Chromatin immunoprecipitation assay of Piwi in Drosophila.

The generation of high-resolution maps of the epigenome is crucial to research in epigenetics, developmental biology, and stem cell biology. In recent years, small RNA pathways have been implicated in epigenetic regulation. All small RNA pathways involve Argonaute proteins as their key biogenesis and effector components. In this chapter, we describe a chromatin immunoprecipitation method for whole-genome mapping of Drosophila Piwi, the defining member of the Argonaute protein family. This method should have general utility for mapping other chromatin-associated factors.