After infection with the Cas9/sgRNA lentivirus, Gtpbp2−/− CD133+CD44− cells and Gtpbp2+/+ CD133+CD44− cells expressed comparable Ki67, proliferated at the same rate, and showed equivalent viability after 5-FU treatment (Supplementary Figs. 12F–12I). Here, MKI67 is linked to infection.