Ribonuclease L and Metal-Ion-Independent Endoribonuclease Cleavage Sites in Host and Viral RNAs

We used 2', 3'-cyclic phosphate cDNA synthesis and Illumina sequencing to identify and quantify metal-ion-independent endoribonuclease cleavage sites in host and viral RNAs. Overall design: To make cDNA libraries, we exploited the 2’, 3’-cyclic phosphate at the end of RNA fragments produced by RNase L and other metal-ion-independent endoribonucleases. Using Arabidopsis thaliana tRNA ligase, RNA fragments with 2’, 3’-cyclic phosphates were covalently attached to defined RNA linkers containing an 8-base long unique molecular identifier (UMI) sequence. Libraries prepared in this manner contain cDNA derived exclusively from RNA fragments with 2', 3'-cyclic phosphates. The UMI sequence allows for detailed quantitation. We optimized and validated 2’, 3’-cyclic phosphate cDNA synthesis and Illumina sequencing methods using viral RNAs cleaved with purified RNase L, viral RNAs cleaved with purified RNase A, and RNA from uninfected and poliovirus-infected HeLa cells.