Figure 9.

Model summarizing that DExD/H proteins contribute to many steps in retroviral posttranscriptional gene expression and coordination of virus assembly. Nuclear export of HIV-1 Rev/Rev responsive element (RRE)-dependent HIV-1 RNA requires DDX3 with CRM1 nuclear export receptor (27). Alternatively, the nuclear export ribonucleoprotein (RNP) of completely spliced viral RNA involves superfamily members RBM15 and DBP5 and NXF1 nuclear export receptor (28,29). Efficient viral translation requires DHX9/RNA helicase A [herein and (5)]. RNA helicase A recognizes structural features of virus 5′ RNA terminus and possibly distal structures, and facilitates efficient protein synthesis in an ATP-dependent manner (2). RNA helicase A also assembles into virions and supports virus infectivity, perhaps by promoting rearrangement of the viral RNP for reverse transcription or by carrying in a host cofactor (12). DDX24 promotes packaging of HIV-1 RNA (30).