Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 33 for “"supercoiling"”.
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DNA supercoiling with a twist
… DNA torsion. Topoisomerases regulate DNA supercoiling, which has been argued to provide a coherent explanation for the main modes of transcriptional control - stringent control, growth-rate control and growth-phase control during the normal cell growth. In this study, we have shown that …
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The effect of supercoiling on small molecule-DNA interactions
Thesis (Ph. D.)--Massachusetts Institute of Technology, Division of Toxicology, 1998.
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Analysis of the structural changes caused by positive DNA supercoiling
… of supercoils in the DNA, with positive supercoiling (overwinding) generated ahead of the enzyme, and negative supercoiling (underwinding) in its wake. While the structural and physiological consequences of negative supercoiling have been well studied, technical challenges have prevented …
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Genome-Wide and Multi-Scale Mapping of DNA Supercoiling in Differentiating Human Stem Cells
… changes in the winding of DNA, known as supercoiling, were shown to impact gene expression and chromosome architecture. Nonetheless, its intrinsic dynamic and multifaceted nature, together with experimental limitations, have hindered the study of the timing and factors orchestrating …
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The role of DNA supercoiling in the coordinated regulation of gene expression in Helicobacter pylori
… characterized yet. Changes in global or local supercoiling of chromosomal DNA are thought to play a role in global gene silencing and gene activation. In Helicobacter pylori, a bacterium with few dedicated transcriptional regulators, the structure of some promoters indicates a dependency on DNA …
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The effect of negative supercoiling on the formation and positioning of nucleosome cores in vitro
The effect of the negative supercoiling of DNA on the formation and positioning of nucleosome cores was investigated in a 1915bp plasmid (pHP2) containing a section of the early H1-H4 histone gene spacer of Psammechinus miliaris, previously shown to position the histone octamer (Retief et al., …
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A role for the Bacillus subtilis Structural Maintenance of Chromosomes (BsSMC) protein in chromosome organization and compaction
… the chromosome. Increasing the amount of supercoiling of DNA is a means to compact the chromosome. This thesis describes a role for BsSMC in supercoiling. I determined that BsSMC can alter the DNA topology of plasmids in vivo. There is also genetic evidence that BsSMC is involved in …
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DNA topology and Pol II CTD phosphorylation as stepwise regulators of chromatin architecture in differentiating human stem cells
… landscape for Pol II and its regulators, through supercoiling, non-B DNA formation, or altered loop anchors. The second is that Pol II activity is tuned by differentiation-specific phosphorylation of its C-terminal domain (CTD), which modulates interactions with co-transcriptional regulators and …
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EFFECT OF MISMATCHED BASE PAIRS ON DNA PLECTONEMES
… Magnetic-tweezers-based studies of DNA supercoiling, performed at high salt concentrations, have shown that in DNA harboring a single mismatch, the plectoneme will always localize at the mismatch. Theoretical studies have predicted that under physiological salt concentrations, plectoneme …
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Specific Binding Affinity of the Non-Catalytic Domain of Eukaryotic Like Type IB Topoisomerase of vaccinia Virus
… 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 topoisomerases(TopIB). …
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Staphylococcus aureus DNA gyrase: mechanism and drug targeting
… (KGlu) salt-dependent and salt-specific supercoiling. This KGlu dependency in S. aureus, but not E. coli gyrase, was partially attributed to the differences in the Cterminal domain of the gyrase A-subunit (GyrA). The discovery of the two novel monovalent alkali metal cation (M+) binding …
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Studies On The In Vitro Transposition Of Bacteriophage Mu Dna
… with a mini-Mu plasmid with in vivo level of supercoiling ({dollar}sigma{dollar} = {dollar}-{dollar}0.025) was dependent on an additional E. coli protein factor which we named supercoiling relief factor (SRF). This protein was shown to be integration host factor (IHF). Low levels of IHF also …
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Deformability and Dynamics in Linear and Looped/Supercoiled DNA with Implications for Damage Sensing
… damage recognition, and unveiled how looping/supercoiling alters DNA mechanics and protein binding. We studied two repair proteins: 1) Rad4 (yeast ortholog of human XPC), which recognizes DNA lesions from UV-light and other environmental genotoxins and initiates nucleotide excision repair; 2) …
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Röntgenstrahlen induzierte DNA- Doppelstrangbrüche in säugen Zellen in Abhängigkeit vom Zellzyklus.
… der DNA zugeschrieben, welche durch das Supercoiling inklusive DSB-Zerstörung verursacht wurde. Eine bedeutende Zunahme der Schweiflänge, zusammenfallend mit bedeutungslosen Änderungen in der Schweifintensität, wurde nach der Elektrophorese der unbestrahlten Nukleoide notiert. Diese …
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Interactions between nucleoid associated proteins and DNA in the presence of mechanical and chemical forces
… to these same local, cooperative effects. DNA supercoiling occurs when DNA wraps around itself to relieve torsional stress. Both DNA supercoiling and NAPs are present in prokaryotic cells, but the role of NAPs in supercoiling activity is not fully understood. Our model demonstrates that NAPs …
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Computational prediction of coiled-coil interaction structure specificity
… in a parallel or antiparallel orientation supercoiling around a central axis. Coiled coils have been observed in a wide range of protein families, and many studies have focused on their sequence and structural diversity over the past half-century. In particular, the observation that coiled …
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The effects of nutrient limitation and growth rate on the regulation of the multi-drug pump genes acrAB in escherichia coli
… by cyclic AMP, and the possible role of negative supercoiling was discussed.
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Profiling hotspots of DNA breaks and learning-induced gene expression in the mouse brain
… for relieving transcription-associated DNA supercoiling, was implicated as the source of these neuronal activity-induced DSBs, facilitating rapid transcriptional induction of immediate early genes (IEGs). However, the locations of these DSBs in vivo and their relation to brain function was …
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