VIRP1 protein shapes nuclear condensates and facilitates potato spindle tuber viroid infection
Researchers identified how VIRP1, a host protein in potato plants, forms nuclear condensates and promotes infection by potato spindle tuber viroid (PSTVd). VIRP1 is the only Solanaceae BET protein with a proline-rich domain that binds PSTVd RNA, and its bromodomain and nuclear localization are critical for efficient viroid accumulation. The findings reveal a mechanism linking chromatin regulation, phase separation, and early viroid infection establishment.
A new study on bioRxiv demonstrates that VIRP1, a bromodomain-containing protein in potato plants, plays a central role in facilitating potato spindle tuber viroid (PSTVd) infection through nuclear condensate formation. The researchers found that VIRP1 is uniquely positioned among Solanaceae BET proteins due to its proline-rich domain overlapping the PSTVd-binding site. VIRP1-deficient plants showed delayed flowering and increased sensitivity to the stress hormone ABA, with altered expression of stress-related genes. Functional studies revealed that VIRP1 forms phase-separated condensates both in living cells and in vitro, with condensate morphology altered by PSTVd RNA and mutations in conserved bromodomain residues. The bromodomain and nuclear localization of VIRP1 proved essential for efficient viroid accumulation, particularly during early infection stages, though the intrinsically disordered C-terminal domain was dispensable. These results suggest VIRP1 acts as a host nuclear factor integrating chromatin functions with early viroid infection mechanisms.
Limitations & open questions
The study does not discuss potential agricultural or practical applications for controlling PSTVd infection through VIRP1 manipulation, nor does it address whether findings in Solanaceae plants might generalize to viroid infections in other plant families.
What different sources said
- bioRxivCenter
VIRP1 bromodomain shapes nuclear condensate formation and has a positive effect on PSTVd accumulation
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