Role of RNA in genome folding: It's all about affinity

In mammalian cells, RNA species make up ∼10% of chromatin by mass and play a structural role in the nucleus by acting as scaffolds and influencing genome organisation. Although many proteins bind nuclear RNAs, these interactions are often non-specific, making it challenging to define RNA's role in genome folding. Nonetheless, a clearer picture is emerging. Some RNAs, like NEAT1 and MALAT1, have high affinity for specific RNA-binding proteins and form the basis for nuclear bodies. In contrast, many nuclear proteins bind RNA weakly, resulting in numerous low-affinity interactions. We propose that these interactions generate a complex RNA-protein network with dynamic, gel-like properties that modulate chromatin folding and transcription factor mobility. This suggests an exciting feedback mechanism in which newly transcribed RNA contributes directly to shaping chromatin architecture.