A high-throughput methods SNIPR-Nm reveals small RNA methylation ratio

Abstract

Small RNAs regulate gene expression and genome stability, and their functions are shaped by 3'-terminal 2'-O-methylation (Nm). Although Nm is universal in plants and mainly marks animal piRNAs, recent evidence reveals Nm on mammalian miRNAs, highlighting broader regulatory roles. However, current sequencing underestimates Nm-modified RNAs due to ligation bias, and existing qPCR-based methods cannot simultaneously quantify abundance and modification, leaving Nm dynamics largely unexplored. We developed a unified enzymatic strategy that integrates poly(A) polymerase and a thermostable ligase to measure both small RNA abundance and 3'-end Nm status. Applied to mouse testis, it enables robust quantification of Nm ratios for piRNAs and miRNAs. Our method offers a versatile tool for dissecting small RNA methylation in development and disease.