Isolation of chromatoid bodies from mouse testis as a rich source of short RNAs.

RNA-protein (RNP) complexes and granules are powerful composites of merged functions and unique properties. The importance of RNPs in carrying out complex tasks in RNA processing and regulation is being increasingly revealed. One of the biggest RNP granules is the chromatoid body (CB) that is believed to orchestrate the RNA posttranscriptional regulation in haploid male germ cells. Here, we describe the CB isolation procedure, from mouse testis. After cross-linking and lysing the cells, the CBs are enriched by slow-speed centrifugation and immunoprecipitated using anti-MVH/DDX4 antibody. The method yields pure fractions of CBs, and it is robust, reproducible and does not require special equipment or abundant starting material. The CB is packed with large amounts of RNA, especially small RNAs. Isolation of the CBs provides a tool to enrich these RNA species.