Yu, Joy Sze;
(2020)
The Role of Wnts in Growth and Planar Cell Polarity.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Wnts are thought to act as morphogens, spreading from producing cells and acting at a long-range to regulate various developmental processes. As such, Wnt gradients have been suggested to regulate growth, patterning and planar cell polarity (PCP) in the Drosophila wing. However, flies relying solely on membrane-tethered Wingless have normal wings with no apparent PCP phenotype, suggesting that Wingless diffusion is dispensable. This raises the following questions. (1) Could the gradients of other Wnts restore long-range signalling in membrane-tethered Wingless flies? (2) Do Wnt gradients contribute to PCP establishment in the wing? Indeed, it has been suggested that Wingless and DWnt4 act redundantly to establish PCP in the fly wing (Wu et al., 2013). To find out whether other Wnts are expressed during wing development, a set of reporters were generated for all seven DWnts. They showed that, in addition to Wingless, DWnt2, DWnt4, DWnt6 and DWnt10 are also expressed in the wing disc. Simultaneous knockouts of these Wnts were created to remove their possible contribution, leaving only membrane-tethered Wingless as the sole source of Wnt. This resulted in wings with no PCP defects, suggesting that Wnt diffusion is not required for PCP establishment in the wing. Subsequently, this study addressed the issue of whether Wnts are required for PCP. All DWnts were inhibited via a Nanobody trapping approach, which sequestered the Wnt chaperone Evi, and hence all DWnts, in the ER. The removal of all DWnts did not impact the PCP of the resulting wing, suggesting Wnts are not required for setting up PCP in the Drosophila wing. Using the same tools generated for addressing the PCP issues, this study also investigated the redundancy of Wnts in wing growth.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | The Role of Wnts in Growth and Planar Cell Polarity |
| Event: | UCL (University College London) |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2020. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10116599 |
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