A deletion in the 3' end of the coding region was created using sgRNAs (targeting TACAGGCGGGAGCAGAA and ACGACCAGAACGAAGAGG) with CRISPR/Cas9 technology. The deletion removes 44 codons (132 bp), from K97 through E140, from the 3' end of the coding region, representing most of the negatively charged tail of the encoded peptide.