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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The isolation of a new type of gamma transducing phage carrying the bipolar argECBH operon of E. coli K12 is described. The argECBH segment is inserted in the phage in a direction which is opposite from that of previously isolated argECBH-carrying phages. A colE1 argECBH plasmid has been constructed. DNA fragments resulting from digestion of these genetic elements with Eco RI and Hind III restriction enzymes have been characterized by agarose gel electrophoresis and electron microscopy, including hetero-duplex analysis. Two fragments are of special significance for studies on the control of arginine synthesis, one of length 9.8 kilobases carrying the whole argECBH region, the other of length 2 kilobases carrying most or all of the control region between argE and argC.
Mol Gen Genet 1977 Mar 07
PMID:Studies on the bipolar argECBH operon of E. coli: characterization of restriction endonuclease fragments obtained from gammadargECBH transducing phages and a ColE1 argECBH plasmid. 32 64

Exonuclease activity in an Escherichia coli K12 mutant S296 is less than 1% of that in the wild type strain (Nikolaev et al., 1976). Another mutant N464 has thermolabile ribonuclease II (Castles and Singer, 1968; Kuwano et al., 1969). Genetic analysis of these mutants by Hfr conjugation and P1 transduction indicates that the structural gene (rnb) for ribonuclease II is located near the pyrF gene (28 min on the E. coli genetic map of Bachmann, Low and Taylor (1976)), and the most probable gene order is tyrT-trp-pyrF-rnb.
Mol Gen Genet 1977 May 20
PMID:Genetic analysis of mutations affecting ribonuclease II in Escherichia coli. 32 98

The induction of prophage lambda by ultraviolet light has been measured in E. coli K12 lysogenic cells deficient in DNA polymerase I. The efficiency of the induction process was greater in polA1 polC(dnaE) double mutants incubated at the temperature that blocks DNA replication than in polA+ polC single mutants. Similarly, the polA1 mutation sensitized tif-promoted lysogenic induction in a polA1 tif strain at 42 degrees. In strains bearing the polA12 mutation, which growth normally at 30 degrees, induction of the prophage occurred after the shift to 42 degrees. It is concluded that dissapearance of the DNA polymerase I activity leads to changes in DNA replication that are able, per se, trigger the prophage induction process.
Mol Gen Genet 1977 Sep 09
PMID:Prophage induction in Escherichia coli K12 cells deficient in DNA polymerase I. 33 8

Toluene treated cells have been used to study the processes of DNA synthesis and DNA degradation in ultra-violet irradiated Escherichia coli K12. Synthesis and degradation are both shown to occur extensively if polynucleotide ligase is inhibited, and to occur to a much lesser extent if ligase activity is optimal. Extensive UV-induced DNA synthesis in toluene-treated cells requires ATP for the initial incision step, and DNA polymerase I. Extensive degradation also depends on the early ATP-dependent incision step, and the subsequent degradation shows a partial requirement for ATP. Curtailment of degradation by ligase requires DNA polymerase activity, but is not dependent upon DNA polymerase I. Apparently this process can be carried out with equal facility by either DNA polymerase II or polymerase III. These observations suggest that extensive DNA polymerase I-dependent repair synthesis and extensive DNA degradation are facets of two divergent pathways of excision repair, both of which depend upon the early uvrABC determined ATP-dependent incision step.
Mol Gen Genet 1977 Nov 29
PMID:DNA synthesis and degradation in UV-irradiated toluene treated cells of E. coli K12: the role of polynucleotide ligase. 34 Sep 17

We have used two different methods to study the rates of RNA polymerase subunit synthesis in haploid Escherichia coli K12, and a KLF10 rPOB, C+ merodiploid derivative, when grown in glucose-minimal medium at 37 degrees C. Our results indicate that the haploid strain produces beta, beta', alpha and sigma in the molar ratios 1.01:0.99: less than or equal to 2.90:0.26; and that all these subunits are reasonably stable during subsequent growth. The merodiploid produces alpha at the same rate as the haploid, beta and beta' at a 42% higher rate, and sigma at twice the rate. Some 40% of the newly synthesised beta and beta' is degraded within one hour; the residuum is as stable as in the haploid. Alpha is stable throughout. By contrast, sigma is subject to a marked and continuous turnover in the merodiploid. These results are discussed in terms of gene dosage and regulatory effects.
Mol Gen Genet 1978 Feb 07
PMID:Over-synthesis and instability of sigma protein in a merodiploid strain of Escherichia coli. 34 86

Recent evidence suggests that the escape synthesis of gal operon following derepression of the prophage lambda in Escherichia coli K12 involves transcription originating at the lambda promoter (PL) to extend through gal under the conditions in which lambda DNA replication is prevented. Whether the observed expression of gal is due to transcription initiating at PL or at the bacterial promoter for gal (Pgal) was examined in the case of lambda DNA replication being normal. The experiments are based on that two types of transcription are distinguished from each other by the following properties: 1. Pgal-promoted transcription is inhibited by chloramphenicol, while PL-promoted transcription is not. 2. PL-promoted transcription suppresses the polar effect caused by nonsense mutation in a bacterial gene, while Pgal-promoted transcription does not do so. -he results have suggested that gal escape synthesis in lambda-induced lysogen results from transcription which initiates not only at PL but also at Pgal. The Pgal-promoted transcription may be a consequence, direct or indirect, of the concomitant replication of gal DNA.
Mol Gen Genet 1978 Feb 16
PMID:Regional replication of the bacterial chromosome induced by derepression of prophage lambda. III. Role of the replication in escape synthesis of gal operon. 34 92

In the paper a convenient procedure for the isolation of specific Eco RI-fragments of E. coli genome and their amplification on Km-resistance plasmid vector CKdelta11 is described. Plasmid CKdelta11 contains Col E1 replicon and has only one Eco RI site. The hybrid molecules were constructed in vitro using Eco RI-digestion followed by ligation. Then appropriated E. coli strain (polyauxotrophic strain E. coli K12 AB 2463) was transformed with ligated DNA mixture and hybrid plasmids, containing arg, leu, his and thr chromosomal markers were selected by molecular cloning and isolated from the obtained E. coli clones. The hybrid plasmids have two Eco RI sites and consist of one Eco RI-fragment of initial plasmid CKdelta11 and one Eco RI-fragment of El coli DNA. The method described allows to isolate and amplify on hybrid plasmids DNA fragments, containing any selectable genes or genes adjacent to the selectable ones.
Mol Biol (Mosk)
PMID:[Construction and molecular cloning of hybrid plasmids containing specific fragments of Escherichia coli DNA]. 34 2

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

A conditional lethal mutator, dnaQ49, was found in Escherichia coli K12. The dnaQ49 mutation caused stimulation of rifampicin-, nalidixic acid- and streptomycin-resistant mutation frequencies 100 to 2000 fold at 30 degrees C and the frequencies were further increased 50 to 100 fold at 35 degrees C or higher temperatures. Cells carrying dnaQ49 were unable to grow in salt-free L-broth at 44.5 degrees C, and DNA synthesis but not protein synthesis of the cells was suppressed under the restrictive conditions. The dnaQ gene was located at about 5 min on the E. coli linkage map and the order of the genes residing in this region was determined to be ton A-dnaE-metD-dnaQ-pro A.
Mol Gen Genet 1978 Jul 25
PMID:A new conditional lethal mutator (dnaQ49) in Escherichia coli K12. 35 54

A temperature-sensitive mutation in the dnaJ gene of Escherichia coli K12 is described which affects replication of the bacterial DNA. The gene is located adjacent to the dnaK gene described previously (Saito and Uchida, 1977). The physical and functional organization of the dnaJ-dnaK region was studied in detail by analyzing the heteroduplexes and functions of various deletion mutants of lambdadnaJdnaK, a transducing phage carrying both of the dna genes. The sizes of dnaJ and dnaK cistrons were estimated to be at most 1.2 +/- 0.5 and 2.1 +/- 0.4 kilobases, respectively. In vivo expression of the dnaJ function by various deletion phages indicated that the dnaK and dnaJ cistrons were transcribed from a promoter located at the head of the dnaK cistron, dnaJ being downstream to dnaK. Presence of a weak promoter which reads only the dnaJ cistron was also suggested. A simple method for isolating independent deletion mutants of phage lambda was described.
Mol Gen Genet 1978 Aug 04
PMID:Organization and expression of the dnaJ and dnaK genes of Escherichia coli K12. 36 36


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