N⁶-Methyladenosine mRNA Modification: From Modification Site Selectivity to Neurological Functions

Area of Science:

• Molecular Biology
• Neuroscience
• Epigenetics

Background:

• N6-methyladenosine (m6A) is the most abundant internal modification on eukaryotic mRNAs, dynamically regulating gene expression.
• m6A plays crucial roles in various biological processes, including embryonic development, organ function, and pathogenesis.
• The precise mechanisms and physiological roles of m6A, particularly in the brain, are still being elucidated.

Purpose of the Study:

• To investigate the site selectivity mechanisms of m6A formation, focusing on the role of microRNAs (miRNAs).
• To explore the physiological functions of m6A modification in cerebellum development and long-term memory consolidation.
• To establish a model for studying memory formation efficacy.

Main Methods:

• Profiling m6A modification in mouse and human cells.
• Manipulating miRNA biogenesis enzymes (Dicer) and individual miRNAs.
• Generating hippocampus-specific postnatal m6A methyltransferase (Mettl3) knockout mice.

Main Results:

• Nucleus-localized miRNAs guide the m6A methyltransferase METTL3 to target mRNAs, influencing m6A site selection.
• Mettl3 knockout in developing mouse cerebellum caused severe defects, including aberrant mRNA splicing and increased apoptosis.
• Mettl3 knockout in the postnatal hippocampus impaired long-term memory consolidation by reducing translation of memory-related genes.

Conclusions:

• miRNAs play a critical role in regulating m6A formation on mRNAs.
• m6A modification is essential for cerebellum development and long-term memory consolidation.
• The developed hippocampus-specific m6A knockout model provides a valuable tool for memory research.