library_construction_protocol: Cells were UV cross-linked then flash-frozen in liquid nitrogen, followed by lysis, RNAse I treatment, and immunoprecipitation (IP) for DDX6. eCLIP was performed as described in Blue, SM, et al. Nature Protocols (2022), PMID 35322209. IP fragments were ligated to 3' RNA adapters and RNA was isolated and reverse-transcribed following SDS-PAGE and Western blot. cDNA products were ligated to 5' adapters and PCR-amplified.