Date of Graduation
8-2023
Document Type
Thesis
Degree Name
Master of Science in Cell & Molecular Biology (MS)
Degree Level
Graduate
Department
Biological Sciences
Advisor/Mentor
Adam Pare
Committee Member
Francis Millett
Second Committee Member
Jeffrey Lewis
Third Committee Member
Shilpa Iyer
Keywords
Compartment Boundary;Developmental Biology;Drosophila Genetics;Embryogenesis;Epitelial Remodeling;Expansion Microscopy
Abstract
The ability of epithelial cells to self-organize is crucial for the development of proper tissue structures and organs in multi-cellular organisms. Epithelia consist of inter-connected cells that form flat sheets, and specific groups of cells within these sheets are partitioned into distinct compartments via compartment boundaries (CBs). These CBs are specialized interfaces between cells characterized by stable, high-tension actomyosin cables, which act as fences to prevent movements between adjacent compartments during tissue reorganization. In the early Drosophila embryo, CBs are established in response to the asymmetrical localization of two cell-surface proteins the Leucine-Rich Repeat (LRR) protein Tartan and the Teneurin Ten-m that set the location of future CBs. Furthermore, filamentous actin and myosin II, which are responsible for generating forces within the cell, are highly enriched at CBs compared to normal cell-cell interfaces. Additionally, there is evidence suggesting that adherens junction (AJ) complexes, which rely on the proteins E-cadherin and Par-3, are differently arranged at CBs, potentially to handle the increased tension and cell adhesion. However, the specific spatial arrangement of these proteins in relation to each other, which gives CBs their unique properties, remains unclear. In this study, two approaches were taken to investigate the molecular nature of CBs. The first method involved a structure-function analysis of the LRR protein Tartan using UAS/Gal4 system. Transgenic embryos that ubiquitously express different truncated versions of Tartan were created to analyze how these deletions control the localization of another transmembrane protein Ten-m and thereby affecting future CB formation. The second approach addressed what differentiates CB contacts from normal contacts at molecular level. To analyze the ultrastructural localization of cytoskeletal and junctional proteins (e.g., Par-3 and myosin II), Drosophila embryos were physically enlarged by adapting existing Expansion Microscopy (ExM) protocols. Narrowing down the necessary portions of Tartan protein required for CB formation will help the researchers reveal the downstream signaling pathways during developmental stages when cells are still undergoing epithelial remodeling. In addition, the findings of this study will enhance the researchers’ comprehension of how the organization of cellular components involved in tension and adhesion, along with the cell surface proteins that control them, contribute to the distinctive properties of CBs.
Citation
Parveen, S. (2023). Molecular Characterization of Compartment Boundary Formation during Epithelial Remodeling in Drosophila melanogaster. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/4875