15 µg Cas9 (~100 pmol) were incubated with 20 µg gRNA (~580 pmol) for 20 min at room temperature (RT). 100 pmol of single-stranded HR template was added right before nucleofection B cells were nucleofected with the Amaxa® Human B Cell Nucleofector® Kit (Lonza). 2-5 x106 cells per transfection were collected, washed once with PBS, and resuspended in 100 µl Nucleofector solution. The cell suspension was added to the Cas9 RNP/HR template mix, and cells were nucleofected with program V-015 in a Nucleofector™ 2b device (Lonza).
For nucleofection of Cas9 as plasmid or mRNA:
2-5 µg lentiCas9-eGFP (Addgene, #63592) or Cas9 mRNA 5meC, ? (Trilink) weremixed with 20 µg gRNA (~580 pmol) and nucleofected under the same conditions.