We are in the preliminary stages of screening ringexpanded nucleoside analogs found previously to be successful NTPase/helicase inhibitors of West Nile virus, Hepatitis C virus and Japanese encephalitis virus (81, 82) . We have observed that a few of these candidate inhibitors have substantial anti-HIV-1 activity at doses that do not incur cytotoxicity to cells treated in tissue culture for 1 week. Further studies are needed before concluding that these compounds exert specific inhibition of DDX3, one of the other cellular helicases, or some other target altogether.