Addition of 60 nM STP0404 to LEDGF/p75 knockout Jurkat T cells also failed to significantly inhibit infection (Fig 4F), revealing that STP0404 does not inhibit the early steps of HIV-1 replication regardless of LEDGF/p75 expression at drug concentrations that fully inhibited the late-stage maturation step. This evidence concerns the gene PSIP1 and infection.