Viewing Nuclear Deformation with Sideways Microscopy

Abstract

Structural information related to rearrangement of the cytoskeletal and nucleoskeletal structure, induced strains, and biochemical distributions are metrics for understanding cell response. However, structural information during applied stress is limited by our ability to image the cells under load. In order to study the mechanics of single cells and subcellular components such as the nucleus, we developed a unique system that couples an Atomic Force Microscope (AFM) with a new imaging technique called PRISM - Pathway Rotated Imaging for Sideways Microscopy. PRISM allows for simultaneous horizontal and vertical fluorescence imaging of a single cell. The combined AFM and PRISM system enables acquisition of 3D images of cell structure with accompanying piconewton resolution force measurements. We use this new technique to observe nuclear deformation from the side in real time. From these experiments we can measure a cell's mechanical response (AFM) and strain maps of punctate labeled nuclei (PRISM). Additionally, we will show how external forces induce a strain in chromosome territories. Our larger goals are to investigate how external mechanical stimuli structurally affects the genome and thereby alters gene expression, motility and differentiation.