Global Co-regulatory Cross Talk Between m⁶A and m⁵C RNA Methylation Systems Coordinate Cellular Responses and Brain...

Area of Science:

• Molecular Biology
• Epigenetics
• RNA Biology

Background:

• N6 adenosine (m⁶A) and C5 cytosine (m⁵C) modifications are regulated by distinct effector proteins.
• These effector proteins are conventionally thought to function independently.

Purpose of the Study:

• To investigate potential cross-regulatory interactions between the m⁶A and m⁵C RNA methylation systems.
• To identify novel co-regulatory relationships and functional connections between these systems.

Main Methods:

• Analysis of reciprocal base modification on effector protein transcripts.
• Global mass spectrometry proteomics following biological perturbation.
• Gene ontology analysis of co-regulated proteins.
• In vitro colocalization assays.

Main Results:

• Evidence of global cross-regulatory interactions and functional connections between m⁶A and m⁵C RNA methylation systems.
• Identification of reciprocal post-transcriptional feedback loops involving effector protein transcripts.
• Discovery of novel co-regulatory cellular responses, including between ALKBH5 (m⁶A eraser) and NSUN4 (m⁵C writer).
• Cross-system control identified across various cellular processes like proteasome and mitochondrial mechanisms, SUMOylation, and phosphorylation.
• Uncovered novel effector protein network relationships, including links to intellectual disability pathways.
• In vitro confirmation of colocalization between m⁶A-RNAs and the m⁵C reader protein ALYREF.

Conclusions:

• The m⁶A and m⁵C RNA methylation systems are not independent but exhibit significant cross-regulation.
• These interactions influence diverse cellular processes, proteomic responses, and are implicated in brain disease mechanisms.
• Findings provide a new framework for understanding RNA metabolism and its role in cellular function and disease.