LEVERAGING HIGH SPATIOTEMPORAL RESOLUTION MICROSCOPY TO UNCOVER MECHANICS OF CORTICAL FORCE GENERATION DURING ASYMMETRIC CELL DIVISION IN THE C. ELEGANS ZYGOTE

Cell division is a fundamental and complex property of life. Molecular forces collaborate in space and time to dynamically build and organize a multifaceted apparatus that orchestrates a tightly regulated event which faithfully attaches, aligns, and separates genetic material. The mitotic spindle apparatus is a remarkable machine that relies on interactions between cytoskeletal biopolymers and associated motor proteins to provide the forces needed to power high dimensional reorganization in a crowded cellular environment. Fluorescence microscopy is a valuable research tool to investigate cell dynamics. As technological innovations and techniques have progressed, probing the molecular interactions which produce forces that position the mitotic spindle at relevant spatiotemporal scales is achievable. While possible, this potential is underutilized, mainly due to lack of expertise and equipment. Dynein is a minus-end molecular motor that produces force by interacting with the cytoskeletal biopolymer tubulin. During nuclear migration and cell division, dynein anchored at the cortex helps to position the mitotic spindle by creating forces at microtubule growing ends that positions the spindle within the cell. While dynein and the positioning of the mitotic spindle has been well studied, the dynamic relationship between microtubules, dynein, and the force generation complex that tethers dynein to the cortex has not been investigated at physiologically relevant scales. How dynein simultaneously interacts with microtubules and the cortex to produce force, and how this process is dynamically regulated throughout mitotic phases is not known. This dissertation addresses that gap by studying cortical force generation during the first mitotic division of the C. elegans embryo. By leveraging high spatiotemporal microscopy to investigate asymmetric cell division, this work develops a strategy that identifies force generation events based on dynein particle motion. This strategy is then expanded to provide insight into the biochemical and temporal regulation of dynein based cortical force generation. In total, this work establishes a new framework to classify molecular behavior and refines our understanding of dynein-based interactions and force generation.