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:3.1.22.1 (DNase II)
429 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this report, we describe the molecular cloning and characterization of DLAD, a novel mammalian deoxy-ribonuclease homologous to DNase II. The full length cDNA for mouse DLAD has been cloned by polymerase chain reaction. The cDNA contains a 1065 bp open reading frame (ORF) encoding a 354 amino acid protein with a calculated molecular mass of 40 767. The predicted protein for DLAD shares 34.4% identity with DNase II. DLAD is also homologous to three predicted proteins, C07B5.5, F09G8.2 and K04H4.6, from the nematode Caenorhabditis elegans. Furthermore, the third ORF of the fowlpox virus genome is found to encode a DLAD homologue showing 37. 1% identity at the amino acid level. Northern blot analysis reveals that expression of the DLAD mRNA is highly restricted to the liver. DLAD mainly exists as a cytoplasmic protein with divalent cation-independent endonuclease activity and cleaves DNA to produce 3'-phosphoryl/5'-hydroxyl ends. It is active under a wide range of pH with maximum activity at pH 5.2. Among known DNase inhibitors tested, aurintricarboxylic acid and Zn(2+)are found to be effective inhibitors of the DLAD activity.
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PMID:DLAD, a novel mammalian divalent cation-independent endonuclease with homology to DNase II. 1049 74

Although apoptotic cells are recognized and engulfed by macrophages via a number of membrane receptors, little is known about the fate of apoptotic cells after the engulfment. We observed in this study that nucleosomal DNA fragments of apoptotic cells disappeared when they were engulfed by the macrophage cell line J774.1 at 37 degrees C. Pretreatment of J774.1 cells with chloroquine inhibited intensive DNA degradation, indicating that the cleavage of nucleosomal DNA fragments of apoptotic cells may take place in the lysosomes of J774. 1. When apoptotic cells were exposed to a lysosome-rich fraction derived from J774.1 cells under an acidic condition, nucleosomal DNA fragments of apoptotic cells were no longer detectable by agarose gel electrophoresis. Additionally, we found that the lysosome-rich fraction of J774.1 cells contained an acid DNase that is similar to DNase II with respect to its m.w., optimal pH, and sensitivity to the inhibitors of DNase II. By exposure of apoptotic cells to the lysosomal-rich fraction, nucleosomal core histones of apoptotic cells were hydrolyzed along with degradation of nucleosomal DNA fragments. Addition of pepstatin A to the reaction buffer resulted in accumulation of approximately 180-bp DNA fragments and inhibition of hydrolysis of nucleosomal core histones. Leupeptin or CA-074 partially inhibited the degradation of nucleosomal DNA fragments and core histones. These findings suggest that lysosomal enzymes of macrophages, e.g., DNase II-like acid DNase and cathepsins, are responsible for the degradation of nucleosomes of apoptotic cells.
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PMID:Role of macrophage lysosomal enzymes in the degradation of nucleosomes of apoptotic cells. 1055 58

DNase II is a well-known deoxyribonuclease (DNase) that catalyzes the hydrolysis of DNA into oligonucleotides under acidic conditions. We have identified a novel DNase that shows homology to DNase II, named DLAD, from a search of an expressed sequence tag data base. The full-length cDNA for rat DLAD cloned by polymerase chain reaction encodes a 356-amino acid polypeptide containing a putative N-terminal signal peptide and 5 potential N-glycosylation sites; there is a predicted catalytic domain resemblance to rat DNase II. The predicted DLAD translation product shares 32.9% identity with DNase II. Interestingly, expression of the DRAD mRNA is highly restricted to the liver. A Myc-His tagged recombinant DLAD recovered mainly from the cytoplasm of transfected HeLa S3 cells has a divalent cation-independent DNase activity. The DLAD activity prefers acidic conditions to neutral. The recombinant protein expressed in HeLa S3 cells inhibits the expression of GFP- and lac Z-expression vectors, suggesting that DLAD may play a role in elimination of exogenous DNA. Identification of the full-length cDNA for DLAD would lead to an understanding of the physiology of this DNase II-like molecule.
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PMID:Cloning of a cDNA encoding a rat DNase II-like acid DNase. 1055 78

We previously found that a novel DNA endonuclease named DLAD (DNase II-Like Acid DNase) is specifically expressed in murine liver. Here, we describe the isolation and characterization of the human DLAD and mouse Dlad genes. Both DLAD and Dlad consist of 6 exons. DLAD encodes a 361 amino acid protein sharing 34.6% amino acid identity with human DNase II. Although a recombinant protein for the putative human DLAD has a divalent cation-independent acid DNase activity, expression of the DLAD mRNA containing the entire open reading frame was not detected in any human tissues tested, except for lung, in which a short 1.1 kb transcript lacking the first two exons is expressed. Interestingly, sequence analysis of Dlad showed that the 1st exon of the urate oxidase gene, Uox, is located on the opposite strand in its 5'-flanking region. The head-to-head organization of DLAD and UOX is conserved in the human genomic sequence. Promoter analysis revealed that the intergenic region between Dlad and Uox has promoter activity for both the Dlad and Uox directions, however, the corresponding human genomic fragment has promoter activity only for DLAD. It is known that murine Uox is expressed only in the liver, whereas human UOX has been inactivated as a pseudogene. On the basis of these results, the expression of DLAD/Dlad and UOX/Uox is suggested to be coordinated by a common regulatory mechanism(s), and the balance between the two enzymes is thought to be important for maintaining the purine nucleotide pool in the liver.
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PMID:Isolation and characterization of the DLAD/Dlad genes, which lie head-to-head with the genes for urate oxidase. 1170 27

Apoptotic cell death is accompanied by degradation of chromosomal DNA. Here, we established in Drosophila a null mutation in the gene for inhibitor of caspase-activated DNase (ICAD) by P-element insertion. We also identified a loss-of-function mutant in Drosophila for DNase II-like acid DNase. The flies deficient in the ICAD gene did not express CAD, and did not undergo apoptotic DNA fragmentation during embryogenesis and oogenesis. In contrast, the deficiency of DNase II enhanced the apoptotic DNA fragmentation in the embryos and ovary, but paradoxically, the mutant flies accumulated a large amount of DNA, particularly in the ovary. This accumulation of DNA in the DNase II mutants caused the constitutive expression of the antibacterial genes for diptericin and attacin, which are usually activated during bacterial infection. The expression of these genes was further enhanced in flies lacking both dICAD and DNase II. These results indicated that CAD and DNase II work independently to degrade chromosomal DNA during apoptosis, and if the DNA is left undigested, it can activate the innate immunity in Drosophila.
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PMID:Activation of the innate immunity in Drosophila by endogenous chromosomal DNA that escaped apoptotic degradation. 1238 65

DNA delivered in nonviral vectors or as naked DNA must overcome a number of extracellular and intracellular barriers to transfection. Since many vectors deliver DNA into cells by the endocytic route, DNA degradation by lysosomal nucleases has been proposed as a significant barrier to transfection, despite the fact that this has not yet been formally demonstrated to occur. To test this hypothesis, we have investigated the role of deoxyribonuclease II (DNase II), the primary acidic endonuclease active in the lysosome, in transfection. Two genetic systems were engineered in which mammalian cells either overexpressed DNase II or were knocked out for the enzyme. In both models, higher levels of DNase II correlated with decreased transfection efficiency by nonviral DNA delivery vectors. These data provide direct evidence implicating lysosomal DNase II as a barrier to transfection.
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PMID:Deoxyribonuclease II is a lysosomal barrier to transfection. 1466 98

The 266 kbp genome sequence of plaque-purified, tissue culture-adapted, attenuated European Fowlpox virus FP9 has been determined and compared with the 288 kbp sequence of a pathogenic US strain (FPVUS). FP9 carries 244 of the 260 reported FPVUS ORFs (both viruses also have an unreported orthologue of conserved poxvirus gene A14.5L). Relative to FPVUS, FP9 differed by 118 mutations (26 deletions, 15 insertions and 77 base substitutions), affecting FP9 equivalents of 71 FPVUS ORFs. To help to identify mutations involved in adaptation and attenuation, the virulent parent of FP9, HP1, was sequenced at positions where FP9 differed from FPVUS. At 68 positions, FP9 and HP1 sequences were identical, reflecting differences between American and European lineages. Mutations at the remaining 50 positions in FP9 relative to FPVUS and HP1, involving 46 ORFs, therefore accounted for adaptation and attenuation. ORFs deleted during passage included those encoding members of multigene families: 12 ankyrin repeat proteins, three C-type lectin-like proteins, two C4L/C10L-like proteins, one G-protein coupled receptor protein, one V-type Ig domain protein, two N1R/p28 proteins and one EFc family protein. Tandem ORFs encoding Variola virus B22R orthologues were fused by a 5.8 kbp deletion. Single-copy genes disrupted or deleted during passage included those encoding a homologue of murine T10, a conserved DNA/pantothenate metabolism flavoprotein, photolyase, the A-type inclusion protein and an orthologue of vaccinia A47L. Gene assignments have been updated for DNase II/DLAD, binding proteins for IL-18 and interferon-gamma, phospholipid hydroperoxide glutathione peroxidase (PHGPX/GPX-4) and for a highly conserved homologue of ELOVL4.
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PMID:Comparison of the genome sequence of FP9, an attenuated, tissue culture-adapted European strain of Fowlpox virus, with those of virulent American and European viruses. 1476 88

We have previously shown that DNA from dying tumor cells may be transferred to living cells via the uptake of apoptotic bodies and may contribute to tumor progression. DNA encoding H-ras(V12) and c-myc oncogenes may be transferred to the nucleus of the phagocyte but will only integrate and propagate in p53- and p21-deficient mouse embryonic fibroblasts, whereas normal cells are resistant to transformation. Here, we show that this protective mechanism (activation of p53 and p21 after uptake of apoptotic bodies) is dependent on DNA fragmentation, where inhibition of the caspase-activated DNase in the apoptotic cells, in conjunction with genetic ablation of lysosomal DNase II in the phagocytes, completely blocks p53 activation and consequently allows DNA replication of transferred DNA. We, therefore, suggest that there is a causal relationship between DNA degradation during apoptosis and p53 activation. In addition, we could further show that Chk2-/- cells were capable of replicating the hyg(R) gene taken up from engulfed apoptotic cells, suggesting involvement of the DNA damage response. These data show that the phagocytosing cell is sensing the degraded DNA within the apoptotic cell, hence preventing these genes from being replicated, probably through activation of the DNA damage response. We, therefore, hypothesize that DNase II together with the Chk2, p53, and p21 pathway form a genetic barrier blocking the replication of potentially harmful DNA introduced via apoptotic bodies, thereby preventing transformation and malignant development.
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PMID:DNase II and the Chk2 DNA damage pathway form a genetic barrier blocking replication of horizontally transferred DNA. 1654 56

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

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