Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of eight different polA alleles on the replication of six different non-transferring enterobacterial plasmids have been tested. Using phage P1CM transduction, different allelic polA mutations were introduced into E. coli K12 strains carrying one of several antibiotic resistance plasmids. Plasmid stability in the transductants was examined by testing clones for drug resistance after growth under various conditions. From the results, the R factors may be divided into three different classes. One plasmid is only affected by PolA conditions which inhibit host cell growth, 3 plasmids (from the same compatibility group) are unstable under conditions in which the cells are severely deficient in DNA polymerase I and two other plasmids (compatible with each other and with the other 4) are immediately lost from such transductants and are unstable in a number of others. Furthermore, the plasmids which are most dependent on DNA polymerase I have been shown to replicate in the presence of chloramphenicol and therefore typigy a class of plasmids which includes bacteriocinogenic factors such as ColE1 and CloDF13, resistance determinant RSF1030 and the E. coli 15 minicircular plasmid.
Mol Gen Genet 1976 Feb 02
PMID:Effects of different alleles of the E. coli K12 pol A gene on the replication of non-transferring plasmids. 76 63

Populations of the E. coli B mixedly infected with the whole chromosome of the amber mutant in respect to two genes under consideration and with a chromosome fragment of the phage T4 "wild" type are examined. The fragment length with which both of the amber mutants defect functions are compensated is determined to measure physical distance between the genes. Distances so obtained do not depend on recombination frequencies and are shown to be additive and "complementary". The latter property means that the sum of the smaller and "complementary", larger distances between two genes on the circular map equals the complete linkage group quantity. Moreover, a "complementary", larger distance is measured directly and independently on a smaller one, whereas current mapping technique fail to do so. The method enables to evaluate a size of rather long phage T4 gene region, for example gene 43, i. e. the structural DNA polymerase gene. Phage T4 genes 34 and 35 are shown to have a common start region for transcription and translation, i. e. they belong to the same operon. In consequences the circular map of physical distances between phage T4 genes is constructed.
Mol Biol (Mosk)
PMID:[Phage T4 partial diploids obtained with the method of DNA interrupted injection. II. The mapping technique based on the physical size measurement of the diploid region]. 76 75

The polC (= dnaE) temperature-sensitive DNA polymerase III mutation from Escherichia coli BT1026 has been transduced into E. coli WP2 (to give CM731) and WP2 uvr A (to give CM741). In excision-deficient CM741 UV-induced Trp+ mutations progressively lost their photoreversibility during post-irradiation incubation at 34 degrees. Immediately after transfer to 43 degrees, however, there was no further loss of reversibility although post-replication strand joining still occurred and uptake of 3H-thymidine into DNA continued for 20 to 30 min. In excision-proficient CM731, UV lesions capable of leading to Strr mutations disappeared during post-irradiation incubation at restrictive temperature and there was no increase in the number remaining after exposure to photoreversing light. In contrast, at permissive temperature, premutational lesions were not lost and became progressively converted into non-photoreverisble mutations. It is concluded that a function of the polC gene is necessary for error-prone repair to occur and that this function is defective at 43 degrees in the enzyme specified by the polC allele from BT1026. This function seems not to be essential for most post-replication or excision repair or for normal DNA replication and may be particularly involved in the insertion of incorrect bases during error-prone repair.
Mol Gen Genet 1976 Feb 27
PMID:Mutagenic DNA repair in Escherichia coli. III. Requirement for a function of DNA polymerase III in ultraviolet-light mutagenesis. 77 14

An E. coli lysate after being gently washed to remove soluble components, supports replicative DNA synthesis, if soluble proteins and the deoxyribonucleotide triphosphates are added. This DNA synthesis is dependent on ATP and on the presence of the gene products of the dnaB, dnaG, and polC (DNA polymerase III) genes. It continues at the replication forks preformed in vivo and "Okazaki fragments" are intermediate products of the reaction. Two different methods were used to prepare the washed DNA containing fraction. The one method involves washing of a cell lysate situated on a dialysis membrane. The other method involves DNAase treatment of a lysate and sedimentation of the degraded DNA through a glycerol gradient. Both washed preparation contain not only the DNA and the replication forks but also functional amounts of DNA polymerase III and of the dnaB gene product. Other factors, that are essential for replicative DNA synthesis, including the dnaG gene product, are washed out of the DNA containing preparations and the system is reconstituted by readdition of the soluble proteins.
Mol Gen Genet 1976 May 07
PMID:Replication of E. coli duplex DNA in vitro. The separation of the DNA containing fractions of a lysate from the soluble enzymes and their complementation properties. 77 84

Sakakibara and Tomizawa (1974a) have described a soluble in vitro system that can carry the semi-conservative replication of the Co1 E1 plasmid. However, the usefulness of this system is restricted by its rapid inactivation during storage. This paper describes a stable soluble system prepared by freeze-thaw lysis of chloramphenicol-treated E. coli cells which replicates added Co1 E1 and C1o DF13 DNA. It differs from the system employed by Sakakibara and Tomizawa in two important points: (1) Its replicative capacity for Co1 E1 DNA is by an order of magnitude higher and (2) it can be stored in liquid nitrogen for several months without loss of activity Plasmid replication in vitro is dependent of DNA polymerase I and requires de novo RNA synthesis. It is completely inhibited by rifampicin, oxolinic acid, and novobiocin. The DNA synthesized during a 60 min incubation at 30 degrees C consists mostly of monomeric supercoils. If Co1 E1 DNA is used as template, a minor portion of the label is also found in closed dimeric catenanes. Density labelling experiments indicate that plasmid DNA synthesis occurs by a semi-conservative replication process.
Mol Gen Genet 1976 Jun 15
PMID:Replication of small plasmids in extracts of Escherichia coli. 78 16

Three mutations of the polA cistron, the structural gene for DNA polymerase I of E. coli, have been ordered by three factor transductional crosses. The three mutant polymerase species have altered properties which may be ascribed to defects located in different portions of the polypeptide chain. Our data indicate that the amino terminal end is encoded by the end of the polA cistron nearer to metE and that transcription and translation proceed clockwise on the E. coli circular map towards the rha locus.
Mol Gen Genet 1976 Sep 23
PMID:Mapping of the polA locus of Escherichia coli K12: orientation in the amino- and carboxy-termini of the cistron. 78 65

Replication of the non-conjugative plasmids ColE1, ColE2 and Col3 has been examined in a number of DNA polymerase I-deficient strains, two of which contain the amber mutation polA1 along with either of two temperature-sensitive supF amber suppressors. These latter two strains produce reduced amounts of DNA polymerase I polymerizing activity of similar, if not identical properties to that produced by polA+ strains. Our results indicate that the ColE plasmids require different amounts of DNA polymerase I for stable plasmid maintenance. Moreover whereas all three plasmids are maintained in a strain defective in the 5' leads to 3' exonuclease activity of DNA polymerase I, ColE2 and ColE3 are not stably maintained between 30 degrees and 43 degrees in a number of DNA POLYMERASE I-deficient strains that are temperature-sensitive for ColE1 replication.
Mol Gen Genet 1976 Sep 23
PMID:ColE plasmid replication in DNA polymerase I-deficient strains of Escherichia coli. 78 67

The effect of different types of buildup of the cohesive ends on the ability of phage lambda DNA molecules to form cyclic and concatemeric forms and on their biological activity in two infection systems--transfection and transformation--was investigated with the aid of E. coli DNA polymerase. A change in the structure of the cohesive ends leads to a change in the aggregating ability of the phage lambda DNA molecules up to an almost complete loss of this ability. The infectious activity of phage lambda DNA in the transfection system is very sensitive to a change in structure of the cohesive ends. It is suggested that phage development in this system requires retention of the ability to form cyclic or concatemeric forms. In the transformation system molecules with any of the modifications of the cohesive ends differ insignificantly from one another in infectivity. This can be attributed to the important role of recombination processes, which can save the defective DNA markers. DNAs with completely normal cohesive ends behave in the transformation system like phage lambda DNA fragments from internal parts of the molecule. No polarity of the cohesive ends is found when phage lambda develops in systems with or without a helper phage.
Mol Biol (Mosk)
PMID:Effect of change in structure of cohesive ends on aggregating ability and biological activity of bacteriophage lambda DNA. 79 59

The enzyme which catalyses template independent synthesis of polydeoxynucleotides from deoxynucleoside diphosphates was separated from E. coli DNA polymerase I by DEAE-cellulose chromatography followed by ultrafiltration through the M-50 Amicon filter. The ultrafiltration data indicate that the molecular weight of the enzyme is not higher than 50,000. The enzyme is not able to use deoxynucleoside triphosphates, ribonucleoside di- or triphosphates as substrates for the polymerization. The reaction of template independent polymerization proceeds with a lag period varying from 2 to 20 hours (for different preparations of enzyme) and is activated by Mg2+ (the optimal concentration 1-2 . 10(-3) M). The pH optimum of the reaction is at 8.5. The optimal concentration of deoxyribonucleoside diphosphates is 10(-3) M, and its increase strongly inhibits polymerization. The enzyme was supposed to be called deoxynucleoside diphosphate: olygonucleotide deoxynucleotidyltransferase (catalyzing polymerization without template). The presence of the enzyme in the preparations of E. coli DNA-polymerase I can explain the ability of the latter to catalyze the untemplated synthesis of poly dG : poly dC.
Mol Biol (Mosk)
PMID:[Separation of the enzyme catalyzing polymerization of deoxyribonucleoside diphosphates from preparations of E. coli DNA-polymerase I]. 80 82

polC, the gene specifying the structure of the replication-specific DNA polymerase III of B. subtilis, was mapped by exploiting azp-12, a mutation conferring resistance to azopyrimidine which determines a mutant, azopyrimidine-resistant enzyme. azp-12 was located in the area of the pyrA locus and is between spcB1 and recA1. azp-12 was linked by transformation to four other mutations which influence the in vitro behaviour of DNA polymerase III--polC25, polC26, mut-1(ts), and DNAF133; the close linkage of these five mutations strongly suggests that they are alleles of the same gene.
Mol Gen Genet 1976 Mar 30
PMID:Mapping of the gene specifying DNA polymerase III of Bacillus subtilis. 81 5


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