To confirm the importance of endogenous POM121C or KPNB1 for HIV-1 replication, we had repeatedly attempted to knock-down POM121C or KPNB1 using shRNA, but unfortunately, depletion of these essential protein seriously affected the viability of cells, which made it impossible to assess HIV-1 infection. The gene discussed is KPNB1; the disease is HIV-1 infection.