Date of Award
Ryan S. Littlefield, Ph.D
Myofibrils produce the forces that shorten muscles during contraction and are composed of proteins arranged in repeating contractile units (sarcomeres). These are composed of various proteins that self-organize into precise, alternating groups. The process of myofibril assembly is robust, flexible, and medically relevant. Various protein isoforms have evolved to modify the assembly process and generate a variety of muscle types with distinct physiologies and dynamics. To study myofibril assembly, I used the nematode Caenorhabditis elegans (C. elegans) which is an ideal model organism for this because it is transparent and has a variety of different muscle types that are responsible for locomotion, egg-laying, and defecation. To visualize myofibril assembly, I used transgenic gene-edited strains that express fluorescently-tagged myofibril proteins to determine when these myofibrillar proteins are expressed during muscle development and assemble into nascent and functional myofibrils. To observe the entire process of myofibril assembly at high resolution, I imaged developing C. elegans embryos with dual-view inverted selective plane illumination microscopy (diSPIM), a novel system to identify, measure, and classify how each muscle component becomes organized. In addition, I used confocal microscopy and functional assays on adult worms to determine whether fluorescent-tagging interferes with normal myofibril organization, growth, and physiology.
Russell, Michael B., "Visualizing Muscle Assembly and Function in C. elegans" (2022). Theses and Dissertations. 85.