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

It was attempted to evaluate passive haemagglutination of antigen coated, tanned erythrocytes as a test by which to demonstrate anti-DNA in systemic lupus erythematosus. The antigens was prepared using a minimum of procedures in order to produce a native preparation. The resulting material had most of the criteria applying to native DNA, but the protein content was about 9%. It contained a thymocyte specific component, but no demonstrable trace of bovine species antigen. The reactions between the antigen and an anti-DNA serum from a patient with suspected SLE were inhibited by DNA and DNA-histone, but not appreciably by ENA, RNA or desoxyribonucleosides. Passive haemagglutination reactions against the antigen were positively correlated to a homogeneous immunofluorescence nuclear pattern and negatively correlated to a speckled pattern. Passive haemagglutination titres against ENA and DNA antigen were not correlated. Seventy-three per cent of randomly selected sera gave either purely DNase sensitive reactions (19%) or reactions of combined sensitivity to DNase and other enzymes. Twenty-eight out of 53 sera reacting in the passive haemagglutination test reacted also in the immunofluorescence test against Chrithidia luciliae kinetoplasts. The latter reactions were DNase sensitive. It applies to both tests that DNase sensitive, but RNase resistant, reactions were well correlated, irrespective of their sensitivity to trypsin while DNase resistant or DNase and RNase sensitive reactions were not correlated. The passive haemagglutination test using a native but relatively crude DNA-preparation coated on tanned sheep erythrocytes supplemented by specificity tests with DNase and RNase treated antigen gives about the same information as the indirect immunofluorescence test against Chrithidia luciliae kinetoplasts. Furthermore, the results show that patients' sera reacting with a homogeneous nuclear pattern in the indirect immunofluorescence test may contain not only anti-DNA and anti-nucleohistone antibodies, but also antibodies to a number of non-histone chromatin associated proteins some of which contain RNA.
 ...
PMID:Antigenic properties of a DNA-preparation from calf thymus used for the demonstration of anti-DNA. 6 25

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.
 ...
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 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.
 ...
PMID:Purified DNAs are transcribed after microinjection into Xenopus oocytes. 19 3

Membranes prepared from A-431 human epidermoid carcinoma cells retained the ability to bind 125I-labeled epidermal growth factor (EGF) in a specific manner. In the presence of [gamma-32P]ATP and Mn2+ or Mg2+, this membrane preparation was capable of phosphorylating endogenous membrane components, including membrane-associated proteins; the major phosphorylated amino acid residue detected in partial acid hydrolysates was phosphothreonine. The binding of EGF to these membranes in vitro resulted in a severalfold stimulation of the phosphorylation reaction; again, the major phosphorylated amino acid residue detected in partial acid hydrolysates was phosphothreonine. Membrane-associated dephosphorylation reactions did not appear to be affected by EGF. The phosphorylation reaction was not stimulated by cyclic AMP or cyclic GMP in the absence or presence of EGF. The phosphorylation system of the membrane was able to utilize [gamma-32P]GTP in both the basal and EGF-stimulated reactions. The enhanced membrane phosphorylation was specific for EGF and its derivatives; a wide variety of other peptide hormones were ineffective. The A-431 membrane preparation also was capable of phosphorylating exogenous proteins, such as histone, phosvitin, and ribonuclease, by a process which was stimulated by EGF. These findings suggest that one of the biochemical consequences of the binding of EGF to membranes is a rapid activation of a cyclic AMP-independent phosphorylating system.
 ...
PMID:Rapid enhancement of protein phosphorylation in A-431 cell membrane preparations by epidermal growth factor. 31 92

A method for the rapid manual isolation of polytene chromosomes and nuclear membranes from salivary glands of Chironomus tentans is presented and the analysis of some of their RNA and protein components before and after treatment with 2 M salt solutions is summarized.--After salt-incubation the chromosomes still display a considerable number of bands which stain with ethidium bromide and which are sensitive to treatment with DNase, RNase, trypsin, and proteinase K, to a lesser extent with pronase and papain. Analysis of the iodinated residual proteins on SDS gels yield three major and two minor bands (MW between 50,000 and 70,000 dalton) which were also shown to be present in interphase chromosomes of Ehrlich ascites cells which had been treated similarly and are also tightly bound constituents of DNA prepared according to Gross-Bellard et al. (1973). This result indicates the existence of a general class of non-histone proteins involved in keeping the DNA in a supercoiled state. Furthermore their presence in salt-treated nuclear membranes of Chironomus salivary gland cells (and Xenopus oocytes, unpubl.) will be of interest with respect to functional aspects of the nuclear matrix.
 ...
PMID:Effect of salt-treatment on manually isolated polytene chromosomes from Chironomus tentans. 35 13

Binding of ethidium bromide (EB) to cells before and after HCl, pepsin and RNase treatment was investiaged by spectophotometric and fluorimetric methods. Binding isotherms, calculated with the McGheevon Hippel equation, taking EB as a non-interacting ligand, revealed the influcence of these treatments on the fluorescence characteristics of the cells which were measured by flow-through cytofluorimetry. Thus pepsin- and RNase-treated cells have a reduced intercalation capacity due to the loss of cytoplasmic RNA and RNA hydrolysis, respectively. HCl alone, or in association with pepsin, increased the equilibrium constant K considerably. Thus at low free EB concentrations the enchanced EB affinity of acid-pretreated cells generates a high fluorescence intensity, by comparison with treatments at neutral pH. This result contradicts the interpretation of high EB binding to acid pretreated cells which is commonly believed to be due to hydrolytic histone removal from potential intercalation sites. With increasing free EB concentrations the fluorescence intensities of RNase- and pepsin-treated cells culminate at the same level due to their amost identical intercalation capacities. Consequently, quantitative DNA analysis of pretreated cell suspensions with EB can only be performed if the alteration, induced by the pretreatment, has previously been studied.
 ...
PMID:Studies of the binding of ethidium bromide to cells before and after enzyme treatment. 38 75

The investigation of fluorescence and light-scattering change of histone F2a, ribonuclease, tyrosine, N-acetyltirosinamide, methyl ether tyrosine by the concentration increasing of NaCl, MgCl2, Na2SO4 in the surrounding medium was carried out. In the case of used salts the changes of tertiary structure and histones aggregations depend on the anion type, which is presented in the environment. The tertiary structure of histones formed in the presence of salt is stabilized by weak (hydrophobic and hydrogenic) interactions.
 ...
PMID:[Structure and aggregation of histones. I. Influence of the ionic composition of the medium on the structure and effectiveness of the intermolecular relationships of histone F2a (H2A+H4)]. 88

Plasma membranes prepared from rat renal cortex contain both a parathyroid hormone-sensitive adenylate cyclase and a potent proteolytic activity which degrades the hormone into peptide fragments. The degree and pattern of degradation was determined by subjecting incubation mixtures to gel filtration and ion exchange chromatography. Estimation of the degree of degradation by acid precipitation of the intact hormone was inadequate since metabolism of the hormone apparently generated acid-insoluble fragments. When parathyroid hormone was incubated with membrane fraction, the capacity of its stimulatory effect on adenylate cyclase decreased steadily. This decrease of PTH activitiy could be closely related to the degradation of intact hormone by the same membrane preparation. The adenylate cyclase and degradative activity appeared to exist in similar membrane structures since they could not be separated by centrifugation through sucrose density gradients. The degradation of the hormone could not be inhibited by Trasylol and pancreatic or soybean trypsin inhibitors and was only slightly inhibited by ribonuclease and benzamidine. Histone (1 mg per ml), on the other hand, was able to decrease the degradation of the hormone and prevent the loss of its activity. Radioimmunoassay of the incubation mixtures showed that the rapid degradation of both amino- and carboxy-terminal regions of the hormone was prevented by histone. The oxidized, inactive hormone was also degraded to the same extent by the renal cortical membrane. Furthermore, the degradative activity was also found in plasma membrane preparations of renal medulla and liver. This lack of hormone and tissue specificity suggests that similar degradative activity exists in all tissues and that caution should be exercised in estimating hormonal potency based on activation of adenylate cyclase.
 ...
PMID:Interaction of parathyroid hormone with membranes of kidney cortex: degradation of the hormone and activation of adenylate cyclase. 119 1

The nucleosomes of transcriptionally active genes can be separated from those of inactive genes by affinity chromatography on organomercury-agarose (Hg-agarose) columns. The basis for this separation is the difference in accessibility of the sulfhydryl groups of histone H3 and certain non-histone proteins in active and inactive chromatin. A new procedure distinguishing between different modes of binding of transcriptionally active nucleosomes to the Hg-agarose column has been applied to study several factors which might influence the binding reaction. Nucleosomes that bind to the column because of salt-labile associations with SH-reactive non-histone proteins, such as the high-mobility-group proteins, HMG-1 and HMG-2, were released by adding 0.5 M NaCl to the eluting buffer. The remaining nucleosomes, in which reactive histone H3 thiol groups can bind covalently to the organomercury, were then displaced from the column by 10 mM dithiothreitol. Both Hg-agarose-bound fractions contain the transcriptionally active DNA sequences of the cell, but inactive nucleosomes, such as those containing alpha-globin DNA, pass through the column. The histones of both Hg-agarose-bound fractions have significantly higher levels of acetylation than do histones of the unbound fraction, but the content of tri- and tetra-acetylated H3 and H4 is significantly higher in the nucleosomes with reactive H3 thiols. The rate of turnover of histone N-acetyl groups is also far greater in the Hg-agarose-bound nucleosomes than in the unbound nucleosomes. Although the overall levels of histone acetylation can be increased significantly by incubating HeLa cells in the presence of the deacetylase inhibitor, 5 mM sodium butyrate, this treatment has little if any effect on the total number of nucleosomes retained on the Hg-agarose column. However, the ability of Hg-agarose chromatography to detect localized changes in chromatin structure is evidenced by an 11-fold increase in the Hg-agarose binding of nucleosomes containing the DNA of the butyrate-inducible alkaline phosphatase gene, compared to the Hg-agarose-bound nucleosomes of control cells. Although nascent RNA chains are present in the Hg-agarose-bound nucleosomes released by dithiothreitol, binding of the SH-reactive nucleosomes to the Hg-agarose column is not dependent on the presence of proteins associated with nascent RNA chains, since binding does not decrease following removal of the nascent transcripts by ribonuclease treatment.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Factors affecting nucleosome structure in transcriptionally active chromatin. Histone acetylation, nascent RNA and inhibitors of RNA synthesis. 170 16

Estrogen administration to male Xenopus causes the cytoplasmic destabilization of the hepatic serum protein coding mRNAs, most notably, albumin, yet has little effect on mRNAs encoding intracellular proteins such as ferritin. This report describes an estrogen-inducible ribonuclease activity found in liver polysomes that degrades albumin mRNA 4 times faster in vitro than it degrades ferritin mRNA. This differential rate of degradation was observed upon incubation of polysome extract with free liver RNA, isolated liver mRNPs, or transcripts from plasmid vectors. A cleavage fragment consisting of a doublet of approximately 194 nucleotides in length was consistently observed upon digestion of transcripts for the full length or 5' half of albumin mRNA. The generation of this cleavage fragment was used as an assay to study properties of the polysome nuclease activity. The 194 doublet is produced by the action of a Mg(2+)-independent endonuclease. This distinguishes the Xenopus liver enzyme from the enzymes that degrade histone or c-myc mRNA in vitro. It is inactivated by 400 mM NaCl or heating at 90 degrees C, but not by placental ribonuclease inhibitor or N-ethylmaleimide. Finally, the polysomal nuclease activity does not degrade double-stranded RNA. We believe the estrogen-induced nuclease activity contains an enzyme(s) that may mediate hormone-regulated changes in mRNA stability in this tissue.
 ...
PMID:Estrogen-induced ribonuclease activity in Xenopus liver. 193 72


1 2 3 4 5 6 7 8 Next >>