A gathering place inside the nucleus
A speckle has no surrounding membrane. Many proteins involved in handling RNA gather there. In human cells grown in the laboratory, reducing two proteins called SON and SRRM2 dispersed other speckle proteins. That experiment helped identify components that hold these bodies together. [1]
Watching genes near speckles
One study followed heat-shock genes in human and hamster cells. Genes close to speckles accumulated more RNA, and live movies helped establish which change came first. More RNA can mean that more was made, less was destroyed, or both. It does not automatically mean faster joining of RNA pieces. [2]
Testing how RNA pieces are joined
In a 2026 study, researchers rapidly removed SON and SRRM2 from engineered human cells. RNA processing became less accurate for a particular group of genes, rich in the DNA letters G and C and containing short introns. The result supports a role in joining RNA pieces for that group; it does not establish the same dependence for every gene. [3]
Removing these proteins changes their own activities as well as the speckles. Further experiments can help distinguish those effects. A visible dot under a microscope, by itself, cannot settle that question. [1] [3]
A useful distinction from the 2026 experiment
Evidence update · 12 October 2026
The study compared RNA being newly made with RNA already accumulated in the cell. The stronger changes in accumulated RNA support asking how RNA is processed and lost, as well as how it is made. This distinction applies to the tested cells and gene group. Nuclear speckles enable processing of RNA from GC-rich isochores (2026).
Primary sources for this update
- Małszycki et al. (2026). Nuclear speckles enable processing of RNA from GC-rich isochores. Primary study. DOI: 10.1016/j.cell.2026.01.011.
Source access: selected primary main Results, rewritten for a public reading level. The study-specific findings above do not certify associated Word drafts, raw data or every proposed nuclear-body mechanism.
Primary studies behind this guide
- Ilik et al. (2020), eLife 9:e60579. SON and SRRM2 are essential for nuclear speckle formation. DOI: 10.7554/eLife.60579. Primary research.
- Kim et al. (published online 2019; 2020 issue), Journal of Cell Biology 219:e201904046. Gene expression amplification by nuclear speckle association. DOI: 10.1083/jcb.201904046. Primary research.
- Małszycki et al. (2026), Cell 189:2024–2039.e25. Nuclear speckles enable processing of RNA from GC-rich isochores. DOI: 10.1016/j.cell.2026.01.011. Primary research.
Scientific text and the identity and fit of the cited studies were checked on 3 October 2026. This guide covers the experiments described here; it is not an exhaustive literature review. Source-access limitations and outstanding work remain.