The first and second coding exons (1 and 2) were targeted with two sgRNAs (5â²-ccccgatgacttcagtacttggg-3â² and 5â²- cctcagacccggaatacggatttt-3â²) using CRISPR/Cas9 technology. Five founder mice were created with at least two different size deletions, both including the end of exon 1, intron 1 and the start of exon 2. The pound # sign is used in the allele symbol because which mouse line was used, or if a mixture was used, is not specified.