DBeQ and NMS-873 potently inhibited Nluc expression after infection with YFVΔSK/Nluc virus particles (Fig. 3A) but did not inhibit Nluc expression after transfection of YFVΔSK/Nluc RNA (Fig. 3B), indicating that VCP/p97 is necessary for YFV entry, prior to the delivery and translation of incoming YFV genomes. This evidence concerns the gene VCP and infection.