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)

The longest DNA molecules synthesized by endogenous reverse transcription in detergent-permeabilized Moloney murine sarcoma virus (Mo-MSV) virions (clone G8-124) are double-stranded DNA molecules of 5,8 kilobase pairs (kbp). This DNA species has been purified by sedimentation of total in vitro synthesized Mo-MSV DNA through neutral sucrose gradients. A physical map of the positions of the cleavage sites for a series of restriction endonucleases has been derived for this 5.8 kbp DNA. Mo-MSV DNA synthesized in vitro was found to induce morphological transformation of NIH-3T3 mouse fibroblasts upon transfection. The foci had a morphology indistinguishable from that of Mo-MSV-induced foci, and the induced transformed phenotype was stable. The 5.8 kbp double-stranded DNA (dsDNA) purified by agarose gel electrophoresis also induced focal transformation. Furthermore, gel-purified, restriction endonuclease-generated fragments of 5.8 kbp dsDNA containing the region from 2.8--4.9 kbp on the physical map of Mo-MSV DNA were able to induce foci. In contrast, endonuclease-generated DNA fragments lacking this region on the map were unable to transform cells upon transfection. When transformants derived by transfection with 5.8 kbp dsDNA were infected with Moloney murine leukemia virus (Mo-MLV) helper virus, Mo-MSV was rescued from a small portion of these cells, suggesting the establishment of the complete viral genome in these cells. One Mo-MSV DNA fragment, spanning 2.8--4.9 kbp on the physical map, was generated by cleavage of 5.8 kbp DNA with endonucleases Hind III + Sal I and currently represents our maximum estimate for the size of the transforming region of the Mo-MSV genome. This fragment includes the Mo-MSV sequences which are found in the DNA of uninfected mouse cells.
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PMID:A defined subgenomic fragment of in vitro synthesized Moloney sarcoma virus DNA can induce cell transformation upon transfection. 8 15

A discrete, 600-nucleotide-long plus-strand DNA has been identified among the products of reverse transcription by virions of Moloney murine leukemia virus. Its polarity was shown by hybridization to minus-strand DNA. It appears to be copied from the right end of minus-strand DNA because (i) its restriction endonuclease cleavage pattern corresponds to the redundant 600-base segment found at either end of the ultimate double-stranded reverse transcription products, (ii) its synthesis is actinomycin D sensitive, and (iii) its synthesis begins during the first hour of a reverse transcription reaction when only the right-hand end of minus-strand DNA is available as template. We therefore call this DNA plus-strong-stop DNA by analogy with the minus-strong-stop DNA copied from the left end of the viral RNA. Both strong-stop DNAs are made early during in vitro reactions and decline in concentration later, consistent with postulated roles as initiators of long minus- and plus-strand DNA. Unlike minus-strong-stop DNA, plus-strong-stop DNA remains as a double-stranded nucleic acid after its synthesis, as shown by S1 nuclease resistance. A primer to initiate plus-strong-stop DNA synthesis has not been identified; the product found thus far has no detectable RNA attached to it.
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PMID:Synthesis of a 600-nucleotide-long plus-strand DNA by virions of Moloney murine leukemia virus. 9 28

Extrachromosomal DNA purified from mink cells acutely infected with the Snyder-Theilen strain of feline sarcoma virus (FeSV) was digested with restriction endonucleases, and the DNA fragments were electrophoretically separated, transferred to a solid substrate, and hybridized with radiolabeled DNA transcripts complementary to different portions of the FeSV RNA genome. Major DNA species 8.4 and 5.0 kilobase pairs (kbp) long represent the linear, unintegrated proviruses of Snyder-Theilen feline leukemia virus and FeSV, respectively. Transfection experiments performed with electroeluted DNAs showed that the 8.4-kbp form led to the production of replicating nontransforming virus in mink and cat cells; in contrast, the 5.0-kbp DNA produced helper virus-independent foci of transformation in mouse NIH/3T3 cells and helper virus-dependent foci in mink cells at an efficiency comparable to that obtained with unfractionated extrachromosomal DNA. Sites of restriction endonuclease cleavage for six enzymes were oriented with respect to one another within the FeSV provirus. EcoRI recognized cleavage sites at 0.3 to 0.4 kbp from each terminus of FeSV DNA, reducing the 5.0-kbp DNA to molecules 4.3 kbp long; this enzyme excised a large internal proviral DNA fragment of corresponding size from the DNA of FeSV-transformed mink nonproducer cells. By using DNA transcripts complementary to different portions of the FeSV genome, sarcoma-specific sequences (the FeSV src gene) were positioned within 2.1 and 3.4 kbp from the 5' end of the proviral DNA with respect to the viral RNA genome. The src gene is flanked at both ends by sequences shared in common with feline leukemia virus. The localization of src sequences to this region suggests that a portion of an FeSV polyprotein which contains feline oncornavirus-associated cell membrane antigen (FOCMA-S) is the major product of this gene.
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PMID:Restriction endonuclease mapping of unintegrated proviral DNA of Snyder-Theilen feline sarcoma virus: localization of sarcoma-specific sequences. 22 70

BALB/c JLS V9 cells recently infected with Harvey sarcoma virus-murine leukemia virus (HSV-MuLV) complex contained unintegrated HSV linear DNA of 6.0-kilobase pair mass. The cells also contained two HSV closed circular DNA species along with MuLV-encoded linear and closed circular DNA species. HSV 6.0-kilobase pair linear DNA induced focal transformation upon transfection of NIH 3T3 mouse fibroblasts, and the biological activity of HSV DNA did not require helper MuLV functions. A physical map of restriction endonuclease cleavage sites along HSV 6.0-kilobase pair linear DNA was derived. Comparison of this map with one for Moloney MuLV DNA showed that the HSV and Moloney MuLV genomes are identical near their viral RNA 3' ends.
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PMID:Physical map of biologically active Harvey sarcoma virus unintegrated linear DNA. 23 80

Physical maps of the genome of Moloney murine leukemia virus (M-MLV) DNA were constructed by using bacterial restriction endonucleases. The in vitro-synthesized M-MLV double-stranded DNA was used as the source of the viral DNA. Restriction endonucleases Sal I and Hind III cleave viral DNA at only one site and, thus, generate two DNA fragments. The two DNA fragments generated by Sal I are Sal IA (molecular weight, 3.5 x 10(6)) and Sal IB (molecular weight, 2.4 x 10(6)) and by Hind III are Hind IIIA (molecular weight, 3.6 x 10(6) and Hind IIIB (molecular weight, 2.3 x 10(6)). Restriction endonuclease Bam I generates four fragments of molecular weights of 2.1 x 10(6) (Bam IA), 2 X 10(6) (Bam IB), 1.25 X 10(6) (Bam IC), and 0.24 x 10(6) (Bam ID), whereas restriction endonuclease Hpa I cleaves the M-MLV double-stranded DNA twice to give three fragments of molecular weights of 4.4 x 10(6) (Hpa IA), 0.84 X 10(6) (Hpa IB), and 0.74 x 10(6) (Hpa IC). Digestion of M-MLV double-stranded DNA with restriction endonuclease Sma I produces four fragments of molecular weights of 3.9 x 10(6) (Sma IA), 1.3 X 10(6) (Sma IB), 0.28 X 10(6) (Sma IC), and 0.21 x 10(6) (Sma ID). A mixture of restriction endonucleases Bgl I and Bgl II (Bgl I + II) cleaves the viral DNA at four sites generating five fragments of approximate molecular weights of 2 x 10(6) (Bgl + IIA), 1.75 X 10(6) (Bgl I + IIB), 1.25 X 10(6) (Bgl I + IIC), 0.40 X 10(6) (Bgl I + IID), and 0.31 x 10(6) (Bgl I + IIE). The order of the fragments in relation to the 5' end and 3' end of the genome was determined either by using fractional-length M-MLV double-stranded DNA for digestion by restriction endonucleases or by redigestion of Sal IA, Sal IB, Hind IIIA, and Hind IIIB fragments with other restriction endonucleases. In addition, a number of other restriction endonucleases that cleave in vitro-synthesized M-MLV double-stranded DNA have also been listed.
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PMID:Genome organization of RNA tumor viruses II. Physical maps of in vitro-synthesized Moloney murine leukemia virus double-stranded DNA by restriction endonucleases. 35 1

Both linear (form III) and closed circular (form I) viral DNAs obtained from mouse cells infected with Moloney murine leukemia virus were cleaved by Sal I, Sma I, Bam HI and Pst I restriction endonucleases. DNA fragments generated by these cleavages were ordered with respect to the 5' and 3' ends of the RNA genome by several techniques, including comparisons of the DNA fragments from cleavages of the linear and closed circular forms, double digestions using different combinations of enzymes and the use of an RNA probe specific for the 3' end. DNA from Hirt extractions of infected cells yielded a discrete species of linear viral DNA whose size was determined by agarose gel electrophoresis to be 5.7 x 10(6) daltons. In the course of characterizing the closed circular DNA, we observed two form I DNA molecules. The larger molecule was the same size as the linear DNA. The second molecule migrated faster on agarose gels and was the predominant species of the two closed circular DNAs. Using the restriction endonuclease maps which we derived, we demonstrate that this novel form I DNA is a smaller homogeneous species of viral DNA, missing about 600 nucleotides found in the linear and larger closed circular DNA molecules. We have localized the site of this missing DNA piece to be at either one or both ends of the linear viral DNA.
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PMID:Restriction endonuclease cleavage of linear and closed circular murine leukemia viral DNAs: discovery of a smaller circular form. 45 38

The integration sites for viral DNA in cells infected with Moloney murine leukemia virus (M-MuLV) were studied by restriction endonuclease cleavage of cellular DNA followed by electrophoresis in agarose gels, blot transfer to nitrocellulose, and detection by M-MuLV-related sequences by hybridization with high-specific-activity 32P-labeled M-MuLV complementary DNA. When EcoRI was used to cleave cellular DNA, numerous DNA fragments with sequence homology to M-MuLV were detected in uninfected mouse cell DNA. These endogenous sequences are mouse specific since they are not detectable in rat cell DNA, and are related to the 38S genomic RNA of M-MuLV. Infected cells contain additional M-MuLV-specific DNA fragments which are not detected in uninfected cells. Different patterns of M-MuLV-specific DNA fragments were detected in each cloned infected line examined. These data suggest the existence of multiple sites for integration of M-MuLV DNA in infected mouse fibroblasts. Cleavage of infected cell DNA with BamHI, which cleaves M-MuLV viral DNA at least twice, released the internal BamHI B fragment from each infected line, confirming the presence of integrated M-MuLV DNA sequences in each infected cell line which retain some features of the sequence organization of unintegrated M-MuLV DNA.
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PMID:Multiple integration sites for Moloney murine leukemia virus in productively infected mouse fibroblasts. 48 Apr 64

Using electron microscopy, a closed circular form of DNA (4.3 mum in contour length) was detected in the nucleus of mouse embryo fibroblasts 2.5 h after infection by Rauscher murine leukemia virus. These circles were distinguishable from mitochondrial DNA by various criteria, including size, absence of secondary features, and resistance to EcoRI endonuclease.
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PMID:Electron microscopic studies of circular DNA in mouse embryo fibroblasts infected by Rauscher leukemia virus. 55 84

DNA was isolated from mouse brain after in vivo gamma-ray irradiation, treated with endonuclease S1 from Aspergillus oryzae if necessary, and analysed further by alkaline and neutral sucrose gradient centrifugation. In parallel, its template activity was determined by DNA polymerase (EC 2.7.7.7, enzyme A of Klenow from Escherichia coli) assay as described previously. Similar experiments were performed with cultured mouse leukaemia cells (L5178Y) irradiated in vitro at 0 degrees C. Irradiation induced single- and double-strand breaks in the DNA of the brain with a yield of 1.0 and 0.1 break per 10(12) dalton per rad (100 eV/break and 770 eV/break), respectively. The yield of single-strand breaks in the brain was lower than that found in the cultured cells, whereas the yield of double-strand breaks was found to be almost the same in both cases. Treatment of irradiated DNA with single-strand-specific S1 endonuclease gave rise to further breaks detected on neutral sucrose gradient analysis. The yield of these breaks was also higher in the brain compared to the cultured cells. The increase per unit dose in the template activity of the DNA from the brain was found to be five times as much as that found in the cultured cells. Then, the average number of deoxyribonucleotides incorporated per break was determined on DNA which had experienced different treatments. The value for the brain DNA irradiated in vivo was found to be five times as much as that found for DNA treated with pancreatic deoxyribonuclease and 10 times as much as those found for DNA from the cultured cells and isolated brain nuclei irradiated in vitro at 0 degrees C. Thus, in vivo irradiation seemed to induce gaps with 3'-OH terminals in addition to simple breaks with or without 3'-OH terminals found in the cultured cells. Radiation-induced single-strand breaks and 3'-OH terminals in the DNA of the brain were repaired following irradiation. Approx. 20--40% of the terminals or breaks induced were, however, remaining at 3 h or more after irradiation, depending on the dose administered.
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PMID:Induction and repair of strand breaks and 3'-hydroxy terminals in the DNA of mouse brain following gamma irradiation. 71 24

A closed circular, double-stranded infectious DNA of Moloney leukemia virus has been described previously. The present report characterizes a second type of infectious, unintegrated viral DNA which is linear, largely double stranded, and of mass comparable to that of the closed circular viral DNA. The linear form is of nonpermuted sequence, and SalI endonuclease cleaves at one site 45% from one end.
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PMID:Infectious, linear, unintegrated DNA of Moloney murine leukemia virus. 99


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