Date of Award
8-22-2025
Date Published
September 2025
Degree Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Biology
Advisor(s)
Heidi Hehnly
Keywords
Array tomography;Cilia;Kupffer's Vesicle (KV);Mitosis;Rab GTPases;Tissue morphogenesis
Subject Categories
Biology | Life Sciences
Abstract
The development of a functional ciliated tissue during embryogenesis is vital for essential physiological processes, such as mucociliary clearance in the respiratory tract, cerebrospinal fluid movement in the brain, and ovum transport in the reproductive system. This developmental process of ciliated tissues requires the coordination of intracellular processes, including membrane trafficking, cilia formation, and cytoskeletal organization. While these processes have been extensively studied in cell culture systems, our understanding of their integration during vertebrate organ formation remains limited. Using high-resolution confocal imaging, optogenetic manipulation, and genetic approaches this thesis examines how these processes drive the development of the zebrafish left-right organizer (LRO), called the Kupffer's vesicle (KV), providing insights into both conserved mechanisms and tissue-specific adaptations during vertebrate organogenesis. Chapter 2 examines the role of Rab GTPase family proteins in KV development, demonstrating that ciliogenesis initiates intracellularly before lumen formation, with Rab11 and Rab35 controlling cystic fibrosis transmembrane conductance regulator (CFTR) trafficking for lumen expansion while Rab8 specifically regulates cilia elongation. This chapter reveals conserved and divergent mechanisms previously characterized in mammalian systems, highlighting the importance of in vivo studies for understanding tissue-specific regulation of membrane trafficking. Chapter 3 investigates mitotic patterning during KV morphogenesis, identifying an FGF-regulated anterior enrichment of cell divisions critical for proper organ formation. This chapter establishes the essential role of spatially controlled cell division in establishing proper KV architecture. Chapter 4 provides a comprehensive analysis of protein localization and ultrastructure in KV. This chapter documents significant variability in ciliary architecture, demonstrating that cilia exhibit structural and molecular diversity that likely contributes to their specialized functions in establishing left-right asymmetry. Collectively, this dissertation bridges knowledge gaps between in vitro studies and vertebrate embryonic development seen in zebrafish. Demonstrating that while zebrafish employ many conserved cellular mechanisms during organogenesis, they also exhibit tissue-specific adaptations that could not be predicted from cell culture models. These findings enhance our understanding of the origins of congenital disorders associated with laterality defects and ciliopathies, and provide a high-resolution, cellular-level framework for further exploring the complex interplay of cellular processes and their inherent heterogeneity that drive organ formation in vivo.
Access
Open Access
Recommended Citation
Ononiwu, Favour Chukwudumebi, "Molecular mechanisms governing left right axis formation during vertebrate development." (2025). Dissertations - ALL. 2211.
https://surface.syr.edu/etd/2211
