During mitosis, the genome is transformed from a decondensed, transcriptionally active state to a highly condensed, transcriptionally inactive state. Mitotic chromosome reorganization is marked by the general attenuation of transcription on chromosome arms, yet how the cell regulates nuclear and chromatin-associated RNAs after chromosome condensation and nuclear envelope breakdown is unknown. SAF-A/hnRNPU is an abundant nuclear protein with RNA-to-DNA tethering activity, coordinated by two spatially distinct nucleic acid–binding domains. Here we show that RNA is evicted from prophase chromosomes through Aurora-B–dependent phosphorylation of the SAF-A DNA-binding domain; failure to execute this pathway leads to accumulation of SAF-A–RNA complexes on mitotic chromosomes, defects in metaphase chromosome alignment, and elevated rates of chromosome missegregation in anaphase. This work reveals a role for Aurora-B in removing chromatin-associated RNAs during prophase and demonstrates that Aurora-B–dependent relocalization of SAF-A during cell division contributes to the fidelity of chromosome segregation.
Cell division requires RNA eviction from condensing chromosomes
The present address of J.A. Sharp, C. Perea-Resa, W. Wang, and M.D. Blower is Department of Biochemistry, Boston University School of Medicine, Boston, MA.
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Judith A. Sharp, Carlos Perea-Resa, Wei Wang, Michael D. Blower; Cell division requires RNA eviction from condensing chromosomes. J Cell Biol 2 November 2020; 219 (11): e201910148. doi: https://doi.org/10.1083/jcb.201910148
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