Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.22.1 (DNase II)
 429 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Retinal death induced by light seems to be a caspase-independent process. In this work we investigate the LEI/L-DNase II pathway, a caspase-independent pathway, in light-induced retinal degeneration in Fischer rats. Measurement of DNase activity in total retinal extracts of light exposed Fischer rats was performed by analysing a plasmid degradation on an agarose gel. The same method was used to measure the in vitro activity of recombinant LEI (reticulocyte lysate) after incubation with calpains. L-DNase II activity is observed in retinal extracts of light exposed Fischer rats and increases with time illumination. In this apoptotic death, the activation of calpains has been shown. Here we show that L-DNase II activation is not catalized by calpains. The present study indicates that the LEI/L-DNase II may be a possible pathway activated during photoreceptor apoptosis in light-induced retinal degeneration but that this pathway is not directly activated by calpains.
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PMID:The LEI/L-DNase II pathway is activated in light-induced retinal degeneration in rats. 1533 Nov 54

BACKGROUND: It has been documented that nitric oxide (NO) donor sodium nitroprusside (SNP) and authentic peroxynitrite are capable of promoting apoptosis in a number of different cell types. Various endonucleases have been proposed as candidates responsible for the internucleosomal cleavage of the genomic DNA observed during apoptosis, but the main effect is attributed to the alkaline-DNases (Mg2+- and caspase-dependent) and acid-DNase. The aim of this study was to examine an in vivo and in vitro possibility for alkaline- and acid-DNases to be activated by SNP and peroxynitrite. RESULTS: The effect on liver tissue alkaline and acid DNase activity together with the markers of tissue and plasma oxidative and nitrosative stress (lipid peroxidation, SH group content, carbonyl groups and nitrotyrosine formation) was investigated in plasma and liver tissue. The activity of liver alkaline DNase increased and that of acid DNase decreased after in vivo treatment with either SNP or peroxynitrite. A difference observed between the in vivo and in vitro effect of oxide donor (i.e., SNP) or peroxynitrite upon alkaline DNase activity existed, and it may be due to the existence of the "inducible" endonuclease. After a spectrophotometric scan analysis of purified DNA, it was documented that both SNP and peroxynitrite induce various DNA modifications (nitroguanine formation being the most important one) whereas DNA fragmentation was not significantly increased. CONCLUSION: Alkaline DNase activation seems to be associated with the programmed destruction of the genome, leading to the fragmentation of damaged DNA sites. Thus, the elimination of damaged cells appears to be a likely factor in prevention against mutation and carcinogenesis.
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PMID:Sodium nitroprusside and peroxynitrite effect on hepatic DNases: an in vitro and in vivo study. 1533 33

The ability of a 43 kDa stichocyte protein from Trichinella spiralis (Tsp43) to interfere with mammalian skeletal muscle gene expression was investigated. A MYC-tagged Tsp43 construct was expressed as a recombinant protein in C2C12 myoblasts. Transfection with low amounts of expression plasmid was required for successful expression of the protein. This construct had apparent toxic effects on transfected myoblasts and ectopic green fluorescent protein expression was suppressed in myoblasts co-transfected with the Tsp43 construct. These effects may result from similarities of Tsp43 to DNase II. Use of the general DNase inhibitor aurintricarboxylic acid (ATA) enhanced expression of MYC-Tsp43 in transfected muscle cells. Myoblasts transfected with Tsp43 did not fuse well when cultured under differentiation conditions without ATA. In contrast, transfected myoblasts transiently cultured with ATA underwent fusion and differentiation. Under short-term differentiation conditions without ATA, unfused myoblasts nevertheless expressed both MYC-Tsp43 and myosin heavy chain. Collectively, the results support that Tsp43 has a role in the T. spiralis life cycle that is distinct from repressing muscle gene expression during the muscle phase of infection. While the function of Tsp43 as a DNase is under debate, the effects of ATA on transfected muscle cells were consistent with this possibility.
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PMID:Fusion and differentiation of murine C2C12 skeletal muscle cells that express Trichinella spiralis p43 protein. 1633 28

Acid endonucleases of the deoxyribonuclease II (DNase II, EC 3.1.22.1) family have been implicated in the degradation of DNA from apoptotic cell corpses formed in the process of normal mammalian development. Although a predicted DNase II has been detected in the chicken through expressed sequence tag (EST) analysis, to date no homolog of these important enzymes has been identified in vivo in any avian species. Here we report the cloning and expression of DNase II from the chicken, Gallus gallus. When expressed, the 363 amino acid glycoprotein is observed to be approximately 45 kDa in size and to exhibit DNA hydrolytic activity at pH 5 consistent with DNase II in other species. Furthermore, chicken DNase II sequence is compared with an identified partial sequence from the zebra finch, Taeniopygia guttata, as well as the previously identified homologs found in the fowlpox and canarypox viruses and the previously cloned mammalian DNases II. Through analysis of its amino acid sequence, comparative gene structure, and conserved synteny, chicken DNase II appears to represent a member of the DNase IIbeta subfamily and the apparent lack of a DNase IIalpha homolog in the chicken has important evolutionary implications for the study of this gene family.
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PMID:Cloning and expression of deoxyribonuclease II from chicken. 1650 43

DNase II is an acid endonuclease that is involved in the degradation of exogenous DNA and is important for DNA fragmentation and degradation during cell death. In an effort to understand its catalytic mechanism, we constructed plasmids encoding nine different histidine (H)-to-leucine (L) mutants for porcine DNase II and examined the enzyme properties of the expressed mutant proteins. Of the mutants, all but H132L were secreted into the medium of expressing cells. Six of the mutated DNase II proteins (H41L, H109L, H206L, H207L, H274L and H322L) showed enzyme activity, whereas the H115L, H132L and H297L mutants exhibited very little activity. The H115L and H297L mutants were found to undergo correct protein folding, but were inactive. To further examine these mutants, we expressed H115A and H297A DNase II mutants; these mutants were inactive, but their DNase activities could be rescued with imidazole, indicating that His115 and His297 are likely to function as a general acid and a general base respectively in the catalytic centre of the enzyme. In contrast with the secreted mutants, the H132L mutant protein was found in cell lysates within 16 h after transfection. This protein was inactive, improperly folded and was drastically degraded via the proteosomal pathway after 24 h. The polypeptide of another substitution for His132 with lysine resulted in the misfolded form being retained in endoplasmic reticulum.
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PMID:Identification of three crucial histidine residues (His115, His132 and His297) in porcine deoxyribonuclease II. 1673 90

Apoptosis is characterized by cell shrinkage, nuclear condensation and internucleosomal DNA cleavage. Besides the central role of caspases and other proteases, cell death triggers DNA degradation so that DNases have an active role in apoptotic cell death. The best-characterized apoptotic DNase is CAD, a neutral Mg-dependent endonuclease. Its activity is regulated by its inhibitor, ICAD, which is cleaved by caspases. Other neutral DNases have been shown to cleave nuclear DNA in apoptotic conditions: endonuclease G, GADD. In cells, the cytosolic pH is maintained to 7.2, mostly due to the activity of the Na(+)/H(+) exchanger. In many apoptotic conditions, a decrease of the intracellular pH has been shown. This decrease may activate different acid DNases, mostly when pH decreases below 6.5. Three acidic DNases II are so far known: DNase II alpha, DNase II beta and L-DNase II, a DNase II, derived from the serpin LEI (Leukocyte Elastase Inhibitor). Their activation during cell death is discussed in this review.
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PMID:Acid DNases and their interest among apoptotic endonucleases. 1698 34

We have developed two microtiter plate assays to quantify the deoxyribonuclease activity in biological fluids. Both assays are based on hydrolysis of biotinylated and fluorescein-labeled DNA substrates, with subsequent immunochemical detection of non-digested DNA. The assay based on hydrolysis of 974 bp PCR product labeled with biotinylated forward and fluorescein-labeled reverse primers is more sensitive (0.05 U/ml) and convenient for quantifying the DNase activity in biological fluids than the assay based on hydrolysis of double-labeled 20 bp oligonucleotide. The DNase activity in urine and blood plasma of healthy donors was measured using the PCR product-based assay. Urine samples revealed greater activity, 1.49+/-1.41 U/ml; blood plasma DNase I-like activity was 0.36+/-0.20 U/ml. DNase II-like activity was not detected in the plasma samples. The data obtained confirm that DNase I-like enzymes are responsible for the majority of deoxyribonuclease activity in blood plasma.
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PMID:Immunochemical assay for deoxyribonuclease activity in body fluids. 1761 45

The level of the acid DNase activity in the hemocytes and digestive gland of the mussel Mytilus galloprovincialis after exposure to model marine pollutants, a detergent, gasoline and a copper salt, as well as to unknown environmental mixture at selected sampling sites, was investigated. The specific enzyme activity in unexposed mussels from mariculture area was higher in hemocytes than in digestive gland. Concentration and time effect patterns of DNase activity revealed tissue- and pollutant-specific responses to model marine pollutants. Since in some cases the pollutant effect could not be detected by measurement of acid DNase in single tissue only, digestive gland/hemocyte (Hep/Hem) ratio was introduced. The Hep/Hem ratio enabled the detection of pollutant effect at the significance level. Field investigations indicated that the digestive gland is a suitable tissue for discrimination of polluted areas from maricultured area. Additionally, the Hep/Hem ratio enabled differentiation within a group of polluted sampling sites that differ in the type of pollutants and/or environmental conditions.
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PMID:Effect of marine pollutants on the acid DNase activity in the hemocytes and digestive gland of the mussel Mytilus galloprovincialis. 1827 21

DNA degradation is one of the hallmarks of programmed cell death, or apoptosis. Recent analyses of this process revealed that apoptotic DNA degradation is mediated by two independent mechanisms. First, the caspase-activated DNase (CAD) cell autonomously cleaves DNA into nucleosomal units in dying cells. Then, after the apoptotic cells are engulfed by macrophages, the fragmented DNA is further degraded by DNase II in the lysosomes of the macrophages. This chapter describes assay procedures for CAD and DNase II. It includes biochemical methods for quantifying DNase activity and cell culture systems to follow cell-autonomous and noncell-autonomous DNA degradation. These techniques are useful for studying DNases that are involved in programmed cell death and for following the engulfment of apoptotic cells by phagocytes.
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PMID:Nucleases in programmed cell death. 1866 75

The alterations of deoxyribonuclease DNase activity in cancer cells were the basis of the utilization of mixed vitamins C and K3 in a nontoxic, adjuvant cancer therapy. In order to localize exactly the altered activities of DNase in cancer cells, histochemical methods were utilized. The deficiency of alkaline and acid DNase activity appeared to be characteristic for non-necrotic cells of malignant human and animal tumors. This enzymatic deficiency appeared in experimental carcinogenesis before the phenotypic signs of malignancy. Tumor promoters directly reduced the activity of both DNases. The incidence of spontaneous malignant human and animal tumors appeared to be inversely proportional to the intensity of the activity of both DNases in normal cells and tissues from which these tumors were derived. The fact that alkaline and acid DNase activity was reactivated during the spontaneous and therapeutically induced necrosis of cancer cells suggests that this enzymatic deficiency of DNase activity in cancer cells was due to the action of specific inhibitors of DNases. Characteristic variations of serum alkaline DNase activity in positive responders to therapy, examined in more than 800 cancer-bearing patients, may be the basis for the development of a useful test for therapeutic prognosis and for monitoring of cancer bearing patients. Acid DNase was selectively reactivated in malignant tumor cells by vitamin C (sodium ascorbate), whereas alkaline DNase was reactivated by vitamin K3. Joint vitamin C and K3 administration produced in vitro and in vivo tumor growth inhibition, potentiation and sensitization of chemo- and/or radiotherapy and a decrease in the number of metastases in animals with experimental tumors. Joint vitamin C and K3 administration may be considered as a possible new, non-toxic, adjuvant cancer therapy, which can be easily introduced into the classic protocols of clinical cancer therapy without any supplementary risk for patients.
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PMID:Altered deoxyribonuclease activity in cancer cells and its role in non toxic adjuvant cancer therapy with mixed vitamins C and K3. 1903 2


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