Nucleades

Nucleades are a proposed class of membraneless nuclear condensates thought to organize genome function. The term does not have wide acceptance in mainstream biology and is used mainly in speculative discussions and some science-fiction contexts. In most usages, nucleades are described as dynamic assemblies formed by phase separation of nucleic acids and RNA-binding proteins within the nucleus.

They are imagined to be niche hubs that associate with chromatin and transcriptional machinery. Morphology is variable; foci can appear and dissolve over minutes to hours, exchanging components with the nucleoplasm. Composition is thought to include DNA or RNA components and a core set of RNA-binding proteins, chromatin-modifying factors, and scaffold proteins.

Proposed roles include organizing chromatin topology, coordinating transcription with RNA processing, and providing temporary platforms for RNA maturation and surveillance. The evidence is largely indirect: observations of punctate nuclear foci in imaging experiments, co-localization with known nuclear bodies, and in vitro phase-separation assays with candidate proteins. However, there is ongoing debate about whether nucleades constitute a distinct, well-defined entity or represent a functional state of existing nuclear condensates such as nuclear speckles or Cajal bodies.

Because the term lacks standard definition, researchers emphasize careful specification of criteria—composition, dynamics, and functional readouts—when attributing a phenomenon to nucleades. See also: nucleolus, nuclear speckles, phase separation, biomolecular condensates.