis. At 11 and 18 days of age the BCG lesions were largest and the number of activated macrophages in the chamber beds was highest. At this time the levels of the five enzymes assayed in the chamber fluids reached their peaks, tuberculin hypersensitivity was well developed, and the bacilli components would still be plentiful. In general, the chamber fluids from 11- and 18-day BCG lesions contained higher enzyme levels than chamber fluids from tuberculin reactions. Active collagenase was only detected in fluids from such BCG lesions. Evidently, the serum in the chamber fluids was sufficient to inhibit the lower amounts of collagenase probably released from smaller BCG lesions and tuberculin reactions (and from the 2-week polystyrene lesions that were also evaluated). These studies demonstrate that in chronic inflammatory reactions, both acid-acting and neutral-acting hydrolytic enzymes are released extracellularly. Tissue components would be hydrolyzed locally wherever the acid-acting hydrolytic enzymes encounter a drop in pH and wherever the concentration of neutral-acting hydrolytic enzymes exceeds the concentration of their inhibitors.
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PMID:Extracellular hydrolytic enzymes of rabbit dermal tuberculous lesions and tuberculin reactions collected in skin chambers. 20 93

The Epstein-Barr virus (EBV)-associated nuclear antigen (EBNA) was purified 85-fold from a nuclear pellet derived from an EBV-transformed B lyphoblastoid cell line by a five-step procedure consisting of preparation of extract, heating at 80 degrees C in phosphate buffer, ammonium sulfate precipitation, preparative ultracentrifugation, and affinity chromatography on double-stranded DNA-cellulose. The purified complement fixing antigen specifically blocked the anticomplement immunofluorescence assay for EBNA. Several properties indicate a close association of EBNA with chromatin, viz. 1) precipitation of antigenic activity by phosphate buffer and subsequent thermal fractionation; 2) partial sensitivity of antigenic activity to DNase (but not to RNase) and restoration of activity by addition of calf thymus DNA; and 3) specific binding of EBNA to double-stranded DNA-cellulose. Other properties of EBNA, including its unusual heat stability, are described.
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PMID:Partial purification and properties of the Epstein-Barr virus-associated nuclear antigen. 20 60

Deoxyribonucleoprotein complexes released 17 h postinfection from adenovirus type 1 (Ad2)-infected HeLa cell nuclei were shown by electron microscopy to contain filaments much thicker (about 200 A [20 nm]) than double-stranded DNA (about 20 A [2 nm]). The complexes were partially purified through a linear sucrose gradient, concentrated, and further purified in a metrizamide gradient. The major protein present in the complexes was identified as the 72,000-dalton (72K), adenovirus-coded single-stranded DNA-binding protein (72K DBP). Three types of complexes have been visualized by electron microscopy. Some linear complexes were uniformly thick, and their length corresponded roughly to that of the adenovirus genome. Other linear genome-length complexes appeared to consist of a thick filament connected to a thinner filament with the diameter of double-stranded DNA. Forked complexes consisting of one thick filament connected to a genome-length, thinner double-stranded DNA filament were also visualized. Both thick and thin filaments were sensitive to DNase and not to RNase, but only the thick filaments were digested by the single-strand-specific Neurospora crassa nuclease, indicating that they correspond to a complex of 72K DBP and Ad2 single-stranded DNA. Experiments with anti-72K DBP immunoglobulins indicated that these nucleoprotein complexes, containing the 72K DBP, correspond to replicative intermediates. Both strands of the Ad2 genome were found associated to the 72K DBP. Altogether, our results establish the in vivo association of the 72K DBP with adenovirus single-stranded DNA, as previously suggested from in vitro studies, and support a strand displacement mechanism for Ad2 DNA replication, in which both strands can be displaced. In addition, our results indicate that, late in infection, histones are not bound to adenovirus DNA in the form of a nucleosomal chromatine-like structure.
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PMID:Structural analysis of viral replicative intermediates isolated from adenovirus type 2-infected HeLa cell nuclei. 20 93

Several virion and nonvirion DNAs were tested for the ability to activate endogenous type C virus in BALB/c-derived mouse cells using the calcium precipitation technique. The DNAs from all herpesviruses tested activated xenotropic type C virus synthesis. These included DNAs from herpes simplex virus types 1 and 2, Epstein-Barr virus, human cytomegalovirus, SA8 virus, infectious bovine rhinotracheitis virus, pseudorabies virus, and herpes saimiri virus (M-DNA). In contrast, DNAs from vaccinia virus, simian virus 40, primate cells, bacteria, mycoplasma, and salmon sperm showed no ability to activate type C virus when tested under the same conditions. Several herpesviruses and vaccinia virus, which were highly infectious for the BALB/c cells used, were tested for their ability to activate type C virus after UV irradiation. All herpesviruses tested were positive, while vaccinia virus was negative. Unirradiated simian virus 40 also showed no ability to activate type C virus. Activation of type C virus by DNA from herpes simplex virus was observed after shearing or sonication of the DNA to an average size of 3 x 10(6) daltons, but was not observed with DNA sonicated to an average size of 1 x 10(6) daltons. Alkali denaturation of DNA from herpes simplex virus or treatment with DNase, but not RNase, destroyed its ability to activate type C virus, as did crosslinking of the DNA with 4,5',8-trimethylpsoralen (psoralen) and light.
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PMID:Activation of endogenous type C virus in BALB/c mouse cells by herpesvirus DNA. 21 61


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