Figure 1. In homeostatic cellular conditions, dynamic fluid droplets demix from surrounding nucleoplasm.

(A) Nucleoli, Cajal bodies (CBs), histone locus bodies (HLBs), speckles, and paraspeckles participate in RNA and RNP biogenesis in the nucleus. Associated with chromosomal loci, these nuclear bodies contain specific RNAs and proteins that pass in and out of nuclear bodies during RNP assembly. Unstable RNAs concentrate in P bodies in the cytoplasm, where mRNA decay factors co‐localize. (B) Analogous dynamics and fluid properties are obtained when a purified RNA‐binding protein with a low‐complexity region is incubated in with RNA and observed over time in vitro. (C) Electron micrograph of a droplet showing overall spherical shape with an irregular outline. Micrographs reproduced from Li et al (2012).