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)

DNA from human parvovirus B19 was prepared from infected serum and examined by electron microscopy. Double-stranded molecules were seen, often with characteristic 'fold-back' ends that were assumed to be due to the inverted terminal repeats of the genome DNA. This double-stranded DNA was mapped with 13 restriction enzymes. More than 40 isolates, including the virus from the original B19 serum, were compared. Although isolates could be grouped by this method, there was no correlation between a particular restriction endonuclease map and any of the several disease presentations of the virus.
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PMID:Structure and mapping of the DNA of human parvovirus B19. 282 62

DNA from one cell culture-adapted and two pathogenic strains of Aleutian disease of mink parvovirus (ADV) was molecularly cloned into the vectors pUC18 and pUC19. The DNA from the two pathogenic strains (ADV-Utah I and ADV-Pullman) was obtained from virus purified directly from the organs of infected mink, whereas the DNA from the nonpathogenic ADV-G was derived from cell culture material. The cloned segment from all three viruses represented a 3.55-kilobase-pair BamHI (15 map units) to HindIII (88 map units) fragment. Detailed physical mapping studies indicated that all three viruses shared 29 of 46 restriction endonuclease recognition sites but that 6 sites unique to the pathogenic strains and 5 sites unique to ADV-G were clustered in the portion of the genome expected to code for structural proteins. Clones from all three viruses directed the synthesis of two ADV-specific polypeptides with molecular weights of approximately 57 and 34 kilodaltons. Both species reacted with sera from infected mink as well as with a monoclonal antibody specific for ADV structural proteins. Because production of these ADV antigens was detected in both pUC18 and pUC19 and was not influenced by isopropyl-beta-D-thiogalactopyranoside (IPTG) induction, their expression was not regulated by the lac promoter of the pUC vector, but presumably by promoterlike sequences found within the ADV DNA. The proteins specified by the clones of ADV-G were 2 to 3 kilodaltons smaller than those of the two pathogenic strains, although the DNA segments were identical in size. This difference in protein molecular weights may correlate with pathogenicity, because capsid proteins of pathogenic and nonpathogenic strains of ADV exhibit a similar difference.
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PMID:Molecular comparisons of in vivo- and in vitro-derived strains of Aleutian disease of mink parvovirus. 282 42

The components of the cell cycle for a feline embryo cell line were defined. Thymidine (6mM)-supplemented medium reversibly arrested cells 1 h into the S phase of the cell cycle and was used in a double blocking procedure to synchronize cells to the early S phase. The kinetics of feline panleukopenia virus replication in synchronized cells was studied by using (i) inclusion body formation, (ii) a plaque assay for cell-associated and cell-free virus under one-step growth conditions, (iii) an enzyme immunoassay for viral protein, (iv) electron microscopy of infected cells, and (v) the detection and identification of viral replicative form DNA by restriction endonuclease analysis. Parallel studies by each of these procedures of the replication of feline panleukopenia virus in cells in which a 6 mM thymidine block was maintained indicated that parvovirus replicated with essentially similar kinetics in both unblocked, synchronized cells and in cells in which the block was maintained. Accordingly, a 6 mM thymidine-supplemented medium, although it effectively blocks cellular DNA synthesis, does not block the replication of parvovirus.
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PMID:Feline panleukopenia virus replicates in cells in which cellular DNA synthesis is blocked. 298 22

We compared the molecular, antigenic, and pathogenic properties of KBSH parvovirus to those of porcine parvovirus (PPV) isolate NADL-8. KBSH, propagated in swine testes cells in culture, possessed two major capsid polypeptides of 83 and 64 kilodaltons that were similar in size to those of PPV. KBSH-infected cells also contained an 86-kilodalton nonstructural polypeptide that was identical in size to the PPV nonstructural polypeptide (NS-1). The KBSH polypeptides were structurally similar but not identical to the corresponding PPV polypeptides, as revealed by partial proteolysis mapping. Viral replicative-form DNA from KBSH-infected cells was similar in size to PPV replicative-form DNA and exhibited similar but not identical restriction endonuclease cleavage patterns to that of PPV replicative-form DNA. Antigenically, the two viruses were also very closely related. By using heterologous and homologous antisera, the two viruses were indistinguishable in hemagglutination inhibition and immunoprecipitation assays. However, pathogenically these viruses were dramatically different. NADL-8 caused fetal death when injected into swine fetuses in utero and viremia and high persisting antibody titers when administered orally to weaning-age swine. KBSH-inoculated fetuses were normal in appearance, and pigs orally exposed to KBSH failed to establish viremia and demonstrated only transient antibody titers. Thus, KBSH appears to be a PPV that is very closely related to a highly pathogenic PPV isolate, yet is itself nonpathogenic in swine. This reduced pathogenic potential of KBSH may be attributable to its poor ability to replicate in swine.
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PMID:KBSH parvovirus: comparison with porcine parvovirus. 299 53

Plasma from a child with homozygous sickle-cell disease, sampled during the early phase of an aplastic crisis, contained human parvovirus B19 virions. Plasma taken 10 days later (during the convalescent phase) contained both immunoglobulin M and immunoglobulin G antibodies directed against two viral polypeptides with apparent molecular weights of 83,000 and 58,000 which were present exclusively in the particulate fraction of the plasma taken during the acute phase. These two protein species comigrated at 110S on neutral sucrose velocity gradients with the B19 viral DNA and thus appear to constitute the viral capsid polypeptides. The B19 genome was molecularly cloned into a bacterial plasmid vector. Restriction endonuclease fragments of this cloned B19 genome were treated with BAL 31 and shotgun cloned into the open reading frame expression vector pJS413. Two expression constructs containing B19 sequences from different halves of the viral genome were obtained, which directed the synthesis, in bacteria, of segments of virally encoded protein. These polypeptide fragments were then purified and used to immunize rabbits. Antibodies against a protein sequence specified between nucleotides 2897 and 3749 recognized both the 83- and 58-kilodalton capsid polypeptides in aplastic plasma taken during the acute phase and detected similar proteins in the tissues of a stillborn fetus which had been infected transplacentally with B19. Antibodies against a protein sequence encoded in the other half of the B19 genome (nucleotides 1072 through 2044) did not react specifically with any protein in plasma taken during the acute phase but recognized three nonstructural polypeptides of 71, 63, and 52 kilodaltons present in the liver and, at lower levels, in some other tissues of the transplacentally infected fetus.
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PMID:Identification of the major structural and nonstructural proteins encoded by human parvovirus B19 and mapping of their genes by procaryotic expression of isolated genomic fragments. 302 88

The genomic and replicative form (RF) DNA of porcine parvovirus (PPV) have been characterized. PPV isolate NADL-8 was found to have a 5000-base single-stranded genome, and a unique strand was encapsidated in virus particles. The RF DNA of isolate NADL-8 was found to be an infectious 5000-base pair (bp) molecule. Select restriction endonuclease sites were mapped along the RF DNA of PPV (NADL-8), and oriented with respect to the viral genomic DNA. The RF DNA of a second isolate of PPV, the less pathogenic, cell culture-adapted NADL-2 virus, was also analyzed. DNA preparations isolated from NADL-2 virus-infected cells contained two viral RF DNA species: a 5000-bp infectious molecule very similar if not identical to the NADL-8 virus RF DNA, and a noninfectious 4700-bp DNA molecule. The 4700-bp RF DNA molecule found in NADL-2 DNA preparations was similar in all respects to the 5000-bp RF DNA, except for a 300-bp deletion in the region encoding the viral capsid proteins. The presence of this defective variant in PPV (NADL-2) virus preparations is discussed in relation to the reduced pathogenic potential of the NADL-2 virus as compared to the NADL-8 virus.
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PMID:Porcine parvovirus DNA: characterization of the genomic and replicative form DNA of two virus isolates. 609 27

We have used DNA transfection to identify several regions of the adenovirus genome needed to induce replication of the defective parvovirus, adenovirus-associated virus (AAV). Previous studies have indicated that only early adenovirus functions are needed to aid the replication of AAV. In this report, we demonstrate that three restriction endonuclease fragments of adenovirus DNA are necessary for production of infectious AAV in 293-31 cells (an adenovirus type 5-transformed human embryonic kidney cell line). These fragments map from 28.5 to 29.4, 59.5 to 75.9, and 89.7 to 100 map units on the adenovirus type 2 genome and correspond to the locations of the VAI RNA gene, early region 2, and early region 4, respectively. The 293-31 cell line, which has been found to express early region 1A and 1B proteins, alone is incapable of supporting AAV replication or even AAV DNA synthesis. Additional experiments with adenovirus type 5 host range mutants (group I, hr1 and group II, hr7) indicate, however, that early region 1A provides an essential function(s) for AAV replication, whereas early region 1B probably does not.
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PMID:Locations of adenovirus genes required for the replication of adenovirus-associated virus. 626 30

We have characterized an immunosuppressive parvovirus related to the minute virus of mice (MVM). The parvovirus, MVM(i), grew efficiently on the murine lymphoma cell line EL-4 and not on the A-9 strain of L-cells which is a host for the prototype MVM. MVM(i) was immunosuppressive for allogeneic mixed leukocyte cultures, inhibiting the generation of cytolytic T lymphocytes. MVM had no effect on mixed leukocyte cultures. MVM and MVM(i) particles were similar in buoyant density, sedimentation rate, appearance in the electron microscope, and polypeptide composition. We present restriction enzyme maps of the DNAs of MVM and MVM(i) which show that they are closely related. Out of 109 restriction endonuclease cleavage sites (representing together about 10% of the nucleotide sequence), 86 sites were shared by MVM and MVM(i), whereas 22 sites were absent from one of the two viruses. MVM(i) DNA had an apparent deletion of about 60 nucleotides relative to MVM, located near the 5' terminus of viral DNA.
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PMID:Characterization of an immunosuppressive parvovirus related to the minute virus of mice. 626 6

Aleutian disease virus (ADV) of mink is a nondefective parvovirus with a single-stranded DNA genome. We characterized the viral DNA forms found in infected cells prepared by a modified Hirt extraction procedure. Double-stranded DNA molecules corresponding in size to 4.8-kilobase-pair duplex monomers and 9.6-kilobase-pair duplex dimers were identified in agarose gels by blot hybridization to 32P-labeled ADV DNA. A rapidly reannealing ADV duplex monomer was isolated on a preparative scale and physically mapped with a series of restriction endonucleases. The map derived was similar to one derived from double-stranded ADV DNA produced by self-primed synthesis on virion DNA, but differed from restriction endonuclease maps reported for other parvovirus DNAs. The purified duplex monomer could be labeled with [32P]dCTP by nick translation and used as a probe in blot hybridization to detect ADV sequences in DNA from small numbers of infected cells. Additional studies indicated that double-stranded ADV DNA could first be detected at 24 h after infection.
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PMID:Characterization of the Aleutian disease virus genome and its intracellular forms. 630 Apr 67

Intracellular, replicative-form DNA of minute virus of mice was characterized by agarose gel electrophoresis, velocity sedimentation, electron microscopy, restriction endonuclease digestion, and sensitivity to the single-stranded nuclease S1. This analysis demonstrated the presence in murine cells infected with minute virus of mice of a 10.0-kilobase pair dimer replicative form, a 5-kilobase pair monomer replicative form, as well as a 5-kilobase viral single-stranded DNA species. Two additional viral DNA species that migrated in 0.5% agarose gels with apparent sizes of 8.0 and 5.5 kilobase pairs were also observed. Further investigation indicated that the 8.0-kilobase pair DNA represents a novel class of metastable, partially replicated, dimeric intermediates. This finding has important implications for the mechanism of parvovirus DNA replication.
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PMID:Characterization of a metastable, partially replicated dimeric intermediate of minute virus of mice. 631 65


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