LAUSR

Tethered Particle Motions assays are a simple but powerful tools for monitoring the effective length of individual DNA strands and other linear bio-polymers in real-time. The technique has been employed in various capacities including characterization of DNA topology, transcription factor - DNA interactions, and monitoring progress of enzymes that translocate along DNA. At its core the technique is relatively simple to implement, only requiring a research-grade microscope and a video camera; however, it is important to note that optical resolution, frame rate, exposure time, particle size, and solution viscosity all affect the ability to discriminate different tether lengths and detect changes. Through a combination of simulations and control experiments we demonstrate these limits, and present a collection of best-practices.