DHX9 is a member of the DEAH box family of proteins that possesses several conserved motifs which include the highly conserved DEAH (Asp-Glu-Ala-His) amino acid sequence motif. The major activity of DEAH box proteins is to function as ATP-dependent RNA helicases. RNA helicases play an important role in all aspects of RNA metabolism and function which include pre-mRNA splicing, RNA synthesis, RNA degradation, RNA export, RNA translation, RNA secondary structure formation, ribosome biogenesis, and the assembly of RNP complexes. Some members of the DEAH box proteins also exhibit functions involved in transcriptional regulation. DHX9 has been shown to act as a bridge between CREB-binding protein (CBP) and RNA polymerase II to coactivate CBP-dependent transcription. A similar observation has been reported for an interaction with BRCA1. DHX9 also exhibits activities associated with nuclear export of retroviral RNAs, translation, RNA editing, and snRNP assembly.