Tertiary structural elements determine the extent and specificity of messenger RNA editing

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Adenosine deaminases acting on RNA (ADAR) enzymes catalyze RNA editing.
• RNA editing specificity is influenced by local RNA sequence and duplex imperfections.

Purpose of the Study:

• To investigate the role of RNA secondary and tertiary structures in modulating ADAR enzyme specificity and activity.
• To explore the functional consequences of structural alterations on RNA editing and gene expression.

Main Methods:

• Surgical alteration of conserved cis elements in the Drosophila paralytic transcript.
• Mutation and counter-mutation analyses to identify critical structural elements.
• Assessment of RNA editing levels and phenotypic consequences.

Main Results:

• A central imperfect RNA duplex is locally required for ADAR modification.
• An accessory RNA duplex containing splicing signals significantly modulates RNA editing.
• A conserved intronic tertiary pseudoknot is essential for specific adenosine deamination.
• A non-coding mutation affecting helix base pairing has phenotypic consequences via splicing.

Conclusions:

• Complex, in vivo RNA tertiary structures regulate ADAR-mediated RNA editing.
• RNA structure plays a critical role in fine-tuning RNA editing events beyond local sequence.
• Computational prediction of RNA tertiary structures may underestimate their in vivo regulatory roles.