TAS-seq enables subcellular single-stranded adenosine profiling by signal peptide-assisted adenosine deamination

RNA structure plays a crucial role in its function and undergoes dynamic changes throughout its life cycle. To study these dynamics, we developed TAS sequencing (TAS-seq), which expresses the deaminase TadA-8e in specific subcellular compartments to modify single-stranded adenosines, particularly within hairpin loops. We applied TAS-seq to the nucleus, cytosol, and endoplasmic reticulum membrane, identifying adenosine structural variations and compartment-specific regulation of RNA stability. Single-cell TAS-seq revealed structural heterogeneity of cytosolic RNAs. Additionally, adenosines labeled by TAS-seq contribute to guide RNA optimization in the CRISPR-Cas13d system. Our method provides insights into compartment-specific RNA structural dynamics, cell-specific heterogeneity, and their functional implications.