Investigating the Structure of RNA/Protein Bodies through Nucleolar Mass Transfer Dynamics

Abstract

One of the major remaining mysteries of biology is how large, microscopically visible intracellular structures self-assemble from nanoscale molecules. Of particular interest are RNA/protein bodies (RNP), which are non-membrane bound organelles. Despite their important roles in the cell, the assembly and dynamics of these bodies are poorly understood. In this work, a recently developed mixing technique is used to measure the transfer of proteins between the nucleolus and the nucleoplasm in X Laevis. Several proteins of interest are investigated and the resulting dynamics are analyzed through different approaches, drawn from past investigations into the structure of the nucleolus. Additionally, new ideas were investigated to increase the robustness of this technique. The investigation yielded significantly different characteristic times of diffusion for the proteins nucleolin, nucleophosmin, and cell division cycle 14a. These findings provide a more complete picture of the RNP body structure. Additionally, A TP dependence for mass transfer dynamics was demonstrated, with ATP depletion arresting mass transfer. Finally, the effectiveness of using actin-disrupting drugs for the mixing technique was evaluated.