RNA-specific local translation is patterned by condensates for multinucleate cell growth

Area of Science:

• Cell Biology
• Molecular Biology
• Biophysics

Background:

• Cellular processes like growth and nuclear division require precise coordination.
• In syncytia, asynchronous nuclear division contrasts with localized growth, posing questions about local regulation and global coordination.
• The protein Whi3, complexed with specific mRNAs, forms condensates essential for cell cycle progression and hyphal elongation in Ashbya gossypii.

Purpose of the Study:

• To investigate the role of Whi3 condensates in regulating local translation.
• To understand how these condensates coordinate cell growth and nuclear division.
• To elucidate the mechanisms by which Whi3-RNA condensates influence mRNA translation.

Main Methods:

• Biochemical assays to analyze condensate composition.
• In vitro studies to assess the impact of condensate properties on translation.
• Microscopy to visualize Whi3 condensates and associated translation in vivo.

Main Results:

• Whi3 condensates are enriched with translation regulators.
• Condensates are associated with spatially patterned translation of specific RNAs near nuclei and growth sites.
• In vitro, Whi3-RNA condensates modulate mRNA translation, with effects dependent on RNA type and condensate size.
• Condensate interfaces act as tunable sites for translation, influenced by composition, RNA valency, and protein charge.

Conclusions:

• Whi3-RNA condensates act as localized regulatory hubs for gene expression.
• These condensates generate a spectrum of translation states based on subcellular location and RNA content.
• The findings provide a framework for understanding how spatial organization of translation impacts cellular processes.