<b>The specificity of Cas9 polyclonal antibody assessed by Western blot.</b> Lysates prepared from various untransfected cell lines (3.5 x 10⁴ cultured cells; Lane 1: HepG2, Lane 2: CHO-K1, Lane 3: HeLa, Lane 4: MCF7, Lane 5: HEK 293, Lane 6: HT1080, Lane 7: NIH 3T3, Lane 8: no cells) and HEK 293 cells expressing Cas9 from the CMV promoter (stable cell line; Lane 10: 2.0 x 103 cells, Lane 11: 5.0 x 10³ cells, Lane 12: 1.0 x 10⁴ cells, Lane 13: 1.5 x 10⁴ cells). One nanogram of recombinant Cas9 (rCas) was used as a positive control (Lane 9). The blot was probed with Cas9 polyclonal antibody (1:1,000 dilution). For detection, an HRP-conjugated goat anti-rabbit secondary antibody was used (1:5,000 dilution), and signal was detected using ECL reagent.