CRISPR/Cas9 technology generated a single nucleotide replacement of A to G in the first start codon (ATG to GTG) resulting in a knockdown of the betaA3 isoform. A silent mutation (ACC to ACG) was also introduced to prevent the binding and re-cutting of the sequence by gRNA after homology-directed repair. Western blot analysis confirmed the absence of the betaA3 isoform but also upregulation of the betaA1 isoform level is astrocytes. (J:306517)