In line with these findings, DDX1 and itsparalog DDX3X were shown to physically associate with nucleocapsidprotein Np and to enhance its binding affinity for double-strandedRNA by two- to four-fold, through a mechanism that does not requirehelicase activity. Among DDX helicases,DDX5 functions as both a viral infection helper and an inhibitor,depending on the virus type. This evidence concerns the gene DDX5 and viral infectious disease.