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)

A 4.8 X 10(6) dalton ECoRI-generated fragment of the R-factor R6-5 carrying the gene for kanamycin resistance (Km) was joined in vitro to ECoRI-treated ColE1 plasmid DNA. Transformation of E. coli with the ColE1-Km recombinant plasmid yielded clones, which were immune to colicin E1, resistant to kanamycin and failed to produce colicin E1. During multiplication of this recombinant plasmid in the presence of chloramphenicol, cells expressed an increased resistance to kanamycin. Transformation studies with the recombinant DNA molecule showed very frequent loss of Km resistance in those cells harbouring a preexisting F'gal plasmid. Since colicin immunity is not affected and the col- phenotype is still present, one has to test for a remaining DNA sequence further existing in ColE1 DNA by cleaving the plasmid DNA with the ECoRI restriction endonuclease. The full length of ColE1 DNA (6.2 kb) was restored, which confirmed that no deletion of ColE1 DNA sequences had occured. The remaining DNA sequence was identified as a 2.0 or 2.2 kb segment. On the basis of the length of the excised fragment it is proposed that the insertion sequence ISI and a part of the inverted repeat sequence with corrdinates 21.0 to 22.0 of the R6-5 DNA are recognised by a nucleolytic function.
Mol Gen Genet 1977 Jan 07
PMID:Excision of a DNA sequence determining kanamycin resistance from a ColE1-Km recombinant plasmid. 31 42

Fragments produced by partial digestion of Saccharomyces cerevisiae ribosomal DNA (rDNA) with the restriction endonuclease EcoRI were ligated in vitro to the bacterial plasmid RSF2124. The resulting hybrid plasmids were cloned in Escherichia coli. Three hybrid plasmids which contain at least one intact repetitive unit of the multiple, tandem sequences of the yeast rDNA genes have been further characterized. These plasmids have been used to construct a map of the EcoRI, SmaI, HindII and HindIII restriction sites in the individual repetitive units of yeast rDNA.
Mol Gen Genet 1977 Mar 16
PMID:Construction and restriction endonuclease mapping of hybrid plasmids containing Saccharomyces cerevisiae ribosomal DNA. 32 73

Two rad mutants of yeast, rad10 and rad16, are shown to be defective in the removal of UV-induced pyrimidine dimers since DNAs obtained from irradiated cells following a post-irradiation incubation in the dark still retain UV-endonuclease-sensitive sites. Both rad10 and rad16 mutants are in the same pathway of excision-repair as the rad1, rad2, rad3 and rad4 mutants.
Mol Gen Genet 1977 Apr 29
PMID:Defective thymine dimer excision in radiation-sensitive mutants rad10 and rad16 of Saccharomyces cerevisiae. 32 68

The cleavage map of the plasmid RK2 was determined for the five restriction endonucleases EcoRI, HindIII, BamH-I, SalI and HpaI. DNA has been inserted into several of these sites and cloned in Escherichia coli. Efforts to obtain derivatives of RK2 reduced in size by restriction endonuclease digestion of the plasmid were not successful and indicated that genes required for the maintenance of this plasmid in E. coli are not tightly clustered. An RK2 derivative possessing an internal molecular rearrangement was obtained by transformation with restriction endonuclease digests of the plasmid.
Mol Gen Genet 1977 Apr 29
PMID:Physical and genetic studies with restriction endonucleases on the broad host-range plasmid RK2. 32 69

The bacteriophages T3 and T7 are not modified and restricted by E. coli strains with different host specificity (E. coli B, K, O) in vivo. The phages code for a gene product with the ability to overcome classical restriction (ocr): ocr- mutants are subject to modification and restriction via DNA methylation vs cleavage. The T3 genome possesses recognition sites for the restriction endonuclease R.EcoB which, unless the DNA is B-specifically modified, trigger 5-7 DNA cleavages. The ocr gene function of T3 and T7 is located within the gene 0.3 region of these phages and is not identical with the sam (SAMase) function of T3. The mechanism of ocr protection remains unclear, while it is certain that this protection by the gene 0.3 protein is exerted in the infected cell and not through "over-all" modification in the preceding growth cycle of the phage.
Mol Gen Genet 1977 May 20
PMID:Active protection by bacteriophages T3 and T7 against E. coli B- and K-specific restriction of their DNA. 32 8

Crude extracts of Salmonella typhimurium were found to contain an endonuclease that degraded double-stranded linear DNA from bacteria and phages to fragments with a molecular weight of about 8 X 10(5). The nuclease did not have an absolute requirement for Mg2+. One discrete intermediate product had a molecular weight of 6-6 X 10(6). Extracts from two different mutants were tested: one completely lacked the endonuclease activity (strain DB5575), and the other showed an absolute requirement for Mg2+ (strain 4543). No biological role has yet been found for this endonuclease of S. typhimurium.
J Gen Microbiol 1977 Aug
PMID:A Salmonella typhimurium endonuclease that converts native DNA to fragments of about 8 X 10(5) daltons. 33 42

A precise genetic-physical map of the tna-ilv region at 82 min on the genetic map of E. coli is obtained through deletion mapping and analysis by restriction endonuclease EcoRI of plasmids, derived from an F' carrying the genes between aroE and ilv. A locus, designated het, which in its diploid state results in slow growth and heterogeneity of cell size due to distorted cell division, maps between bglB and asn, 30-45 kb counterclockwise of ilv. The pattern of R.EcoRI cleavage sites in the het region is identical with the pattern obtained by Marsh and Worcel (1977) who analyzed DNA labeled preferentially in the region of the DNA replication origin (oriC). We suggest that oriC is identical with the het site and that it can be allocated to a position 32 kb counterclockwise of the ilv operon.
Mol Gen Genet 1977 Dec 14
PMID:Origin of replication, oriC, of the Escherichia coli chromosome: mapping of genes relative to R.EcoRI cleavage sites in the oriC region. 34 4

The EcoRI digestion products of phage T4 DNA have been examined using a phage DNA transformation assay. A 2.6 X 10(6) Dalton fragment was found to contain the rII genes. This fragment was purified and then treated with HindIII endonuclease. The cleavage products were ligated to the vector plasmid pBR313 and viable recombinant plasmids recovered. A genetic assay was employed to demonstrate that the recombinants contained T4 DNA and to localize on the phage genetic map the EcoRI and HindIII sites cleaved during the construction of the plasmids. Preliminary characterization suggests that a fragment covering the beginning of the rIIA gene possibly contains a promotor which is active in uninfected cells.
Mol Gen Genet 1978 Feb 27
PMID:Construction and properties of recombinant plasmids containing the rII genes of bacteriophage T4. 34

The DNA of an E. coli K12 strain harboring ten wildtype Mu prophages was restricted with endonuclease EcoRI, and the fragments ligated into the plasmid vector pMB9. Upon transformation of a strain carrying a heat inducible (Mu cts62) prophage, one temperature-resistant transformant was isolated. This transformant strain harbors the hybrid plasmid pKN001, containing the EcoRI.C fragment of Mu DNA as shown by restriction and heteroduplex analysis. Stable transformants of pKN001 are immune to superinfection with phage Mu. Transformation of Mu sensitive bacteria with pKN001 results in killing of the recipients (10(-4) surviving bacteria). The killing function is not expressed upon transformation of Mu-immune (lysogenic) bacteria.
Mol Gen Genet 1978 Mar 20
PMID:Cloning of a restriction fragment of phage mu DNA coding for early functions. 34 45

Specialized transducing phages lambda asn harboring chromosomal DNA and genetic markers on either side of the asn gene were isolated. Phages carrying chromosomal DNA counterclockwise of the asn gene can upon infection establish themselves as self-replicating plasmids in asn, recA hosts lysogenic for lambda. It is concluded that this bypassing of normal lambda immunity is due to the presence of the chromosomal replication origin, oriC, in this class of phages. Genetic analysis and the determination of restriction endonuclease cleavage patterns of the different lambda asn lead to the allocation of oriC within 1.5 megadaltons of the asn gene towards the uncA, uncB genes at 82 min on the genetic map of E. coli. The clockwise order of genes on the chromosomes is found to be: bglB, (pst, glmS), (uncA, uncB), oriC, asn, trkD, rbs, rrnC, ilv.
Mol Gen Genet 1978 Apr 17
PMID:Origin of replication, oriC, or the Escherichia coli chromosome on specialized transducing phages lambda asn. 35 92


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