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)

We have analyzed the restriction digest patterns of the mitochondrial DNA from 41 cytoplasmic petite strains of Saccharomyces cerevisiae, that have been extensively characterized with respect to genetic markers. Each mitochondrial DNA was digested with seven restriction endonucleases (EcoRI, HPaI, HindIII, BamHI, HhaI, SalI, and PstI) which together make 41 cuts in grande mitochondrial DNA and for which we have derived fragment maps. The petite mitochondrial DNAs were also analyzed with HpaII, HaeIII, and AluI, each of which makes more than 80 cleavages in grande mitochondrial DNA. On the basis of the restriction patterns observed (i.e., only one fragment migrating differently from grande for a single deletion, and more than one for multiple deletions) and by comparing petite and grande mitochondrial DNA restriction maps, the petite clones could be classified into two main groups: (1) petites representing a single deletion of grande mitochondrial DNA and (2) petites containing multiple deletions of the grande mitochondrial DNA resulting in rearranged sequences. Single deletion petites may retain a large portion of the grande mitochondrial genome or may be of low kinetic cimplexity. Many petites which are scored as single continuous deletions by genetic criteria were later demonstrated to be internally deleted by restriction endonuclease analysis. Heterogeneous sequences, manifested by the presence of sub-stoichiometric amounts of some restriction fragments, may accompany the single or multiple deletions. Single deletions with heterogeneous sequences remain useful for mapping if the low concentration sequences represent a subset of the stoichiometric bands. Using a group of petites which retain single continuous regions of the grande mitochondrial DNA, we have physically mapped antibiotic resistance and mit- markers to regions of the grande restriction map as follows: C (99.3--1.4 map units)--OXI-1 (2.5--15.7)--OXI-2 (18.5--25)--P (28.1--34.2)--OXI-3 (32.2--61.2--OII (60--62)--COB (64.6--80.8--0I (80.4--85.7)--E (95--98.9).
Mol Gen Genet 1978 Jul 25
PMID:Restriction enzyme analysis of mitochondrial DNAs of petite mutants of yeast: classification of petites, and deletion mapping of mitochondrial genes. 35 53

Endonuclease alpha isolated from the nucleus of the yeast Saccharomyces cerevisiae is a DNA endonuclease which has been shown to act preferentially on denatured T7 DNA. The purified enzyme is more active with UV-irradiated native T7 DNA than with unirradiated substrate. The relation between damage, measured by pyrimidine dimer concentration, and excess endonuclease activity is most readily explained by local denaturation caused by presence of pyrimidine dimers. When three radiation sensitive mutants of yeast were tested for the level of endonuclease alpha present, none were found lacking the enzyme. However, nuclei of strain rad 1-1, a mutant that may be defective in heteroduplex repair as well as excision repair, were found to contain reduced levels of the endonuclease. The enzyme isolated from this strain had less than one half the specific activity of similar preparations from wild type yeast.
Mol Gen Genet 1978 Nov 29
PMID:Endonuclease alpha from Saccharomyces cerevisiae shows increased activity on ultraviolet irradiated native DNA. 36 83

A restriction endonuclease map of EcoRI fragment f6 of F sex factor DNA was constructed and aligned with pre-existing physical and genetic maps. Results of genetic complementation tests and analysis of proteins synthesized in minicells from PstI and BglII sub-fragment clones, or from a specific BglII fragment deletion, have allowed mapping of the locations of the origin of DNA transfer and many of the transfer genes known to lie on f6. The proteins detected account for 78% of the coding capacity of fragment f6.
Mol Gen Genet 1978 Oct 24
PMID:The control region of the F sex factor DNA transfer cistrons: restriction mapping and DNA cloning. 36 64

ColE1amp plasmids carrying the entire bio gene cluster were constructed in vitro using ColE1amp as the cloning vehicle and a lambda transducing phage, lambdaatt2, as the source of bio DNA. Restriction endonuclease EcoRI digests of ColE1amp and lambdaatt2 DNA were joined by polynucleotide ligase and plasmids bearing the entire bio gene cluster were selected, after transformation, in bio deletion strains of E. coli. Recombinant DNA molecules contained one ColE1amp fragment (7.4 X 10(6) daltons) and one lambdaatt2 DNA fragment (5.4 X 10(6) daltons). Clones carrying ColE1 amp-bio plasmids produce elevated levels of biotin and biotin synthetase activity.
Mol Gen Genet 1978 Nov 09
PMID:Isolation and characterization of a ColE1 plasmid containing the entire bio gene cluster of Escherichia coli K12. 36 79

Detailed examination of the structure of cloned DNA fragments of the R6-5 antibiotic resistance plasmid has revealed a substantial degree of polynucleotide sequence heterogeneity and indicates that sequence rearrangements in plasmids and possible other replicons occur more frequently than has hitherto been appreciated. The sequences changes in cloned R6-5 fragments were shown in some instances to have occurred prior to cloning, i.e. existing in the original population of R6-5 molecules that was obtained from a single bacterial clone and by several different criteria judged to be homogeneous, and in others to have occurred either during the cloning procedure or during subsequent propagation of hybrid molecules. The molecular changes that are described involved insertion/deletion of the previously characterized IS2 insertion element, formation of a new inverted repeat structure probably by duplication of a preexisting R6-5 DNA sequence, sequence inversion, and loss and gain of restriction endonuclease cleavage sites.
Mol Gen Genet 1978 Nov 16
PMID:Instability of plasmid DNA sequences: macro and micro evolution of the antibiotic resistance plasmid R6-5. 36 83

Replicating DNA molecules of the mini R6-5 plasmid, pKTO71, were purified by equilibrium centrifugation in two successive ethidium bromide-caesium chloride gradients, converted to linear forms by cleavage with either HindIII or BglII restriction endonuclease, and examined in the electron microscope. Determination of the replication fork positions in 65 replicating molecules demonstrated that replication is initiated at a unique location on the plasmid and that it proceeds uni-directionally from this site. The direction of replication is such that the origin-proximal BglII cleavage site is replicated late or, in the case of the parent R6-5 plasmid, is such that the R-determinant region of the molecule is replicated early. The origin of replication, located by these experiments at R6-5 coordinate 98.6 kb, is clearly distinct from that of the R6-5 incompatibility determinant which has been shown to be located on an adjacent PstI-generated DNA fragment whose termini have R6-5 coordinates 96.8 and 97.9 kb. This result indicates that the incompatibility function is not an origin DNA sequence.
Mol Gen Genet 1979 Jan 05
PMID:Plasmid replication functions. III. Origin and direction of replication of a "mini" plasmid derived from R6-5. 37 38

Digestion of non-glucosylated and cytosine-substituted T4 phage (T4dC) DNA with SalI restriction endonuclease showed that the DNA had nine SalI-sensitive sites. There were eight SalI sites in DNA from a strain which had a deletion in the rII-denB-ndd region. The comparison of two digestion patterns indicated that one of the SalI-sensitive sites was present in the deleted region and that the SalI-F fragments (8.4 x 10(6) daltons) was located adjacent to the SalI-C or SalI-D fragments (15.5 x 10(6) daltons) on the T4 chromosome. The DNA gave no detectable cleavage product when digested with BamHI endonuclease alone, while, when digested successively with BamHI and SalI, the DNA yielded two new digestion products in place of one fragment formed by SalI alone. The BamHI-sensitive site was in the SalI-A fragment (25.2 x 10(6) daltons). The usefulness of this information for making cleavage maps of T4 phage chromosome is discussed.
Mol Gen Genet 1979 Jan 05
PMID:Studies of viable T4 bacteriophage containing cytosine-substituted DNA (T4dC phage). II. Cleavage of T4dC DNA by endonuclease SalI and bam HI. 37 40

A detailed molecular dissection of the yeast mitochondrial genome can be made with restriction endonucleases that generate site-specific cuts in DNA. The ordering of restriction fragments provides the basis of the physical mapping of mitochondrial transcripts and antibiotic resistance (antR) loci, and is a means of analyzing the molecular organization of mtDNA of petite and mit- deletion mutants. We have previously mapped the sites in the mtDNA of yeast strain MH41-7B recognized by the endonucleases Eco RI, Hpa I, Hind III, Bam HI, Sal I, Pst I, and Hha I, providing a total of 41 cleavage sites. We have now mapped the sites recognized by the endonucleases Xba I, Hinc II, Bgl II, Pvu II, Xho I, and Sst I, which make 6, 13, 5, 6, 2, and 2 cuts, respectively. Fragment maps for each of these endonuclease sites were derived by analysis of the products of double-enzyme digests and by hybridization of 3H-cRNA probes transcribed from low-kinetic-complexity petite mtDNAs to restriction fragments generated by various combinations of enzymes.
Mol Gen Genet 1979 Feb 16
PMID:Physical mapping of the Xba I, Hinc II, Bgl II, Xho I, Sst I, and Pvu II restriction endonuclease cleavage fragments of mitochondrial DNA of S. cerevisiae. 37 13

Escherichia coli mutants defective in DNA uracil N-glycosidase (ung-) or endonuclease VI active against apurinic/apyrimidinic sites in DNA (xthA-) exhibit enhanced sensitivity towards 5-bromodeoxyuridine relative to the wild type strain, pointing to involvement of these enzymes in repair of bromouracil-induced lesions in DNA. Mutants defective in DNA polymerase I, either in polymerizing activity (polAl-) or (5' leads to 3')-exonuclease activity (polA107-) exhibit unusually high sensitivity (including marked lethality) in the presence of 5-bromodeoxyuridine. The results indicate that DNA polymerase I, and its associated (5'--3')-exonuclease activity, are involved in repair of bromouracil-induced lesions and are not readily replaced, if at all, by DNA polymerases II and III. Thermosensitive mutant in DNA ligase gene (lig ts7) shows high sensitivity towards 5-bromodeoxyuridine at 42 degrees C indicating the role of the enzyme in repair of bromouracil-induced lesions in DNA. Involvement of DNA uracil N-glycosidase, and endonuclease active against apurinic/apyrimidinic sites in recognition and repair of 5-bromouracil-induced damage permits of some inferences regarding the nature of this damage (lesions), in particular dehalogenation of incorporated bromouracil to uracil residues.
Mol Gen Genet 1979 Mar 20
PMID:Genetic evidence for the nature, and excision repair, of DNA lesions resulting from incorporation of 5-bromouracil. 37 26

Hybrid plasmids were constructed from fragments of F'ara episomes formed by the restriction endonuclease EcoRI and a linear form of the plasmid ColE1 created by cleavage with EcoRI. Hybrid plasmids were constructed containing the entire ara region or the ara region with various parts deleted. E. coli K12 host strains were constructed which contained different deletions of the ara region. The hybrid plasmids were transferred to those strains whose ara deletion complemented that of the plasmid. The initial differential rates of synthesis of L-arabinose isomerase, the product of the araA gene, were determined for the Ara+, plasmid containing strains. These studies demonstrated that strains containing delta(araOIBA)718 produce elevated levels of araC protein, suggesting the araC promoter has been altered by this deletion. Evidence is also presented which suggests that araC protein activates the ara-BAD operon to higher levels when it is present in cis rather than trans. Amplification of the products of the cloned genes is observed when compared to haploid levels in some cases.
Mol Gen Genet 1979 Jun 20
PMID:Regulation of the L-arabinose operon in strains of Escherichia coli containing ColE1-ara hybrid plasmids. 38 53


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