In order to examine the function of the whole <i>Myosin VI</i> molecule in epithelial tissues, the whole <i>Myosin VI</i> molecule or its separate domains (the head + neck domains or the tail domain) tagged to Green Fluorescent Protein (GFP) were expressed in somatic cells under the control of Ga14 protein and their localisation in the cells was observed. The expression of the tagged proteins under the control of a <i>Myosin VI-Ga14</i> line allowed us to observe all the epithelial cells that express <i>Myosin VI</i> during the whole life cycle. In many epithelial cells the head domain seems to pull the whole molecule towards the cell nucleus, where the minus end of the actin filaments is localised, however it was found that the tail is the domain that anchors the whole molecule to specific areas of the cells away from the nucleus, probably by the binding to cargo molecules. The role of <i>Myosin VI</i> in dorsal closure was found when four <i>Myosin VI</i> mutants that were produced in our laboratory failed to close the dorsal hole during embryogenesis. The genotype and phenotype of two of the mutants, <i>jar<sup>R39</sup></i> and <i>jar<sup>R235</sup></i> are described. Deletion of <i>Myosin VI</i> caused detachment of cells in the leading edge and the amnioserosa and folding-in of the tissue. A similar phenotype was observed when a <i>Myosin VI</i> dominant negative was expressed. In regions of ruptured tissue DE-cadherin and Armadillo was mislocalised, therefore <i>Myosin VI</i> seems to interact with these proteins during cell adhesion. Actin filaments were found to be disorganised at the leading edge and in the lateral epidermis at regions of ruptured tissue, suggesting that <i>Myosin VI</i> is also necessary for actin dynamics during dorsal closure.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:657808 |
| Date | January 2004 |
| Creators | Millo, Hadas |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/11166 |
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