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:3.1.30.2 (endonuclease)
18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interferon superinduction, in the case of cell pretreatment with low doses of interferon (priming), may be explained by activation of 2',5'-oligoadenylate synthetase and endonuclease L, since the latter, as expected, leads to a more rapid amplification of the standard scheme of interferon induction based on the antirepression mechanism. In the given case, endonuclease L will further increase the degradation rates for messages, which encode repressor proteins controlling interferon gene expression. Under ordinary induction, these messages are destroyed only by short-lived nuclease activated by double-stranded RNA. Cell pretreatment with high doses of interferon (blocking) considerably increases the concentrations of protein kinase and 2',5'-oligoadenylate synthetase in the cell. However, it seems that during blocking protein kinase plays the main role in inhibition of interferon synthesis, and this leads to almost complete depression of translation in the cell. When protein kinase is not sufficiently activated, blocking does not occur since treatment of cells with high concentrations of interferon does not hinder priming induced by 2',5'-oligoadenylate synthetase and endonuclease L. The proposed model is consistent with the findings that both interferon-treated primed and blocked cells are able to produce interferon more rapidly than normal cells. The analysis, based on a computer simulation model, suggests that priming and blocking of interferon may be based on processes controlling its induction and antiviral activity.
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PMID:Theoretical analysis of the regulation of interferon expression during priming and blocking. 756 95

We have isolated the nuclear matrices from Pisum sativum cell nuclei using three methods: i. standard procedure involving extraction of cell nuclei with 2 M NaCl and 1% Triton X-100; ii. the same with pretreatment of cell nuclei with 0.5 mM CuSO4 (stabilisation step); and iii. method including lithium diiodosalicylate extraction. We compared the polypeptide pattern and residual DNA content of the nuclear matrices isolated. The nuclear matrices displayed a specific endonuclease activity which was due to the presence of a 32 kDa protein. The isolated nuclear matrices bound specifically the scaffold-attached (SAR) DNA derived from human beta interferon gene, in the exogenous SAR binding assay. Using the DNA-protein binding blot assay we demonstrated the presence of two nuclear matrix proteins of 66 kDa and 62 kDa which bound specifically SAR DNA.
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PMID:Interaction of the Pisum sativum nuclear matrix proteins with SAR DNA. 765 65

In the 35 years since the discovery of interferon, significant biological activity has been described for interferon-alpha (IFN alpha) in various cancers, particularly haematological malignancies such as hairy cell leukaemia and chronic myelogenous leukaemia. Except for localised therapy in bladder and ovarian cancer, activity against most solid tumours has been disappointing. Other notable exceptions include Kaposi's sarcoma, renal cell carcinoma and malignant melanoma, tumours known to be susceptible to immunological attack. More recently, broad spectrum antiviral activity has been demonstrated for both recombinant and naturally occurring IFN alpha. Hepatitis C is responsive to IFN alpha in about 40% of patients, but long term remissions are rare. In contrast, long term suppression of hepatitis B is common following IFN alpha therapy. Both diseases respond in a dose proportional fashion, with daily doses of 5 million units (MU) significantly more effective than lower doses. The mechanism of action in viral diseases involves the expression of unique antiviral proteins such as endonuclease and 2'-5'-oligoadenylate synthetase which enhance the destruction of viral RNA. General cellular protein synthesis is also inhibited, including cytochrome P450 enzymes. This forms the basis for potential drug interactions, with IFN alpha slowing the clearance of highly metabolised drugs such as theophylline. As an antitumour agent, the mechanism of action of IFN alpha is unclear, particularly in haematological cancers. In melanoma and renal cell carcinoma, antitumour effects may be mediated by augmented immune responses including activation of natural killer lymphocytes and enhanced expression of cell surface antigens (e.g. MHC I and II). Conversely, antibody formation to recombinant IFN alpha may result in a loss of activity. This has been observed in both renal cell cancer and hepatitis B and C. The elimination half-life of IFN alpha is short, 4 to 5 hours, but biological activity extends for 2 to 3 days after administration, which facilitates daily or thrice weekly administration. Clearance of IFN alpha is mediated by catabolism in the renal tubules; no intact drug is excreted in the urine. It is probable that the antiviral indications of IFN alpha will expand as the agent is more clearly recognised as a primary endogenous defence against various viral conditions.
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PMID:Interferon-alpha in malignant and viral diseases. A review. 768 71

The authors quantified hepatitis C virus (HCV) RNA in serum by the competitive RT-PCR assay to correlate the replicative level of HCV with [1] various stages of the carrier states or [2] a sustained response to interferon therapy. The competitive RT-PCR assay employed is based on co-amplification of the target RNA with known amounts of synthetic mutated RNA having a novel restriction endonuclease (EcoRI) site. The titer of circulating HCV RNA defined as log10 (copy numbers/ml serum) were lower in asymptomatic blood donors (5.4 +/- 2.0) and in patients with chronic persistent hepatitis (7.3 +/- 1.1) compared with those having chronic active hepatitis (7.9 +/- 0.8), liver cirrhosis (7.8 +/- 0.7) and hepatocellular carcinoma (7.9 +/- 0.7). The initial titer of circulating HCV RNA of long-term responders before interferon therapy (7.1 +/- 1.2) was significantly lower than that of short-term responders (8.3 +/- 0.5) and non-responders (8.1 +/- 0.4). Multivariate multiple logistic regression showed that the titer of HCV RNA before therapy was the strongest independent predictor of a sustained response to interferon therapy. These results showed that the replicative level of hepatitis C virus is higher in advanced liver disease and that the replicative state of HCV is the most important factor influencing sustained response to interferon treatment.
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PMID:Quantitative analysis of hepatitis C virus RNA: relationship between the replicative level and the various stages of the carrier states or the response to interferon therapy. 839 41

The frequency in human genomic DNA of three human interferon (IFN) alpha genes which differ from each other by a single base substitution was examined in 11 normal individuals. The polymerase chain reaction (PCR) was used to amplify the coding sequence for the Hu-IFN-alpha 2, Hu-IFN-alpha A, and Hu-IFN-alpha 2(Arg) sequences from genomic DNA. The PCR products were then cloned and individual clones were sequenced. PCR products were also analyzed by restriction endonuclease analysis for the IFN-alpha 2 and IFN-alpha A genes by use of a HinfI site which is eliminated by the substitution of an A for a G in IFN-alpha A. The IFN-alpha A gene which was cloned from the myeloblastoid cell line KG-1 was not observed in any of the 201 clones sequenced from normal individuals or in the Namalwa cell line. It was detected in KG-1 cell genomic DNA where it represented 49% of the clones sequenced. Similarly the IFN-alpha 2(Arg) gene was not detected in normal individuals or in the KG-1 cell line but only in the lymphoblastoid cell line from which it was cloned. In Namalwa cells the IFN-alpha 2(Arg) sequence represented 35% of the clones sequenced while the IFN-alpha 2 sequence comprised 59%. Therefore, both the IFN-alpha A and IFN-alpha 2(Arg) sequences represent alleles of the IFN-alpha 2 gene.
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PMID:Human interferon-alpha A, -alpha 2, and -alpha 2(Arg) genes in genomic DNA. 850 97

The nuclear matrices from White bush (Cucurbita pepo var. patisonina) cell nuclei have been isolated using three methods: I, standard procedure involving extraction of cell nuclei with 2 M NaCl and 1% Triton X-100; II, the same with pre-treatment of cell nuclei with 0.5 mM CuSO4 (stabilisation step); and III, method with extraction by lithium diiodosalicylate (LIS), and compared the polypeptide pattern. The isolated matrices specifically bind SAR DNA derived from human beta-interferon gene in the exogenous SAR binding assay and in the gel mobility shift assay. Using IgG against the 32 kDa endonuclease we have found in the DNA-protein blot assay that this protein is one of the proteins binding SAR DNA. We have identified three proteins with molecular mass of 65 kDa, 60 kDa and 32 kDa which are responsible for SAR DNA binding in the gel mobility shift assay experiments.
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PMID:Identification of the proteins responsible for SAR DNA binding in nuclear matrix of Cucurbita pepo. 858 59

Three variants of human interferon (IFN)-alpha 8a gene, that is, IFN-alpha 8b, and IFN-alpha 8c, have been reported previously. They differ from each other by changes in their coding region at nucleotide positions 359-360, 372, and 550. Human genomic DNA obtained from over 28,000 healthy blood donors and from 4 human cell lines was used in the polymerase chain reaction (PCR) designed for specific amplification of the IFN-alpha 8 gene fragments. The resulting PCR product was analyzed by (1) restriction endonuclease digestion, (2) DNA sequencing, and (3) allele-specific secondary PCR amplification. Only one sequence for IFN-alpha 8 was identified, and that was for IFN-alpha 8b. The sequences for IFN-alpha 8a and IFN-alpha 8c were not detected after PCR amplification either in the pooled leukocytes obtained from > 28,000 individuals or in cell lines tested. These data suggest that the naturally occurring variant or allele for IFN-alpha 8 in the population is IFN-alpha 8b. IFN-alpha 8a and IFN-alpha 8c variants were consistently below the level of detection of the assays and, if present at all in the population, are very rare.
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PMID:Interferon-alpha 8b is the only variant of interferon-alpha 8 identified in a large human population. 883 18

The genes for type I interferon (IFN), which include 14 IFN-alpha genes, 1 IFN-beta gene, 1 IFN-omega gene, and a number of IFN-omega pseudogenes, are clustered on human chromosome 9. Among IFN-alpha genes, a number of variants have been reported. Three variants of IFN-alpha 7 (IFN-alpha 7a, IFN-alpha 7b, and IFN-alpha 7c) and IFN-alpha 14 (IFN-alpha 14a, IFN-alpha 14b, and IFN-alpha 14c) and two variants of IFN-alpha 21 (IFN-alpha 21a and IFN-alpha 21b) are identified. The variants differ from each other by base changes in the coding region and can be distinguished by selective restriction enzyme analysis and DNA sequencing. We have used polymerase chain reaction (PCR) with IFN species-specific oligonucleotide primers for amplification of IFN-alpha 7, IFN-alpha 14, and IFN-alpha 21 gene sequences. Genomic DNA obtained from over 28,000 normal healthy individuals were collected in six pools for PCR amplification. To identify the presence of variant sequences, the resulting PCR products of specific IFN-alpha genes were analyzed by restriction endonuclease digestion and DNA sequencing, with a limit of detection of minor components to 1% and 10%, respectively. The results show that only one variant form for each of IFN-alpha 7, IFN-alpha 14, and IFN-alpha 21, namely, IFN-alpha 7a, IFN-alpha 14c, and IFN-alpha 21b, is detectable in the genomic DNA of the population examined. Similar results were obtained from the analysis of a human myeloblastoid cell line, KG-1.
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PMID:Identification of interferon-alpha 7, -alpha 14, and -alpha 21 variants in the genome of a large human population. 891 Jul 71

Double infection with two interferon (IFN)-sensitive strains of herpes simplex virus (HSV), HSV-1(17syn) and HSV-2(UW268), showed reduced inhibition of virus growth by IFN. Intertypic recombinants with IFN resistance were obtained from the doubly infected cultures. These results indicate that HSV IFN resistance is controlled by at least two genetic regions. Restriction endonuclease analysis demonstrated that the recombinants were similar to HSV-2 in their genomic structure but the BamHI-A, BglII-I and BglII-N fragments of HSV-2 were commonly lost in the recombinants, suggesting that any of these fragments could be associated with HSV-2 IFN resistance. We cloned these fragments and BamHI-E, which overlaps BglII-N, from an IFN-resistant HSV-2 strain, HSV-2(G), and examined each fragment for its ability to rescue IFN resistance of HSV-2(UW268) by co-transfecting with the HSV-2(UW268) genome. Of the HSV-2(G) fragments, only BglII-N increased plating efficiency of progeny viruses in IFN-treated cells. An IFN-resistant HSV-2 clone was obtained from the BglII-N of HSV-2(G) and HSV-2(UW268) genome co-transfected culture, and a part of BglII-N of HSV-2(UW268) was replaced with that of HSV-2(G) in the HSV-2 clone. Thus, it was concluded that one of the HSV regions encoding IFN resistance is located on the BglII-N fragment of HSV-2.
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PMID:The BglII-N fragment of herpes simplex virus type 2 contains a region responsible for resistance to antiviral effects of interferon. 951 35

We investigated whether murine peritoneal macrophages treated with cisplatin or interferon (IFN)-gamma alone, or in combination, could undergo apoptosis, and whether this results either from the cytotoxic effect of the activating agents or indirectly in an autocrine manner by the cytotoxic molecules released by them upon activation. Our data suggest that cisplatin, which has been shown to induce apoptosis in a number of normal as well as tumor cell types, did not induce apoptosis in murine peritoneal macrophages nor was apoptosis caused by IFN-gamma. However, combined treatment with cisplatin and IFN-gamma induced apoptosis in macrophages as studied by percent DNA fragmentation assay, qualitative analysis of DNA on agarose gel electrophoresis, and morphological and nuclear alterations studied by phase contrast and fluorescence microscopy. The factor responsible for inducing apoptosis in macrophages was found to be a higher concentration of NO produced by them upon activation with cisplatin and IFN-gamma. Macrophages treated with cisplatin or IFN-gamma alone produced a low level of NO and did not undergo apoptosis. The inhibitor of NO synthase, L-NMMA, prevented apoptosis in macrophages treated with cisplatin and IFN-gamma, suggesting the involvement of NO in the induction of apoptosis in macrophages. The role of NO in inducing apoptosis in macrophages was further confirmed by the observation that direct treatment with sodium nitroprusside, a NO donor, resulted in apoptosis in macrophages. We have also shown that NO-induced apoptosis in macrophages activated with cisplatin and IFN-gamma requires activation of an endonuclease, as the endonuclease inhibitor, aurine tricarboxylic acid, prevented apoptosis in them.
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PMID:Murine peritoneal macrophages treated with cisplatin and interferon-gamma undergo NO-mediated apoptosis via activation of an endonuclease. 963 24


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