Nucleic Acid-Binding Assay of Argonaute Protein Using Fluorescence Polarization.

Nucleic acid binding by the Argonaute protein is an important trigger step in the Argonaute-dependent gene silencing system. We established an in vitro method to detect the nucleic acid binding activity of the Argonaute protein by fluorescence polarization. In this chapter, we will describe the expression and purification of the prokaryotic (Rhodobacter sphaeroides) Argonaute protein, and the nucleic acid-binding analysis using a Fluorescence Polarization System (Beacon 2000).