Download MendeleyMolecular basis of polyadenylated RNA fate determination in the nucleus.
Bugai, A., Hohmann, U., Lorenzo, A., Graf, M., Fin, L., Rouviere, J.O., Tirian, L., Dou, Y., Le Rest, M., Polak, P., Johnsen, D., Jakobsen, L., Andersen, J.S., Brennecke, J., Plaschka, C., Jensen, T.H.(2026) Nature 655: 1070-1078
- PubMed: 42310446 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1038/s41586-026-10650-0
- Primary Citation Related Structures:
28WY, 28WZ, 28XA, 28XB, 9RV1 - PubMed Abstract:
Eukaryotic genomes generate a plethora of polyadenylated (pA + ) RNAs 1,2 , which are packaged into ribonucleoprotein particles (RNPs). To ensure faithful gene expression, functional pA + RNPs, including protein-coding RNPs, are exported to the cytoplasm, whereas transcripts within non-functional pA + RNPs are degraded in the nucleus 1-4 . How cells distinguish these opposing fates remains unknown. The DExD-box ATPase UAP56 (also known as DDX39B) is a central component of functional pA + RNPs, and promotes their docking to the nuclear pore complex-anchored TREX-2 5,6 , which triggers transcript release from UAP56 to facilitate export 7 . Here we reveal that the poly(A) tail exosome targeting (PAXT) connection 8 binds a TREX-2-like module, which releases pA + RNAs from UAP56 for decay by the nuclear exosome. The core of this module consists of a LENG8-PCID2-SEM1 trimer, which we show is structurally and biochemically equivalent to the central GANP-PCID2-SEM1 trimer of TREX-2. Mutagenesis and transcriptomic data demonstrate that the nuclear fate of pA + RNPs is governed by the contending actions of nucleoplasmic PAXT and nuclear pore complex-associated TREX-2, which interpret RNA-bound UAP56 as a signal for RNA decay or export, respectively. As RNA targets of PAXT are generally short and intron-poor, we propose an overall model for pA + RNP fate determination whereby the distinct sub-nuclear localizations of PAXT and TREX-2 govern the degradation of short non-functional pA + RNAs while allowing export of their longer and functional counterparts.
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
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