The adenylate-uridylate-rich element (AU-rich element; ARE) in the 3' UTR was targeted with gRNAs (targeting GTGCAAATATAAATAGAGGG and TGCTTATGAATGTATTTATT) using CRISPR/Cas9 technology, resulting in a 71 bp deletion (TCTATTTATATTTGCACTTATTATTTATTATTTATTTATTATTTATTTATTTGCTTATGAATGTATTTATT). (J:306876)