Superficially wild-type. CRISPR/Cas9 engineered STOP-IN null mutant of col-129. Universal 43bp-long knock-in insertion with 3-frame stop codon (STOP-IN cassette). left flanking sequence: ccgtctggcaccaaatgATGACTGTTGTCCCACA right flanking sequence: AGGAGGCAAGCAACGTCAAGTCTACGAGTCCCTGTTC inserted sequence between the two flanking sequence (STOP-IN cassette): GGGAAGTTTGTCCAGAGCAGAGGTGACTAAGTGATAAgctagc. sgRNA: ATGACTGTTGTCCCACAAGG Method Reference: G3 (Bethesda).