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 18 of 18 for “"Xenopus egg"”.
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Disruption of UHRF1 expression in chicken DT40 cells
… nuclear significantly blocked DNA replication in Xenopus egg extracts. However, the mechanism underlying the role of UHRF1 in DNA replication remains unclear. Considering the effects of UHRF1 depletion on DNA replication is independent of cell cycle checkpoints and transcription events in Xenopus …
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Investigating the Mechanism of Geminin Inactivation
… molecular mechanism of geminin inactivation in Xenopus egg extracts. Experiments undertaken during this project have demonstrated that geminin is both stable and inactive in Xenopus egg extracts. In addition some factors essential for the inactivation of geminin have been identified. The …
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Linker Histone Medicated Regulation of Mitotic Chromosome Compaction and Individualization
… condensins and topo II to mitotic chromatin in Xenopus egg extracts. Using an in vitro reconstitution system, I showed that H1.8 inhibits binding of purified condensins and topo II to nucleosome arrays. I also showed that condensin binding to nucleosome arrays is sensitive to magnesium dependent …
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Characterization of a Novel Chromatin-Induced Mechanism that Couples Microtubule Disassembly and Nuclear Re-Formation
… the end of mitosis is poorly understood. Using Xenopus egg extracts, we endeavored to identify uncharacterized proteins that bind to purified mitotic chromosomes. In doing so we discovered Vespera, a protein which is functionally antagonistic to the CPC. We show that Vespera promotes microtubule …
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Molecular Mechanisms of Mitotic Spindle Assembly and Accurate Chromosome Segregation
… a novel mechanism of mitotic spindle assembly in Xenopus egg extracts and mammalian cells. I show that the MRN (Mre11, Rad50, and Nbs1) complex is required for metaphase chromosome alignment. Consistent with the result of my colleague using Xenopus egg extracts, disruption of MRN function by …
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Xenopus DPPA2 is a Direct Inhibitor of Microtubule Polymerization Required for Nuclear Assembly
… remain poorly understood. Here we use cell-free Xenopus egg extracts to investigate the contribution of the DNA-binding protein Dppa2 to nuclear assembly. In Dppa2-depleted extracts, nuclei are small and deformed, assemble incomplete nuclear envelopes and fail DNA replication. We show that Dppa2 …
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Control of Chromosome Segregation by the Aurora B Complex
… for chromatin-dependent spindle formation in Xenopus egg extracts. The failure of microtubule stabilization caused by depletion of the chromosomal passenger complex is rescued by codepletion of the microtubule-depolymerizing kinesin MCAK, whose activity is negatively regulated by Aurora B. We …
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Mechanisms and Regulation of Organelle Transport in Xenopus Melanophores
… issues by studying pigment granule motility in Xenopus melanophores. These dermal cells are able to cyclically transport pigment granules, termed melanosomes, either to aggregate to the cell center or disperse throughout the cell in response to hormonal stimulus to effect color changes in the …
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Protein Phosphatase 1 at the Kinetochore Regulates Chromosome Segregation
… Using the biochemical tools available in the Xenopus egg extract system, I show here that PP1 binds to the protein KNL1 (Spc105, Blinkin, CASC5) through an evolutionarily conserved RVxF motif. KNL1 is a member of the KMN network that forms the microtubule binding interface at the kinetochore. …
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The Influence of DNA Methylation on Both H2A.Z Nucleosome Dynamics and the Zinc Finger and Homeoboxes Transcription Factor Family
… of crude physiological cytoplasmic extract from Xenopus laevis eggs coupled with sperm nuclei, we confirm that the H2A.Z and DNA methylation antagonism is conserved in Xenopus laevis. We further find that the degree of this H2A.Z and DNA methylation antagonism increases, and that the amount of …
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Identification and Characterization of Hells-CDCA7, a Nucleosome Remodeling Complex Required for Mitotic Chromosome Structure
… mass spectrometry on chromatin isolated from Xenopus egg extracts. By comparing interphase and M phase, I reveal how the chromatin proteome is affected by the cell cycle. I find that although topoisomerase II associates with chromatin throughout the cell cycle, its catalytic activity is …
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Regulation of Chromosome Segregation by the Chromosomal Passenger Complex
… the regulation of chromosome segregation, using Xenopus egg extracts. The CPC contains the kinase Aurora B, which is well known for its phosphorylation of serine 10 on histone H3 (H3S10). While this phosphorylation is a hallmark of M-phase, its functional significance is enigmatic. In the first …
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The Role of the Protein MTBP in DNA Replication
… the role of MTBP in DNA replication using the Xenopus egg extract cell-free system. I found that MTBP and Treslin co-immunoprecipitate in metaphase and interphase extracts, suggesting that they form a complex throughout the cell cycle. MTBP, like Treslin, is recruited onto chromatin before the …
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The role of Cdc7 and cyclin-dependent kinases in DNA replication and S phase
… <br/><br/>Using the cell-free system of Xenopus egg extracts, a small molecule inhibitor of Cdc7, PHA-767491, was characterised. PHA-767491 was then used to demonstrate that Cdc7 executes its activity early in S phase before the Cdk-dependent step. Cdc7 is not rate limiting for the …
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Experimental evidnece for hysteresis in the cell cycles of Xenopus Laevis egg extracts
… of M-phase promoting factor (MPF) activity in Xenopus laevis eggs and egg extracts. Although this model was in agreement with existing and subsequent experimental data, fundamental predictions that the cell cycle is driven by a hysteresis loop have never been validated experimentally. The …
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Regulated Recruitment of the Chromosomal Passenger Complex to Chromatin and Microtubules Promotes Accurate Cell Division
… the INCENP SAH domain supports the SAC. Using Xenopus egg extract and human tissue culture cells, we show that the kinase domain of Haspin is autoinhibited during interphase by a previously unidentified Haspin basic inhibitory segment (HBIS) downstream of the kinase domain. Upon entry into …
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Molecular mechanisms of Sorting nexin-9 in membrane triggered actin polymerisation
… of SNX9 membrane binding domains in Xenopus egg extract-based actin polymerisation assays demonstrates that PX-BAR domains are es- sential for two distinct actin architectures. To visualise this, I used Cryogenic Electron Tomography (cryo-ET) to study the actin nucleating from 10% …
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Regulation of Anaphase Promoting Complex/Cyclosome to Control M Phase Exit
… </p> <p>Prior to fertilization, vertebrate eggs are arrested in metaphase of meiosis II by CSF activity, a key component of which is the APC/C inhibitor Emi2. Although the roles and regulation of Emi2 in maintaining CSF arrest have been extensively studied, its function during the oocyte …