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)

Abnormal tubulofilamentous structures have been identified in electron micrographs of thin sections and negatively stained impression grids prepared from brains of animals with scrapie and other spongiform encephalopathies, and we showed that such tubules contain a core of filamentous structures resembling scrapie-associated fibrils (SAF). We treated impression grids from brains of scrapie-infected hamsters with several substances that bind to or cleave proteins and nucleic acids to see if they had any effect on the abnormal tubulofilamentous structures. Treatment with three proteolytic enzymes reduced the caliber of the tubules from about 50 nm to 30 nm; subsequent treatment of the 30-nm tubules with DNase I left many typical SAF as well as transitional forms in which twisted SAF emerged from tubules. DNase treatment of the original thicker tubules had no effect, and no SAF were seen on grids. Treatment of the 30-nm tubules with any of three other nucleases (micrococcal, mung bean, and BAL-31) also produced SAF. However, treatment with RNase A had no effect either on the original 50-nm tubules or on the 30-nm tubules produced by proteolysis. Detergent treatment of any of the preparations produced SAF. Treatment with ethidium bromide resulted in staining of the tubules that was inhibited by magnesium ions. The data suggest that the abnormal tubulofilamentous particles found in spongiform encephalopathies may consist of an outer cylinder of protein, an inner cylinder of DNA, and an innermost core of SAF.
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PMID:Evidence that DNA is present in abnormal tubulofilamentous structures found in scrapie. 313 Jun 30

Messenger RNAs in eukaryotic cells exhibit a broad range of stabilities in vivo. Globin mRNA has a half life in excess of 50 h, but the half life of the c-myc oncogene mRNA is less than 20 min. Regulation of gene expression may be accomplished by a variety of mechanisms, including altering mRNA stability. We have examined the nuclear and cytoplasmic fractions of cells for factors affecting the metabolism of mRNA. Here we report that a HeLa whole-cell extract contains a factor that protects beta-globin mRNA from attack by RNases in a mouse erythroleukemia cell cytoplasmic extract. The factor is non-dialysable, inactivated by proteinase K and heat treatment, and resistant to RNase and DNase digestion. The HeLa cell factor resembles placental RNase inhibitor in that the mRNA-protecting activity is effective against RNase A and that treatment of the extract with N-ethylmaleimide completely destroys the protective activity. However, purified placental RNase inhibitor was unable to inhibit the RNase activity in the MELC cytoplasmic extract. These results suggest that the HeLa cell extract contains an RNase inhibitor (or inhibitors) with an activity or specificity that is distinct from that of placental RNase inhibitor.
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PMID:Cellular factor affecting the stability of beta-globin mRNA. 316 61

In this study we evaluated some pathophysiological aspects of pancreatic and liver ribonucleases and alkaline deoxyribonuclease and their clinical usefulness in diagnosing pancreatic cancer. Pancreatic RNase was found to be a sensitive index of pancreatic malignancy; however it was not specific in distinguishing pancreatic malignancy from chronic pancreatitis or other pathologies. Liver RNase and alkaline DNase did not provide better results than pancreatic RNase. These three enzymes were found to be age-dependent and related to each other. Therefore serum nucleases are not useful for clinical purposes since they are influenced, at least in part, by different non-specific factors.
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PMID:Ribonucleases and deoxyribonucleases in pancreatic cancer: clinical value and pathophysiological interrelationships. 320 63

Procedures are described for identification of very infrequent in vivo 3'-ends of RNA. After purification by filter hybridization, the 3'-ends were labeled with [5'-32P] cytosine-3'-P in the RNA ligase reaction. Significantly fewer counts were incorporated in the ligase reaction than in the polynucleotide kinase reaction to label 5'-ends. The incorporation was increased by increasing the RNA concentration 5-10 fold by using only one round of filter hybridization. Non-specific RNA binding could be eliminated by RNase A treatment of the filter if a great excess of denatured heterologous DNA was immobilized along with the DNA probe. Significant amounts of DNA were released when eluting the hybrid RNA from such filters. DNA inhibited the ligase reaction, while its DNase products were even more inhibitory. Treatment of the DNase products with alkaline phosphatase completely eliminated the inhibition. We detected no spurious 5'- or 3'-ends generated in the hybrid RNA by RNase A activity used to reduce the non-specific RNA. Also, RNase T1 could be used in place of RNase A to eliminate non-specific RNA binding, but about 25 times more RNase T1 (microgram/microgram) was needed. We used partial alkali digestion to sequence 3'-ends. A major (one hit) and minor (two hit) set of products were produced which could be distinguished from each other by alkaline phosphatase treatment and homochromatography of the products.
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PMID:Isolating and sequencing the infrequent 3'-ends of a specific mRNA. 331 56

Cell ghosts have been prepared from mature chicken erythrocytes using 0.05% saponin. Such preparations are capable of incorporating label from [3H]UTP and provide a system, where the nucleus is permeable to nucleotides and macromolecules, for studying the low-level RNA synthesis characteristic of these cells. RNase A (50 micrograms/ml) eliminated all radioactivity binding to DE-81 filters, indicating that the product was RNA; and DNase (10 micrograms/ml) and actinomycin D (10 micrograms/ml) each inhibited UMP incorporation by 70%, suggesting that the synthesis was DNA-dependent. Polymerization was inhibited 90% by 0.1 microgram/ml alpha-amanitin, and maximum synthesis occurred in the presence of high salt (0.175 M KCl) and Mn2+ (0.5 mM). Polyacrylamide gel electrophoresis indicated that the newly synthesized RNA was heterogeneous in size, having a distribution from 5 to 60 S with a significant fraction migrating as 8-12 S. Approximately 15% of the total RNA was bound by an oligo(dT)-cellulose column, suggesting that some RNA processing was occurring, although attempts to detect the incorporation of label from [alpha-32P]GTP into a 5'-cap structure were unsuccessful. In comparison to RNA synthesis in reticulocyte nuclei, both the rate and extent of transcription in erythrocyte nuclei were much reduced. Moreover, about 25-30% of the reticulocyte nascent RNA was released from the nuclei during a 60-min incubation, while no release was observed for the erythrocyte nuclei. Hybridization of radiolabeled RNA to excess chicken DNA indicated that the majority (80%) of the in vitro transcripts were complementary to unique sequence DNA (C0t1/2 = 4.5 X 10(3)). When RNA synthesized by either erythrocyte or reticulocyte nuclei was hybridized to cDNA complementary to reticulocyte polysomal mRNA, about 8% of the reticulocyte nuclear RNA but less than 1% of the erythrocyte nuclear RNA were resistant to RNase A digestion. Taken together, these data suggest that nuclei prepared by saponin lysis of chicken erythrocytes synthesize messenger-like RNA via endogenous polymerase II activity. A fraction of this RNA is polyadenylated but contains few, if any, globin sequences or other transcripts found on reticulocyte polysomes.
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PMID:Synthesis of messenger-like RNA in avian erythrocyte nuclei. 390 27

Spheroplasts are insensitive to colicin E(2) and do not show deoxyribonucleic acid (DNA) degradation even in the presence of massive amounts of E(2). However, when both endonuclease I and E(2) were present, spheroplast DNA was degraded by an endonucleolytic activity which gave rise primarily to double-strand DNA cleavages, producing fragments having an average molecular weight of 9 x 10(6). Pancreatic ribonuclease could substitute for colicin E(2) in the reconstitution system, but pancreatic deoxyribonuclease could not replace endonuclease I. However, colicin E(2) could not activate transfer ribonucleic acid-inhibited endonuclease I in an in vitro system where pancreatic ribonuclease caused full stimulation.
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PMID:Reconstitution of colicin E2-induced deoxyribonucleic acid degradation in spheroplast preparations. 459 17

A cytochemical technique for the ultrastructural localization of substrates using enzyme-gold complexes is reported. RNase A and DNase I have been labeled with gold particles. The RNase-gold and dNase-gold complexes obtained were applied on thin sections of glutaraldehyde-fixed and Epon-embedded tissues. Different cellular compartments were labeled by these enzyme-gold complexes. Using the RNase-gold complex the rough endoplasmic reticulum appeared decorated with gold particles. The gold marker was also present over the nucleus, especially over the nucleolus; mitochondria were weakly labeled. Using the DNase-gold complex, gold particles were concentrated over the euchromatin of the nucleus and the mitochondria. The heterochromatin and the nucleolus showed a less intense labeling. For both enzyme-gold complexes, the Golgi area, the secretory granules and the extracellular space appeared free of label. In those control conditions where the substrates were added to the enzyme-gold complexes a major reduction in the labeling was observed. A quantitative evaluation of the labeling was performed. This evaluation confirmed the qualitative observations and the marked reduction of labeling occurring under the control conditions. The combination of the specificity of the enzyme-substrate interactions with the size and electron density of the gold particles and the good ultrastructural preservation of the tissues resulted in a very specific labeling with high resolution. These results demonstrate the possibility of detecting substrates by means of enzyme-gold complexes at the electron microscope level.
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PMID:Ultrastructural localization of nuclei acids by the use of enzyme-gold complexes. 626 46

The late oocyte karyosphere of Rana temporaria consists mainly of fibrillar nucleoli and micronucleoli, Fibrillar material containing the pore complexes (pseudomembranes) and modified synaptonemal complexes. Nuclease treatment of the karyosphere reveals regularly repeating bands in the nuclei and micronuclei, the fibrillar material associated with the nuclei being attenuated. After a subsequent treatment with DNase-1, RNase A and 1.5 M Nacl and karyosphere is disintegrated to involve remains of extracted nucleoli and fibrillar material containing pore complexes. 0.025 N NaOH extracted the bulk of the karyosphere and left only the islets if fibrillar material. The nuclear envelope proved to be far more stable to the above treatments. It retained its structure and was loosened partly only after 1.5 M NaCl or 0.025 N NaOH extraction, the pore complexes disappearing only after alkaline extraction. It is assumed that the karyosphere represents a skeletal structure (matrix) of the oocyte nucleus.
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PMID:[Karyosphere and nuclear envelope ultrastructure of oocytes of the common frog Rana temporaria after nuclease treatment and extraction of chromatin and alkali-soluble proteins]. 697 62

The nucleus--centrosome complex from Physarum polycephalum myxamoebae has been purified. The complex contained the centriole pair and pericentriolar material in association with the nucleus. Apart from some unusually stable microtubules, which appeared to be involved in maintaining the nucleus-centrosome association, endogenous microtubule arrays had been stripped from the complex during isolation. When the nucleus--centrosome complex was incubated with purified brain or myxamoebal tubulins the growth of 45-70 microtubules was initiated onto the pericentriolar material. The number and length of the nucleated microtubules was proportional to the tubulin concentration. Pretreatment of the nucleus--centrosome complex with DNase 1, RNase A, antitubulin antibody and anticentriolar antibody did not affect pericentriolar nucleation capacity, although pretreatment with DNase 1 did expose perinuclear nucleation sites that had a much lower minimal tubulin concentration for assembly than the pericentriolar site. After pretreatment with trypsin pericentriolar material and nucleation were destroyed, and microtubule elongation occurred directly onto the centriole microtubules.
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PMID:Microtubule nucleation by the isolated microtubule-organizing centre of Physarum polycephalum myxamoebae. 710 28

Casein kinase 2 was released from rat liver cells nuclei by digestion with DNase I plus RNase A. This treatment also released three major substrates of 50, 40-42, and 37 kDa. Casein kinase 2 and substrates were also extracted by DNase or RNase separately. However, in DNase extracts only the 37 kDa protein was phosphorylated by casein kinase 2, whereas in RNase extracts all three substrates were phosphorylated. When the DNase extracts were subsequently treated with RNase the 40-42 substrates were then phosphorylated, indicating that their interaction with RNA prevents their phosphorylation by casein kinase 2. The ratio of B: alpha subunits of casein kinase 2 present in the nuclease extracts was higher than that of the purified enzyme, which is assumed to be 1:1. A further analysis by sucrose gradient centrifugation revealed that under physiological salt conditions casein kinase 2 from nuclease extracts formed large aggregates (higher than 300 kDa) which were disrupted at 400 mM KCl. At the latter KCl concentration CK-2 activity was localized at a position corresponding to a M(r) of 230-250 kDa, which is still higher than the typical tetrameric form of the enzyme.
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PMID:Casein kinase 2 and protein substrates are released from rat liver cells nuclei by DNase or RNase digestion. 804 72


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