Abstract
Eukaryotic cells contain various types of cytoplasmic, non-membrane bound ribonucleoprotein (RNP) granules that consist of non-translating mRNAs and a versatile set of associated proteins. One prominent type of RNP granules are Processing bodies (P bodies), which majorly harbors translationally inactive mRNAs and an array of proteins mediating mRNA degradation, translational repression and cellular mRNA transport (Sheth and Parker, 2003). Another type of RNP granules, the stress granules (SGs), majorly contain mRNAs associated with translation initiation factors and are formed upon stress-induced translational stalling (Kedersha et al., 2000 and 1999). Multiple evidence obtained from studies in unicellular organisms supports a model in which P bodies and SGs physically interact during cellular stress to direct mRNAs for transport, decay, temporal storage or reentry into translation (Anderson and Kedersha, 2008; Decker and Parker, 2012). The quantification, distribution and colocalization of P bodies and/or SGs are essential tools to study the composition of RNP granules and their contribution to fundamental cellular processes, such as stress response and translational regulation. In this protocol we describe a method to quantify P bodies and SGs in somatic tissues of the nematode Caenorhabditis elegans.