Generation of stable cell lines

To obtain Cas9‐stably expressing THP‐1 cells, THP‐1 cells transduced with lentiCas9‐Blast were selected with blasticidin (10 μg/ml) for 10 days. Single‐cell clones were selected by dilution into 96‐well plates, and Cas9 expression was assessed by Western blot (using the anti‐CRISPR/Cas9 antibody, {"type":"entrez-protein","attrs":{"text":"EPR19619","term_id":"523386337","term_text":"EPR19619"}}EPR19619‐92, ab210752; data not shown).

To obtain guide‐expressing THP‐1 cell lines, THP‐1 Cas9‐expressing cells were transduced with the FgH1tUTG vector containing the guide of interest. Virally transduced cell lines were sorted for eGFP‐positive cells using a BD Influx cell sorter (top 5% eGFP‐expressing population).