In situ visualization of m6A sites in cellular mRNAs

Area of Science:

• Molecular Biology
• Epigenetics
• Cell Biology

Background:

• N 6-methyladenosine (m6A) is a prevalent RNA modification crucial for RNA function and cellular processes.
• Limited methods exist for visualizing m6A modifications in specific RNA molecules within living cells, hindering the study of spatial m6A regulation.
• Understanding m6A's spatial distribution is key to deciphering its role in gene expression and cellular physiology.

Purpose of the Study:

• To develop a novel method for the in situ visualization of specific m6A sites in target RNAs.
• To enable simultaneous detection of both m6A-modified and unmodified transcript copies within cells.
• To investigate the spatial regulation and dynamics of m6A-modified transcripts at single-cell resolution.

Main Methods:

• Development of DART-FISH (Detection of AlkB-Regulated Targets by Fluorescence In Situ Hybridization).
• Application of DART-FISH for visualizing m6A sites in various mRNAs across different cell types.
• Single-cell resolution analysis of m6A site location and stoichiometry.

Main Results:

• DART-FISH successfully visualized specific m6A sites in diverse mRNAs within multiple cell types.
• The method provided single-cell resolution data on the location and abundance (stoichiometry) of m6A modifications.
• m6A modification was found not to be sufficient for mRNA localization to stress granules during oxidative stress.

Conclusions:

• DART-FISH is a powerful new technique for visualizing specific m6A sites in situ within individual cells.
• This method facilitates the study of m6A-modified transcript dynamics and localization.
• The findings provide new insights into the functional consequences of m6A modifications, particularly concerning mRNA localization under stress conditions.