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 action of Escherichia coli restriction endonuclease R1 (EcoR1) on DNA isolated from Saccharomyces cerevisiae (strain MAR-33) generates three predominent homogenously sized DNA fragments (species of 1.8, 2.2 and 2.5 kilo nucleotide base pairs (KB). Many DNA species of molecular weight greater than 2 million daltons can be recognized upon incomplete EcoR1 digestion of yeast DNA. Four additional DNA species ranging from 0.3--0.9 KB can be identified as the second major class of EcoR1-yeast DNA products. Hybridization with radioactive ribosomal RNA (rRNA) and competition with nonradioactive rRNA show that of the three predominent EcoR1-yeast DNA species, the 2.5 KB species hybridizes only with the 25S rRNA while the lighter 1.8 KB species hybridizes with the 18S rRNA. The intermediate DNA species of 2.2 KB hybridizes to a small extent with the 25S rRNA and could be a result of the presence of the 2.5 KB DNA species. The mass proportions and hybridization values of these 3 DNA species account for about 60% of the total ribosomal DNA (rDNA). The 5 Eco-R1-yeast DNA species of less than 0.9 KB (4 major and 1 minor species) hybridize to varying degrees with the 2 rRNA and can be grouped in two classes. In one class there are 3 DNA species that hybridize exclusively with the 18S rRNA. In the second class there are 2 DNA species that besides hybridizing predominently with the 25S rRNA also hybridize with the 18S rRNA. The 7 EcoR1-yeast DNA species (excluding the 2.2 KB DNA species) that hybridize with the two rRNA account for nearly a 5 million dalton DNA segment, which is very close to the anticipated gene size of rRNA precursor molecule. If the 2.2 KB DNA species is a part of the rDNA that is not transcribed or 5 sRNA then the cistron encoding the rRNA in S. cerevisiae has at least 8 EcoR1 recognition sites resulting in 8 DNA fragments upon digestion with the EcoR1. Consideration is given to the relationship of the rRNA species generated by EcoR1 digestion and the chromosomes containing ribosomal cistrons.
Mol Gen Genet 1976 Aug 19
PMID:Characterization of yeast ribosomal DNA fragments generated by EcoR1 restriction endonuclease. 78 55

Lambda-transducing phages carrying segments of the Escherichia coli chromosome in the aroE-trkA region have been isolated and shown by hybridization to carry an rRNA gene (rrnD). The most likely gene order is trkA aroE rrnD. The EcoRI and SmaI endonuclease cutting pattern of the rrnD gene is identical with the one of rrnB, differented from rrnC.
Mol Gen Genet 1976 Aug 02
PMID:A ribosomal RNA gene of Escherichia coli (rrnD) on lamnda daro E specialized transducing phages. 79 95

The size and degree of homogeneity of the repetitive units in purified ribosomal DNA (gamma DNA) from Saccharomyces cerevisiae have been analyzed by restriction endonuclease digestion and heteroduplex mapping. Digestion of the gamma DNA with EcoRI yields seven fragments, digestion with Hind II+III yields five fragments, digestion with Hind III alone yields two fragments, and digestion with Sma I yields one fragment. The sum of the fragment molecular weights after digestion with each of the endonucleases is 5.5-5.6 x 10(6). When the DNA strands of the Sma I fragment are dissociated and reannealed, only homoduplexes are formed. We have concluded from these results that the repeating units in yeast ribosomal DNA are 5.6 x 10(6) datons and are homogeneous in size and composition.
Mol Gen Genet 1976 Nov 17
PMID:Restriction endonuclease analysis of ribosomal DNA from Saccharomyces cerevisiae. 79 60

The 2 micron circular DNA from S. cerevisiae has been cloned on bacteriophage lambda. The two forms of circular DNA which exist in equilibrium due to recombination between inverted repeat sequences were separated as stable clones, and a map of targets for restriction endonucleases EcoRI, HindIII and HpaI was constructed. The circular DNAs isolated from a particular oligomycin resistant strain and its parent oligomycin snesitive strain were compared by restriction endonuclease analysis, and no difference was detected. The potential uses of cloned 2 micron DNA in determining the possible biological role of these plasmids are considered.
Mol Gen Genet 1976 Nov 17
PMID:A map of the restriction targets in yeast 2 micron plasmid DNA cloned on bacteriophage lambda. 79 64

The 1400 base pair repeat produced by digestion of calf satellite I DNA (phi = 1.714 g/cm3) with EcoRI, was cloned in E. coli. The hybrid plasmid (pGM 214) which contains the ColE1-Ap vector (pSF 2124) and the 1400 base pair fragment replicates stably in E. coli and can be amplified by chloramphenicol treatment. No clone was found in which more than one "repeat unit" of the satellite I DNA was present in the chimaera plasmid. Digestion of the original satellite I and the plasmid pGM 214 with R-SmaI shows that the satellite DNA replicated in E. coli is cleaved by the restriction endonuclease SmaI whereas the original satellite I DNA from calf thymus is not, suggesting that the satellite I contains a large amount of modified cytosine or guanosine, probably 5-methyl-cytosine. R-EcoRI* produces a number of fragments with the satellite I in the range of 300 base pairs to 1400 base pairs. A physical map of pGM 214 (and pSF 2124) with R-EcoRI, R-HincII, R-HindIII, R-SmaI, R-BamI and R-EclI was constructed. The 1400 base pair "repeat unit" in the pGM 214 is efficiently transcribed in vitro by purified RNA polymerase, starting from a pSF 2124 promoter. The restriction enzyme EclI produces a 350 base pair repeat with calf satellite II (phi = 1,722 g/cm3), whereas the satellite I is not cut by this enzyme.
Mol Gen Genet 1976 Nov 24
PMID:Cloning of calf thymus satellite I DNA in Escherichia coli. 79 69

The enzymes involved in host-controlled modification and restriction by Bacillus subtilis strain N were detected in cell free extracts. In the presenct of Mg2+ the N-specific endonucleases cleaved unmodified DNA but did not attack phi-105C. N DNA carrying N-specific modification. The restriction endonuclease required neither SAM nor ATP for its activity. The N-specific modification enzyme was active only in the presence of SAM, indicating that modification in this syteem is a methylation of DNA.
Mol Gen Genet 1975 Jul 10
PMID:In vitro modification and restriction of phage phi-105c DNA with Bacillus subtilis N cell-free extract. 80 94

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

It is known that DNA from phage T7 is not cleaved by restriction endonuclease EcoRI. However, DNA from phage T7am28 (gene 5) mutant (Studier, 1969) was found to be cleaved by the endonuclease at one site. The site is located at 0.46 fractional length from the left end of the molecule. The mutation which makes T7 DNA sensitive to the endonuclease is separable from the amber nutation and located between am28 and am233 (gene 6).
Mol Gen Genet 1977 Jan 18
PMID:EcoRI-sensitive mutation of T7 phage. 84 Feb 25

Streptomyces coelicolor A3(2) and S. lividans 66, which lack chloramphenicol acetyltraferase, gave rise to vhloramphenicol-sensitive (CmlS) variants spontaneously at frequencies of 0-5 to 2%. The fertility type of S. coelicolor in respect of the SCPI plasmid (SCPI+, SCPI- or NF) had no effect on chloramphenicol sensitivity or on the frequency at which CmlS variants arose. CmlS isolates spontaneously reverted to CmlR at frequencies one to three orders of magnitude lower than the frequency with which CmlS strains arose from CmlR. CmlR revertants obtained spontaneously from CmlS clones again produced CmlS isolates at the normal frequency of several per cent. Therefore, CmlS and CmlR are reversible phenotypes. In crosses between marked CmlR and CmlS S. coelicolor strains, transfer of chloramphenicol resistance into the sensitive strain apparently occurred independently of chromosomal recombination. Mapping experiments excluded the possibility that segregation of a chromosomal locus determines CmlR versus CmlS phenotype. In crosses between SCPI- strains, fertility was not significantly different in CmlR x CmlS, CmlR x CmlR and CmlS x CmlS combinations. Covalently closed circular DNA from CmlS and CmlR strains of S. coelicolor was indistinguishable in molecular weight and restriction endonuclease cleavage pattern. It is suggested that chloramphenicol resistance in S. coelicolor A3(2) is affected by some kind of transposable genetic element that may be capable of extra-chromosomal existence.
J Gen Microbiol 1977 Feb
PMID:Chloramphenicol acetylransferase-independent chloramphenicol resistance in Streptomyces coelicolor A3(2). 85 41

Replicating DNA molecules of a deletion mutant of the conjugative R-plasmid R 6 K are cleaved at a single site by the EcoRI restriction endonuclease. Electron microscope examination and measurements of the EcoRI treated replicative intermediate molecules indicate that replication can be initiated at two sites on the plasmid DNA molecule. The two sites are located at about 23 and 39% of total length, respectively, from the EcoRI cleavage site. About 5% of the replicating molecules use both replication initiation sites simultaneously.
Mol Gen Genet 1975 Sep 15
PMID:Two replication initiation sites on R-plasmid DNA. 110 50


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