Absolute quantification of mammalian microRNAs for therapeutic RNA cleavage and detargeting.

MicroRNAs (miRNAs) are small regulatory RNAs that destabilize partially complementary transcripts and cleave perfectly paired targets. miRNAs are often expressed in a specific tissue, allowing miRNA-directed cleavage to be used to prevent genome editing or gene replacement therapy in unintended cell types, a strategy called detargeting. miRNA intracellular concentration influences the potency of gene silencing, yet the absolute steady-state levels of just a few miRNAs have been determined in mammalian tissues.

Mouse Pachytene piRNAs Cleave Hundreds of Transcripts, But Alter the Steady-State Abundance of Only a Minority of Targets.

In animals, 18-35-nt piRNAs guide PIWI proteins to regulate complementary RNAs. During male meiosis, mammals produce an exceptionally abundant class of piRNAs called pachytene piRNAs. Pachytene piRNAs are required for spermatogenesis and have been proposed to control gene expression by various mechanisms.