Single-Molecule Fluorescence Microscopy in Living Caenorhabditis elegans.

Transportation of organelles and biomolecules is vital for many cellular processes. Single-molecule (SM) fluorescence microscopy can expose molecular aspects of the dynamics that remain unresolved in ensemble experiments. For example, trajectories of individual, moving biomolecules can reveal velocity and changes therein, including pauses. We use SM imaging to study the dynamics of motor proteins and their cargo in the cilia of living C. elegans. To this end, we employ standard fluorescent proteins, an epi-illuminated, wide-field fluorescence microscope and mostly open-source software. This chapter describes the setup we use, the preparation of samples, a protocol for single-molecule imaging in C. elegans and data analysis.