Structural features within the NORAD long noncoding RNA underlie efficient repression of Pumilio activity

Area of Science:

• Molecular Biology
• Genomics
• RNA Biology

Background:

• Long noncoding RNAs (lncRNAs) play crucial roles in mammalian cells, but their structure-function relationships are poorly understood.
• The NORAD lncRNA acts as a decoy for Pumilio proteins, influencing mRNA regulation, genomic stability, and aging.
• Understanding lncRNA structural principles is key to deciphering their regulatory mechanisms and designing novel RNA therapeutics.

Purpose of the Study:

• To investigate the structural organization and RNA-RNA interactions of human NORAD under cellular stress.
• To elucidate how NORAD's structure spatially clusters Pumilio binding sites and influences gene expression.
• To apply these structural insights for the rational design of artificial lncRNA decoys.

Main Methods:

• In-cell probing of RNA structure and long-range RNA-RNA interactions.
• Analysis of NORAD structure and interactions under arsenite-induced stress.
• Computational and experimental design of artificial RNA decoys.

Main Results:

• NORAD exhibits a modular structure with independently functioning domains.
• Arsenite stress induces structural relaxation and stress granule targeting of NORAD.
• NORAD's unique structure clusters Pumilio binding sites, leading to derepression of Pumilio targets.
• Designed artificial decoys demonstrated effective modulation of microRNA activity.

Conclusions:

• lncRNA sequence dictates spatial clustering of function into distinct domains.
• Structural principles of lncRNAs can be leveraged for the rational design of functional RNA molecules.
• This study provides a framework for understanding lncRNA structure-function and designing RNA-based tools.