Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.21.1 (DNase)
 7,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

On the basis of morphological and biochemical differences, the exocrine pancreatic tissue has been divided in peri- and teleinsular regions. In the present study the enzymatic profile of these regions has been investigated by the immunofluorescent technique using antibodies against nine pancreatic enzymes (alpha-amylase, lipase, chymotrypsinogen A, trypsinogen, elastase, carboxypeptidase A and B, DNase and RNase A). These antibodies were specific to their antigens without cross reaction. By immunofluorescence, most acinar cells of the normal rat pancreas were positive to the nine enzymes tested. However, an inhomogeneity in the staining pattern was found; specifically, the cells located in the periinsular region of many islets showed a brighter fluorescence than acinar cells in the teleinsular tissue. These data add a new parameter to describe the inhomogeneity of the exocrine pancreas.
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PMID:Immunohistochemical localization of exocrine enzymes in normal rat pancreas. 11 Aug 72

Incubation of Neurospora crassa conidia with ribonuclease (RNase) A reduces transport of L-phenylalanine by those cells. Under similar conditions, oxidized RNase A, RNase T1, and RNase T2 do not have this effect. Incubation of conidia with active RNase covalently attached to polyacrylamide beads reduces L-phenylalanine transport. This indicates that the site of enzymatic action is at the cell surface. At the lower concentration of enzyme used in this study, incubation with RNase A reduces transport of L-phenylalanine by the general (G) amino acid permease. Increasing the enzyme concentration results in reduction of transport by the neutral aromatic (N)-specific permease. The increased transport activity that accompanies onset of conidial germination is also sensitive to incubation with RNase A. Application of the enzyme to actively transporting cells does not release amino acid transported prior to enzyme addition. Cells cultured on media supplemented with [2-14C] uridine release isotopic activity after RNase A incubation. Analogous treatments with Pronase, RNase T1, RNase T2, or deoxyribonuclease I do not release isotope activity. Pronase treatment does reduce L-phenylalanine transport. Incubation of conidia with RNase A also inhibits germination of those conidia.
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PMID:Effects of ribonuclease A on amino acid transport in Neurospora crassa. 12 24

A new ribonuclease has been isolated from Escherichia coli. The enzyme is present in the 100,000 times g supernatant fraction and has been purified over 200-fold. Studies of the enzyme reveal that: 1. The enzyme shows a marked preference for oligoribonucleotides; indeed, the reaction rate is inversely proportional to the chain length of the substrate. The enzyme does not attack polynucleotides even at high concentrations of enzyme and has no detectable DNase activity. 2. The enzyme is stimulated strongly by Mn2+, less strongly by Mg2+, and not at all by Ca2+ and monovalent cations. 3. The enzyme is purified free of RNase I, RNase II, RNase III, polynucleotide phosphorylase, and other known ribonucleases of E. coli. The enzyme displays identical properties when isolated from mutants of E. coli that are deficient in the above ribonucleases. 4. The enzyme has a marked thermostability, a point of further distinction from RNase II.
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PMID:A novel oligoribonuclease of Escherichia coli. I. Isolation and properties. 24 Aug 24

Different systemic organs of fetal mice were continuously labelled with 5-3H-uridine during the organogenesis periods, and chased for various lengths of time after birth. In the autoradiographs made on paraffin-embedded sections of the organs taken after the chase for longer periods than 1 week, including a 12-months chase, specific labels were present exclusively in all the nuclei. The specific nuclear labels were resistant to RNase A or H digestion and to acid hydrolysis with 1 N HCl at 60 degrees C for 5 min, but were completely abolished by DNase digestion or prolonged acid hydrolysis for 10 min, the optimum condition for the Feulgen reaction to stain DNA. Electrophoretic analysis of the total nucleic acids extracted from the different organs chased for 3 or 12 months showed all the tritium radioactivity to be present in the DNA fraction before digestion with DNase or RNase A, and to be completely absent from the DNA fraction and shifted to the RNA fraction, or to be largely destroyed by degradation, after each digestion, respectively. By HPLC analysis of the total nucleic acid extract after further successive digestions with nuclease P1 and alkaline phosphatase into the constituent nucleotides, it was shown that all tritium activity was incorporated in uridine, without any detectable label in other nucleotides. By the simultaneous labeling of human peripheral lymphocytes at the late S-phase with 5-3H-uridine and BrdU, it was demonstrated that the autoradiographic labels, which, this time, were labile to RNase A digestion, were present in the G-bands of the spread chromosomes as identified by BrdU immunohistochemistry. The findings strongly indicate the presence of a novel class of nuclear RNA (nRNA). This type of RNA (a) may be localized in the nucleus in close association or hybridization with nuclear DNA, (b) have a life span as long as that of the cell, and (c) be duplicated in the late phase of DNA replication. The nRNA may play a fundamental role as gene repressor existing in the G-bands of metaphase chromosomes in the process of ontogeny and cytodifferentiation.
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PMID:A novel class of nuclear RNA (nRNA) with a long life span as a gene repressor candidate. 137 66

msDNA-Ec67 is produced in a clinical strain of Escherichia coli and composed of a 67-base single-stranded DNA, which is linked to the 2'-OH group of the 15th rG residue of a 58-base RNA molecule by a 2',5'-phosphodiester linkage (Lampson, B. C., Sun, J., Hsu, M.-Y., Vallejo-Ramirez, J., Inouye, S., and Inouye, M. (1989) Science 243, 1033-1038). The production of msDNA-Ec67 is dependent upon retron-Ec67, which consists of the msr-msd region and the gene for reverse transcriptase (RT). These two elements were separately cloned into plasmids; p67-BHO.6 contained the msr-msd region and pRT-67 contained the RT gene under the lpp-lac promoter-operator. msDNA-Ec67 was produced only when cells were transformed with both plasmids. In addition, msDNA-Ec67 was synthesized in a cell-free system using total RNA prepared from cells harboring plasmid p67-BHO.6 and purified Ec67-RT. Using this cell-free system, the priming reaction, during initiation of DNA synthesis, was demonstrated to be a specific template-directed event; only dTTP was incorporated into a 132-base precursor RNA yielding a 133-base compound. This specific dT addition could be altered to dA or dC by simply substituting the 118th A residue of the putative msr-msd transcript with a T or G residue. The priming reaction was blocked when A was substituted for G at the 15th residue of the precursor RNA transcript, which corresponds to the branched rG residue in msDNA. DNA chain elongation could be terminated by adding ddNTP in the cell-free system, forming a sequence ladder. The DNA sequence determined from this ladder completely agreed with the msDNA sequence. The RT extension reaction was completely blocked when the RNA preparation was treated with RNase A but not when the preparation was treated with DNase. This clearly demonstrates that RNA but not DNA is responsible for the msDNA production. A part of the fully extended cell-free product contained a 13-base RNA strand resistant to RNase A, which is consistent with the previously proposed model. In this model, the 5'-end sequence of the msr-msd transcript (a2; bases 1-13) forms a duplex with the 3'-end sequence (a1) of the same transcript, thus serving as a primer, as well as a template for msDNA synthesis by RT. Our results are inconsistent with a model recently proposed by Lease and Yee (Lease, R. A., and Yee, T. (1991) J. Biol. Chem. 266, 14497-14503).
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PMID:Cell-free synthesis of the branched RNA-linked msDNA from retron-Ec67 of Escherichia coli. 137 31

Abnormal tubulofilamentous particles were identified by electron microscopy using a simple touch negative staining technique from brains of mice infected with four strains of the scrapie agent. Treatment by three proteolytic enzymes and subsequent treatment with DNase and mung bean nuclease of grids prepared from the infected animals confirmed previous observations that the tubulofilamentous particles observed in scrapie-effected brains are complex structures. The core of the tubulofilamentous particle scrapie-associated fibrils was revealed by treatment with SDS. Treatment with proteolytic enzymes and subsequent treatment with DNase or mung bean nuclease or S1 nuclease also revealed typical and transitional stages of scrapie-associated fibrils. However, treatment with RNase A had no effect. The data suggest that nucleic acid is a single-stranded DNA protected by a protein coat.
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PMID:Evidence of ssDNA in tubulofilamentous particles: their relationship to scrapie-associated fibrils. 167 41

Adsorbed layers of pancreatic RNase A on molecularly smooth mica in aqueous solution attract inorganic mica surfaces whereas they repel similarly adsorbed RNase A layers. As the clean mica surface is covered with RNase A, the attractive interaction slowly diminishes with time and eventually converts to a purely repulsive interaction. Solvent is squeezed out of the solution in the gap during compression of the two surfaces so that the adsorbed protein concentration, as measured directly by the refractive index, increases significantly. The kinetics of this process is analyzed using surface force-distance measurements. All these results are predicted for constrained equilibrium by a discrete lattice model [Scheutjens, J. M. H. M. & Fleer, G. J. (1985) Macromolecules 18, 1882-1900]. Reasonable values are obtained for the constants of the model. We also report on the equilibrium behavior and interaction of densely adsorbed RNase A layers in aqueous solutions of varying ionic strength and pH. With increasing ionic strength, intramolecular forces dominate with diminished electrostatic repulsion. Thus, the adsorbed protein layer becomes more compact while unattached protein molecules coil and fold, making them less likely to form strong intermolecular bridges. Only at very low ionic strength (0.1 mM KCl), when electrostatic forces dominate, does the membrane potential model come close to predicting the long-distance repulsive behavior. Thus, at higher ionic strengths, other non-electrostatic interactions (such as hydrophobic interactions) possibly dominate. An increase in the pH of the solution from 5 to 9.2, the pI of RNase A, significantly reduces the electrostatic repulsion between protein molecules in favor of hydrophobic attractive interactions. This results in lower short-range steric repulsion. However, in contrast to the ionic-strength effect, an increased long-range repulsive force with a much longer decay length is observed. This may be due to contaminants such as DNase that have their pI at a pH other than 9.2. Thus, as with the changing-ionic-strength study, thinner and denser adsorbed layers are formed. Finally, for the kinetic studies, two characteristic length scales--the thickness of the adsorbed layer and the "jump-in" distance--vary linearly with the square root of time. This is consistent with our earlier results and once again implies a diffusion-driven process.
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PMID:Attractive and repulsive interactions between and within adsorbed ribonuclease A layers. 192 77

The purpose of this study was to reveal the presence of Z-helical conformation in normal crystalline lens DNA. Z-DNA antigen was prepared against poly(dG-dC).poly(dG-dC), which had been converted to the Z-helix conformation in high salt and then stabilized by bromination. Circular dichroism (CD) spectra confirmed the presence of left-handed Z-helix DNA. Antibodies to Z-DNA were raised in three rabbits immunized with brominated (Br-) poly(dG-dC).poly(dG-dC). These antibodies do not cross-react with polynucleotides in the B-helical form, but are specific to the left-handed Z-DNA conformation. DNA was isolated from three different regions of the calf lens. Anti-Z-DNA antisera, affinity purified IgG polyclonal anti-Z-DNA antibodies and monoclonal anti-Z-DNA antibodies were used as immunoprobes to detect the presence of S-DNA sequences. DNA from the cortex region of the lens reacted strongly with the anti-Z-DNA antibodies, but no binding could be observed in the DNA from the nucleus region. Digestion of lens DNA with DNase 1 dramatically decreased Z-DNA antibody binding, while RNase A and T1 treatment had no effect on Z-DNA immunoreactivity. This study has demonstrated that: (a) Z-DNA antibodies developed for our study can bind in high salt solutions (4M NaCl) to purified lens DNA sequences isolated from a variety of different calf lens cell types. By this criterion, lens DNA contains sequence determinants which may assume or are in the Z-helix conformation.
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PMID:The presence of Z-helical conformation in DNA of the calf lens. 204 43

Autoimmune serum from a patient with scleroderma was shown by indirect immunofluorescence to label nucleoli in a variety of cells tested including: rat kangaroo PtK2, Xenopus A6, 3T3, HeLa, and human peripheral blood lymphocytes. Immunoblot analysis of nucleolar proteins with the scleroderma antibody resulted in the labeling of a single protein band of 34 kD molecular weight with a pI of 8.5. Electron microscopic immunocytochemistry demonstrated that the protein recognized by the scleroderma antiserum was localized exclusively in the fibrillar region of the nucleolus which included both dense fibrillar and fibrillar center regions. Therefore, we have named this protein "fibrillarin". Fibrillarin was found on putative chromosomal nucleolar organizer regions (NORs) in metaphase and anaphase, and during telophase fibrillarin was found to be an early marker for the site of formation of the newly forming nucleolus. Double label indirect immunofluorescence and immunoelectron microscopy on normal, actinomycin D-segregated, and DRB-treated nucleoli showed that fibrillarin and nucleolar protein B23 were predominantly localized to the fibrillar and granular regions of the nucleolus, respectively. RNase A and DNase I digestion of cells in situ demonstrated that fibrillarin was partially removed by RNase and completely removed by DNase. These results suggest that fibrillarin is a widely occurring basic nonhistone nucleolar protein whose location and nuclease sensitivity may indicate some structural and/or functional role in the rDNA-containing dense fibrillar and fibrillar center regions of the nucleolus.
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PMID:Fibrillarin: a new protein of the nucleolus identified by autoimmune sera. 293 2

Rabbits infected with the L strain of rinderpest virus (RV) produced high titres of antinuclear antibodies (ANA) which reached a maximum two weeks after inoculation but rapidly disappeared by 6-8 weeks. These ANAs reacted with HeLa cells by indirect immunofluorescence test resulting in a homogeneous nuclear fluorescence. In order to investigate the target antigens of ANAs, the effects on the nuclear fluorescence pattern of pretreating HeLa cells were examined: DNase 1 treatment resulted in a decrease in the fluorescence whereas no changes were evident after RNase A treatment. Some group of sera showed decreased fluorescence in the cells from which histones were acid extracted, but other groups did not change in fluorescence. Sera which had failed to react with acid extracted cells gave positive fluorescence following histone reconstitution. The results indicate that DNA and nucleohistone are the major target antigens for ANAs. In addition, antibodies against nucleoli and extractable nuclear antigens were induced in some rabbits.
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PMID:Characterization of antinuclear antibodies induced in rabbits by rinderpest virus infection. 305 91


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