The adenylate-uridylate-rich element (AU-rich element; ARE) and constitutive decay element (CDE) in the 3' UTR were targeted with gRNAs (targeting GTGCAAATATAAATAGAGGG and TCAGCGTTATTAAGACAATT) using CRISPR/Cas9 technology, resulting in a 229 bp deletion (CTATTTATATTTGCACTTATTATTTATTATTTATTTATTATTTATTTATTTGCTTATGAATGTATTTATTTGGAAGGCCGGGGTGTCCTGGAGGACCCAGTGTGGGAAGCTGTCTTCAGACAGACATGTTTTCTGTGAAAACGGAGCTGAGCTGTCCCCACCTGGCCTCTCTACCTTGTTGCCTCCTCTTTTGCTTATGTTTAAAACAAAATATTTATCTAACCCAATT). (J:306876)