Glutamic acid codon 176 (GAA) was changed to alanine (GCA) (p.E176A) using a sgRNA and an ssODN template (AAACGCAAAGATATCTCGGAGGCGGCCGAGACGGTGAATAAAGTTGTTGCACGCCTGCTGCGCAGAATGCAGAAACGGGAGTCGGAGTTCAAAGGT) with CRISPR/Cas9 technology. This mutation blocks PARylation (poly(ADP) ribosylation) of the residue in the encoded peptide. (J:325965)