71 |
Role of the mitotic spindle in the equal segregation of an extrachromosomal element in Saccharomyces cerevisiaeCui, Hong, Ph. D. 10 September 2012 (has links)
The Saccharomyces cerevisiae plasmid, 2 micron circle, resides in the yeast nucleus at a high copy number. It provides no apparent growth advantage to its host, nor imposes any significant growth disadvantage. The plasmid is an excellent paradigm for studying mechanisms utilized in the persistence of a eukaryotic selfish DNA element that is selectively neutral. The plasmid achieves stable propagation and copy number maintenance by combining a partitioning system and an amplification system. The partitioning proteins Rep1p and Rep2p promote the recruitment of the histone H3 variant Cse4p and the yeast cohesin complex to the partitioning locus STB during S phase, leading to the formation of a functional partitioning complex which segregates the plasmid equally during mitosis. The integrity of the mitotic spindle is a pre-requisite for the specific nuclear localization of the plasmid as well as for plasmid association with a subset of the partitioning proteins such as Cse4p and the cohesin complex. The work presented in this thesis reveals, using tools of molecular genetics and cell biology, the involvement and possible functions of a microtubule associated nuclear motor protein, Kip1p, in the 2 micron circle partitioning pathway. The plasmid missegregates in kip1[Delta] cells, but not in cells harboring deletions of genes coding for the other nuclear motors. Kip1p interacts with the plasmid partitioning system and promotes the association of Cse4p and the cohesin complex with STB. Lack of Kip1p function delocalizes the plasmid from its characteristic nuclear locale in close proximity to the spindle pole body. The distance between a reporter plasmid and the spindle pole body is nearly doubled in a kip1[Delta] host strain. We propose that, unlike the conventional roles played by nuclear motors in spindle function and chromosome segregation, the Kip1p motor assists the 2 micron circle in associating with the mitotic spindle and translocating to its ‘partitioning center’. / text
|
72 |
Mathematical modelling of the cell cycle stress responseRadmaneshfar, Elahe January 2012 (has links)
No description available.
|
73 |
The roles of Dgp71WD at the centrosome and spindle in DrosophilaReschen, Richard Frederick January 2011 (has links)
No description available.
|
74 |
Structural studies and assembly dynamics of the bacterial cell division protein FtsZPacheco-Gomez, Raul January 2008 (has links)
No description available.
|
75 |
Cell proliferation, apoptosis and migration within the human fetal retinaKosmin, Alan Simon January 1998 (has links)
No description available.
|
76 |
Anillin Stabilizes Membrane-cytoskeleton Interactions During Drosophila Male Germ Cell CytokinesisGoldbach, Philip Daniel 09 June 2011 (has links)
The scaffolding protein anillin plays a crucial role during cytokinesis – the physical separation of daughter cells following chromosome segregation. Anillin binds filamentous F-actin, non-muscle myosin II and septins, and in cell culture models has been shown to restrict actomyosin contractility to the cleavage furrow. Whether anillin also serves this function during the incomplete cytokinesis that occurs in developing germ cells has remained unclear. Localization of anillin to several actin-rich structures in developing male germ cells also suggests potential roles for anillin outside of cytokinesis. In this study, I demonstrate that anillin is required for cytokinesis in dividing Drosophila spermatocytes. In addition, spermatid individualization is defective in anillin-depleted cells, although similarities to another cytokinesis mutant, four wheel drive, suggest this may be a secondary effect of failed cytokinesis. Anillin, septins and myosin II stably associate with the cleavage furrow in wild-type dividing spermatocytes. Anillin is necessary for recruitment of septins to the cleavage furrow, and for maintenance of Rho, F-actin and myosin II at the equator in late stages of cytokinesis. Membrane trafficking appears unaffected in anillin-depleted cells, although, unexpectedly, ectopic expression of one membrane trafficking marker, DE-cadherin-GFP, suppresses the cytokinesis defect. DE-cadherin-GFP recruits β-catenin (armadillo) and α-catenin to the cleavage furrow and stabilizes F-actin at the equator. Taken together, my results suggest that the anillin-septin and cadherin-catenin complexes can serve as alternative means to promote tight physical coupling of F-actin and myosin II to the cleavage furrow and successful completion of cytokinesis.
|
77 |
Targeting Cell Cycle Checkpoints to Specifically Kill CancerBurgess, A. J. Unknown Date (has links)
No description available.
|
78 |
Targeting Cell Cycle Checkpoints to Specifically Kill CancerBurgess, A. J. Unknown Date (has links)
No description available.
|
79 |
Targeting Cell Cycle Checkpoints to Specifically Kill CancerBurgess, A. J. Unknown Date (has links)
No description available.
|
80 |
Targeting Cell Cycle Checkpoints to Specifically Kill CancerBurgess, A. J. Unknown Date (has links)
No description available.
|
Page generated in 0.0635 seconds