DEAD box proteins, characterized by the conserved motif Asp-Glu-Ala-Asp (DEAD), are putative RNA helicases. They are implicated in a number of cellular processes involving alteration of RNA secondary structure such as translation initiation, nuclear and mitochondrial splicing, and ribosome and spliceosome assembly. Based on their distribution patterns, some members of this family are believed to be involved in embryogenesis, spermatogenesis, and cellular growth and division. DDX3 is a DEAD box protein, which interacts specifically with hepatitis C virus core protein resulting a change in intracellular location. The DDX3 gene has a homolog located in the nonrecombining region of the Y chromosome. The protein sequence is 91% identical between this gene and the Y-linked homolog.

2-8°C (short-term); -20°C (long-term)