To further examine the impact of MARCH1 downregulation by miRNA-25 and miRNA-93 on HIV-1 infectivity, we treated MDMs with control or small interfering RNAs (siRNAs) that target MARCH1, prior to infection with WT or Vpu-defective HIV-1 and determined the infectivity of progeny viruses (Fig. 7B; Fig. S5E). Here, MARCHF1 is linked to infection.