DEAD-box helicases modulate dicing body formation in Arabidopsis

Area of Science:

• Cell Biology
• Molecular Biology
• Plant Science

Background:

• Eukaryotic cells utilize membraneless organelles for cellular process regulation.
• Mechanisms governing the formation and stress-induced changes of these organelles remain largely unknown.
• Nuclear dicing bodies (D-bodies) are critical membraneless organelles in plants.

Purpose of the Study:

• To investigate the role of DEAD-box helicases in the formation and alteration of plant nuclear dicing bodies (D-bodies).
• To elucidate the molecular mechanisms underlying D-body dynamics, particularly liquid-liquid phase separation (LLPS).
• To determine the impact of viral infection on D-body formation and associated helicases.

Main Methods:

• Identification of DEAD-box RNA helicases (RH6, RH8, RH12) as novel D-body components in *Arabidopsis thaliana*.
• Analysis of helicase interactions with SERRATE, a key D-body protein, to understand phase separation.
• Observation of helicase and D-body dynamics during *Turnip mosaic virus* infection.

Main Results:

• RNA helicase 6 (RH6), RH8, and RH12 were identified as previously unknown components of nuclear dicing bodies.
• These helicases promote the liquid-liquid phase separation (LLPS) of SERRATE, driving D-body formation.
• Viral infection led to decreased accumulation of these helicases and a reduction in D-bodies.

Conclusions:

• RH6, RH8, and RH12 play crucial roles in modulating D-body formation through LLPS.
• The study reveals a mechanism linking viral infection to the disruption of D-body dynamics via these helicases.
• Findings provide insights into the regulation of membraneless organelles in response to cellular stress.