RNArich

RNArich is a term used in molecular biology to describe regions or collections of biomolecules that exhibit a higher-than-typical concentration of RNA. In this usage, RNArich can refer to subcellular compartments with abundant RNA content as well as sets of transcripts that show elevated RNA levels under particular conditions. The concept provides a framework for studying how RNA abundance influences cellular organization and function.

Subcellular RNArich domains include well-known RNA-rich organelles such as the nucleolus and cytoplasmic granules formed during stress, including stress granules and P-bodies. These structures often arise from multivalent interactions between RNA molecules and RNA-binding proteins and can be stabilized by phase separation. The RNA composition of RNArich regions is diverse, spanning ribosomal, messenger, and noncoding RNAs, with the relative representation shifting in response to cellular state.

Biological roles attributed to RNArich environments include regulation of RNA processing, transport, translation, and degradation. They can act as hubs that concentrate RNA-binding proteins and cofactors to coordinate gene expression and RNA quality control. In stress or disease, the size, composition, and dynamics of RNArich regions may change, reflecting alterations in RNA metabolism.

Methods to study RNArich include high-resolution RNA in situ techniques, such as single-molecule RNA FISH, as well as sequencing approaches on subcellular fractions. Proximity labeling and affinity purification can reveal RNA-protein networks within RNArich domains, while live-cell imaging tracks their dynamics.

RNArich is a descriptive term rather than a single defined entity; its precise usage varies by study. It serves as a heuristic for exploring how RNA abundance shapes cellular architecture and regulatory networks.