The fact that unlike the MARCH8 protein, MARCH3 does not harbor a tyrosine motif in its C-terminal CT (Figure S2) may explain why the M8/3-cCT chimera harboring MARCH3’s CT could not inhibit HIV-1 Env-mediated infection, but it still does not explain why this chimera also lost the ability to inhibit VSV-G-mediated infection that remains sensitive to the tyrosine motif mutant (Figure 1C). This evidence concerns the gene ERVW-1 and infection.