Biomechanical analysis of the developing Drosophila embryo has historically focused on the role of individual cells. Cells translate genetic information into protein machinery that is capable of generating forces. With this perspective, the field has tried to identify which cells are responsible for the morphological changes that occur during embryogenesis. Taking a different perspective, this work considers the cumulative effect of all cells in a coherent epithelium. This reveals a mechanical trade-off between cell-type dependent tensions and embryo-imposed constraints on cells. To investigate this further, a 2.5-D cellular finite element model is built and used to analyze the mechanics of one stage of development, germband retraction. This analysis finds that germband retraction is robust to cell-type dependent tensions, but contingent on the initial cell geometry. Experiments then test the embryoâs mechanical robustness to environmental perturbation. A non-specific heat shock stress to the embryo results in delayed development and the formation of holes in the epithelium. These holes disrupt the mechanical integrity of the tissue preventing development beyond germband retraction. The model is expanded to explain how germband retraction fails, thus providing a mechanical explanation for failure due to holes in heat-shocked embryos. This dissertation finds that embryogenesis is a mechanically robust process that is not dependent on any single group of differentiated cells, but rather is contingent on coherent and contiguous epithelial tissues that maintain developmental information through cell morphology.
| Identifer | oai:union.ndltd.org:VANDERBILT/oai:VANDERBILTETD:etd-03292016-114626 |
| Date | 06 April 2016 |
| Creators | McCleery, Winston Tyler |
| Contributors | M. Shane Hutson |
| Publisher | VANDERBILT |
| Source Sets | Vanderbilt University Theses |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.vanderbilt.edu/available/etd-03292016-114626/ |
| Rights | restrictsix, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Vanderbilt University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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