The structure of the mammalian bornavirus polymerase complex

Journal article

Borna disease virus 1 (BoDV-1) is a non-segmented RNA virus with one of the smallest known RNA virus genomes. BoDV-1 replicates in the nucleus of infected cells using a virally encoded polymerase complex composed of the large protein and phosphoprotein. Here, we present the BoDV-1 polymerase complex at resolutions up to 2.8 Å, describing the fully ordered large polymerase protein bound to tetrameric phosphoprotein. The complex is maintained through the ordered C-terminal region of one copy of the phosphoprotein. Analysis of the model reveals a conserved methyltransferase domain, though key S-adenosyl methionine binding residues are missing. While no RNA is observed in our models, analysis of a sample under reaction conditions induces an opening and closing of the template entry and exit channels, respectively. Higher-order polymerase assemblies suggest oligomerisation as a conserved feature of negative strand RNA virus polymerases. We provide a molecular framework to investigate bornavirus replication and transcription.

Authors: Carrique, L; Günl, F; Deng, A; Grimes, JM; Keown, JR

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Nature Research
• Journal: Nature Communications
• Volume: 16
• Issue: 1
• Pages: 7508-7508
• Article number: 7508
• Publication date: 2025-08-13
• Acceptance date: 2025-08-04
• DOI: 10.1038/s41467-025-62906-4
• EISSN: 2041-1723
• ISSN: 2041-1723
• Language: English
• Keywords: Polymerase; Phosphoprotein; Biology; RNA polymerase; Reverse transcriptase; Molecular biology; Transcription factor II D; RNA-dependent RNA polymerase; RNA polymerase II; RNA; Genetics; Virology; Cell biology; Gene; Promoter; Gene expression