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Identification and Spatiotemporal Contro... - Document (2 M) |
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| Author |
Alford, Lea Marie |
| Title |
Identification and Spatiotemporal Control of the Asymmetrical Membrane Cortex in Cleavage Stage Sea Urchin Embryos |
| Date created |
2009 |
| Abstract |
Polarity established by the first cleavages in sea urchin embryos was investigated in this thesis revealing precocious embryonic polarity. Studies of embryonic polarity have focused on protostomes such as <italics>C. elegans</italics>, and those on deuterostomes have focused on later developmental stages. I find asymmetries in the sea urchin membrane cell cortex as early as the first division after fertilization as a result of new membrane addition in the cleavage furrow. Membrane domains and the polarity determinants Par6, aPKC, and Cdc42 are polarized to the apical, or free, cell surface, while the cell-cell contact site remains distinct. Using immunofluorescence, fluorescence recovery after photobleaching (FRAP), and specific inhibitor treatments, myosin filaments were identified as the major regulator of membrane cortex polarity. However, membrane domains and cortical polarity determinants are differentially regulated with respect to blastomere dissociation. These asymmetries are required for proper spindle alignment and cleavage plane determination and are responsible for polarized fluid phase endocytosis. The work in this thesis and future studies addressing the connection between the membrane cortex and myosin filaments has and will lead to a greater understanding of the maintenance of embryonic polarity in cleavage stage sea urchin embryos. |
| Use Restrictions |
I hereby allow Boston College to include and preserve my dissertation/thesis in electronic form in the Boston College Institutional Repository, which shall include the right to publicly post my dissertation/thesis on the World Wide Web. I will retain copyright ownership, but I grant to Boston College the non-exclusive right to copy, distribute, and publicly display my dissertation/thesis in any form as may be necessary or convenient in the future as file formats, storage media, and distribution mechanisms evolve. |
| Subject |
cell polarity |
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membrane domain |
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myosin II |
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PAR proteins |
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sea urchin |
| Publisher |
Boston College |
| Link to Item |
2345/978 |
| Thesis Advisor |
Burgess, David R. |
| Degree Name |
PhD |
| Degree Grantor |
Boston College. Graduate School of Arts & Sciences. |
| Sys. No. |
000000958 |
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