Structural analyses of an RNA stability element interacting with poly(A).

Area of Science:

• Molecular Biology
• Structural Biology
• Bioinformatics

Background:

• Cis-acting RNA elements regulate polyadenylated RNA stability.
• The element for nuclear expression (ENE) stabilizes RNA by sequestering the poly(A) tail through triplex formation, inhibiting decay.
• Double ENEs (dENEs), a subclass of ENEs, feature two ENE motifs and have been identified in diverse genomes.

Purpose of the Study:

• To investigate the structure of a rice-derived dENE (TWIFB1) before and after poly(A) binding.
• To elucidate the local and global structural changes in dENE upon poly(A) interaction.
• To understand the directionality and specific motifs involved in dENE-poly(A) binding.

Main Methods:

• Biochemical structure probing
• Small-angle X-ray scattering (SAXS)
• Cryo-electron microscopy (cryo-EM)

Main Results:

• The study determined the directionality of poly(A) binding to the dENE.
• A specific motif within the dENE protects the 3'-most seven adenylates of the poly(A) tail.
• No significant global conformational change was observed in the dENE upon poly(A) binding.

Conclusions:

• The dENE-poly(A) interaction protects a specific region of the poly(A) tail.
• dENEs do not undergo substantial global structural rearrangements when binding poly(A).
• These findings expand our understanding of poly(A) tail biology and RNA-RNA interactions.