Multiplexed In Situ Imaging of Site-Specific m6A Methylation with Proximity Hybridization Followed by Primer Exchange Amplification (m6A-PHPEA)

Post-transcriptional modification of N6-methyladenosine (m6A) is crucial for ribonucleic acid (RNA) metabolism and cellular function. The ability to visualize site-specific m6A methylation at the single-cell level would markedly enhance our understanding of its pivotal regulatory functions in the field of epitranscriptomics. Despite this, current in situ imaging techniques for site-specific m6A are constrained, posing a significant barrier to epitranscriptomic studies and pathological diagnostics. Capitalizing on the precise targeting capability of deoxyribonucleic acid (DNA) hybridization and the high specificity of the m6A antibody, we present a method, termed proximity hybridization followed by primer exchange amplification (m6A-PHPEA), for the site-specific imaging of m6A methylation within cells. This approach enables high-resolution, single-cell imaging of m6A methylation across various RNA molecules coupled with efficient signal amplification. We successfully imaged three distinct m6A methylation sites concurrently in multiple cell types, revealing cell-to-cell variability in expression levels. This method promises to illuminate the dynamics of m6A-modified RNAs, potentially revolutionizing epitranscriptomic research and the development of advanced pathological diagnosis for chemical modifications.