Putative proximal enhancer sequence between -1413 and -510 bp upstream of the transcription start site (chr14:78545488 (build GRCm39)) was targeted with sgRNAs (targeting CAAGGTTTATAGGTGTTCTA and CCTCTCTTACGGGAGTCTAT) using CRISPR/Cas9 technology, resulting in a 909 bp deletion. (J:307332)