Nanopore Direct RNA Sequencing Enables Reproducible, Site-Resolved Pseudouridine Quantification in Human Ribosomal RNA

Pseudouridine is the most abundant post-transcriptional modification in human ribosomal RNA, with over 110 annotated sites and variable stoichiometry across biological contexts. Existing quantification methods are low-throughput or constrained to predefined panels. We benchmarked nanopore direct RNA sequencing using the Dorado v5.1 model against mass spectrometry-validated sites in human liver tissue, induced pluripotent stem cells, and HeLa cells. Nanopore sequencing detected 95 of 117 validated sites and accurately quantified stoichiometry at 85% of sites with high reproducibility. Low GC-content environments were the primary source of failure. These results establish nanopore sequencing as a scalable tool for epitranscriptomic pseudouridine profiling.