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

Monomeric pBR322 DNA that had been linearized at its unique SalI site transformed wild-type Escherichia coli with 10(2) to 10(3) times less efficiency than CCC plasmid DNA. Dose-response experiments indicated that a single linear plasmid 'molecule' was sufficient to produce a transformant. Transformation with linearized pBR322 DNA was reduced 10 to 40 fold in recA1 , recBC- or recF- backgrounds. In contrast, transformation with CCC DNA was unaffected by the rec status of the host. Transformation with linear pBR322 DNA was increased 3-fold in a DNA ligase-overproducing ( lop11 ) mutant and decreased to a similar degree by transient inactivation of ligase in a ligts7 mutant. A proportion (ranging from about 9% in the wild-type to 42% in a recBC, lop11 mutant) of the transformants obtained with SalI-linearized pBR322 monomeric DNA contained deleted plasmids. Deletion rates were generally higher in rec- strains. Dephosphorylation of the termini on linear DNA or the creation of blunt-ended pBR322 molecules (by end-filling the SalI 5' protrusions or by cleavage with PvuII) decreased the transformation frequency whilst increasing the deletion rate. Linear pBR322 dimeric DNA gave transformation frequencies in recA+ and recA- strains that were reduced only 3 to 7 fold respectively relative to frequencies obtained with dimeric CCC DNA. Furthermore, in contrast to transformation with linear monomeric DNA, deletions were not observed. We propose that the majority of transformants arise, not by simple intracellular reannealing and ligation of the two cohesive SalI-termini of a linear molecule, but by intramolecular recombination.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Gen Genet 1984
PMID:Recombination-dependent recircularization of linearized pBR322 plasmid DNA following transformation of Escherichia coli. 637 76

A soluble extract of Xenopus laevis ovaries catalyzed ATP-dependent concatenation of linear duplex DNA molecules. DNA ligase and a unique X. laevis DNA binding protein were required for the formation of concatemers. A linear DNA concatenation system was reconstituted using T4 DNA ligase and homogeneous X. laevis DNA binding protein. This system catalyzed intermolecular ligation of DNA molecules into linear concatemers of up to ten or more times monomer length.
J Mol Biol 1984 Jan 05
PMID:DNA binding protein from ovaries of the frog, Xenopus laevis which promotes concatenation of linear DNA. 653 81

Two types of DNA-duplexes containing the repeating fragments of natural promoters have been obtained starting from synthetic oligodeoxyribonucleotides TGCATTATAA, AACTAGTT, AGTTAACT. Deca- and octanucleotides have been synthesized by solid phase method with stepwise or blockwise chain elongation. UV- and CD-spectroscopy has been used to study the physico-chemical properties of the synthetic oligonucleotides. Polycondensation of oligonucleotides induced by water-soluble carbodiimide (chemical ligation) or T4-polynucleotide ligase allowed to synthesize the promoter models. The degree of polymerization varied from 2 to 8 in case of chemical ligation and from 2 to 30 in case of enzymatic ligation. A new chain length regulation technique has been developed by means of addition of a terminator of polycondensation (unphosphorylated oligonucleotide) in the reaction mixture.
Mol Biol (Mosk)
PMID:[DNA-like duplexes containing repetitive sequences. VII. Chemico-enzymatic synthesis of polymers with fragments of natural promotors]. 670 55

Fanconi's anemia, a hereditary autosomal disease with chromosomal instability, elevated incidence of cancer and clinical symptoms is accompanied by a DNA repair deficiency. Fibroblasts from patients with Fanconi's anemia were found to be impaired in the DNA repair of UV damage. Nucleoid decondensation and recondensation after UV irradiation were less efficient in fibroblasts from patients with Fanconi's anemia than in those from a healthy proband. These data confirm our earlier findings that DNA ligase is deficient in Fanconi's anemia.
Mol Gen Genet 1982
PMID:UV-repair is impaired in fibroblasts from patients with Fanconi's anemia. 695 46

A procedure has been developed for the rapid purification of the enzyme T4 DNA ligase. The procedure involves the induction at 42 degrees C of a lambda lysogen containing the gene for T4 DNA ligase (Murray, N.E., Bruce, S.A., and Murray, K. (1979) J. Mol. Biol. 132, 493-504), followed by purification of the ligase activity by phosphocellulose and hydroxylapatite chromatography. This results in the purification of large amounts of ligase with very high specific activity. The enzyme is free of contaminating exo- and endonuclease activities and active in the ligation of DNA fragments possessing cohesive or blunt-end termini.
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PMID:The rapid purification of T4 DNA ligase from a lambda T4 lig lysogen. 698 6

Three biochemically distinct DNA ligase activities have been identified in mammalian cell extracts. We have recently purified DNA ligase II and DNA ligase III to near homogeneity from bovine liver and testis tissue, respectively. Amino acid sequencing studies indicated that these enzymes are encoded by the same gene. In the present study, human and murine cDNA clones encoding DNA ligase III were isolated with probes based on the peptide sequences. The human DNA ligase III cDNA encodes a polypeptide of 862 amino acids, whose sequence is more closely related to those of the DNA ligases encoded by poxviruses than to replicative DNA ligases, such as human DNA ligase I. In vitro transcription and translation of the cDNA produced a catalytically active DNA ligase similar in size and substrate specificity to the purified bovine enzyme. The DNA ligase III gene was localized to human chromosome 17, which eliminated this gene as a candidate for the cancer-prone disease Bloom syndrome that is associated with DNA joining abnormalities. DNA ligase III is ubiquitously expressed at low levels, except in the testes, in which the steady-state levels of DNA ligase III mRNA are at least 10-fold higher than those detected in other tissues and cells. Since DNA ligase I mRNA is also present at high levels in the testes, we examined the expression of the DNA ligase genes during spermatogenesis. DNA ligase I mRNA expression correlated with the contribution of proliferating spermatogonia cells to the testes, in agreement with the previously defined role of this enzyme in DNA replication. In contrast, elevated levels of DNA ligase III mRNA were observed in primary spermatocytes undergoing recombination prior to the first meiotic division. Therefore, we suggest that DNA ligase III seals DNA strand breaks that arise during the process of meiotic recombination in germ cells and as a consequence of DNA damage in somatic cells.
Mol Cell Biol 1995 Oct
PMID:Mammalian DNA ligase III: molecular cloning, chromosomal localization, and expression in spermatocytes undergoing meiotic recombination. 756 92

The aim of this paper was to test the possibility to ligate and hydrolyse DNA sequences containing thiomodified ends and bonds. T4 DNA ligase was shown to ligate DNA fragments regardless of whether it contains phosphorylated or thiophosphorylated 5'-end. But the cleavage of an internally thiomodified phosphodiester bond was found to be totally inhibited when using the non-palindromic restrictase Bbs I. The special properties of this restriction endonuclease should allow the development of an oriented cloning strategy when combined with T4 ligase and a thiophosphorylation of DNA fragments.
Biochem Mol Biol Int 1995 Aug
PMID:The accessibility of thiophosphorylated groups in DNA fragments to the enzymatic activity of ligases and restriction endonuclease Bbs I. 758 Sep 99

Purification of DNA fragments from acrylamide or agarose gels is a commonly used technique in the molecular biology laboratory. This article describes a rapid, efficient, and inexpensive method of purifying DNA fractions from an agarose gel. The purified DNA is suitable for use in a wide range of applications including ligation using DNA ligase. The procedure uses standard high-melting-temperature agarose and normal TBE electrophoresis buffer. In addition, the protocol does not involve the use of highly toxic organic solvents such as phenol.
Mol Biotechnol 1995 Apr
PMID:Purification and cloning of DNA fragments fractionated on agarose gels. 762 Sep 74

Three distinct DNA ligases, I to III, have been found previously in mammalian cells, but a cloned cDNA has been identified only for DNA ligase I, an essential enzyme active in DNA replication. A short peptide sequence conserved close to the C terminus of all known eukaryotic DNA ligases was used to search for additional homologous sequences in human cDNA libraries. Two different incomplete cDNA clones that showed partial homology to the conserved peptide were identified. Full-length cDNAs were obtained and expressed by in vitro transcription and translation. The 103-kDa product of one cDNA clone formed a characteristic complex with the XRCC1 DNA repair protein and was identical with the previously described DNA ligase III. DNA ligase III appears closely related to the smaller DNA ligase II. The 96-kDa in vitro translation product of the second cDNA clone was also shown to be an ATP-dependent DNA ligase. A fourth DNA ligase (DNA ligase IV) has been purified from human cells and shown to be identical to the 96-kDa DNA ligase by unique agreement between mass spectrometry data on tryptic peptides from the purified enzyme and the predicted open reading frame of the cloned cDNA. The amino acid sequences of DNA ligases III and IV share a related active-site motif and several short regions of homology with DNA ligase I, other DNA ligases, and RNA capping enzymes. DNA ligases III and IV are encoded by distinct genes located on human chromosomes 17q11.2-12 and 13q33-34, respectively.
Mol Cell Biol 1995 Jun
PMID:Molecular cloning and expression of human cDNAs encoding a novel DNA ligase IV and DNA ligase III, an enzyme active in DNA repair and recombination. 776 Aug 16

Fishes represent the stem vertebrate condition and have maintained several gene arrangements common to mammalian genomes throughout the 450 Myr of divergence from a common ancestor. One such syntenic arrangement includes the GPI-PEPD enzyme association on Xiphophorus linkage group IV and human chromosome 19. Previously we assigned the Xiphophorus homologue of the human ERCC2 gene to linkage group U5 in tight association with the CKM locus. CKM is also tightly linked to the ERCC2 locus on human chromosome 19, leading to speculation that human chromosome 19 may have arisen by fusion of two ancestral linkage groups which have been maintained in fishes. To investigate this hypothesis further, we isolated and sequenced Xiphophorus fish genomic regions exhibiting considerable sequence similarity to the human DNA ligase 1 amino acid sequence. Comparison of the fish DNA ligase sequence with those of other species suggests several modes of amino acid conservation in this gene. A 2.2-kb restriction fragment containing part of an X. maculatus DNA ligase 1 exon was used in backcross hybrid mapping with 12 enzyme or RFLP loci. Significant linkage was observed between the nucleoside phosphorylase (NP2) and the DNA ligase (LIG1) loci on Xiphophorus linkage group VI. This assignment suggests that the association of four DNA repair-related genes on human chromosome 19 may be the result of chance chromosomal rearrangements.
Mol Biol Evol 1993 Nov
PMID:Cloning and gene map assignment of the Xiphophorus DNA ligase 1 gene. 790 41


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