UNC-CH Physics and Astronomy Thesis Proposal Presentation

Chad Hobson

“Cell Nuclear Mechanics as Studied Through Custom Microscopy and Methodologies”

Cell nuclei not only serve to encapsulate the genome, but additionally provide mechanical rigidity to the cell as the stiffest sub-cellular structure. Alterations in chromatin compaction levels, the integrity of nuclear lamina, and nuclear morphology are associated with a variety of disease states including, but not limited to, heart disease, progeria, and various cancers. Our lab takes a unique approach to studying these issues through developing novel methods that combine cutting-edge microscopy with force probes to both visualize and mechanically perturb cells in a controlled environment. To date, I have developed portions of our combined atomic force microscope and light sheet microscope (AFM-LS) system, used the AFM-LS system to study nuclear mechanics and DNA damage, developed and reviewed mechanical models of cell nuclei, and created a novel methodology (SPIM-FRAP) to map intranuclear diffusion. Here, I propose the continued use of our AFM-LS system coupled with SPIM-FRAP to measure mobility of nuclear repair proteins and small molecules in constricted environments. Additionally, I propose a comparison of mechanical properties and intranuclear diffusion among disease cell lines that show varied mechanisms of DNA damage. Finally, our AFM-LS system is well suited to study strain in chromatin, which has implications for gene expression and chromosome territories. Combined together, these studies will inform the collective understanding of the complex relationship between nuclear mechanics and disease.