Structure and assembly of Borna disease virus 1 nucleoprotein-RNA complexes.
Sugita, Y., Hirai, Y., Goto, S.H., Fujiwara, T., Tomonaga, K., Noda, T., Horie, M.(2026) Sci Adv 12: eaeb0835-eaeb0835
- PubMed: 41961918 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1126/sciadv.aeb0835
- Primary Citation Related Structures: 
21AL - PubMed Abstract: 
Structures of nucleoprotein (N)-RNA complexes of the Bornaviridae , a virus family in the order Mononegavirales , have not been reported. Here, using cryo-electron microscopy (cryo-EM), we report high-resolution structures of Borna disease virus 1 (BoDV-1) N-RNA complex assemblies, including a dominant hexameric ring-like complex and less populated heptameric and octameric forms, the first RNA-bound N structures reported from this family. These structures reveal key features of N-RNA engagement and a BoDV-1-specific stoichiometry of eight nucleotides per N, providing a framework for comparison with related negative-strand RNA viruses. In addition to these RNA-bound complexes, we identified multiple RNA-free oligomers, indicating substantial conformational flexibility of N. Mutational analyses identified residues essential for nucleocapsid formation and RNA synthesis. Cryo-EM of mutant complexes captured RNA-free assemblies, suggesting that initial N oligomerization precedes RNA binding. These findings clarify the structural organization of the N-RNA complex and suggest how oligomeric plasticity contributes to nucleocapsid assembly.
- Hakubi Center for Advanced Research, Kyoto University, Kyoto, Japan.
Organizational Affiliation: 
















