3′-UTR reporter vectors were generated by inserting 3′-UTR sequences into the 3′-UTR of the luciferase gene in the psiCHECK-2 dual luciferase reporter vector (Promega) (Suzuki et al. 2015 (link), 2018 (link)). Mutations were introduced by a PCR-based approach. Primer sequences are given in Supplemental Table S2.