Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Human neutrophils adherent to a polystyrene plastic surface are vigorously activated, whereas those adherent to fibronectin manifest only a priming response. The basis of these metabolic differences was further characterized; polystyrene-adherent cells, which were shown to spread quickly upon adhesion, exhibited an increase of cytoskeleton-associated actin (F-actin) (measured by a nitrobenzoxadiazole-phallacidin fluorescent staining assay) and a decrease of monomeric G-actin concentration (measured by a DNase inhibition assay); in contrast, fibronectin-adherent cells exhibited little spreading and decreased their F-actin, after 1.5 min of adhesion, to 33.49 +/- 6.9% (mean +/- SD, n = 5) of initial levels found in suspended cells before plating. Actin depolymerization in fibronectin-adherent cells was confirmed by measuring G-actin, which sharply increased during the first minute of adhesion, rising from 0.065 +/- 0.007 to 0.20 +/- 0.035 microgram/microgram of protein (mean +/- SEM, p less than 0.05), and then remained elevated during 5 min of observation. In contrast, soluble fibronectin induced a decrease of G-actin in suspended cells. Cells pretreated with 1 microM cytochalasin D and allowed to adhere to a plastic surface did not spread, failed to generate O2-, and exhibited elevated concentrations of G-actin (0.1 to 0.2 microgram/microgram of protein) during the 5 min of observation. Actin changes, as well as respiratory burst, in adherent cells were shown to proceed through a pertussis toxin-insensitive pathway. Fluo-3 measurements of intracellular Ca2+ concentrations ([Ca2+]i) showed a fourfold and twofold [Ca2+]i increase in polystyrene- and fibronectin-adherent cells, respectively, after 2 min. The small rise in [Ca2+]i in fibronectin-adherent cells corresponds to a primed response of these cells to subsequent activation with FMLP. Ionomycin (1 microM) added to neutrophils just before adhesion on fibronectin induced full activation, i.e., O2- production and actin polymerization. The metabolic events controlling metabolic priming and actin depolymerization are as yet uncharacterized, but fibronectin receptor-linked responses beyond the mediation of cell adhesion have now been identified, suggesting complex metabolic functions of integrin receptors.
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PMID:Comparison of actin changes and calcium metabolism in plastic- and fibronectin-adherent human neutrophils. 150 Jul 23

In the heart, mRNA accumulations for sarcomeric actins and myosin heavy chains (MHC) are subject to diverse regulatorial processes. To study cardiac contractile protein transcriptional regulations, an in vitro transcription system using nonenzymatically isolated rat cardiac nuclei was characterized. Transcription was shown to be rapid and continuous during the first 20 min of incubation and 5.4-fold less than that seen from comparably isolated hepatocyte nuclei. Neither RNase nor DNase activities were detectable. Direct transcriptional analyses of the alpha- and beta-MHC and cardiac and skeletal alpha-actin genes from cardiac nuclei were performed. In 23-24-day-old rats, significant levels of transcription were seen for alpha-MHC and for the sarcomeric alpha-actins. beta-MHC was just detectable, and no positive signals were ever seen for fibronectin. We then compared the perecentages of MHC and sarcomeric alpha-actin expressions determined from 1) the transcriptional assays and 2) total isolated RNA (alpha-MHC: 90.1 +/- 4.8% (transcription), 93.0 +/- 4.7% (accumulation); beta-MHC: 9.9 +/- 4.8%, 7.0 +/- 4.7%; cardiac alpha-actin: 84.0 +/- 2.5%, 84.9 +/- 2.5%; skeletal alpha-actin: 16.1 +/- 2.5%, 15.0 +/- 2.5%). The results support the conclusion that the primary mechanisms controlling the accumulations of these gene products are transcriptional. Additionally, we show that an anti-sense mRNA showing strong homology or identity with the 5' end of the beta-MHC gene is transcribed in cardiac nuclei but not in hepatocyte nuclei.
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PMID:Cardiac expressions of alpha- and beta-myosin heavy chains and sarcomeric alpha-actins are regulated through transcriptional mechanisms. Results from nuclear run-on assays in isolated rat cardiac nuclei. 161 95

Sodium deoxycholate extraction was used to isolate extracellular matrix from various cultured cells: human and murine embryonic fibroblasts, epithelial lines of mouse (MPTR), rat (IAR 2 and IAR 20), pig (SPEV) and cow (FBT). Protein composition of the matrix was studied by sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunofluorescence. The matrix morphology was investigated by scanning electron microscopy. In cell lines FBT and MPTR the major component of the matrix was laminin, whereas in other lines and fibroblasts it was fibronectin. The matrix of the majority of lines had a fibrillar structure, and the fibrils usually formed networks. MPTR cells had a punctate matrix composed of laminin and collagen type IV, densely covering the substratum. The treatment of the matrix by hyaluronidase and/or DNAase I did not influence its protein composition. The isolated matrix of different structure and composition may serve a biological substratum in studies of normal tumor cell behavior in tissue culture.
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PMID:[Isolation and characteristics of the extracellular matrix of cultured cells]. 304 77

Fibronectin (Fn) is an integral constituent of the endothelial cell surface and the basement membrane. The mechanism for binding DNA/anti-DNA complexes to Fn was examined in a solid-phase assay. In physiological buffer, a low-affinity binding of DNA was observed with Fn and optimal binding was seen at pH 6.5 and in the absence of Ca2+. Further, the interaction of DNA to Fn was inhibited when DNA was complexed to anti-DNA antibody. However, complement Clq mediated the binding of complexes to Fn at pH 7.4 and it was proportional to the extent of the dissociation of Cl. Cl inactivator (Cl-In) appeared to play a modulating role; whereas at low concentrations (Cl:Cl-In::4: less than 1) it enhanced the binding of complexes to Fn, higher concentrations inhibited the binding. Further, sera from patients with active systemic lupus erythematosus reacted with Fn, which was shown to be dependent on the presence of Clq and was minimally affected by DNase treatment of sera, indicating a relatively minor role of DNA in the direct binding of DNA to Fn. These findings support "circulating immune complex" hypothesis in the pathogenesis of lupus glomerular immune complex deposition disease.
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PMID:Interaction of fibronectin with DNA/anti-DNA complexes from systemic lupus erythematosus: role of activated complement Cl in modulation of the interactions. 325 31

The association of glycoconjugates with the cytoskeletal framework was examined in detergent-extracted cells. Sparse cultures of fibroblasts that assemble only minimal amounts of extracellular matrix were extracted under mild conditions with Triton X-100 which remove most of the lipids and soluble cellular proteins. The detergent-resistant framework retains lectin binding sites in the nucleus, in the perinuclear area occupied by the rough endoplasmic reticulum-Golgi system of the intact cell, and in a network throughout the cytoskeletal framework. Fluorescent-antibody staining with antibody against collagen type I and fibronectin reveals extensive perinuclear staining of the remnant rough endoplasmic reticulum-Golgi system. In contrast, only sporadic staining of the pericellular area is obtained with these antibodies, in sparse cultures of whole cells. Lectin binding sites were detected in the nucleus and are attributed to chromatin-associated glycoconjugates. They can be removed by DNase under conditions that preserve the cytoplasmic lectin binding sites and the nuclear matrix. The results suggest a high degree of integration of the membrane residues of the cytoplasmic elements and the nuclear matrix with the skeletal framework and indicate a possible role for the glycoconjugates in this structural integration.
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PMID:Association of glycoconjugates with the cytoskeletal framework. 668 32

Medium conditioned by tissue from the CNS of the snail, Helisoma, is capable of promoting neurite outgrowth in isolated neurons from adult central ganglia. The conditioning factor(s) (CF), contained in conditioned medium (CM), is produced only by central ganglionic rings and buccal ganglia and not by other tissues, including hemolymph. CF requires a minimum of 24 h to be produced or released into the medium. At 12 h growth-promoting activity was not detectable. CF binds tightly to the polylysine substratum and its activity is not mimicked by addition of various sera, NGF or fibronectin. CF activity is abolished by chymotrypsin, trypsin or heating to 100 degrees C, but is stable to DNase and RNase treatment. The percentage of cells exhibiting neurite outgrowth is approximately linear with the amount of neural tissue used to condition the medium up to 2 ganglionic rings/ml. Addition of more ganglia fails to stimulate a greater response. This apparent plateau of CM activity appears to be a function of production and/or release of CF, rather than a saturation effect on plated cells, since dose-response curves for dilutions of CM are approximately linear regardless of the number of ganglia used for conditioning. In addition, anisomycin inhibits 35% of CF appearance under conditions of over 90% protein synthesis inhibition in the ganglia used to produce the CM. Under these conditions anisomycin has no apparent effect on the maintenance of electrical excitability. The inhibitor data suggest that 65% of CF is derived from a pre-existing storage pool and that the remainder is synthesized during the 72 h conditioning period.
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PMID:Nerve growth-promoting factor produced in culture media conditioned by specific CNS tissues of the snail Helisoma. 669 14

To clarify the pathogenesis of lupus nephritis, we developed an assay that defines a glomerular binding activity (GBA) in both murine and human lupus sera highly correlated with nephritis. In the current study, we used a cross-adsorption strategy to establish that the GBA in MRL lpr serum binds to the glomerular basement membrane (GBM). We subsequently observed that this binding to the GBM was competitively inhibited by either exogenous DNA or histone, abrogated by pretreatment of the GBM with DNAse, and restored after DNase treatment with DNA/histone in a synergistic fashion. GBM binding was also completely inhibited by pretreatment of GBM with collagenase but not heparatinase. The effect of collagenase was not reversed by the subsequent addition of DNA, but was restored by the sequential re-addition of type IV collagen and DNA. By using purified basement membrane components, we found that MRL lpr serum bound avidly to DNA coated on type I collagen but less well (or not at all) to DNA coated on type IV collagen, laminin, or fibronectin. Histone pretreatment of type IV collagen before DNA addition, however, synergistically enhanced binding in a fashion similar to that seen with native GBM. Thus, the GBA in MRL lpr serum seems to be comprised of autoantibodies that bind to histones and/or DNA that adhere to type IV collagen within the GBM. These data support the planted Ag hypothesis as the principal pathogenic mechanism in lupus nephritis and suggest that multiple autoantibodies may contribute to this disorder.
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PMID:Glomerular binding activity in MRL lpr serum consists of antibodies that bind to a DNA/histone/type IV collagen complex. 786 8

Pituitary hormones are essential for the maintenance of the corpus luteum in the pregnant mouse during the first half of gestation. Thereafter, hormones from the placenta take over the luteotropic role of the pituitary hormones. Mouse placental lactogen-I (mPL-I) and mPL-II, two PRL-like hormones produced in the placenta, are probably necessary for the maintenance of the corpus luteum in the latter half of pregnancy. A culture system of luteal cells from pregnant mice was developed to investigate the role of hormones from the placenta that may be important for the function of the corpus luteum. Mice were killed on days 10, 14, and 18 of pregnancy, and the corpora lutea were excised from the ovaries and digested in 0.1% collagenase, 0.002% DNase for 1 h. The resulting luteal cell suspension was plated onto 96-well plates coated with fibronectin (1 x 10(5) cells/well) and cultured for 1-3 days. Medium was changed daily. The cells were treated with various concentrations and combinations of mPL-I, mPL-II, mouse PRL, androstenedione, dihydrotestosterone, 17beta-estradiol (E2), testosterone, hydroxyflutamide, cycloheximide, actinomycin D, and fadrozole to study the effects of these different treatments on progesterone (P4) production. The three lactogens (mPL-I, mPL-II, and mouse PRL) all stimulated the release of P4 from the luteal cells. The potency of the lactogens was similar and did not depend on the stage of pregnancy at which the luteal tissue was obtained. However, the responsiveness of the cells to all hormone-stimulated P4 release was gradually reduced the later in pregnancy the tissue was collected. Androgens also stimulated the release of P4 from the luteal cells, and when administered together, the lactogens and the androgens acted synergistically to stimulate P4 release. The androgens acted directly but not through conversion to E2, as determined by the findings that 1) the effects of the androgens could not be reproduced by E2 administration, 2) nonaromatizable androgen dihydrotestosterone was as effective as aromatizable androgens, and 3) aromatase inhibitor did not prevent the action of the androgens to stimulate the P4 release. The effect of the androgens on the P4 release was rapid, occurring within 15 min of hormone administration. It was not prevented by inhibitors of protein and RNA synthesis, and the intracellular androgen receptor antagonist hydroxyflutamide did not affect the androgen action. Therefore, the androgen effects were not mediated through the intracellular androgen receptor and de novo protein synthesis was not needed for androgen-stimulated P4 release.
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PMID:Interaction of mouse placental lactogens and androgens in regulating progesterone release in cultured mouse luteal cells. 923 73

The authors have already described that a series of short peptides, modelled after sequences related to human extracellular matrix (ECM) proteins and sharing some common structural features, activate Th1 clones through a process involving peptide presentation in HLA-DR proteins. Those peptides induce also LAK- and NK-dependent cytotoxicity as well as activation of monocytes/macrophages present in human peripheral blood mononuclear cell (PBMC) populations. The release of interleukin 2 (IL-2) and interferon gamma (IFN-gamma) by Th cells present in PBMC depleted of macrophages, or B cells is reported, after incubation in the presence of those peptides, fibronectin or Staphylococcus aureus protein A. The authors found that all the molecules tested needed at least the presence of a type of antigen-presenting cell (APC) to exert their stimulatory effect. Some peptides seem to be preferentially presented to Th cells by B cells, while others seem to depend on monocyte/macrophages for this presentation. The dependence on one or another APC seems to be due to differences in the sequences of these peptides. The immunomodulatory agents studied also gave rise to a clear increase in a DNase activity associated with secretion granules of PBMC. That there is a correlation between the release of IL-2 and this DNase activity when using a complete PBMC population, B cell-depleted PBMC or macrophage-depleted PBMC stimulated with the peptides tested has been found.
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PMID:Correlation between the release of IL-2 and granule-associated DNase activity in human lymphomononuclear cells stimulated with immunomodulating peptides and proteins. Role of different antigen-presenting cells. 936 41

The effects of a mixture of oligo- and polydeoxyribonucleotides (PDRN) on the growth and protein secretion of cultured human skin fibroblasts were investigated. Both intact and DNAase-digested PDRN stimulated cell proliferation to a similar extent. When cultured fibroblasts were incubated with radioactive amino acids in the presence of intact or digested PDRN the incorporation of the tracer into secreted proteins increased significantly. This stimulation appears to be specific for certain protein components, including fibronectin. These results are interpreted assuming that PDRN and the nucleotides and nucleosides resulting from its degradation, can act as signal transducers or, alternatively, can be internalized and utilized to provide purine and pyrimidine rings for the salvage pathways.
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PMID:Effect of polydeoxyribonucleotides on human fibroblasts in primary culture. 1037 56


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