CRISPR/Cas9 genome editing is used to insert an internal ribosome entry site (IRES) fused to a Cre recombinase sequence, a viral 2A oligopeptide (T2A) that mediates ribosomal skipping, and a tdTomato variant of red fluorescent protein (RFP) sequence into the 3'UTR of the gene. (J:279524)