To examine the anti-HIV-1 potency of this CRISPR/Cas9
system during infection, we transduced MT-4 cells, which
are knownas one of theTcell lines that aremost susceptible
to replication-competent WT HIV-1 (31, 32), with two
lentiviral vectors for expression of Cas9 and one of the
HIV-1-targeting gRNAs indicated in Figure 1a. Because T5
gRNA targets the LTR, the T5 lentiviral vector should have
been blocked by T5-directed self-targeting CRISPR/Cas9
activity in the lentiviral vector-producing step. However,
we obtained transduced cells that were resistant to
puromycin and blasticidin.