Distinct RNA Physical Microenvironments Shape Unique Properties and Functions within Biomolecular Condensates

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Biomolecular condensates are crucial for cellular regulation, forming via multivalent interactions.
• While protein microenvironments in condensates are studied, RNA microenvironments remain less understood.
• Understanding RNA's physical environment is key to deciphering its role in cellular processes.

Purpose of the Study:

• To develop a quantitative method for measuring RNA physical microenvironments within biomolecular condensates.
• To investigate the distinct physical properties of RNA compared to proteins in condensates.
• To explore the relationship between RNA microenvironment and its function and organization.

Main Methods:

• Development of a novel chemical method integrating RNA-labeling chemistry.
• Utilizing environmentally sensitive fluorophores for detection.
• Employing fluorescence lifetime imaging microscopy (FLIM) for quantitative analysis.

Main Results:

• RNAs exhibit unique micropolarity and microviscosity, differing from proteins within condensates.
• RNAs remain miscible in condensates, unlike some protein systems that demix.
• Micropolarity differences influence RNA partitioning and distribution among condensates.
• Elevated RNA micropolarity correlates with enhanced ribozyme catalytic activity.

Conclusions:

• RNA physical microenvironments actively shape RNA organization and function within biomolecular condensates.
• Transient RNA-protein interactions, influenced by micropolarity, contribute to condensate behavior.
• This work provides new insights into the physical forces governing RNA within cellular compartments.