Day 3: Split the cells into 10 cm plates at 1:10 and 1:20 ratio and add blasticidin. Observe daily and change blasticidin media every 3-4 days until colonies appear.
Validate the expression of the GOI using qPCR, WB, etc.
N.B. To increase the probability of getting single-copy integration of the targeting expression construct, use the amount of vector that results in less than five drug-resistant colonies in the absence of integrase. Using that amount in the presence of integrase should result in >15 colonies.
It is good to have an empty vector control (to generate Bsd-resistant cells, but without GOI).
Important! We observed that in some clones the expression of the GOI can reduce over time. Best to freeze an early passage of the selected single clones after validation, and check the expression of the GOI before any important experiments.