m6A sites in the coding region trigger translation-dependent mRNA decay

Area of Science:

• Molecular Biology
• RNA Biology
• Gene Regulation

Background:

• N6-Methyladenosine (m6A) is a key RNA modification influencing mRNA stability.
• m6A's role in mRNA degradation has been primarily linked to the 3' untranslated region.
• The precise mechanisms and efficiency of m6A-mediated decay are still under investigation.

Purpose of the Study:

• To investigate novel m6A-dependent RNA decay pathways.
• To characterize the role of m6A modifications within the coding sequence (CDS) of mRNAs.
• To elucidate the mechanism and functional significance of CDS-m6A decay (CMD).

Main Methods:

• Utilized human cell lines to study RNA modifications.
• Employed techniques to analyze m6A site distribution and impact on mRNA stability.
• Investigated the role of translation, ribosome pausing, and protein factors like YTHDF2 in the decay process.
• Tracked transcript localization to processing bodies (P-bodies).

Main Results:

• Discovered a new pathway, CDS-m6A decay (CMD), initiated by m6A sites in the mRNA coding sequence.
• Demonstrated that CDS m6A sites induce faster and more efficient transcript degradation than 3' UTR sites.
• Showed CMD is a translation-dependent process involving ribosome pausing and transcript destabilization.
• Identified YTHDF2 recruitment and translocation to P-bodies as key steps in CMD.

Conclusions:

• CMD is a previously unrecognized pathway for mRNA decay.
• m6A modifications in the CDS play a significant role in regulating gene expression.
• CMD is particularly important for controlling the expression of developmental regulators and retrogenes.