Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The restriction endonuclease from Haemophilus parainfluenzae, endoR.HpaI cleaves lambdacI857s7 DNA into 14 fragments. The sizes of these fragments were determined and a physical map was constructed. The ordering of the fragments was carried out using different deletion and substitution mutants of lambda phage, double cleavages with another restriction enzyme, endoR.BamHI, and partial protection of individual HpaI recognition sites by the antibiotics distamycin A and actinomycin D. HpaI produces fragments from the left arm of the lambda DNA genome, which may help in investigating the structure and function of this part of the phage.
Gene 1978 Sep
PMID:Physical mapping of bacteriophage lambda DNA with restriction endonuclease HpaI. 73 55

Replicative form DNA of bacteriophage M13 was cleaved into specific fragments by an endonuclease isolated from Hemophilus aegyptius (endoR.HaeII) and an endonuclease from Arthrobacter luteus (endoR.AluI). The fragments were ordered as to construct a circular map of the phage M13 genome by: (a) using each fragment as a primer for the synthesis in vitro of its respective neighbour and (b) digesting the isolated fragments with the Hemophilus aegyptius enzyme endoR.HaeII or the Hemophilus aphirophilus enzyme endoR.HapII and subsequent analysis of the overlapping sets of fragments. The resulting physical map was correlated with the M13 genetic map by marker rescue experiments with amber mutant phage DNAs and purified wild-type fragments. From the results of these analyses it has been concluded that gene II and gene V are contiguous on the genetic map. Evidence is provided that there is an internal start of RNA synthesis within the C-terminal region of gene II which then ultimately leads to the synthesis of X protein. Furthermore, we conclude that there is an intergenic space of considerable length (450-500 base pairs) which is located between gene II and gene IV on the M13 genome. The function of this intergenic region as the origin site for phage DNA replication is discussed.
Eur J Biochem 1976 Sep
PMID:Restriction-enzyme-cleavage maps of bacteriophage M13. Existence of an intergenic region on the M13 genome. 78 38

Three sites recognized by SmaI endonuclease, purified from Serratia marcescens SB, have been located on lambda DNA at 0.406, 0.656, and 0.825 fractional lengths from the left end of the DNA molecule.
J Virol 1976 Sep
PMID:Cleavage of lambda DNA by a site-specific endonuclease from Serratia marcescens. 78 56

Small circular DNA molecules from genetically characterized clones of Saccharomyces cerevisiae have been studied by restriction endonuclease analysis and electron microscopy. The circular monomers (6000 bases) are shown to contain two inverted repeats of the same sequence (600 bases) situated opposite each other along the perimeter. Four endonuclease EcoRI fragments are obtained in 1:1:1:1 stoichiometry, and their sum gives a length of about 12,000 bases. The two large fragments and the two small ones differ from each other by 200 bases. We propose a model for the structure of the monomer molecule. Two classes of monomers can be generated by intramolecular recombinations within inverted repeats; they differ by the relative orientation of nonrepeated segments. The structure of dimers as predicted by the model is verified by self-renaturation of single-stranded circles. Inverted repeats in circular molecules may be related to the insertion release faculty of II episome in the chromosomes.
Proc Natl Acad Sci U S A 1976 Sep
PMID:Circular DNA of a yeast episome with two inverted repeats: structural analysis by a restriction enzyme and electron microscopy. 78 82

Repair synthesis induced by 4-nitroquinoline-1-oxide (4NQO) in L6 myoblasts before and after cellular fusion was measured by [3H] thymidine incorporation into unreplicated DNA. The level of repair synthesis was reuced after the cells had fused into myotubes. The terminal addition of radioactive nucleotides into DNA strands occurred only to a minor extent, and the dilution of [3H] thymidine by intracellular nucleotide pools was shown not to be responsible for the observed difference in repair synthesis, Both the initial rate and the overall incorporation of [3H] thymidine were found to be 50% lower in the myotubes. 4NQO treatment of myoblasts and myotubes induced modifications in the DNA which were observed as single-strand breaks during alkaline sucrose sedimentation. After the myoblasts were allowed a post-treatment incubation, most of the single-strand breaks were not longer apparent. In contrast, a post-treatment incubation of myotubes did not change the extent of single-strand breakage seen. Both myoblasts and myotubes were equally effective in repairing single-strand breaks induced by X radiation. It would appear that when myoblasts fuse, a repair enzyme activity is lost, probably an endonuclease that recognizes one of the 4 NQO modifications of DNA. The result observed is a partial loss of repair synthetic ability and a complete loss of ability to remove the modification that appears as a single-strand break in alkali.
J Cell Biol 1976 Sep
PMID:Reduced DNA repair during differentiation of a myogenic cell line. 82 55

The ultraviolet-light induction of DNA damage has been measured in the epidermis of hairless mice with the use of damage-specific endonucleases from Micrococcus luteus. The rates of induction of endonuclease-sensitive sites in HRS/J/Anl and Skh:hairless-1 mice were 6.1 +/- 0.5 X 10(-11) and 6.5 +/- 0.8 X 10(-11)/dalton/J/sq m from a FS40 fluorescent sun lamp (280 to 400 nm), respectively. Enzymatic photoreactivation with yeast photoreactivating enzyme showed that approximately 80% of the endonuclease-sensitive sites were cycloburyl pyrimidine dimers. In both strains of mice the pyrimidine dimers remained in high-molecular-weight DNA for 24 hr after irradiation. These data show that mouse epithelial cells in vivo have little or no capacity for the excision repair of pyrimidine dimers.
Cancer Res 1977 Sep
PMID:Induction and persistence of pyrimidine dimers in the epidermal DNA of two strains of hairless mice. 88 73

Five peaks of endonuclease activity showing a preference for ultraviolet-damaged DNA have been chromatographically identified from extracts of Micrococcus luteus. They are numerically designated as I to V in order of their elution from phosphocellulose (Whatman P-11) columns. The first two of these peaks have been highly purified by a combination of gel filtration and affinity chromatography and are catalytically homogeneous judging from their effect on transforming DNAs. Peak I, which has an isoelectric point of 4.7, is heat-stable, requires high ionic strength for optimal activity, acts with equal facility on ultraviolet-irradiated native and denatured DNA, and has been designated as Py pyrimidine dimer Py correndonuclease I. Peak II which has a pI value of 8.7, is heat-labile, is inhibited by high ionic strength, acts on ultraviolet-irradiated native but not denatured DNA, and has been designated as Py pyrimidine dimer Py correndonuclease II. Both enzymes are inhibited by Ca2+ and Zn2+, do not show any cofactor or sulfhydryl requirement, act optimally between pH 7.0 and 7.4, and have molecular weights between 11,000 and 15,000. Py pyrimidine dimer Py correndonuclease I requires a dose about 1.6 times that for Py pyrimidine dimers Py correndonuclease II for incision saturation of irradiated phiX174 RFI DNA.
J Biol Chem 1977 Sep 25
PMID:Micrococcus luteus correndonucleases. I. resolution and purification of two endonucleases specific for DNA containing pyrimidine dimers. 89 8

Upon denaturation, T5 DNA yields a large number of discrete, single-chain fragments that can be resolved by agarose gel electrophoresis. The positions of the more prominent of these fragments in the T5 duplex were determined by analyzing their sensitivity to digestion with lambda exonuclease and their distribution among EcoRI fragments of T5 DNA. These experiments also provide firm evidence concerning the polarity of the strands in T5 DNA. An analogous study was carried out on the fragments produced by treating exonuclease III-degraded T5 DNA with the single-strand-specific SI endonuclease. This procedure yielded over 40 discrete duplex fragments that could be resolved with considerable precision by agarose gel electrophoresis. The positions of most of these fragments were determined by analyzing EcoRI fragments of T5st(+) and T5st(0) DNA. Over 20 sites where single-chain interruptions can occur in T5 DNA were identified, and the distribution of interruptions within the terminal repetition was shown to be identical at both ends of the molecule. A precise value for the size of the terminal repetition in T5 DNA was obtained by analyzing SI endonuclease digests of ligase-repaired, circular T5 DNA in agarose gels. The repeated segment represented 8.3% of the T5st(+) DNA. The results of this study also provide information concerning the properties of lambda exonuclease. Hydrolysis by this enzyme was not terminated when single-chain interruptions were encountered either in the strand being degraded or in the complementary strand.
J Virol 1977 Sep
PMID:Localization of single-chain interruptions in bacteriophage T5 DNA. II. Electrophoretic studies. 89 94

The 5' terminal sequences of several adenovirus 2 (Ad2) mRNAs, isolated late in infection, are complementary to sequences within the Ad2 genome which are remote from the DNA from which the main coding sequence of each mRNA is transcribed. This has been observed by forming RNA displacement loops (R loops) between Ad2 DNA and unfractionated polysomal RNA from infected cells. The 5' terminal sequences of mRNAs in R loops, variously located between positions 36 and 92, form complex secondary hybrids with single-stranded DNA from restriction endonuclease fragments containing sequences to the left of position 36 on the Ad2 genome. The structures visualized in the electron microscope show that short sequences coded at map positions 16.6, 19.6 and 26.6 on the R strand are joined to form a leader sequence of 150-200 nucleotides at the 5' end of many late mRNAs. A late mRNA which maps to the left of position 16.6 shows a different pattern of second site hybridization. It contains sequences from 4.9-6.0 linked directly to those from 9.6-10.9. These findings imply a new mechanism for the biosynthesis of Ad2 mRNA in mammalian cells.
Cell 1977 Sep
PMID:An amazing sequence arrangement at the 5' ends of adenovirus 2 messenger RNA. 90 10

Large pools of empty viral capsids accumulate in cells infected by subgroup B human adenoviruses. Such infected cells also yield DNA-containing incomplete particles in larger quantities than cells infected with serotypes representing other adenovirus subgroups. DNA isolated from carefully purified classes of Ad7 incomplete particles was analyzed by restriction endonuclease cleavage, gel electrophoresis and electron microscopy. At least 90% of the DNA molecules in each sample consisted of sequences that extended from the left end of the viral genome map by variable lengths toward the right end. The average length of DNA is linearly related to the average buoyant density of the incomplete particles from which the DNA is isolated. The results indicate that each capsid contains one DNA molecule. There is also a specific association of the left end of the viral genome with assembled or assembling capsids. The characteristic distributions of Ad7 incomplete particles may result from intracellular pools of assembly intermediates in which the incompletely packaged DNA has been fragmented in vivo or by shear during preparative procedures.
Cell 1977 Sep
PMID:Viral DNA sequences from incomplete particles of human adenovirus type 7. 90 15


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>