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)

The effect of Rolly No. 11 strain herpes simplex virus infection of HeLa cells in culture on deoxynucleotide metabolism and the level of various enzymes concerned with the biosynthesis of DNA has been investigated. Of 18 enzyme activities studied, thymidine kinase, DNA polymerase and deoxyribonuclease were markedly augmented, a finding in agreement with previous reports. Deoxycytidine kinase, ribonucleotide reductase, thymidylate kinase and deoxycytidylate deaminase activities, in contrast with previous reports, did not increase; the activities of the other enzymes studied, also did not increase. Whereas most of the radioactivity derived from [14-C] thymidine in the acid-soluble fraction of the uninfected cells was present as deoxythymidine triphosphate, that present in the infected cells was primarily in the form of deoxythymidine monophosphate. Thus, in the infected cell deoxythymidylate kinase is a rate-limiting enzyme in the biosynthesis of deoxythymidine triphosphate. A marked increase in the pools of the four naturally occurring deoxynucleoside triphosphates (dTTP, dCTP, dATP, dGTP) was found. The rate of formation of the virus-induced enzymes was determined, as were the various nucleoside triphosphate pools and the other phosphorylated derivatives of thymidine; a maximum was reached for all these csmponents between 6 to 8 h post infection. Although an apparent greater synthesis of DNA occurred in the uninefected cells, when the specific activity of the radioactive deoxythymidine triphosphate was taken into account, there was actually a greater rate of DNA synthesis in the infected cells, with the peak at 8 h post infection.
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PMID:Deoxyribonucleotide metabolism in Herpes simplex virus infected HeLa cells. 16 49

The experimental conditions were studied which allow hormonal levels to affect the incorporation of labelled deoxyribonucleosides triphosphates (dNTP's) into mitochondrial DNA by isolated liver mitochondria, obtained either from thyroidectomized young male rats (T) or from animals of the same age thyroidectomized and then treated with triiodothyronine (T + T3). It was demonstrated that: (a) extramitochondrial DNA, on which extramitochondrial DNA polymerase may act, was absent; (b) the permeability to dNTP's, the thymidine kinase activity, the energy supply, and the nuclease activities were unaffected by hormonal conditions; (c) the bacterial contaminations contribute for only 1% to incorporation. The characterization of incorporation product showed that: (a) such product was indeed DNA, as it was DNase-degradable for about 90%; (b) the labelled DNA was indeed mitochondrial DNA, as a 10 minutes preincubation with acriflavine or ethydium bromide (Eth. Br.) inhibited the synthesis by 90%.
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PMID:Effect of thyroidectomy and in vivo administration of triiodothyronine on DNA synthesis in isolated mitochondria. 18 48

DNA extracted from purified virions of equine herpesvirus type 1 (EHV-1) was examined for its transfectivity and transforming ability. The infectivity of the herpesvirus DNA was demonstrated by addition of calcium phosphate-DNA coprecipitates to monolayers of permissive horse cells, with resultant plaque formation. The efficiency of transfection (50 to 100 plaque-forming units/microgram of DNA) was reduced by treatment of the viral DNA with deoxyribonuclease or sonication but not with Pronase or antivirus neutralizing serum. When nonpermissive mouse 3T3 Cells lacking the enzyme thymidine kinase (TK-) were transfected with intact EHV-1 DNA, clones of cells transformed to the TK+ phenotype were isolated in selective HAT medium (hypoxanthine, aminopterin, thymidine), which prevents growth of the TK- parental phenotype. The efficiency of transformation ranged from one to five transformants per microgram of EHV-1 DNA. The TK activity of the biochemically transformed cells was characterized by biochemical, electrophoretic, and immunological techniques. By these criteria, the TK activity was identical to the EHV-1 TK and different from the host wild-type enzyme. In contrast to the parental TK+ 3T3 cells, the EHV-1-transformed TK+ cells were unable to grow in the presence of arabinosylthymine, a drug selectively phosphorylated by herpesvirus TKs. These results indicate that stable transfer of EHV-1 genes into nonpermissive cells can be achieved with purified viral DNA.
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PMID:Biological properties of equine herpesvirus type 1 DNA: transfectivity and transforming capacity. 21 45

The DNA polymerase, thymidine kinase and deoxyribonuclease activities were studied in cells infected with wild type (wt), ultraviolet (UV)-irradiated and defective herpes simplex virus type 1. All three enzymatic activities were expressed in cells infected with wt virus. In cells infected with UV-irradiated virus, the thymidine kinase and deoxyribonuclease activities were inhibited and the DNA polymerase activity was markedly suppressed. In cells producing defective virus, there was thymidine kinase activity, but the viral deoxyribonuclease activity was considerably reduced. The DNA polymerase activity was fully expressed in cells producing defective virus at passage level 5, but at passage level 6, the activity of the viral DNA polymerase declined.
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PMID:Herpes simplex virus DNA polymerase, thymidine kinase and deoxyribonuclease activities in cells infected with wild type, ultraviolet-irradiated and defective virus. 22 1

Treponema pallidum (Nichols) was extracted from infected rabbit tissue, and cell lysates were prepared for monitoring thymidine kinase and deoxyribonucleic acid polymerase activities. No thymidine kinase could be demonstrated in preparations of T. pallidum or the cultivable T. phagedenis biotype Reiter. Significant levels of deoxyribonucleic acid polymerase were detected in both treponemal samples. Interestingly, comparisons of polymerase activity among a spectrum of bacterial genera revealed a direct correlation between enzyme concentrations and estimated generation time. Incorporation of [3H]uridine and [3H]thymidine into macromolecules by intact T. pallidum and the Reiter treponeme was examined. Selective ribonuclease-deoxyribonuclease digestion and cesium chloride gradient banding demonstrated that T. pallidum, independent of the host, and T. phagedenis were capable of synthesizing deoxyribonucleic acid only from the [3H]-uridine precursor.
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PMID:Capacity of virulent Treponema pallidum (Nichols) for deoxyribonucleic acid synthesis. 37 16

In nuclei of hepatocytes of human embryos from the 18th to 40th week of antenatal development the activity of synthesis enzymes lowers: thymidine kinase is 7 times at low, uridine kinase - 11 times as low. In parallel during the same period a decrease in the activity of nucleases drops: DNase - by 15 times, RNase - by 11 times. The activity of these enzymes in the liver of adult persons (22-35 years old) is similar to their activity in the liver of human embryo to the moment of birth.
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PMID:[A comparative study of activity of nucleic acid metabolism in human embryonic liver]. 120 5

The density decrease of vaccinia virus-infected L-M cells observed in a Ficoll density gradient by 2 h postinfection was found to be dependent on RNA synthesis and protein synthesis but independent of DNA synthesis. Using low multiplicities of infection, the required RNA and protein species appeared to be synthesized before parental viral DNA became sensitive to DNase, i.e., while the bulk of input virus was still at the core stage of uncoating. To date only thymidine kinase and a vaccinia virus-specific cell surface antigen (as well as the putative uncoating protein) have been shown to be "early early" proteins, i.e., synthesized while parental viral DNA is still enclosed within the core. Both heat- and UV-inactivated virus failed to cause the cell density decrease. The need for a functioning viral genome implies that the required early early RNA and protein species are virus specific and not cell specific. Thus the protein leading to the density decrease of L-M cells, induced very early after infection with vaccinia virus, represents one of the first bits of viral genetic information expressed after infection. Since antibody-neutralized virus is still capable of causing the phenomenon of cell density decrease, the basis of neutralization of vaccinia virus by specific antibody must be other than by inhibiting early early transcription and/or translation.
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PMID:Evidence for an "early early" vaccinia virus-induced protein which causes a density change of infected L-M cells. 123 18

At least two genes encode isoenzymes of rat 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase. Alternative splicing of one of these genes generates a skeletal muscle-specific transcript from an upstream promoter and a liver-specific transcript from a downstream promoter. A potent glucocorticoid response element was identified in the first intron of the gene, i.e. between liver exon I and exon II. The element is approximately 3.5 kilobase pairs (kb) downstream of the liver isoenzyme transcription start site and 13 kb upstream of exon II of the gene and confers dexamethasone-sensitive expression of chloramphenicol acetyltransferase (CAT) activity from a heterologous thymidine kinase promoter and from both homologous 5'-flanking regions of the gene. This glucocorticoid response element also exhibits androgen- but not estrogen-sensitive expression of CAT activity in HeLa cells cotransfected with the appropriate receptor expression vector. DNase footprint and sequence analysis revealed that the element is comprised minimally of two adjacent 15-mer glucocorticoid receptor dimer binding sites situated in opposite orientations. Glucocortcoid regulation of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase gene expression in liver and skeletal muscle is mediated by a single complex glucocorticoid response element located in the first intron of the skeletal muscle/liver gene.
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PMID:Regulation of gene expression of rat skeletal muscle/liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase. Isolation and characterization of a glucocorticoid response element in the first intron of the gene. 133 34

The immune response of patients with nasopharyngeal carcinoma to Epstein-Barr virus (EBV) antigens is diagnostic of the tumour. Existing tests use EBV antigens produced in EBV-infected lymphoblastoid cells, but the virus replicates poorly in these cells. Serum samples from 18 patients diagnosed as having nasopharyngeal carcinoma were screened by western blot analysis, enzyme-linked immunosorbent assay (ELISA), and immunofluorescence tests for antibodies to the EBV-coded alkaline deoxyribonuclease (DNase), thymidine kinase, and membrane antigen (gp340/220) produced in recombinant baculovirus or bovine papillomavirus systems. Each protein was a useful diagnostic marker for nasopharyngeal carcinoma, although in the gp340/220 ELISAs there was substantial overlap for both IgG and IgA antibodies between serum samples from nasopharyngeal carcinoma patients and those from healthy donors seropositive for EBV. The EBV thymidine kinase was the most sensitive predictor of nasopharyngeal carcinoma; all such samples showed both IgG and IgA antibody responses to this protein and all gave clearly distinct titres from those of the EBV-seropositive donors in the IgA test. Each of the recombinant systems described is suitable for use in large-scale screening programmes for the early diagnosis of nasopharyngeal carcinoma.
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PMID:Diagnosis of nasopharyngeal carcinoma by means of recombinant Epstein-Barr virus proteins. 167 75

The intron 2 of the murine thymidine kinase (TK) gene was observed to contain two DNase hypersensitive site. In vitro footprinting experiments indicated specific binding sites for nuclear proteins which were characterized within the sequence of intron 2. Two GC boxes (binding sites for transcription factor SP1) and two new protein binding regions, one at the promoter proximal end of intron 2, the other one close to the border to exon 3 were found. Oligonucleotides were synthesized comprising the two new binding sites and were shown in gel mobility shift experiments to be capable of forming specific complexes with nuclear proteins. These proteins are present in growing as well as in quiescent cells suggesting that the sites described here do not contribute to growth regulation of TK expression. That they might play a role in upregulation of TK expression is, however, indicated by the results of CAT assays in which inclusion of downstream sequences of the TK gene containing parts or all of intron 2 were found to positively modulate the activity of the TK promoter.
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PMID:Presence of regulatory sequences within intron 2 of the mouse thymidine kinase gene. 176 10


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