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)

Adenovirus type 5 DNA has low infectivity (Graham & van der Eb, 1973) which can be increased by various techniques, one of which is the dimethyl sulphoxide (DMSO) boost (Stow & Wilkie, 1976). In this report, it is shown that DMSO treatment of adenovirus 5 DNA-infected HeLa cells results in a 10-fold increase in plaque formation, and that this can be used to facilitate marker rescue experiments. Double DNA infections were performed by the calcium phosphate method, co-precipitating intact temperature-sensitive mutant DNA with purified wild-type DNA restriction endonuclease fragments. Analysis of the plaquing ability of these mixtures and any progeny virus has resulted in the assignment of six temperature-sensitive mutations to discrete physical locations on the adenovirus type 5 genome. These locations are discussed with respect to the mutant phenotypes and the transcription-translation products of the appropriate regions.
J Gen Virol 1978 Dec
PMID:Mapping of adenovirus type 5 temperature-sensitive mutations by marker rescue in enhanced double DNA infections. 74 9

Mitotic chromosomes of L cells (metaphase plates) were dehistonized by centrifugation through a layer of 2 M NaCl and then treated with restriction endonuclease Bam HI. Alternatively, they were pretreated with EcoRI endonuclease, dehistonized, and additionally digested with EcoRI or HindIII. The DNA remaining attached to the axial structure of the chromosomes was isolated and investigated in renaturation experiments. It was found to be enriched in reiterated base sequences belonging to the satellite and to abundant intermediate repeats. The CsCl density gradient ultracentrifugation of this DNA separated the satellite from the fraction containing intermediate repeats.
Nucleic Acids Res 1978 Dec
PMID:DNA adjacent to attachment points of deoxyribonucleoprotein fibril to chromosomal axial structure is enriched in reiterated base sequences. 74 91

1. We have isolated large fragments of the mtDNA of the yeast Saccharomyces carlsbergensis and digested these with restriction endonucleases. The digestion products were separated by electrophoresis in agarose gels. 2. Endonucleases EcoRI, HindII + III, HpaI, HindIII and HapII yield 9, 11, 6, 0 and greater than 80 fragments, respectively. 3. By analysis of partial digestion products and by redigesting the fragments obtained with one endonuclease with a second, we have established the order of all EcoRI and HindII + III fragments. The map is circular and its contour length is 22.1 +/- 0.35 mum, in good agreement with earlier estimates of the size of yeast mtDNA, using electron microscopy and renaturation kinetics. 4. A comparison of the fragmentation pattern of mtDNAs from S. carlsbergensis and various strains of Saccharomyces cerevisiae with endonuclease HindII + III suggests that the overall gene order is similar.
Mol Gen Genet 1975 Dec 30
PMID:The organization of genes in yeast mitochondrial DNA II. The physical map of EcoRI and HindII + III fragments. 76 43

The gal3 mutation of E. coli is an insertion of a DNA sequence, 1,100 base pairs in length, into the operator-promoter region of the galactose operon. This mutation reverts spontaneously to gal+ by excision of the insertion to produce stable, inducible revertants, or by tandem duplications of the gal operon to produce unstable, constitutive revertants. The nature of a third class of revertants, which are stable and constitutive, is the subject of the present study. The stable, constitutive class of revertants included approximately 30% of all gal+ revertants obtained from a gal3 (lambda) strain. Although the constitutive reversions could be transduced by lambda, the efficiency was found to be extremely poor and the rare transductants which did appear seemed to originate from abnormal transducing particles. It was concluded that these reversions were not normally packaged by lambda. In order to facilitate the packaging of these reversions, the chlD-pgl region was deleted from the parent gal3 (lambda) strain. Unexpectedly, the gal3 mutation in the majority of these deletions reverted to produce stable, constitutive reversions exclusively. The explanation proposed was that the chlL-pgl deletions had also removed part of the gal operator-promoter. These revertants were not considered to be true representatives of the stable, constitutive class. The specificity of deletion end-points at the insertion was found only in the gal3 (lambda) strain, and not in gal+, gal+(lambda), or gal3 strains. Moreover, the frequency of spontaneous chlD-pgl deletions increased 10- to 15-fold in presence of the gal3 insertions. A lambdagal phage bearing a true stable, constitutive reversion (galc200) was isolated from the revertant strain by subsequent deletion of the chlD-pgl segment (delta31). Electron micrographs of lambdagal+ and lambdac200 delta31(chlD pgl) DNA heteroduplexes were interpreted to indicate that the stable, constitutive reversion had arisen by a deletion of 3/4 of the gal3 insertion sequence. The main conclusions are: (i) the stable, constitutive reversions of gal3 can arise by partial deletions of the insertion sequence, apparently by elimination of the nucleotide sequence which causes polarity; (ii) the chlD-pgl deletions may exhibit preferential termination at the right extremity of the gal3 insertion in presence of prophage lambda; and (iii) the gal3 insertion appears to inhibit the production of lambdagal particles by providing a nucleotide sequence which is recognized and degraded by a specific endonuclease. It is suggested that inhibition of transducing particle formation by gal3 and the preferred termination of deletions at gal3 might represent related phenomena.
Mol Gen Genet 1976 Dec 31
PMID:Reversion of the gal3 mutation of Escherichia coli: partial deletion of the insertion sequence. 77 85

The kinetics of cleavage of DNA from Adenovirus Type 1 (Ad1), Type 5 (Ad5) and Type 6 (Ad6) by restriction endonuclease EcoRI was investigated by quantitative evaluation of the fluorescence from ethidium stained DNA fragments separated on agarose gels. The apparent rate constants of cleavage at different cleavage sites have been determined and large differences in the cleavage rates of the individual sites within one type of DNA were found. From the kinetics of cleavage information on the sequence of the DNA fragments can be obtained. The order of the fragment A, B, C, D of Ad6 DNA obtained after complete cleavage by restriction endonuclease Eco RI was found to be A-D-C-B; the order of the corresponding fragments A, B, C of Ad1 and Ad5 DNA was found to be A-C-B.
Nucleic Acids Res 1976 Dec
PMID:Kinetic studies on the cleavage of adenovirus DNA by restriction endonuclease Eco RI. 79 36

An endonuclease of Escherichia coli active on a DNA treated with methylmethane sulfonate has been separated from an endonuclease active on depurinated sites. The former enzyme is disignated here as endonuclease II, while the latter enzyme is designated as apurinic acid endonuclease. Endonuclease II is also active on DNA treated with methylnitrosourea, 7-bromomethyl-12-methylbenz[a]anthracene, and gamma-irradiation. A third fraction which contains activities for both depurinated and alkylated sites needs further study. Endonuclease II, molecular weight 33,000, has been purified 12,500-fold and does not have exonuclease III activity. Apurinic acid endonuclease, molecular weight 31,500, has been purified 11,000-fold and does not have exonuclease III activity. Exonuclease III, molecular weight 26,000, has been purified 2300-fold and does not have endonucleolytic activity at depurinated reduced sites or at alkylated sites in DNA. Therefore, these are three separate proteins. Exonuclease III can produce, presumably by its exonucleolytic activity, double-strand breaks in heavily alkylated DNA under conditions where it does not make single-strand endonucleolytic breaks at either depurinated-reduced or alkylated sites.
Proc Natl Acad Sci U S A 1976 Dec
PMID:Endonuclease II, apurinic acid endonuclease, and exonuclease III. 79 74

A 2000 base pair (bp) DNA fragment can be excised from sea urchin (S. purpuratus) histone gene repeat units with restriction endonuclease Eco R1. This DNA, which has been cloned in a bacterial plasmid, is known to encompass two of the five histone genes. The fragment has a single endonuclease Hind III cleavage site in one of the genes and a Hae III cleavage site in the other gene. We now report the nucleotide sequences of 62 bp adjacent to the Hind III site and 42 bp adjacent to the Hae III cleavage site. The results identify the cloned DNA as histone genes, show that it codes for histone proteins H2A and H3, and locate and orient H2A and H3 genes with respect to restriction endonuclease sites in the repeat unit.
Cell 1976 Dec
PMID:Identification and location of the histone H2A and H3 genes by sequence analysis of sea urchin (S. purpuratus) DNA cloned in E. coli. 79 48

Restriction endonuclease R from Bacillus subtilis strain R cleaves nonmodified SPP 1 DNA in approximately 80, and lambda DNA in about 200 different sites. DNA digests with this endonuclease and with endonuclease Hae III from Haemophilus aegyptius show identical fragmentation patterns on gel electrophoresis, indicating that the two enzymes recognise the same nucleotide sequence. The polynucleotide kinase reaction was used in conjunction with two-dimensional ionophoretic nucleotide mapping methods to identify the 5'-nucleotide sequences at the sites of cleavage by the B. subtilis restriction endonuclease. The results show that the recognition sequence is (see article) where arrows indicate the points of strand scission. Each of the four possible nucleotides can occur in the positions flanking the recognition site.
Mol Gen Genet 1975 Dec 30
PMID:Restriction and modification in B. subtilis. Nucleotide sequence recognised by restriction endonuclease R. Bsu R from strain R. 81 3

We report the isolation and some properties of the mitochondrial ribosomal RNA (mt-rRNA) of Drosophila melanogaster, and a restriction map of the mtDNA of this organism which shows the position of the rRNA genes and of the A + T-rich region in the DNA. The mt-rRNAs are about 860 and 1500 nucleotides long and have the unusual composition of about 20% G+C. Some 25% of the mtDNA is very rich in A+T and is visualized as a contiguous early melting region in denaturation mapping. We mapped the three cleavage sites of the restriction endonuclease Hae III and the four sites of Hind III on mtDNA relative to each other and relative to the early melting region. The rRNA genes have been positioned on this map. The two rRNA genes are next to each other, separated by a gap of about 160 bases. We determined the polarity of the rRNA molecules: transcription proceeds in the direction small-to-large rRNA. Despite great divergence in nucleotide composition and sequence, the properties of mt-rRNA and the arrangement of mt-rRNA genes are very similar in Drosophila and vertebrate animals.
Cell 1976 Dec
PMID:Characterization and mapping of mitochondrial ribosomal RNA and mitochondrial DNA in Drosophila melanogaster. 82 33

Ataxia telangiectasia, Bloom's syndrome and normal fibroblasts were compared as to the capacity of their cellular extracts to enhance the priming activity of gamma-irradiated colicin E1 DNA for purified DNA polymerase. It was found that an ataxia strain had substantially lower, and a Bloom's syndrome strain had slightly lower capacity than a normal strain; while the activities of apurinic site specific endonuclease in these extracts were comparable.
Biochim Biophys Acta 1977 Dec 14
PMID:DNA repair enzymes in ataxia telangiectasia and Bloom's syndrome fibroblasts. 92 14


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