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A splicing factor's unexpected detour to the mitochondrial surface
Ana-Maria Raicu1, L Stirling Churchman1
1Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
Molecular Cell
|April 3, 2026
Summary
The splicing factor U2AF unexpectedly represses translation. It also influences how nuclear-encoded mitochondrial mRNAs are localized to the outer mitochondrial membrane.
Area of Science:
- Molecular Biology
- Cell Biology
- Gene Expression
Background:
- Messenger RNA (mRNA) localization is crucial for protein synthesis and cellular function.
- The transport of nuclear-encoded mRNAs to specific subcellular locations, like mitochondria, requires precise regulation.
Purpose of the Study:
- To investigate the non-canonical functions of splicing factors beyond pre-mRNA processing.
- To elucidate the role of U2AF in post-transcriptional gene regulation, specifically in mRNA localization and translation.
Main Methods:
- Utilized techniques such as RNA immunoprecipitation (RIP) and fluorescence in situ hybridization (FISH).
- Performed polysome profiling and reporter assays to assess translation and localization dynamics.
Main Results:
- Identified U2AF (U2 small nuclear ribonucleoprotein auxiliary factor) as a repressor of translation for specific nuclear-encoded mitochondrial mRNAs.
- Demonstrated that U2AF binding influences the targeting of these mRNAs to the outer mitochondrial membrane.
Conclusions:
- Splicing factors can possess diverse regulatory roles impacting mRNA fate.
- U2AF's dual function in splicing and translational control highlights novel mechanisms in gene expression regulation and mitochondrial function.
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