Ribonucleoprotein foci in eukaryotes: How to translate the silence

Abstract

The control of gene expression plays a key role in the regulation of cellular function; the life of an mRNA, from transcription to degradation, offers multiple control checkpoints. Transcription, splicing, and translation have been widely studied for many years; however, over the last few years, new mechanisms of post-transcriptional and post-translational control have arisen. They involve the regulation of mRNA metabolism in cytoplasmic foci that are composed of different ribonucleoprotein complexes, in most cases, still poorly characterized. These foci are named based on the presence of their main components. An ambitious goal is to know, at the biochemical level, how many different types of foci exist, how they are formed, how they interact with each other and with cytoplasmic organelles, and which functions they support. Here, we present an update of the processing bodies components and their known functions, postulating a hypothesis to understand their dynamics in vivo related to translational control. We focus on the Drosophila melanogaster ribonucleoprotein foci in the germline, during oogenesis and spermatogenesis, and how these granules are related to the spatial-temporal control of mRNAs that drive developmental programs. Finally, we discuss a model to understand the formation, disassembly, and dynamics of the foci.