Figure 3

DDX1 and DDX3 promote Rev-dependent RNA export. (A) The domain structures of DDX3, Rev and DDX1 are illustrated. CRM1 binds to the helicase core of DDX3. DDX1 directly interacts with Rev. The protein regions involved in these interactions are highlighted. NES, nuclear export signal; NLS, nuclear localization signal; OD1, oligomerization domain 1; RBD, RNA binding domain. (B) The secondary structures of the RRE RNA. The IIB stem-loop is highlighted in light green which serves as the binding site of Rev. (C) A hypothetical model to illustrate the roles of DDX1 and DDX3 in Rev-mediated RNA export. DDX1 binds to Rev and promotes Rev oligomerization on the RRE IIB. Then the oligomerized Rev molecules recruit the CRM1/DDX3 binary complex (one or multiple copies) and together export viral RNA into the cytoplasm.