How do cells hold important RNA molecules in reserve and release them at the right moment?

A new study published in Nature Cell Biology characterizes a spatially and temporally regulated compartment of intron-retained RNAs at the periphery of nuclear speckles.

Combining compartment-resolved RNA sequencing, single-molecule and super-resolution imaging, and sequence-based deep learning, the researchers identified RNAs with long-lived retained introns that persist in the nucleus for hours. Many of these transcripts encode regulators of genome maintenance, DNA repair, telomere maintenance, and mitosis.

When cells enter mitosis, the retained introns are removed in a coordinated, kinase-dependent process, and the mature transcripts become available to early G1 daughter cells.

The study shows that these RNAs occupy a distinct niche at the nuclear speckle periphery. During mitosis, their retained introns undergo coordinated, kinase-dependent removal, followed by the accumulation of spliced transcripts in the cytoplasm of early G1 daughter cells.

These findings connect intronic sequence features, subnuclear organization, and mitotic remodelling to the temporal control of RNA processing and localization. They also suggest a potential mechanism for coordinating RNA availability across cell division.

Congratulations to all authors and collaborators!

Read the paper here:
https://doi.org/10.1038/s41556-026-02040-5