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Showing 1 to 20 of 111 for “"topoisomerase"”.
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The role of topoisomerase II in amsacrine resistance
… including acridines, have been shown to induce topoisomerase II-associated DNA breaks both in cultured mammalian cells and in vitro in the presence of purified mammalian DNA topoisomerase II. However, mechanisms linking these protein-associated DNA breaks with drug cytotoxicity are poorly …
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Mechanistic Characterization of the Mitochondrial Type I DNA Topoisomerase and a Study of Genes Containing Type I DNA Topoisomerase-Related Domains
<p>The mitochondrial type I DNA topoisomerase (mt-topo I) serves an important function in the mitochondrion by relaxing mtDNA supercoils to allow for replication of the mitochondrial genome as well as for gene expression. The mt-topo I's role in essential processes, such as replication and …
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Enzyme Architecture and Flexibility Affect DNA Topoisomerase I Function
<p>DNA topoisomerase I (Top1) is a highly conserved enzyme composed of four domains: a positively charged N-terminus; a DNA binding/core domain that circumscribes duplex DNA; a non-conserved linker domain; and a C-terminal/catalytic domain. Top1 catalyzes changes in DNA topology by transient …
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Investigating the mitotic roles of Topoisomerase 2 Alpha and Topoisomerase 2 Beta-Binding Protein 1 in the maintenance of chromosome structure and genome stability
Type II Topoisomerases are essential, evolutionarily conserved proteins, important throughout the cell cycle. They act by generating a transient double-stranded DNA break in one molecule and manoeuvring a second DNA segment through the resultant gap. This ability to catenate and decatenate DNA …
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CDC45 Function Alters Cell Sensitivity to DNA Topoisomerase I Poisons
<p>Eukaryotic DNA topoisomerase I (Top1) is a highly conserved enzyme that functions to manage the torsional strain of DNA during cellular processes such as transcription, replication, chromatid condensation and recombination. The enzyme binds duplex DNA and through a series of strand cleavage and …
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Genome Instability Associated with DNA Topoisomerase Activity during Gene Transcription
Las lesiones que se producen en el ADN suponen un desafío continuo para la integridad genómica, siendo las roturas de doble cadena del ADN (DSBs) la lesión más citotóxica para la célula. Numerosos estudios han mostrado recientemente que una fuente fisiológica de DSBs es la actividad de las …
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Aktivitätsregulierung der humanen DNS-Topoisomerase I durch den RNS-Spleißfaktor PSF/p54nrb
Experimentelle Stimulierung der humanen DNS-Topoisomerase I durch den Spleißfaktor PSF/p54nrb. Hierbei wurde aus A431-Zellextrakten ein Trimer aus Topoisomerase I und zwei weiteren Proteinen koisoliert. Nach Identifizierung der zwei weiteren Proteine als Spleißfaktor PSF und dessen kleinerem …
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Aktive DNS-Topoisomerase II Alpha ist eine Komponente des salzresistenten zentrosomalen Strukturgerüstes
… wir, daß der monoklonale, für die DNA-topoisomerase IIalpha spezifische Antikörper Ki-S1 nicht nur die Kerne menschlicher A431-Zellen, sondern auch extranucleäre Strukturen färbt (Meyer et. al., 1997, J. Cell. Biol. 136, 775). Diese Strukturen waren wahrscheinlich Zentrosomen. In dieser …
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Stabilization of Topoisomerase 2 Mutants Initiates the Formation of Duplications in DNA
<p>Topoisomerase 2 (Top2) is an enzyme that helps maintain genome integrity by resolving topological structures that arise during cellular processes such as replication and transcription. To resolve these structures, a Top2 dimer creates a transient double-strand break (DSB) in the DNA. Each …
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Investigation of anthracycline based topoisomerase II inhibitors in triple negative breast cancer
… for treatment. Mitoxantrone (MTX), a topoisomerase II inhibitor belonging to the anthracenedione class, is used in BCa therapy. This thesis investigates the potential and mechanism of action of the MTX analogue KP71 and two metal organic frameworks (MOFs), UiO-66 and UiO-66-NH2, loaded …
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The physiological role of the two isoforms of DNA topoisomerase II in human cells
Unique functions of DNA topoisomerase IIalpha and IIbeta have been suggested. A human cell line which carries a homozygeous mutation of the nuclear localization sequence of the topoisomerase IIalpha gene expresses the isoform outside the nucleus at the onset of mitosis. At mitosis topoisomerase …
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Investigation of the Substrate Recognition Characteristics and Kinetics of Mammalian Mitochondrial DNA Topoisomerase I
<p>Topoisomerases are DNA-modifying enzymes found in prokaryotes, eukaryotes, viruses and organelles such as chloroplast and mitochondria. Information about these enzymes in eukaryotic systems is mostly limited to nuclear enzymes, although our laboratory has been characterizing the biochemical and …
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Role of topoisomerase I in the stability of the ribosomal DNA of Saccharomyces cerevisiae
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 1998.
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Toxicidade genética das antraciclinas : associação entre estrutura química e ação inibitória sobre a topoisomerase II
… de compostos está relacionada à inibição da topoisomerase II (topo II) – uma enzima que atua no relaxamento da supertorção da dupla hélice de DNA, através da quebra e posterior religação de suas fitas - as diferenças observadas podem ser atribuídas ao mecanismo envolvido neste bloqueio …
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Specific Binding Affinity of the Non-Catalytic Domain of Eukaryotic Like Type IB Topoisomerase of vaccinia Virus
<p>Topoisomerases are ubiquitous proteins that alter supercoiling in double stranded DNA (dsDNA) during transcription and replication and. <em>vaccinia</em> and the closely related poxvirus <em>variola</em> virus, at 314 amino acids in length, encode the smallest of the type I …
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Age-Associated Hepatic Drug Transporter Expression and Its Implications for Pediatric Pharmacotherapyflexibility affect DNA topoisomerase I function
<p>Members of the ATP-binding cassette (ABC) family of drug transporter proteins translocate various endogenous and exogenous substrates across intra- and extracellular membranes. Two specific ABC transporters, the multidrug resistance 1/P-glycoprotein (MDR1/P-gp) and the multidrug resistance …
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Heavy metal toxicity in human lung fibroblasts and inhibition of human topoisomerase-I as a potential mechanism
… of heavy metals inside the body. The enzyme Topoisomerase-I acts on the DNA topological stability and previous works have shown inhibitory effects on the enzyme, can affect DNA sustainability. In this project, the toxicity of cadmium, lead, copper and zinc on human lung fibroblasts at …
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Studies on Type I and Type II DNA Topoisomerases From Mammalian Mitochondria
<p>Mammalian mitochondria contain a unique DNA topoisomerase I with characteristics of both nuclear and bacterial type I DNA topoisomerases. This enzyme, purified from bovine liver, requires cations as cofactors and possesses optimal activity at pH 7.0, 37°C and either 150 mM K+ or Na+ ions. …
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