Mesenchymal-to-Epithelial Transition of the Drosophila melanogaster embryonic midgut
Epithelial plasticity is a fundamental process in embryonic development, tissue regeneration, and disease progression, enabling cells to transition between mesenchymal and epithelial states. While the epithelial-to-mesenchymal transition (EMT) has been extensively studied, the reverse process, me...
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| Format: | Doctoral Thesis |
| Language: | English |
| Published: |
Philipps-Universität Marburg
2024
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| Online Access: | PDF Full Text |
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| Summary: | Epithelial plasticity is a fundamental process in embryonic development, tissue
regeneration, and disease progression, enabling cells to transition between mesenchymal
and epithelial states. While the epithelial-to-mesenchymal transition (EMT) has been
extensively studied, the reverse process, mesenchymal-to-epithelial transition (MET), in
which cells establish polarity, remains less well understood. During the embryonic
development of Drosophila, midgut cells migrate and simultaneously undergo a
secondary MET. This study aims to contribute to the understanding of MET by providing
a comprehensive analysis of cellular and molecular dynamics of the Drosophila midgut.
I established a DnaseII-dependent Gal4 driver line that is exclusively expressed in the
midgut. With this driver, I tracked the entire migration process of midgut cells during
MET and observed that these cells reduce their velocity before undergoing shape changes,
indicating an increasing basal attachment.
Simultaneously, actin and microtubules undergo substantial rearrangements during MET,
with specific orientation patterns correlating with cell elongation and monolayer
formation. Furthermore, I investigated MET-associated morphodynamics in E-Cadherin
and Laminin mutants, discovering that disruptions in cell-cell junctions lead to a failure
in cell elongation, while basal cues are crucial for monolayer establishment and cell
elongation during MET.
Additionally, I established a new UAS line with a membrane marker that showed an
enhanced signal in the midgut when combined with the new Gal4 line. This enabled the
development of a method to track cell shape changes using laser-scanning microscopy
and Light-sheet microscopy.
This thesis provides a comprehensive investigation of the morphological changes and
cytoskeletal dynamics during MET in the Drosophila embryonic midgut, including the
temporal sequence of events and the impact of different proteins such as E-Cadherin and
Laminin. However, further research is necessary to fully understand the intricate
molecular mechanisms and signaling pathways that regulate MET. |
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| Physical Description: | 150 Pages |
| DOI: | 10.17192/z2024.0469 |